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2026 Volume 42 Issue 11
2026, 42(11): 2259-2274
doi: 10.11862/CJIC.20260125
Abstract:
Due to their low power consumption, wider viewing angle, fast response, low driving voltage, and remarkable flexibility, organic light-emitting diodes (OLEDs) have been the focus of intensive research activities both in industry and academia. Compared to the vacuum evaporation method, the solution-processable technique has several advantages such as operational simplicity, low cost, and large-area device manufacture, which is crucial to its commercial applications. Metal complexes are one of the most promising emitters to construct high-performance solution-processed OLEDs because of their high photoluminescence quantum yields (PLQYs), easily tunable excited-state properties, and good chemical stability. This review briefly summarizes the design strategies for the synthesis of metal complexes, in particular iridium, platinum, gold, and other metal complexes, and their applications in conventional and large-area solution-processed OLEDs. In addition, the current status, challenges, and future research prospects in the studies of metal complex-based solution-processed OLEDs are discussed, which is of interest and importance to the development of metal complex-based high-performance solution-processed OLEDs in the future.
Due to their low power consumption, wider viewing angle, fast response, low driving voltage, and remarkable flexibility, organic light-emitting diodes (OLEDs) have been the focus of intensive research activities both in industry and academia. Compared to the vacuum evaporation method, the solution-processable technique has several advantages such as operational simplicity, low cost, and large-area device manufacture, which is crucial to its commercial applications. Metal complexes are one of the most promising emitters to construct high-performance solution-processed OLEDs because of their high photoluminescence quantum yields (PLQYs), easily tunable excited-state properties, and good chemical stability. This review briefly summarizes the design strategies for the synthesis of metal complexes, in particular iridium, platinum, gold, and other metal complexes, and their applications in conventional and large-area solution-processed OLEDs. In addition, the current status, challenges, and future research prospects in the studies of metal complex-based solution-processed OLEDs are discussed, which is of interest and importance to the development of metal complex-based high-performance solution-processed OLEDs in the future.
2026, 42(11): 2290-2310
doi: 10.11862/CJIC.20260187
Abstract:
N2O2-dipyrrin metal complexes are emerging as a unique class of functional metallic platforms, owing to the efficient light-harvesting properties of the parent skeleton and the structural stability induced by multidentate coordination. Compared to traditional N, N-bidentate dipyrrin ligands, the N2O2 tetradentate ligand, through two pyrrole nitrogen and two phenolate oxygen donors, constructs a potential trianionic coordination environment. This design enhances the rigidity of the molecular skeleton while retaining axial coordination and tunability at the metal center, thereby significantly expanding the structural and functional diversity of the resulting complexes. In recent years, this field has gradually expanded from early main-group metal coordination systems (e.g., Al, Si, Ge, and Sn) to heavy main-group metals (e.g., Ga, In, Sb, and Bi), as well as redox-active transition metal systems (e.g., Mn, Co, Ni, Cu, Pt, and Au). This review, centered on N2O2 tetradentate ligands, systematically surveys related studies by metal center and functional type, and further compares the effects of metal radius, axial ligands, substituent electronic effects, and ligand non-innocence on photophysical, electrochemical, and catalytic behaviors across different systems. By summarizing representative photophysical and electrochemical parameters, this review emphasizes the developmental trend of these complexes from rigid luminescent frameworks toward tunable metal-ligand cooperative platforms. It also discusses current key bottlenecks in near-infrared efficiency, structural stability, comparable electrochemical data, validation of biological applications, and elucidation of catalytic mechanisms, aiming to provide more targeted guidance for future molecular design and functional applications.
N2O2-dipyrrin metal complexes are emerging as a unique class of functional metallic platforms, owing to the efficient light-harvesting properties of the parent skeleton and the structural stability induced by multidentate coordination. Compared to traditional N, N-bidentate dipyrrin ligands, the N2O2 tetradentate ligand, through two pyrrole nitrogen and two phenolate oxygen donors, constructs a potential trianionic coordination environment. This design enhances the rigidity of the molecular skeleton while retaining axial coordination and tunability at the metal center, thereby significantly expanding the structural and functional diversity of the resulting complexes. In recent years, this field has gradually expanded from early main-group metal coordination systems (e.g., Al, Si, Ge, and Sn) to heavy main-group metals (e.g., Ga, In, Sb, and Bi), as well as redox-active transition metal systems (e.g., Mn, Co, Ni, Cu, Pt, and Au). This review, centered on N2O2 tetradentate ligands, systematically surveys related studies by metal center and functional type, and further compares the effects of metal radius, axial ligands, substituent electronic effects, and ligand non-innocence on photophysical, electrochemical, and catalytic behaviors across different systems. By summarizing representative photophysical and electrochemical parameters, this review emphasizes the developmental trend of these complexes from rigid luminescent frameworks toward tunable metal-ligand cooperative platforms. It also discusses current key bottlenecks in near-infrared efficiency, structural stability, comparable electrochemical data, validation of biological applications, and elucidation of catalytic mechanisms, aiming to provide more targeted guidance for future molecular design and functional applications.
2026, 42(11): 2311-2325
doi: 10.11862/CJIC.20260196
Abstract:
Second-order nonlinear optical (NLO) materials are key functional materials for converting optical energy into optical field information, and they have important applications in fields such as tunable light sources, optical switches, precision detection, and nonlinear imaging. Currently, how to achieve predictable control of macroscopic second-order NLO responses through structural design remains a key challenge in this field. Metal-organic frameworks (MOFs) consist of metal ions/clusters (or metal nodes) and organic ligands assembled in a periodic arrangement via coordinate bonds. They provide a unique platform for constructing non-centrosymmetric structures, organizing localized polar units, regulating the alignment of chromophores, and introducing tunable pore environments. In this review, we discuss current research advances in second-order NLO MOF materials, including the microscopic optical origins of second-order nonlinearity, characterization methods, structural design, response tuning, and functional applications. Finally, we summarize the remaining challenges and provide perspectives on future developments in this field.
Second-order nonlinear optical (NLO) materials are key functional materials for converting optical energy into optical field information, and they have important applications in fields such as tunable light sources, optical switches, precision detection, and nonlinear imaging. Currently, how to achieve predictable control of macroscopic second-order NLO responses through structural design remains a key challenge in this field. Metal-organic frameworks (MOFs) consist of metal ions/clusters (or metal nodes) and organic ligands assembled in a periodic arrangement via coordinate bonds. They provide a unique platform for constructing non-centrosymmetric structures, organizing localized polar units, regulating the alignment of chromophores, and introducing tunable pore environments. In this review, we discuss current research advances in second-order NLO MOF materials, including the microscopic optical origins of second-order nonlinearity, characterization methods, structural design, response tuning, and functional applications. Finally, we summarize the remaining challenges and provide perspectives on future developments in this field.
