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2015 Volume 34 Issue 5
2015, 34(5): 641-649
doi: 10.14102/j.cnki.0254-5861.2011-0611
Abstract:
Armchair graphene nanoribbons with different proportions of edge oxygen atoms are analyzed in this study using the crystal orbital method, which is based on density functional theory. Although buckled edges are present, all the nanoribbons are energetically favorable. Unlike the adjacent edge oxygen atoms, the isolated edge oxygen atoms cause semiconductor-metal transitions by introducing edge states. For graphene nanoribbons with all oxygen atoms on the edges, band gap and carrier mobility vary with ribbon width. Furthermore, this behavior is different from that of hydrogen-passivated graphene nanoribbons because of different effective widths, which are pictorially presented with crystal orbitals. The carrier mobilities are as 18%~65% magnitude as those of hydrogen-passivated nanoribbons and are of the order of 103 cm2·V−1·s−1.
Armchair graphene nanoribbons with different proportions of edge oxygen atoms are analyzed in this study using the crystal orbital method, which is based on density functional theory. Although buckled edges are present, all the nanoribbons are energetically favorable. Unlike the adjacent edge oxygen atoms, the isolated edge oxygen atoms cause semiconductor-metal transitions by introducing edge states. For graphene nanoribbons with all oxygen atoms on the edges, band gap and carrier mobility vary with ribbon width. Furthermore, this behavior is different from that of hydrogen-passivated graphene nanoribbons because of different effective widths, which are pictorially presented with crystal orbitals. The carrier mobilities are as 18%~65% magnitude as those of hydrogen-passivated nanoribbons and are of the order of 103 cm2·V−1·s−1.
2015, 34(5): 650-658
doi: 10.14102/j.cnki.0254-5861.2011-0594
Abstract:
Single crystals of two 1,3-phenylenebis(oxy)diacetic acid (C10H10O8) compounds 1 and 2 were obtained via slow evaporation. The compounds were characterized by elemental analysis, IR and single-crystal X-ray diffraction. Compound 1 (C10H14O8) crystallizes in the triclinic system, space group P1 with a=6.3751(6), b=8.5311(8), c=11.4510(11) Å, α=93.3650(10), β=105.3190(10), γ=97.2140(10)°, V=593.15(10) Å3, Z=2, Mr=262.21, Dc=1.468 g/cm3, F(000)=276, GOOF(000)=1.005, μ=0.129 mm-1, the final R=0.0361 and wR=0.0802 for 1854 observed reflections with I>2σ(I). Compound 2 (C30H28N2O12) crystallizes in the triclinic system, space group P1 with a=9.7416(13), b=11.839(2), c=12.9828(13) Å, α=74.191(4), β=77.953(2), γ=74.726(3)°, V=1374.5(3) Å3, Z=2, Mr=608.54, Dc=1.470 g/cm3, F(000)=636, GOOF(000)=1.061,μ=0.115 mm-1, the final R=0.0500 and wR=0.1221 for 3966 observed reflections with I>2σ(I). Both compounds 1 and 2 exhibit 3D supramolecular structures under hydrogen bonding interactions. The results of preliminary antibacterial activity show that the title compounds display moderate antibacterial activities against the tested gram positive bacteria (S. aureus, C. albicans and B. subtilis) and gram negative bacteria (E. coli and P. aeruginosa).
Single crystals of two 1,3-phenylenebis(oxy)diacetic acid (C10H10O8) compounds 1 and 2 were obtained via slow evaporation. The compounds were characterized by elemental analysis, IR and single-crystal X-ray diffraction. Compound 1 (C10H14O8) crystallizes in the triclinic system, space group P1 with a=6.3751(6), b=8.5311(8), c=11.4510(11) Å, α=93.3650(10), β=105.3190(10), γ=97.2140(10)°, V=593.15(10) Å3, Z=2, Mr=262.21, Dc=1.468 g/cm3, F(000)=276, GOOF(000)=1.005, μ=0.129 mm-1, the final R=0.0361 and wR=0.0802 for 1854 observed reflections with I>2σ(I). Compound 2 (C30H28N2O12) crystallizes in the triclinic system, space group P1 with a=9.7416(13), b=11.839(2), c=12.9828(13) Å, α=74.191(4), β=77.953(2), γ=74.726(3)°, V=1374.5(3) Å3, Z=2, Mr=608.54, Dc=1.470 g/cm3, F(000)=636, GOOF(000)=1.061,μ=0.115 mm-1, the final R=0.0500 and wR=0.1221 for 3966 observed reflections with I>2σ(I). Both compounds 1 and 2 exhibit 3D supramolecular structures under hydrogen bonding interactions. The results of preliminary antibacterial activity show that the title compounds display moderate antibacterial activities against the tested gram positive bacteria (S. aureus, C. albicans and B. subtilis) and gram negative bacteria (E. coli and P. aeruginosa).
2015, 34(5): 659-666
doi: 10.14102/j.cnki.0254-5861.2011-0609
Abstract:
The title compound 2-(1-(3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole-5-carbonyl)piperidin-4-yl)-N-isopropylthiazole-4-carboxamide (C21H22BrClN6O2S, Mr=536.04) has been synthesized, and its structure was characterized by IR spectra, 1H-NMR, 13C-NMR, EA, and single-crystal X-ray diffraction. The crystal of the title compound belongs to monoclinic system, space group P/c with a=15.146(3), b=11.573(2), c=26.937(5) Å, β=103.64(3)°, V=1839.0(6) Å3, Z=4, Dc=1.557 g/cm3, μ(MoKa)=0.71073 mm-1, F(000)=2192, R=0.0601 and wR=0.1392. There exist one intramolecular hydrogen bond at N-H···N and four intermolecular weak interactions at O(2)···H(1), Cl(1)···H(12), O(1)···Cl(1) and S(1)···O(2). Bioassay results indicated that the title compound had good fungicidal and antiviral activities against tobacco mosaic virus.