2026, 42(11): 2275-2289
doi: 10.11862/CJIC.20260185
Abstract:
Magnetic resonance (MR) imaging is a real-time, noninvasive, and indispensable modality in biomedical research and clinical diagnosis. Due to the limited intrinsic sensitivity of MR imaging, 30%-50% of clinical MR imaging scans require the administration of paramagnetic Gd(Ⅲ)-based contrast agents (GBCAs) to enhance the MR signal intensity. All currently clinically approved GBCAs are “always-on” contrast-enhanced Gd(Ⅲ) agents, which do not respond to specific biological species. The development of bioresponsive GBCAs to improve the specificity of MR imaging has attracted considerable effort over the past three decades. Among these advances, many galactosyl-conjugated Gd(Ⅲ) agents have been developed as model bioresponsive molecular scaffolds for visualizing β-galactosidase activity, gene expression, gene therapy, senescence, and tumors. This review focuses on the structural designs and the diagnostic applications of β-galactosidase-responsive Gd(Ⅲ) MR agents. According to the unique coordination environment changes upon enzymatic activation, we classified these chelates into two major categories: the number of water molecules that directly bind to Gd(Ⅲ) (q)-modulated and the rotational tumbling rate of Gd(Ⅲ) complexes (τr)-modulated Gd(Ⅲ) complexes.
Magnetic resonance (MR) imaging is a real-time, noninvasive, and indispensable modality in biomedical research and clinical diagnosis. Due to the limited intrinsic sensitivity of MR imaging, 30%-50% of clinical MR imaging scans require the administration of paramagnetic Gd(Ⅲ)-based contrast agents (GBCAs) to enhance the MR signal intensity. All currently clinically approved GBCAs are “always-on” contrast-enhanced Gd(Ⅲ) agents, which do not respond to specific biological species. The development of bioresponsive GBCAs to improve the specificity of MR imaging has attracted considerable effort over the past three decades. Among these advances, many galactosyl-conjugated Gd(Ⅲ) agents have been developed as model bioresponsive molecular scaffolds for visualizing β-galactosidase activity, gene expression, gene therapy, senescence, and tumors. This review focuses on the structural designs and the diagnostic applications of β-galactosidase-responsive Gd(Ⅲ) MR agents. According to the unique coordination environment changes upon enzymatic activation, we classified these chelates into two major categories: the number of water molecules that directly bind to Gd(Ⅲ) (q)-modulated and the rotational tumbling rate of Gd(Ⅲ) complexes (τr)-modulated Gd(Ⅲ) complexes.
2026, 42(11): 2326-2334
doi: 10.11862/CJIC.20260119
Abstract:
In this work, a pair of iron(Ⅱ) spin-crossover complexes derived from chiral ligands, [Fe(L-R)(NCS)2] (1-R; L-R=(R)-N1,N2-bis(pyridin-2-ylmethyl)propane-1,2-diamine) and [Fe(L-S)(NCS)2] (1-S; L-S=(S)-N1,N2-bis(pyridin-2-ylmethyl)propane-1,2-diamine), together with their racemic analogue [Fe(L)(NCS)2] (1-rac; where L represents an equimolar mixture of L-R and L-S), were synthesized, and the influence of chirality on molecular packing and spin-crossover behavior was investigated. Structural and circular dichroism analyses reveal a hierarchical transfer of chirality from the ligands to the coordination metal centers, which is ultimately amplified into the supramolecular single-crystal architecture. Consequently, 1-R and 1-S crystallize in the enantiomorphic tetragonal space groups P41212 and P43212, respectively, forming opposite-handed quadruple-helical networks, whereas 1-rac adopts the achiral space group Aea2. Magnetic and calorimetric measurements demonstrate that both enantiopure complexes undergo a complete, reversible one-step SCO transition with T1/2 (spin-transition temperature) of 158 K. In contrast, 1-rac remains trapped in the high-spin state across the entire investigated temperature range.
In this work, a pair of iron(Ⅱ) spin-crossover complexes derived from chiral ligands, [Fe(L-R)(NCS)2] (1-R; L-R=(R)-N1,N2-bis(pyridin-2-ylmethyl)propane-1,2-diamine) and [Fe(L-S)(NCS)2] (1-S; L-S=(S)-N1,N2-bis(pyridin-2-ylmethyl)propane-1,2-diamine), together with their racemic analogue [Fe(L)(NCS)2] (1-rac; where L represents an equimolar mixture of L-R and L-S), were synthesized, and the influence of chirality on molecular packing and spin-crossover behavior was investigated. Structural and circular dichroism analyses reveal a hierarchical transfer of chirality from the ligands to the coordination metal centers, which is ultimately amplified into the supramolecular single-crystal architecture. Consequently, 1-R and 1-S crystallize in the enantiomorphic tetragonal space groups P41212 and P43212, respectively, forming opposite-handed quadruple-helical networks, whereas 1-rac adopts the achiral space group Aea2. Magnetic and calorimetric measurements demonstrate that both enantiopure complexes undergo a complete, reversible one-step SCO transition with T1/2 (spin-transition temperature) of 158 K. In contrast, 1-rac remains trapped in the high-spin state across the entire investigated temperature range.
2026, 42(11): 2343-2352
doi: 10.11862/CJIC.20260105
Abstract:
Herein, we report the solvothermal synthesis of two distinct Anderson-type heptanuclear cobalt clusters, 1-BzO [Co7(L)2(acac)4(BzO)4(iPrO)2][Co(acac)2]·8CH3CN and 1-OAc [Co7(L)2(acac)4(OAc)4(MeO)2][Co(acac)2]·9CH3CN, utilizing 2-(hydroxymethyl)-2-(pyridin-4-yl)propane-1,3-diol (H3L), benzoic acid (BzOH)/salicylic acid, and cobalt acetylacetonate(Co(acac)2). Despite sharing identical metallic skeletons, variations in their peripheral ligands significantly govern their electrocatalytic behavior. Electrochemical evaluations demonstrated that 1-OAc exhibited markedly superior catalytic activity for the hydrogen evolution reaction (HER) in neutral electrolyte, achieving an overpotential of only 303 mV at a current density of 10 mA·cm-2 with a Tafel slope of 184 mV·dec-1.