The title compound 2-(1-(3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole-5-carbonyl)piperidin-4-yl)-N-isopropylthiazole-4-carboxamide (C21H22BrClN6O2S, Mr=536.04) has been synthesized, and its structure was characterized by IR spectra, 1H-NMR, 13C-NMR, EA, and single-crystal X-ray diffraction. The crystal of the title compound belongs to monoclinic system, space group P/c with a=15.146(3), b=11.573(2), c=26.937(5) Å, β=103.64(3)°, V=1839.0(6) Å3, Z=4, Dc=1.557 g/cm3, μ(MoKa)=0.71073 mm-1, F(000)=2192, R=0.0601 and wR=0.1392. There exist one intramolecular hydrogen bond at N-H···N and four intermolecular weak interactions at O(2)···H(1), Cl(1)···H(12), O(1)···Cl(1) and S(1)···O(2). Bioassay results indicated that the title compound had good fungicidal and antiviral activities against tobacco mosaic virus.
2015, 34(5): 667-672
doi: 10.14102/j.cnki.0254-5861.2011-0539
Abstract:
The new title compound N-(2-hydroxy ethyl) tetrahydropalmatine ammonium bromide has been synthesized starting from palmatine hydrochloride. The structure of the product was confirmed by 1H NMR, MS (ESI) and single-crystal X-ray diffraction. The title compound crystallizes in the triclinic system, space group P1 with a=10.5887(11), b=10.8652(9), c=12.0914(12) Å, β=84.808(9)°, V=1253.3(2) Å3, Z=2, Dc=1.355 g/cm3, F(000)=530, μ=1.680 mm-1, the final R=0.0833 and wR=0.2371 for 5112 observed reflections (I>2σ(I)). X-ray analysis indicates that the two planar parts (C(2) C(3) C(4) C(5) C(6) C(7) N(1) C(20) C(21) C(21)) and (C(7) C(8) C(9) C(10) C(12) C(14) N(15) C(16) C(17)) are not coplanar, with the dihedral angles to be 67.9°. Weak interactions mainly between O(5)-H(5)···O from two water molecules and O(5)···Br are observed.
The new title compound N-(2-hydroxy ethyl) tetrahydropalmatine ammonium bromide has been synthesized starting from palmatine hydrochloride. The structure of the product was confirmed by 1H NMR, MS (ESI) and single-crystal X-ray diffraction. The title compound crystallizes in the triclinic system, space group P1 with a=10.5887(11), b=10.8652(9), c=12.0914(12) Å, β=84.808(9)°, V=1253.3(2) Å3, Z=2, Dc=1.355 g/cm3, F(000)=530, μ=1.680 mm-1, the final R=0.0833 and wR=0.2371 for 5112 observed reflections (I>2σ(I)). X-ray analysis indicates that the two planar parts (C(2) C(3) C(4) C(5) C(6) C(7) N(1) C(20) C(21) C(21)) and (C(7) C(8) C(9) C(10) C(12) C(14) N(15) C(16) C(17)) are not coplanar, with the dihedral angles to be 67.9°. Weak interactions mainly between O(5)-H(5)···O from two water molecules and O(5)···Br are observed.
2015, 34(5): 673-680
doi: 10.14102/j.cnki.0254-5861.2011-0617
Abstract:
Two new thieno[2,3-d]pyrimidin-4(3H)-one derivatives, C24H22ClN3O2S (5a) and C25H25N3O2S (5b), have been synthesized via a tandem aza-Wittig reaction. This tandem reaction has many attractive aspects such as easily accessible and versatile starting materials, mild conditions and high yields. Both compounds have been characterized by elemental analysis, HR-MS, IR, NMR spectra and X-ray single-crystal diffraction. Compound 5a crystallizes in monoclinic, space group P21/c with a=9.986(3), b=14.263(4), c=15.530(5) Å, β=93.806(5)°, V=2207.1(11) Å3, Mr=451.96, Z=4, Dc=1.360 g/cm3, F(000)=944, μ=0.294 mm−1, MoKα radiation (λ=0.71073 Å), the final R=0.0444 and wR=0.1219 for 3407 observed reflections with I>2σ(I). Compound 5b crystallizes in triclinic, space group P1 with a=8.974(4), b=10.766(5), c=12.260(6) Å, β=93.047(7)°, V=1122.1(9) Å3, Mr=431.54, Z=2, Dc=1.277 g/cm3, F(000)=456, μ=0.170 mm−1, MoKα radiation (λ=0.71073 Å), the final R=0.0378 and wR=0.1072 for 3806 observed reflections with I>2σ(I). The preliminary antibacterial activities of 5a and 5b were investigated. Compound 5a showed 71.3% and 79.2% in vitro inhibition against Fusarium oxysporium and Rhizoctonia solani, respectively. Compound 5b showed 75.3% in vitro inhibition against Rhizoctonia solani.