Herein, we report the solvothermal synthesis of two distinct Anderson-type heptanuclear cobalt clusters, 1-BzO [Co7(L)2(acac)4(BzO)4(iPrO)2][Co(acac)2]·8CH3CN and 1-OAc [Co7(L)2(acac)4(OAc)4(MeO)2][Co(acac)2]·9CH3CN, utilizing 2-(hydroxymethyl)-2-(pyridin-4-yl)propane-1,3-diol (H3L), benzoic acid (BzOH)/salicylic acid, and cobalt acetylacetonate(Co(acac)2). Despite sharing identical metallic skeletons, variations in their peripheral ligands significantly govern their electrocatalytic behavior. Electrochemical evaluations demonstrated that 1-OAc exhibited markedly superior catalytic activity for the hydrogen evolution reaction (HER) in neutral electrolyte, achieving an overpotential of only 303 mV at a current density of 10 mA·cm-2 with a Tafel slope of 184 mV·dec-1.
2026, 42(11): 2362-2370
doi: 10.11862/CJIC.20260178
Abstract:
A novel manganese-based hybrid material (TMBE)2[MnBr4] (1) was successfully synthesized via the slow evaporation method, using (2-bromoethyl)trimethylammonium bromide ((TMBE)Br) and MnBr2·4H2O. Single-crystal structural analysis reveals that 1 crystallizes in the Pca21 space group, with Mn2+ coordinating with Br- to form isolated tetrahedra, while the organic cation separates the inorganic anions, resulting in a zero-dimensional crystal structure. Differential scanning calorimetry measurements demonstrate that compound 1 undergoes a reversible first-order phase transition with a maximum phase transition temperature of 413 K. Dielectric, variable-temperature fluorescence, and magnetic measurements showed that compound 1 exhibited synchronous switching behavior of dielectric constant, luminous intensity, and magnetization near 344 K. These results indicate that halogen substitution on organic cations is an effective strategy for constructing high-temperature phase-transition materials that integrate dielectric, optical, and magnetic synergistic responses triggered by structural phase transitions.
A novel manganese-based hybrid material (TMBE)2[MnBr4] (1) was successfully synthesized via the slow evaporation method, using (2-bromoethyl)trimethylammonium bromide ((TMBE)Br) and MnBr2·4H2O. Single-crystal structural analysis reveals that 1 crystallizes in the Pca21 space group, with Mn2+ coordinating with Br- to form isolated tetrahedra, while the organic cation separates the inorganic anions, resulting in a zero-dimensional crystal structure. Differential scanning calorimetry measurements demonstrate that compound 1 undergoes a reversible first-order phase transition with a maximum phase transition temperature of 413 K. Dielectric, variable-temperature fluorescence, and magnetic measurements showed that compound 1 exhibited synchronous switching behavior of dielectric constant, luminous intensity, and magnetization near 344 K. These results indicate that halogen substitution on organic cations is an effective strategy for constructing high-temperature phase-transition materials that integrate dielectric, optical, and magnetic synergistic responses triggered by structural phase transitions.
2026, 42(11): 2371-2380
doi: 10.11862/CJIC.20260193
Abstract:
The magnetic properties of two isostructural rare-earth borate compounds Cd4LnO(BO3)3 [Ln=Yb (1), Dy (2)], whose crystal structures have been previously reported, were investigated. Single crystals of compound 1 were obtained and structurally characterized by single-crystal X-ray diffraction. The phase purity and isostructural relationship of compounds 1 and 2 were confirmed by powder X-ray diffraction, together with infrared spectroscopy. Their band gaps and thermal stabilities were characterized by UV-Vis-NIR spectroscopy and thermogravimetric analysis. Single-crystal X-ray diffraction reveals that [YbO6] are connected via edge-sharing to form 1D chains of rare-earth magnetic ions in compound 1, and these chains are separated by borate groups and Cd2+ ions. Magnetic studies indicate that antiferromagnetic interactions dominate in both compounds 1 and 2, and no long-range magnetic order was observed down to 2 K.
The magnetic properties of two isostructural rare-earth borate compounds Cd4LnO(BO3)3 [Ln=Yb (1), Dy (2)], whose crystal structures have been previously reported, were investigated. Single crystals of compound 1 were obtained and structurally characterized by single-crystal X-ray diffraction. The phase purity and isostructural relationship of compounds 1 and 2 were confirmed by powder X-ray diffraction, together with infrared spectroscopy. Their band gaps and thermal stabilities were characterized by UV-Vis-NIR spectroscopy and thermogravimetric analysis. Single-crystal X-ray diffraction reveals that [YbO6] are connected via edge-sharing to form 1D chains of rare-earth magnetic ions in compound 1, and these chains are separated by borate groups and Cd2+ ions. Magnetic studies indicate that antiferromagnetic interactions dominate in both compounds 1 and 2, and no long-range magnetic order was observed down to 2 K.
2026, 42(11): 2399-2410
doi: 10.11862/CJIC.20260209
Abstract:
We report a class of Au(Ⅰ)-based multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters designed for deep blue emission [(PzIPr)AuOBO and (SIPr)AuOBO], which exhibited a substantially shortened delayed lifetime and a narrow full width at half maximum (FWHM=40 nm). Remarkably, dual emission from both TADF and phosphorescence was observed in these MR-TADF complexes. The photoluminescence quantum yield (PLQY) of the emitters reached up to 0.99, a result attributed to the Au(Ⅰ)-activated triplet radiative transfer pathway. Solution-processed organic light-emitting diode (OLED) devices fabricated with (PzIPr)AuOBO delivered deep blue emission with CIE coordinates of (0.15, 0.07) and a maximum external quantum efficiency (EQE) of 7.0%.
We report a class of Au(Ⅰ)-based multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters designed for deep blue emission [(PzIPr)AuOBO and (SIPr)AuOBO], which exhibited a substantially shortened delayed lifetime and a narrow full width at half maximum (FWHM=40 nm). Remarkably, dual emission from both TADF and phosphorescence was observed in these MR-TADF complexes. The photoluminescence quantum yield (PLQY) of the emitters reached up to 0.99, a result attributed to the Au(Ⅰ)-activated triplet radiative transfer pathway. Solution-processed organic light-emitting diode (OLED) devices fabricated with (PzIPr)AuOBO delivered deep blue emission with CIE coordinates of (0.15, 0.07) and a maximum external quantum efficiency (EQE) of 7.0%.
2026, 42(11): 2411-2419
doi: 10.11862/CJIC.20260211
Abstract:
Under ultra-high vacuum, surface synthesis of 2D conjugated metal-organic frameworks (MOFs) was carried out through molecular beam epitaxy (MBE) growth to address the challenge of traditional solvothermal methods in achieving large-scale, defect-free single-crystal synthesis. Here, we chose an iconic 2D conjugated MOF, Cu3(HOTP)2 (HOTP represents the deprotonated derivative of 2,3,6,7,10,11-hexahydroxytriphenylene), as a case study to investigate the diversified self-assembly of Cu atoms and HHTP ligands, as well as the synthesis mechanism of the MOF fragment on the surface with and without O2 annealing conditions by scanning tunneling microscopy. The results show that dumbbell-shaped [Cu(HOTP)2] complexes, the target fragment of MOFs, can be successfully generated in an O2 atmosphere, yet large-area extended MOFs remain elusive, highlighting oxidation and ligand deprotonation as two key factors that hinder the on-surface synthesis of Cu3(HOTP)2.
Under ultra-high vacuum, surface synthesis of 2D conjugated metal-organic frameworks (MOFs) was carried out through molecular beam epitaxy (MBE) growth to address the challenge of traditional solvothermal methods in achieving large-scale, defect-free single-crystal synthesis. Here, we chose an iconic 2D conjugated MOF, Cu3(HOTP)2 (HOTP represents the deprotonated derivative of 2,3,6,7,10,11-hexahydroxytriphenylene), as a case study to investigate the diversified self-assembly of Cu atoms and HHTP ligands, as well as the synthesis mechanism of the MOF fragment on the surface with and without O2 annealing conditions by scanning tunneling microscopy. The results show that dumbbell-shaped [Cu(HOTP)2] complexes, the target fragment of MOFs, can be successfully generated in an O2 atmosphere, yet large-area extended MOFs remain elusive, highlighting oxidation and ligand deprotonation as two key factors that hinder the on-surface synthesis of Cu3(HOTP)2.
2026, 42(11): 2459-2474
doi: 10.11862/CJIC.20260129
Abstract:
A series of cyclopentadienyl iron(Ⅱ) complexes of bidentate phosphine ligands bearing pendant amine bases, R-N(CH2P(Ph)2)2 [Ln: n=1 (R=n-propyl), 2 (R=benzyl), 3 (R=o-CH2Py)], were synthesized: [CpFe(Ln)I] (1a-1c: n=1-3), [CpFe(Ln)(NCMe)]I (2a-2c: n=1-3), and [CpFe(Ln)(NCMe)]PF6 (3a-3c: n=1-3), to mimic the structure and function of the distal iron unit in the diiron active site of [FeFe]-hydrogenases. By varying the R substituents of pendant amines, we aimed to investigate how amine basicity regulates the reactivity of these iron complexes. The iodo complexes 1a-1c underwent facile ligand substitution by MeCN, affording iodide complexes 2a-2c. The returns from 2a-2c to 1a-1c in chloroform were spectroscopically probed to demonstrate a linear correlation between rate constants and the pKa values of the pendant amines. Nevertheless, the returns were completely inhibited in the hexafluorophosphate (PF6-) complexes 3a-3c. Further insights from electrochemical investigations revealed that one-electron reduction of the Fe(Ⅱ) complexes leads to the formation of 17-electron Fe(Ⅰ) species, whereby an additional chemical process should be involved to liberate the labile ligand (I- or MeCN) from the metal centre to result in a precious vacancy. The observation was corroborated by density functional theory (DFT) calculations, which predicted the creation of a vacant site at the intermediate upon reduction. Particularly, the electrocatalytic activity of these iron complexes towards proton reduction was found to be significantly influenced by the basicity of the pendant amine, whereas low basic amines generally result in high efficiency. Our results revealed the crucial role of the substituent on the pendant amine in manipulating the chemistry of metal-based ligand exchange as well as electrocatalytic proton reduction.
A series of cyclopentadienyl iron(Ⅱ) complexes of bidentate phosphine ligands bearing pendant amine bases, R-N(CH2P(Ph)2)2 [Ln: n=1 (R=n-propyl), 2 (R=benzyl), 3 (R=o-CH2Py)], were synthesized: [CpFe(Ln)I] (1a-1c: n=1-3), [CpFe(Ln)(NCMe)]I (2a-2c: n=1-3), and [CpFe(Ln)(NCMe)]PF6 (3a-3c: n=1-3), to mimic the structure and function of the distal iron unit in the diiron active site of [FeFe]-hydrogenases. By varying the R substituents of pendant amines, we aimed to investigate how amine basicity regulates the reactivity of these iron complexes. The iodo complexes 1a-1c underwent facile ligand substitution by MeCN, affording iodide complexes 2a-2c. The returns from 2a-2c to 1a-1c in chloroform were spectroscopically probed to demonstrate a linear correlation between rate constants and the pKa values of the pendant amines. Nevertheless, the returns were completely inhibited in the hexafluorophosphate (PF6-) complexes 3a-3c. Further insights from electrochemical investigations revealed that one-electron reduction of the Fe(Ⅱ) complexes leads to the formation of 17-electron Fe(Ⅰ) species, whereby an additional chemical process should be involved to liberate the labile ligand (I- or MeCN) from the metal centre to result in a precious vacancy. The observation was corroborated by density functional theory (DFT) calculations, which predicted the creation of a vacant site at the intermediate upon reduction. Particularly, the electrocatalytic activity of these iron complexes towards proton reduction was found to be significantly influenced by the basicity of the pendant amine, whereas low basic amines generally result in high efficiency. Our results revealed the crucial role of the substituent on the pendant amine in manipulating the chemistry of metal-based ligand exchange as well as electrocatalytic proton reduction.
2026, 42(11): 2335-2342
doi: 10.11862/CJIC.20260074
Abstract:
Utilizing the photoactive ligand 9-anthracenecarboxylic acid (9-HAc) as a structural building block, we report the solvothermal synthesis of two dinuclear Dy3+ complexes, [Dy2(9-Ac)6(DMA)2] (1) and [Dy2(9-Ac)6(NMP)2] (2) (DMA=N,N-dimethylacetamide, NMP=N-methylpyrrolidone). Single-crystal X-ray diffraction analysis reveals that both complexes contain dinuclear Dy2 units, in which the Dy(Ⅲ) centers adopt eight-coordinated triangular dodecahedral geometries. Upon irradiation with a 300 W Xe lamp, the powder samples of 1 and 2 changed from pale pink and pale yellow to brown/dark brown, respectively, accompanied by pronounced quenching of ligand-centered emission. Time-dependent UV-Vis absorption spectra showed the gradual growth of a broad absorption band in the visible region. Electron paramagnetic resonance spectra displayed signals at g=2.002 after irradiation, confirming the formation of photogenerated radicals through a photoinduced electron-transfer process. IR spectra and powder X-ray diffraction patterns collected before and after irradiation indicate that the coordination frameworks are retained during the photochemical process. The photochromic and luminescence responses of these complexes were further used for inkless printing and information-encryption demonstrations.