Two new thieno[2,3-d]pyrimidin-4(3H)-one derivatives, C24H22ClN3O2S (5a) and C25H25N3O2S (5b), have been synthesized via a tandem aza-Wittig reaction. This tandem reaction has many attractive aspects such as easily accessible and versatile starting materials, mild conditions and high yields. Both compounds have been characterized by elemental analysis, HR-MS, IR, NMR spectra and X-ray single-crystal diffraction. Compound 5a crystallizes in monoclinic, space group P21/c with a=9.986(3), b=14.263(4), c=15.530(5) Å, β=93.806(5)°, V=2207.1(11) Å3, Mr=451.96, Z=4, Dc=1.360 g/cm3, F(000)=944, μ=0.294 mm−1, MoKα radiation (λ=0.71073 Å), the final R=0.0444 and wR=0.1219 for 3407 observed reflections with I>2σ(I). Compound 5b crystallizes in triclinic, space group P1 with a=8.974(4), b=10.766(5), c=12.260(6) Å, β=93.047(7)°, V=1122.1(9) Å3, Mr=431.54, Z=2, Dc=1.277 g/cm3, F(000)=456, μ=0.170 mm−1, MoKα radiation (λ=0.71073 Å), the final R=0.0378 and wR=0.1072 for 3806 observed reflections with I>2σ(I). The preliminary antibacterial activities of 5a and 5b were investigated. Compound 5a showed 71.3% and 79.2% in vitro inhibition against Fusarium oxysporium and Rhizoctonia solani, respectively. Compound 5b showed 75.3% in vitro inhibition against Rhizoctonia solani.
2015, 34(5): 681-687
doi: 10.14102/j.cnki.0254-5861.2011-0583
Abstract:
A new cinnamide derivative, (E)-1-(4-(bis(4-methoxyphenyl)methyl)piperazin- 1-yl)-3-(4-acetoxy-3-methoxyphenyl)prop-2-en-1-one (C31H34N2O6, Mr=530.60), has been synthesized by the condensation of 1-(bis(4-methoxyphenyl)methyl)piperazine and (E)-3-(4- acetoxy-3-methoxyphenyl)acrylic acid. The compound was characterized by 1H NMR, 13C NMR, H RMS and single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system, space group P212121 with a=24.946(5), b=7.6380(15), c=14.555(3) Å, V=2773.3(10) Å3, Z=4, Dc=1.271 g/cm3, F(000)=1128, μ=0.088 mm-1, MoKα radiation (λ=0.71073 Å), the final R=0.0641 and wR=0.1170. A total of 3009 unique reflections were collected, of which 1760 with I>2σ(I) were observed. Intramolecular C(17)-H(17B)···O(3) and C(22)-H(22A)···O(3) interactions as well as intermolecular C(27)-H(27A)···O(3) hydrogen bonds help to stabilize the crystal structure. The title compound was evaluated for the anti-ischemic activity in vitro and in vivo. The bioassay results indicated that the title compound displayed efficient activities against glutamine-induced neurotoxicity in PC12 cells and significantly prolonged the survival time of mice subjected to acute cerebral ischemia.
A new cinnamide derivative, (E)-1-(4-(bis(4-methoxyphenyl)methyl)piperazin- 1-yl)-3-(4-acetoxy-3-methoxyphenyl)prop-2-en-1-one (C31H34N2O6, Mr=530.60), has been synthesized by the condensation of 1-(bis(4-methoxyphenyl)methyl)piperazine and (E)-3-(4- acetoxy-3-methoxyphenyl)acrylic acid. The compound was characterized by 1H NMR, 13C NMR, H RMS and single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system, space group P212121 with a=24.946(5), b=7.6380(15), c=14.555(3) Å, V=2773.3(10) Å3, Z=4, Dc=1.271 g/cm3, F(000)=1128, μ=0.088 mm-1, MoKα radiation (λ=0.71073 Å), the final R=0.0641 and wR=0.1170. A total of 3009 unique reflections were collected, of which 1760 with I>2σ(I) were observed. Intramolecular C(17)-H(17B)···O(3) and C(22)-H(22A)···O(3) interactions as well as intermolecular C(27)-H(27A)···O(3) hydrogen bonds help to stabilize the crystal structure. The title compound was evaluated for the anti-ischemic activity in vitro and in vivo. The bioassay results indicated that the title compound displayed efficient activities against glutamine-induced neurotoxicity in PC12 cells and significantly prolonged the survival time of mice subjected to acute cerebral ischemia.
2015, 34(5): 688-694
doi: 10.14102/j.cnki.0254-5861.2011-0615
Abstract:
The title compound N-((3-(2-nitrophenyl) propanoyl)oxy)-N-phenylbenzamide (C22H18N2O5, Mr=390.38) was synthesized with nitrobenzene as the starting materials and structurally characterized by 1H NMR, 13C NMR, IR, H RMS(E-SI) and single-crystal X-ray diffraction. The crystalline structure of the title compound was studied in detail. The single-crystal X-ray diffraction revealed that the compound crystallizes in monoclinic, space group P21/n, with a=14.4481(7), b=8.0089(5), c=16.6808(9) Å, α=90.00(5), β=100.069(5), γ=90.00(5)°, Mr=390.38, V=1900.46(18) Å3, Z=4, Dc=1.364 g/cm-3, μ=0.098, F(000)=816.0, the final R=0.0530 and wR=0.1141 for 2525 observed reflections (I>2σ(I)), R(all data)=0.0813, wR(all data)=0.1335, completeness to theta of 26.020 is 99.8% and GOF=1.085. The crystal structure contains three branched chains with its center placed at the midpoint of N. The phenyl ring (C(8)~C(13)) makes a dihedral angle of 83.5(1)℃ with the phenyl ring (C(1)~C(6)), and 80.5(1)℃ with the nitro-substituted benzene ring (C(17)~C(22)), indicating that the three rings are not coplanar. Hydrogen bonds (C(10)-H(10)···O(3)), (C(15)-H(15B)···O(4) and C(16)-H(16B)···O(4)) together with π-π stacking interactions stabilize the structure of the molecule. The preliminary biological test shows that the title compound has good antitumor activity against A549 in vitro with the IC50 value of 3.17 μmol.