Utilizing the photoactive ligand 9-anthracenecarboxylic acid (9-HAc) as a structural building block, we report the solvothermal synthesis of two dinuclear Dy3+ complexes, [Dy2(9-Ac)6(DMA)2] (1) and [Dy2(9-Ac)6(NMP)2] (2) (DMA=N,N-dimethylacetamide, NMP=N-methylpyrrolidone). Single-crystal X-ray diffraction analysis reveals that both complexes contain dinuclear Dy2 units, in which the Dy(Ⅲ) centers adopt eight-coordinated triangular dodecahedral geometries. Upon irradiation with a 300 W Xe lamp, the powder samples of 1 and 2 changed from pale pink and pale yellow to brown/dark brown, respectively, accompanied by pronounced quenching of ligand-centered emission. Time-dependent UV-Vis absorption spectra showed the gradual growth of a broad absorption band in the visible region. Electron paramagnetic resonance spectra displayed signals at g=2.002 after irradiation, confirming the formation of photogenerated radicals through a photoinduced electron-transfer process. IR spectra and powder X-ray diffraction patterns collected before and after irradiation indicate that the coordination frameworks are retained during the photochemical process. The photochromic and luminescence responses of these complexes were further used for inkless printing and information-encryption demonstrations.
2026, 42(11): 2353-2361
doi: 10.11862/CJIC.20260137
Abstract:
Perfluoroalkyl substances (PFAS) are widely present in solid matrices and aqueous environments, and their bioaccumulation and inherent toxicity pose potential threats to human health. To meet the demand for rapid, sensitive PFAS detection, we synthesized two metal-organic frameworks, UiO-66-NH2(Ce) and UiO-66-NH2(Zr), with different metal centers, via a solvothermal method using 2-aminoterephthalic acid as the ligand. Detailed characterizations confirmed that the as-synthesized samples possessed satisfactory phase purity, acid-base stability, and thermal stability. Both MOFs exhibited turn-on fluorescence responses toward perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). Compared to UiO-66-NH2(Zr), UiO-66-NH2(Ce) exhibited better performance, achieving a limit of detection as low as 0.17 μmol·L-1 for PFOS, along with rapid response and excellent anti-interference capability. Mechanistic studies revealed that the MOFs interacted with the acidic head groups of PFAS through electrostatic interaction, thereby triggering the fluorescence response. Meanwhile, the different metal centers regulate the intensity of host-guest interactions within the framework via their polarizability, thereby modulating the sensing performance. This work provides a tailored MOF system for the facile detection of PFAS in water and reveals the key structural factors governing the sensing performance of MOF-based materials.
Perfluoroalkyl substances (PFAS) are widely present in solid matrices and aqueous environments, and their bioaccumulation and inherent toxicity pose potential threats to human health. To meet the demand for rapid, sensitive PFAS detection, we synthesized two metal-organic frameworks, UiO-66-NH2(Ce) and UiO-66-NH2(Zr), with different metal centers, via a solvothermal method using 2-aminoterephthalic acid as the ligand. Detailed characterizations confirmed that the as-synthesized samples possessed satisfactory phase purity, acid-base stability, and thermal stability. Both MOFs exhibited turn-on fluorescence responses toward perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). Compared to UiO-66-NH2(Zr), UiO-66-NH2(Ce) exhibited better performance, achieving a limit of detection as low as 0.17 μmol·L-1 for PFOS, along with rapid response and excellent anti-interference capability. Mechanistic studies revealed that the MOFs interacted with the acidic head groups of PFAS through electrostatic interaction, thereby triggering the fluorescence response. Meanwhile, the different metal centers regulate the intensity of host-guest interactions within the framework via their polarizability, thereby modulating the sensing performance. This work provides a tailored MOF system for the facile detection of PFAS in water and reveals the key structural factors governing the sensing performance of MOF-based materials.
Modulation of charge transport in platinum(Ⅱ) bis(acetylide) complexes by coordination configuration
2026, 42(11): 2381-2388
doi: 10.11862/CJIC.20260207
Abstract:
Platinum(Ⅱ) bis(acetylide) organometallic complexes exhibit appealing photophysical properties originating from versatile metal-ligand orbital interactions, yet how their coordination geometry governs single-molecule charge transport remains poorly understood. Herein, we have synthesized two geometric isomers, trans-/cis-Pt(PEt3)2(C≡CPhSMe)2 (1-t and 1-c, PhSMe=4-methylthiophenyl), and systematically investigated their single-molecule charge-transport properties by scanning tunneling microscope break junction (STM-BJ) technique and the combination of density functional theory and non-equilibrium Green′s function (DFT-NEGF) calculations. 1-t demonstrated a well-defined conductance peak at 10-4.5G0, where G0 is the quantum conductance (ca. 77 500 nS). In contrast, no detectable conductance signature was recorded for 1-c, whose conductance fell below the instrumental detection limit of 10-6.0G0, indicating a more than one-order-of-magnitude conductance suppression. Transition-voltage spectroscopy (TVS) and theoretical studies verify that charge transport in both isomers follows a HOMO-dominated tunneling mechanism and provide a calibrated transmission coefficient (T(E)). Theoretical analyses further reveal two synergistic physical origins for the explicit conductance suppression. First, the bent perpendicular geometry of 1-c induces a severely asymmetric spatial distribution of frontier molecular orbitals over the two acetylide ligands, yielding asymmetric electrode-molecule coupling at two Au—S anchoring interfaces and lowering electron transmission probability. Second, the shortened inter-ligand distance in the cis-configuration not only activates through-space electronic hopping between two acetylide moieties but also results in reverse ring currents localized on the platinum-acetylide structure, which further triggers destructive quantum interference (DQI) and eventually suppresses the conductance in 1-c. By comparison, the linear trans-geometry supports efficient through-bond charge transport with symmetric electrode coupling. This work establishes coordination configuration as an effective structural factor for modulating charge transport characteristics in organometallic molecular wires.