The title compound N-((3-(2-nitrophenyl) propanoyl)oxy)-N-phenylbenzamide (C22H18N2O5, Mr=390.38) was synthesized with nitrobenzene as the starting materials and structurally characterized by 1H NMR, 13C NMR, IR, H RMS(E-SI) and single-crystal X-ray diffraction. The crystalline structure of the title compound was studied in detail. The single-crystal X-ray diffraction revealed that the compound crystallizes in monoclinic, space group P21/n, with a=14.4481(7), b=8.0089(5), c=16.6808(9) Å, α=90.00(5), β=100.069(5), γ=90.00(5)°, Mr=390.38, V=1900.46(18) Å3, Z=4, Dc=1.364 g/cm-3, μ=0.098, F(000)=816.0, the final R=0.0530 and wR=0.1141 for 2525 observed reflections (I>2σ(I)), R(all data)=0.0813, wR(all data)=0.1335, completeness to theta of 26.020 is 99.8% and GOF=1.085. The crystal structure contains three branched chains with its center placed at the midpoint of N. The phenyl ring (C(8)~C(13)) makes a dihedral angle of 83.5(1)℃ with the phenyl ring (C(1)~C(6)), and 80.5(1)℃ with the nitro-substituted benzene ring (C(17)~C(22)), indicating that the three rings are not coplanar. Hydrogen bonds (C(10)-H(10)···O(3)), (C(15)-H(15B)···O(4) and C(16)-H(16B)···O(4)) together with π-π stacking interactions stabilize the structure of the molecule. The preliminary biological test shows that the title compound has good antitumor activity against A549 in vitro with the IC50 value of 3.17 μmol.
2015, 34(5): 695-702
doi: 10.14102/j.cnki.0254-5861.2011-0577
Abstract:
Two thiouronium iodide salts, (E)-2-methyl-1,3-diphenylisothiouronium iodide (1) and 1,3-dibenzyl-2-methylisothiouronium iodide (2), were synthesized and characterized by single-crystal X-ray diffraction, 1H NMR, IR, UV-vis and luminescence spectra. Single-crystal X-ray diffraction reveals that compound 1 crystallizes in monoclinic system, P21/n space group with a=11.273(2), b=10.318(2), c=12.962(3) Å, β=99.03(3)°, V=1489.0(5) Å3 and Z=4; compound 2 crystallizes in monoclinic system, C2/c space group with a=11.706(2), b=14.119(3), c=20.930(4) Å, β=103.84(3)°, V=3358.8(12) Å3 and Z=8. The thiouroniums of both compounds are Y-shaped planar structures to form a cross-conjugated system. The averaged bond lengths of C-N and C-S indicate the presence of "Y" aromaticity. The researches on UV-vis and luminescence spectra of compounds 1 and 2 indicate that they can form inclusion complex with β-CD in the aqueous solution.
Two thiouronium iodide salts, (E)-2-methyl-1,3-diphenylisothiouronium iodide (1) and 1,3-dibenzyl-2-methylisothiouronium iodide (2), were synthesized and characterized by single-crystal X-ray diffraction, 1H NMR, IR, UV-vis and luminescence spectra. Single-crystal X-ray diffraction reveals that compound 1 crystallizes in monoclinic system, P21/n space group with a=11.273(2), b=10.318(2), c=12.962(3) Å, β=99.03(3)°, V=1489.0(5) Å3 and Z=4; compound 2 crystallizes in monoclinic system, C2/c space group with a=11.706(2), b=14.119(3), c=20.930(4) Å, β=103.84(3)°, V=3358.8(12) Å3 and Z=8. The thiouroniums of both compounds are Y-shaped planar structures to form a cross-conjugated system. The averaged bond lengths of C-N and C-S indicate the presence of "Y" aromaticity. The researches on UV-vis and luminescence spectra of compounds 1 and 2 indicate that they can form inclusion complex with β-CD in the aqueous solution.
2015, 34(5): 703-709
doi: 10.14102/j.cnki.0254-5861.2011-0578
Abstract:
A new 2-naphthate (NA-)-based coordination complex, [Cu3(µ3-OH)4(NA)2]n (1), was hydrothermally prepared and structurally and magnetically characterized. 1 crystallizes in the monoclinic P21/c space group with a=19.990(7), b=5.616(2), c=9.179(3) Å, β=96.536(6)°, V=1023.8(7) Å3, Dc=1.950 g/cm3, Mr=300.49, Z=4, F(000)=602, μ=3.138 mm-1, the final R=0.0317 and wR=0.0818 for 4944 observed reflections with I>2σ(I). Complex 1 exhibits an extended corner-sharing {Cu3(µ3-OH)}5+ triangle-based layered structure with the NA- ligands located on both sides. The interplay of the typical anti- and ferromagnetic interactions mediated by µ3-OH- and µ-syn, syn-carboxylate heterobridges leads to the overall intralayer ferromagnetic couplings of 1.
A new 2-naphthate (NA-)-based coordination complex, [Cu3(µ3-OH)4(NA)2]n (1), was hydrothermally prepared and structurally and magnetically characterized. 1 crystallizes in the monoclinic P21/c space group with a=19.990(7), b=5.616(2), c=9.179(3) Å, β=96.536(6)°, V=1023.8(7) Å3, Dc=1.950 g/cm3, Mr=300.49, Z=4, F(000)=602, μ=3.138 mm-1, the final R=0.0317 and wR=0.0818 for 4944 observed reflections with I>2σ(I). Complex 1 exhibits an extended corner-sharing {Cu3(µ3-OH)}5+ triangle-based layered structure with the NA- ligands located on both sides. The interplay of the typical anti- and ferromagnetic interactions mediated by µ3-OH- and µ-syn, syn-carboxylate heterobridges leads to the overall intralayer ferromagnetic couplings of 1.