Platinum(Ⅱ) bis(acetylide) organometallic complexes exhibit appealing photophysical properties originating from versatile metal-ligand orbital interactions, yet how their coordination geometry governs single-molecule charge transport remains poorly understood. Herein, we have synthesized two geometric isomers, trans-/cis-Pt(PEt3)2(C≡CPhSMe)2 (1-t and 1-c, PhSMe=4-methylthiophenyl), and systematically investigated their single-molecule charge-transport properties by scanning tunneling microscope break junction (STM-BJ) technique and the combination of density functional theory and non-equilibrium Green′s function (DFT-NEGF) calculations. 1-t demonstrated a well-defined conductance peak at 10-4.5G0, where G0 is the quantum conductance (ca. 77 500 nS). In contrast, no detectable conductance signature was recorded for 1-c, whose conductance fell below the instrumental detection limit of 10-6.0G0, indicating a more than one-order-of-magnitude conductance suppression. Transition-voltage spectroscopy (TVS) and theoretical studies verify that charge transport in both isomers follows a HOMO-dominated tunneling mechanism and provide a calibrated transmission coefficient (T(E)). Theoretical analyses further reveal two synergistic physical origins for the explicit conductance suppression. First, the bent perpendicular geometry of 1-c induces a severely asymmetric spatial distribution of frontier molecular orbitals over the two acetylide ligands, yielding asymmetric electrode-molecule coupling at two Au—S anchoring interfaces and lowering electron transmission probability. Second, the shortened inter-ligand distance in the cis-configuration not only activates through-space electronic hopping between two acetylide moieties but also results in reverse ring currents localized on the platinum-acetylide structure, which further triggers destructive quantum interference (DQI) and eventually suppresses the conductance in 1-c. By comparison, the linear trans-geometry supports efficient through-bond charge transport with symmetric electrode coupling. This work establishes coordination configuration as an effective structural factor for modulating charge transport characteristics in organometallic molecular wires.
2026, 42(11): 2389-2398
doi: 10.11862/CJIC.20260208
Abstract:
This paper investigates the relationship between the crystal structures and solubility characteristics of 2-bromoisobutyric acid-coordinated zirconium-oxo clusters, namely Zr5O4[BrC(CH3)2COO]10(OnPr)2(nPrOH)4 (named Zr5Br10) and Zr6O4(OH)4(OOCC(CH3)2Br)12 (named Zr6Br12), and evaluates the electron beam lithography performance of Zr5Br10 for the first time. Structural analysis reveals that molecular symmetry plays an important role in regulating cluster solubility: the low-symmetry Zr5Br10 exhibits excellent film-forming ability, whereas the highly symmetric Zr6Br12 is extremely insoluble. During the patterning process, the lithographic performance of Zr5Br10 films is highly dependent on development dynamics. In a low-polarity “poor solvent” (n-heptane) system, the film achieved ultra-high sensitivity (38.1 μC·cm-2) and excellent contrast (12.5). X-ray photoelectron spectroscopy (XPS) characterization further unveils the negative-tone cross-linking mechanism of this photoresist, where electron beam-induced decarboxylation and C—Br bond cleavage lead to the in-situ rearrangement of newly formed active metal centers, forming an insoluble three-dimensional Zr—O—Zr network.
This paper investigates the relationship between the crystal structures and solubility characteristics of 2-bromoisobutyric acid-coordinated zirconium-oxo clusters, namely Zr5O4[BrC(CH3)2COO]10(OnPr)2(nPrOH)4 (named Zr5Br10) and Zr6O4(OH)4(OOCC(CH3)2Br)12 (named Zr6Br12), and evaluates the electron beam lithography performance of Zr5Br10 for the first time. Structural analysis reveals that molecular symmetry plays an important role in regulating cluster solubility: the low-symmetry Zr5Br10 exhibits excellent film-forming ability, whereas the highly symmetric Zr6Br12 is extremely insoluble. During the patterning process, the lithographic performance of Zr5Br10 films is highly dependent on development dynamics. In a low-polarity “poor solvent” (n-heptane) system, the film achieved ultra-high sensitivity (38.1 μC·cm-2) and excellent contrast (12.5). X-ray photoelectron spectroscopy (XPS) characterization further unveils the negative-tone cross-linking mechanism of this photoresist, where electron beam-induced decarboxylation and C—Br bond cleavage lead to the in-situ rearrangement of newly formed active metal centers, forming an insoluble three-dimensional Zr—O—Zr network.
2026, 42(11): 2420-2428
doi: 10.11862/CJIC.20260235
Abstract:
Three novel orange-yellow emitting Cu(Ⅰ) complexes—[Cu2I2(bpen)(POP)2] (1), [Cu2Br2(bpen)(POP)2]·2CH2Cl2 (2), and [Cu2Cl2(bpen)(POP)2] (3)—were successfully synthesized using the bridging nitrogen ligand (bpen), and diphosphine ligand (POP) as functional ligands. The crystal structures and photophysical properties of these three target complexes were comprehensively characterized by single-crystal X-ray diffraction, 1H NMR, infrared spectroscopy, UV-Vis absorption spectroscopy, and fluorescence spectroscopy. Fluorescence measurements revealed maximum emission wavelengths of 592, 598, and 599 nm for the three complexes. All complexes exhibited outstanding orange-yellow luminescence. Mechanistic analysis indicates that modulating ligand conjugation effects and adjusting bridging coordination modes can effectively control excited-state behavior of the complexes and then enable precise tuning of their luminescent performance.
Three novel orange-yellow emitting Cu(Ⅰ) complexes—[Cu2I2(bpen)(POP)2] (1), [Cu2Br2(bpen)(POP)2]·2CH2Cl2 (2), and [Cu2Cl2(bpen)(POP)2] (3)—were successfully synthesized using the bridging nitrogen ligand (bpen), and diphosphine ligand (POP) as functional ligands. The crystal structures and photophysical properties of these three target complexes were comprehensively characterized by single-crystal X-ray diffraction, 1H NMR, infrared spectroscopy, UV-Vis absorption spectroscopy, and fluorescence spectroscopy. Fluorescence measurements revealed maximum emission wavelengths of 592, 598, and 599 nm for the three complexes. All complexes exhibited outstanding orange-yellow luminescence. Mechanistic analysis indicates that modulating ligand conjugation effects and adjusting bridging coordination modes can effectively control excited-state behavior of the complexes and then enable precise tuning of their luminescent performance.