2015, 34(5): 710-718
doi: 10.14102/j.cnki.0254-5861.2011-0557
Abstract:
A new metal-organic coordination polymer [Ni(oba)(mbix)(H2O)]n·nH2O (H2oba=4,4'-oxydibenzoic acid, mbix=1,3-bis(imidazol-1-ylmethyl)-benzene) 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR, TG, UV and single-crystal X-ray diffraction. Green crystals crystallize in the triclinic system, space group P1 with a=10.1915(18), b=11.415(2), c=12.314(2)Å, α=74.263(3), β=84.545(2), γ=74.369(3)°, V=1327.6(4) Å, C28H26N4NiO7, Mr=589.24, Dc=1.474 g/cm3, F(000)=612, Z=2, μ(MoKα)=0.786 mm-1, the final R=0.0332 and wR=0.0869 for 4622 observed reflections (I>2σ(I)). The structure of 1 exhibits a one-dimensional chain-like structure. In addition, natural bond orbital (NBO) analysis was performed by the PBE0/LANL2DZ method in Gaussian 03 Program. The calculation results show obvious covalent interaction between the coordinated atoms and Ni(II) ion.
A new metal-organic coordination polymer [Ni(oba)(mbix)(H2O)]n·nH2O (H2oba=4,4'-oxydibenzoic acid, mbix=1,3-bis(imidazol-1-ylmethyl)-benzene) 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR, TG, UV and single-crystal X-ray diffraction. Green crystals crystallize in the triclinic system, space group P1 with a=10.1915(18), b=11.415(2), c=12.314(2)Å, α=74.263(3), β=84.545(2), γ=74.369(3)°, V=1327.6(4) Å, C28H26N4NiO7, Mr=589.24, Dc=1.474 g/cm3, F(000)=612, Z=2, μ(MoKα)=0.786 mm-1, the final R=0.0332 and wR=0.0869 for 4622 observed reflections (I>2σ(I)). The structure of 1 exhibits a one-dimensional chain-like structure. In addition, natural bond orbital (NBO) analysis was performed by the PBE0/LANL2DZ method in Gaussian 03 Program. The calculation results show obvious covalent interaction between the coordinated atoms and Ni(II) ion.
2015, 34(5): 719-724
doi: 10.14102/j.cnki.0254-5861.2011-0544
Abstract:
In this work, a new two-dimensional Cd(II) coordination polymer, [Cd3(L)2(cis-1,4- chdc)2(trans-1,4-chdc)] (1, L=11-fluoro-dipyrido[3,2-a:2',3'-c]phenazine and 1,4-H2chdc=1,4- cyclohexanedicarboxylatic acid), has been prepared under hydrothermal conditions. It crystallizes in triclinic, space group P1 with a=8.6951(8), b=10.8362(9), c=14.9445(13) Å, α=76.443(2), β=81.8670(10), γ=82.0640(10)°, V=1347.0(2) Å3, Z=1, C60H48Cd3F2N8O12, Mr=1448.26, Dc=1.785 g/cm3, F(000)=722, μ(MoKa)=1.255 mm-1, R=0.0333 and wR=0.0790. The 1,4-chdc2- carboxylates bridge the Cd(II) cations to form a tri-nuclear Cd(II) cluster, which are held together by the cis-1,4-chdc2- ligands to generate a double-stranded chain. Further, the trans-1,4-chdc2- ligands bridge adjacent double-stranded chains to yield an interesting two-dimensional network. The π-π interactions among L ligands of neighboring networks result in an interesting three-dimensional supramolecular architecture. In addition, the thermal behavior and luminescent property of 1 have been studied.
In this work, a new two-dimensional Cd(II) coordination polymer, [Cd3(L)2(cis-1,4- chdc)2(trans-1,4-chdc)] (1, L=11-fluoro-dipyrido[3,2-a:2',3'-c]phenazine and 1,4-H2chdc=1,4- cyclohexanedicarboxylatic acid), has been prepared under hydrothermal conditions. It crystallizes in triclinic, space group P1 with a=8.6951(8), b=10.8362(9), c=14.9445(13) Å, α=76.443(2), β=81.8670(10), γ=82.0640(10)°, V=1347.0(2) Å3, Z=1, C60H48Cd3F2N8O12, Mr=1448.26, Dc=1.785 g/cm3, F(000)=722, μ(MoKa)=1.255 mm-1, R=0.0333 and wR=0.0790. The 1,4-chdc2- carboxylates bridge the Cd(II) cations to form a tri-nuclear Cd(II) cluster, which are held together by the cis-1,4-chdc2- ligands to generate a double-stranded chain. Further, the trans-1,4-chdc2- ligands bridge adjacent double-stranded chains to yield an interesting two-dimensional network. The π-π interactions among L ligands of neighboring networks result in an interesting three-dimensional supramolecular architecture. In addition, the thermal behavior and luminescent property of 1 have been studied.
2015, 34(5): 725-728
doi: 10.14102/j.cnki.0254-5861.2011-0545
Abstract:
A new Zn(II) complex, [Zn(1,2,3-HBTC)(L)]2 (1, L=2-(2-chloro-6-fluorophenyl)- 1H-imidazo[4,5-f][1,10]phenanthroline and 1,2,3-H3BTC=1,2,3-benzentricarboxylic acid), was synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. It crystallizes in triclinic, space group P1 with a=10.455(2), b=11.533(2), c=12.499(3) Å, α=116.97(3), β=94.08(3), γ=103.29(3)°, V=1280.2(4) Å3, Z=1, C56H28Cl2F2N8O12Zn2, Mr=1244.50, Dc=1.614 g/cm3, F(000)=628, μ(MoKa)=1.124 mm-1, R=0.0502 and wR=0.1417. In compound 1, two 1,2,3-HBTC anions bridge two Zn(II) atoms to give a dimeric structure with Zn···Zn distance of 3.15 Å. Adjacent dimers interact through π-π stackings between two L ligands to result in a supramolecular layer. Moreover, N-H···O and O-H···N hydrogen bonds further stabilize the 2D supramolecular architecture of 1. In addition, the luminescent property of 1 has been studied.
A new Zn(II) complex, [Zn(1,2,3-HBTC)(L)]2 (1, L=2-(2-chloro-6-fluorophenyl)- 1H-imidazo[4,5-f][1,10]phenanthroline and 1,2,3-H3BTC=1,2,3-benzentricarboxylic acid), was synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. It crystallizes in triclinic, space group P1 with a=10.455(2), b=11.533(2), c=12.499(3) Å, α=116.97(3), β=94.08(3), γ=103.29(3)°, V=1280.2(4) Å3, Z=1, C56H28Cl2F2N8O12Zn2, Mr=1244.50, Dc=1.614 g/cm3, F(000)=628, μ(MoKa)=1.124 mm-1, R=0.0502 and wR=0.1417. In compound 1, two 1,2,3-HBTC anions bridge two Zn(II) atoms to give a dimeric structure with Zn···Zn distance of 3.15 Å. Adjacent dimers interact through π-π stackings between two L ligands to result in a supramolecular layer. Moreover, N-H···O and O-H···N hydrogen bonds further stabilize the 2D supramolecular architecture of 1. In addition, the luminescent property of 1 has been studied.
2015, 34(5): 729-734
doi: 10.14102/j.cnki.0254-5861.2011-0421
Abstract:
The boroxine-linked organic aluminum compound LAl[OB(3-C4H3O)]2(μ-O) was accomplished by reacting LAlH2 {L=(Z)-4-[(2,6-diisopropylphenyl)amino]pent-3-en-2-ylidene-2,6-diisopropylaniline} with furan-3-ylboronic acid in good yield. The title compound belongs to the orthorhombic system, space group Pnma with a=10.9774(15), b=19.369(3), c=17.362(3) Å, V=3691.5(9) Å3, C37H47AlB2N2O5, Mr=648.37, Z=4, Dc=1.167 Mg/m3, μ(MoKα)=0.097 mm-1, F(000)=1384, S=1.000, the final R=0.0589 and wR=0.1445 for 9138 observed reflections (I>2σ(I)) and R=0.0683 and wR=0.1517 for all data. This compound is an unique example of a spiro-centered aluminum atom, showing the inorganic AlO3B2 ring fused to the organic C3N2 part. It was characterized by 1H NMR, IR, elemental analysis, and single-crystal X-ray structural analysis. Furthermore, the compound was studied by TG analysis as well as DSC.
The boroxine-linked organic aluminum compound LAl[OB(3-C4H3O)]2(μ-O) was accomplished by reacting LAlH2 {L=(Z)-4-[(2,6-diisopropylphenyl)amino]pent-3-en-2-ylidene-2,6-diisopropylaniline} with furan-3-ylboronic acid in good yield. The title compound belongs to the orthorhombic system, space group Pnma with a=10.9774(15), b=19.369(3), c=17.362(3) Å, V=3691.5(9) Å3, C37H47AlB2N2O5, Mr=648.37, Z=4, Dc=1.167 Mg/m3, μ(MoKα)=0.097 mm-1, F(000)=1384, S=1.000, the final R=0.0589 and wR=0.1445 for 9138 observed reflections (I>2σ(I)) and R=0.0683 and wR=0.1517 for all data. This compound is an unique example of a spiro-centered aluminum atom, showing the inorganic AlO3B2 ring fused to the organic C3N2 part. It was characterized by 1H NMR, IR, elemental analysis, and single-crystal X-ray structural analysis. Furthermore, the compound was studied by TG analysis as well as DSC.
2015, 34(5): 735-740
doi: 10.14102/j.cnki.0254-5861.2011-0600
Abstract:
A new 3D complex, [Co(L)(bpe)0.5(H2O)2]n (1, H2L=5-iodo-benzene-1,3-dioxya cetic acid, bpe=1,2-bis(4-pyridyl)ethylene), has been hydrothermally synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. It is formulated as C16H16CoINO8, crystallizes in monoclinic, space group P21/c, with a=9.806(2), b=6.5492(13), c=28.187(8) Å, β=100.12(3)°, V=1782.0(7) Å3, Z=4, Dc=1.998 g/m3, F(000)=1052, Μr=536.13, the final R=0.0393 and wR=0.0858 for 3134 observed reflections with I>2σ(I). Complex 1 displays a 3D framework with multiform helical features, left- and right-handed triple helical braids and single helical chains, which can be simplified as a new type of (3,4)-connected lattice with a (6·102)(62·104) Schläfli symbol. Moreover, the thermal analysis of complex 1 has also been investigated.