2026, 42(11): 2429-2437
doi: 10.11862/CJIC.20260223
Abstract:
Herein, we report the synthesis of a novel tetramethylcucurbit[6 ]uril (TMeQ[6])-based supramolecular self-assembly with a formula of (H3O)(1,5-NDS)0.5·TMeQ[6]·13H2O (1) by introducing 1,5-naphthalenedisulfonic acid (1,5-H2NDS) as the structure-directing agent to react with TMeQ[6] under hydrothermal conditions. Single-crystal X-ray diffraction (SCXRD) measurement reveals that TMeQ[6] molecules are assembled into 1D zig-zag supramolecular chains and then 2D wave-like supramolecular layers via hydrogen bonds, which further interact with the 1,5-NDS2- sulfonate anionic guest through the noncovalent interactions between the outer surface of TMeQ[6] and 1,5-NDS2- to generate the final 3D supramolecular framework. Because the structure contains “free” uncoordinated portals, self-assembly 1 showed Cs+ capture capacity, as evidenced by the highly similar crystal structure of Cs+-loaded self-assembly 2, except that one Cs+ cation sits at the center of one TMeQ[6] portal. Furthermore, fluorescence sensing experiments also revealed that self-assembly 1 may act as a ratiometric fluorescent sensor for sulfadiazine (SD), ciprofloxacin (CFX), and levofloxacin (LFX).
Herein, we report the synthesis of a novel tetramethylcucurbit[
2026, 42(11): 2438-2450
doi: 10.11862/CJIC.20260226
Abstract:
Polyvinylpyrrolidone (PVP-K30)-modified Cu-IR808 nanoparticles (NPs) were obtained via a facile one-step coordination-driven self-assembly approach. This nanoplatform integrates the IR808 (a near-infrared heptamethine cyanine dye) with Cu2+ at the atomic level, enabling efficient integration of photodynamic therapy (PDT)/photothermal therapy (PTT) modules with the chemodynamic therapy (CDT) module. Systematic characterization revealed that the NPs were quasi-spherical with an average size of approximately 150.0 nm and exhibited strong near-infrared absorption at 808 nm. Functional studies demonstrated that under 808 nm laser irradiation, the Cu-IR808 NPs exhibited remarkable photothermal conversion efficiency (29.9%), photo-induced reactive oxygen species (ROS) generation capacity, and photothermal-enhanced Fenton-like catalytic activity (methylene blue degradation at 45.0 ℃ increased ca. 2.4-fold compared to room temperature). In vitro experiments confirm that Cu-IR808-mediated combination therapy effectively suppresses tumor cell viability, while biosafety assessments indicate good cytocompatibility and hemocompatibility (the hemolysis rate was below 5.0%).
Polyvinylpyrrolidone (PVP-K30)-modified Cu-IR808 nanoparticles (NPs) were obtained via a facile one-step coordination-driven self-assembly approach. This nanoplatform integrates the IR808 (a near-infrared heptamethine cyanine dye) with Cu2+ at the atomic level, enabling efficient integration of photodynamic therapy (PDT)/photothermal therapy (PTT) modules with the chemodynamic therapy (CDT) module. Systematic characterization revealed that the NPs were quasi-spherical with an average size of approximately 150.0 nm and exhibited strong near-infrared absorption at 808 nm. Functional studies demonstrated that under 808 nm laser irradiation, the Cu-IR808 NPs exhibited remarkable photothermal conversion efficiency (29.9%), photo-induced reactive oxygen species (ROS) generation capacity, and photothermal-enhanced Fenton-like catalytic activity (methylene blue degradation at 45.0 ℃ increased ca. 2.4-fold compared to room temperature). In vitro experiments confirm that Cu-IR808-mediated combination therapy effectively suppresses tumor cell viability, while biosafety assessments indicate good cytocompatibility and hemocompatibility (the hemolysis rate was below 5.0%).
2026, 42(11): 2451-2458
doi: 10.11862/CJIC.20260166
Abstract:
Through a functional coupling strategy, the photosensitizing Ru center and catalytically active Au sites were precisely integrated into a covalent organic framework (COF), successfully constructing the Ru-Au bimetallic COF (Ru-Au-COF). Its photocatalytic N2 reduction performance was systematically studied. Due to the integration of the photosensitizing Ru center, the material exhibited excellent light-harvesting capability. Meanwhile, the high-density loading of catalytically active Au centers provided an effective number of functional sites for N2 activation. Photocatalytic studies showed that Ru-Au-COF exhibited excellent photocatalytic nitrogen fixation activity, with an ammonia production rate of 231.7 μmol·g-1·h-1, which was nearly four times higher compared to the material without Au sites (Ru-COF).
Through a functional coupling strategy, the photosensitizing Ru center and catalytically active Au sites were precisely integrated into a covalent organic framework (COF), successfully constructing the Ru-Au bimetallic COF (Ru-Au-COF). Its photocatalytic N2 reduction performance was systematically studied. Due to the integration of the photosensitizing Ru center, the material exhibited excellent light-harvesting capability. Meanwhile, the high-density loading of catalytically active Au centers provided an effective number of functional sites for N2 activation. Photocatalytic studies showed that Ru-Au-COF exhibited excellent photocatalytic nitrogen fixation activity, with an ammonia production rate of 231.7 μmol·g-1·h-1, which was nearly four times higher compared to the material without Au sites (Ru-COF).
2026, 42(11): 2475-2492
doi: 10.11862/CJIC.20260044
Abstract:
Using a core-shell structured nanocomposite (AuNP@SiO2@GQD/mSiO2) containing gold nanoparticles (AuNP), silica (SiO2), graphene quantum dots (GQD), and mesoporous silica (mSiO2) as the carrier, a photoelectrochemical sensor was constructed with chitosan (CTS) as the film-forming agent, coated onto a glassy carbon electrode (GCE), and immobilized glucose oxidase (GOx), yielding the final assembly of AuNP@SiO2@GQD/mSiO2/GOx/CTS/GCE. Analysis of the experimental results indicates that the relatively weak interactions between the immobilized enzyme molecules and the mSiO2 shell of the core-shell nanocomposite, including electrostatic interactions, weak bonding forces, and hydrogen bonding, help maintain the intrinsic chemical microenvironment of GOx molecules. On the GOx-incorporated electrode, the reversible reaction of the electroactive group on the GQD surface and a typical quasi-reversible, surface-controlled electrochemical reaction involving two electrons and two protons were observed, demonstrating excellent heterogeneous charge-transfer efficiency with a normalized rate of 255.5 s-1. A distinct electrochemical luminescence peak appeared at approximately -2.1 V for the GQD-based electrode when a co-reactant was present in the solution. After optimizing the working parameters of the electro-chemiluminescence sensor, including co-reactant concentration, buffer pH, and scanning rate, we evaluated its glucose-sensing performance. The sensor exhibited strong and stable electro-chemiluminescence signals, a wide linear response range for the substrate (10-10-10-4 mol·L-1), and a low detection limit (8.55×10-11 mol·L-1).