A new 3D complex, [Co(L)(bpe)0.5(H2O)2]n (1, H2L=5-iodo-benzene-1,3-dioxya cetic acid, bpe=1,2-bis(4-pyridyl)ethylene), has been hydrothermally synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. It is formulated as C16H16CoINO8, crystallizes in monoclinic, space group P21/c, with a=9.806(2), b=6.5492(13), c=28.187(8) Å, β=100.12(3)°, V=1782.0(7) Å3, Z=4, Dc=1.998 g/m3, F(000)=1052, Μr=536.13, the final R=0.0393 and wR=0.0858 for 3134 observed reflections with I>2σ(I). Complex 1 displays a 3D framework with multiform helical features, left- and right-handed triple helical braids and single helical chains, which can be simplified as a new type of (3,4)-connected lattice with a (6·102)(62·104) Schläfli symbol. Moreover, the thermal analysis of complex 1 has also been investigated.
2015, 34(5): 741-748
doi: 10.14102/j.cnki.0254-5861.2011-0608
Abstract:
The ligand ethylenediamine-3,5-dichloro salicylaldehyde (HS) and its crystal Co(II) complex (MS) were yielded. The compounds have been characterized on the basis of elemental analysis, IR and 1H NMR spectral studies. X-ray single-crystal diffraction of crystal MS1 showed a classical Salen-N2O2 tetrahedral coordination model, space group P1 with a=25.73(2), b=9.899(9), c=6.753(6) Å, β=103.467(10)°, V=1673(3) Å3, Z=4, C16H10Cl4CoN2O2, Mr=462.99, Dc=1.838 g/cm3, F(000)=924, µ(MoKα)=1.678 mm-1 (λ=0.71073 Å), R=0.0275 and wR=0.0567 for 1247 observed reflections with I>2σ(I). Furthermore, luminescent properties were evaluated by UV-Visible absorption and FL spectra. Meanwhile, the thermal stability of compound HS was investigated. TG-DTG showed that the decomposition temperature (Td) of the molecules is up to 256℃ and the compound has fine performance in thermal stability. The results also indicated that the target compound HS exhibited certain chemiluminescence properties under the conditions of different time of 365 nm UV light and different temperature. In general, this kind of multi-functional compounds has potential applications in the fields of information storage and nonlinear optical materials.
The ligand ethylenediamine-3,5-dichloro salicylaldehyde (HS) and its crystal Co(II) complex (MS) were yielded. The compounds have been characterized on the basis of elemental analysis, IR and 1H NMR spectral studies. X-ray single-crystal diffraction of crystal MS1 showed a classical Salen-N2O2 tetrahedral coordination model, space group P1 with a=25.73(2), b=9.899(9), c=6.753(6) Å, β=103.467(10)°, V=1673(3) Å3, Z=4, C16H10Cl4CoN2O2, Mr=462.99, Dc=1.838 g/cm3, F(000)=924, µ(MoKα)=1.678 mm-1 (λ=0.71073 Å), R=0.0275 and wR=0.0567 for 1247 observed reflections with I>2σ(I). Furthermore, luminescent properties were evaluated by UV-Visible absorption and FL spectra. Meanwhile, the thermal stability of compound HS was investigated. TG-DTG showed that the decomposition temperature (Td) of the molecules is up to 256℃ and the compound has fine performance in thermal stability. The results also indicated that the target compound HS exhibited certain chemiluminescence properties under the conditions of different time of 365 nm UV light and different temperature. In general, this kind of multi-functional compounds has potential applications in the fields of information storage and nonlinear optical materials.
2015, 34(5): 749-756
doi: 10.14102/j.cnki.0254-5861.2011-0585
Abstract:
Two complexes with formulas [NiL][(NiL)(IPA)2]·8H2O (1) and [(NiL)(H2O)2] [(NiL)(PMA)]·4H2O (2) (L=5,5,7,12,12,14-hexamethyl-1,4,8,11- tetraazacyclotetradecane, IPA2-=isophthalic anion, PMA4-=1,2,4,5-benzenetetracarboxylic anion) were synthesized and characterized by elemental analyses and IR spectra. The crystal structures were determined by X-ray diffraction. In complex 1, the [NiL]2+ bridged IPA2- to give [(NiL)(IPA)2]2- monomer, and the [NiL]2+ bridged PMA4- to form a one-dimensional chain [(NiL)(PMA)]n2n- in complex 2. The [NiL]2+ and [(NiL)(IPA)2]2-/[(NiL)(PMA)]2- are connected through intermolecular hydrogen bonding to generate three-dimensional supramolecular structures.
Two complexes with formulas [NiL][(NiL)(IPA)2]·8H2O (1) and [(NiL)(H2O)2] [(NiL)(PMA)]·4H2O (2) (L=5,5,7,12,12,14-hexamethyl-1,4,8,11- tetraazacyclotetradecane, IPA2-=isophthalic anion, PMA4-=1,2,4,5-benzenetetracarboxylic anion) were synthesized and characterized by elemental analyses and IR spectra. The crystal structures were determined by X-ray diffraction. In complex 1, the [NiL]2+ bridged IPA2- to give [(NiL)(IPA)2]2- monomer, and the [NiL]2+ bridged PMA4- to form a one-dimensional chain [(NiL)(PMA)]n2n- in complex 2. The [NiL]2+ and [(NiL)(IPA)2]2-/[(NiL)(PMA)]2- are connected through intermolecular hydrogen bonding to generate three-dimensional supramolecular structures.