Using a core-shell structured nanocomposite (AuNP@SiO2@GQD/mSiO2) containing gold nanoparticles (AuNP), silica (SiO2), graphene quantum dots (GQD), and mesoporous silica (mSiO2) as the carrier, a photoelectrochemical sensor was constructed with chitosan (CTS) as the film-forming agent, coated onto a glassy carbon electrode (GCE), and immobilized glucose oxidase (GOx), yielding the final assembly of AuNP@SiO2@GQD/mSiO2/GOx/CTS/GCE. Analysis of the experimental results indicates that the relatively weak interactions between the immobilized enzyme molecules and the mSiO2 shell of the core-shell nanocomposite, including electrostatic interactions, weak bonding forces, and hydrogen bonding, help maintain the intrinsic chemical microenvironment of GOx molecules. On the GOx-incorporated electrode, the reversible reaction of the electroactive group on the GQD surface and a typical quasi-reversible, surface-controlled electrochemical reaction involving two electrons and two protons were observed, demonstrating excellent heterogeneous charge-transfer efficiency with a normalized rate of 255.5 s-1. A distinct electrochemical luminescence peak appeared at approximately -2.1 V for the GQD-based electrode when a co-reactant was present in the solution. After optimizing the working parameters of the electro-chemiluminescence sensor, including co-reactant concentration, buffer pH, and scanning rate, we evaluated its glucose-sensing performance. The sensor exhibited strong and stable electro-chemiluminescence signals, a wide linear response range for the substrate (10-10-10-4 mol·L-1), and a low detection limit (8.55×10-11 mol·L-1).
2026, 42(11): 2493-2503
doi: 10.11862/CJIC.20260070
Abstract:
A theranostic nanoprobe (HA-Mn-MOF) integrating T1-weighted magnetic resonance imaging (MRI) with sonodynamic-chemodynamic synergistic therapy was constructed. The probe was based on a hyaluronic acid (HA)-modified manganese porphyrin metal-organic framework (MOF). HA-mediated active targeting enables tumor-specific enrichment, while the porphyrin units act as sonosensitizers to enhance the sonodynamic therapy (SDT) effect. The manganese centers not only deplete overexpressed glutathione (GSH) in the tumor microenvironment (TME) but also catalyze a Fenton-like reaction with endogenous H2O2, generating hydroxyl radical (·OH) and O2 in situ. This chemodynamic therapy (CDT) simultaneously alleviates tumor hypoxia, significantly potentiating the SDT efficacy and thereby achieving efficient killing of breast cancer cells. Moreover, HA-Mn-MOF exhibited pH and GSH dual-responsive MRI activation, with a T1 relaxation rate of 4.16 L·mmol-1·s-1, which was 2.7 times that under physiological conditions.
A theranostic nanoprobe (HA-Mn-MOF) integrating T1-weighted magnetic resonance imaging (MRI) with sonodynamic-chemodynamic synergistic therapy was constructed. The probe was based on a hyaluronic acid (HA)-modified manganese porphyrin metal-organic framework (MOF). HA-mediated active targeting enables tumor-specific enrichment, while the porphyrin units act as sonosensitizers to enhance the sonodynamic therapy (SDT) effect. The manganese centers not only deplete overexpressed glutathione (GSH) in the tumor microenvironment (TME) but also catalyze a Fenton-like reaction with endogenous H2O2, generating hydroxyl radical (·OH) and O2 in situ. This chemodynamic therapy (CDT) simultaneously alleviates tumor hypoxia, significantly potentiating the SDT efficacy and thereby achieving efficient killing of breast cancer cells. Moreover, HA-Mn-MOF exhibited pH and GSH dual-responsive MRI activation, with a T1 relaxation rate of 4.16 L·mmol-1·s-1, which was 2.7 times that under physiological conditions.
2026, 42(11): 2504-2514
doi: 10.11862/CJIC.20260008
Abstract:
A new Cd(Ⅱ) complex [Cd(4, 4′-bipy)(H2O)4] (4-MBS)2 was synthesized by solvothermal method for the detection of Fe3+. The complex was characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. Its fluorescence properties were investigated. Solid-state fluorescence results showed that the complex′s fluorescence emission originated from the π*→π transition of 4, 4′-bipy. Fluorescence sensing experiments indicate that the complex exhibited high sensitivity for the recognition of Fe3+ with a detection limit of 0.27 μmol·L-1. Cyclic sensing experiments demonstrated that the complex exhibited excellent stability. The crystal structure was determined by single-crystal X-ray diffraction analysis, revealing the presence of abundant O—H…O and C—H…π interactions; Hirshfeld surface analysis further proved the existence of O—H…O and C—H…π interactions in the complex, and there are also other interactions such as H…H. These effects work together to enhance the structural stability and fluorescence-sensing ability of the complex. Finally, the mechanism of Fe3+ quenching of the complex was studied, and the results show that the interaction between Fe3+ and O atoms and the energy competition absorption between Fe3+ and the complex jointly lead to the fluorescence quenching of the complex.
A new Cd(Ⅱ) complex [Cd(4, 4′-bipy)(H2O)4] (4-MBS)2 was synthesized by solvothermal method for the detection of Fe3+. The complex was characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. Its fluorescence properties were investigated. Solid-state fluorescence results showed that the complex′s fluorescence emission originated from the π*→π transition of 4, 4′-bipy. Fluorescence sensing experiments indicate that the complex exhibited high sensitivity for the recognition of Fe3+ with a detection limit of 0.27 μmol·L-1. Cyclic sensing experiments demonstrated that the complex exhibited excellent stability. The crystal structure was determined by single-crystal X-ray diffraction analysis, revealing the presence of abundant O—H…O and C—H…π interactions; Hirshfeld surface analysis further proved the existence of O—H…O and C—H…π interactions in the complex, and there are also other interactions such as H…H. These effects work together to enhance the structural stability and fluorescence-sensing ability of the complex. Finally, the mechanism of Fe3+ quenching of the complex was studied, and the results show that the interaction between Fe3+ and O atoms and the energy competition absorption between Fe3+ and the complex jointly lead to the fluorescence quenching of the complex.