2015, 34(5): 757-763
doi: 10.14102/j.cnki.0254-5861.2011-0599
Abstract:
Two luminescent hetero-trinuclear complexes [Pt2Cu(μ-dpppy)2(C≡CC6H4R-4)4](ClO4) (R=H, 1; R=CH3, 2; dpppy=2,6-bis(diphenylphosphino)pyridine) have been synthesized and characterized by elemental analyses, ESI-MS, 1H and 31P{1H} NMR spectroscopy, and X-ray crystallography for 2. Their photophysical properties in the solid state and in solutions at room temperature and in frozen glasses at 77 K were studied. Both complexes 1 and 2 show strong orange-red emission in the solid state at room temperature and in frozen glasses at 77 K, and weak emission in solutions.
Two luminescent hetero-trinuclear complexes [Pt2Cu(μ-dpppy)2(C≡CC6H4R-4)4](ClO4) (R=H, 1; R=CH3, 2; dpppy=2,6-bis(diphenylphosphino)pyridine) have been synthesized and characterized by elemental analyses, ESI-MS, 1H and 31P{1H} NMR spectroscopy, and X-ray crystallography for 2. Their photophysical properties in the solid state and in solutions at room temperature and in frozen glasses at 77 K were studied. Both complexes 1 and 2 show strong orange-red emission in the solid state at room temperature and in frozen glasses at 77 K, and weak emission in solutions.
2015, 34(5): 764-770
doi: 10.14102/j.cnki.0254-5861.2011-0517
Abstract:
The crystal structure of the metal-organic frame Ca(C5H9O5)2·CH3OH·2H2O (1) has been synthesized and characterized. Complex 1 belongs to a tetragonal P43212 space group. In complex 1, the sugar moiety shows a beta-L configuration of pyranose form. The calcium(II) is eight-coordinated, binding to four such sugar moieties, via O(1), O(2) of two molecules and O(3), O(4) of the other two, with the 4-hydroxy group being deprotonated. The water and methanol molecules are not coordinated to the calcium ion.
The crystal structure of the metal-organic frame Ca(C5H9O5)2·CH3OH·2H2O (1) has been synthesized and characterized. Complex 1 belongs to a tetragonal P43212 space group. In complex 1, the sugar moiety shows a beta-L configuration of pyranose form. The calcium(II) is eight-coordinated, binding to four such sugar moieties, via O(1), O(2) of two molecules and O(3), O(4) of the other two, with the 4-hydroxy group being deprotonated. The water and methanol molecules are not coordinated to the calcium ion.
2015, 34(5): 771-776
doi: 10.14102/j.cnki.0254-5861.2011-0606
Abstract:
A new 3d-4f polymer formulated as {[SmCo2(μ2-Hmimda)3(μ2-H2mimda)·4H2O]·3H2O}n (H3mimda=1-H-2-methyl-4,5-imidazole-dicarboxylic acid) has been hydrothermally synthesized and structurally characterized by elemental analysis, X-ray single-crystal diffraction and magnetic susceptibility measurement. It crystallizes in monoclinic system, space group C2/c, with a=17.251(6), b=16.965(6), c=14.668(5) Å, β=118.565(5)°, Z=4, V=3770(2) Å3, F(000)=1984, the final R=0.0597 and wR=0.1820. In the crystal, the dicarboxylate ligand links the Sm(III) and Co(II) ions to give rise to a heterometallic [SmCo2(μ2-Hmimda)3(μ2-H2mimda)] aggregate which acts as the second building unit. Then, the SBUs further extended a 2D corrugated layer with a (4, 4) topology. The title complex displays strong photoluminescence in the solid state.
A new 3d-4f polymer formulated as {[SmCo2(μ2-Hmimda)3(μ2-H2mimda)·4H2O]·3H2O}n (H3mimda=1-H-2-methyl-4,5-imidazole-dicarboxylic acid) has been hydrothermally synthesized and structurally characterized by elemental analysis, X-ray single-crystal diffraction and magnetic susceptibility measurement. It crystallizes in monoclinic system, space group C2/c, with a=17.251(6), b=16.965(6), c=14.668(5) Å, β=118.565(5)°, Z=4, V=3770(2) Å3, F(000)=1984, the final R=0.0597 and wR=0.1820. In the crystal, the dicarboxylate ligand links the Sm(III) and Co(II) ions to give rise to a heterometallic [SmCo2(μ2-Hmimda)3(μ2-H2mimda)] aggregate which acts as the second building unit. Then, the SBUs further extended a 2D corrugated layer with a (4, 4) topology. The title complex displays strong photoluminescence in the solid state.
2015, 34(5): 777-785
doi: 10.14102/j.cnki.0254-5861.2011-0259
Abstract:
A new three-dimensional nickel (II) hydrogen-bonded molecular self assembly containing [(Ni(nicotinamide)2(thiocyanate)2(H2O)2] complex has been synthesized and characterized by single-crystal X-ray diffraction, FTIR spectroscopy, thermal analysis and magnetic measurements. Structural analysis reveals that the complex crystallizes in triclinic space group P1 (crystal data a=7.5574, b=8.2683, c=9.0056 Å, α=73.010, β=69.698, γ=66.51°) and exhibits a distorted octahedral coordination sphere. Most interesting point in its structure is the involvement of sulphur atom of thiocyanate moiety in the trifurcated hydrogen bonding to build up the hydrogen-bonded self assembly. The magnetic behavior as determined by squid magnetometer (2~300 K temp. range) reveals dominating antiferromagnetic interaction followed by spin canting behavior below 20 K.
A new three-dimensional nickel (II) hydrogen-bonded molecular self assembly containing [(Ni(nicotinamide)2(thiocyanate)2(H2O)2] complex has been synthesized and characterized by single-crystal X-ray diffraction, FTIR spectroscopy, thermal analysis and magnetic measurements. Structural analysis reveals that the complex crystallizes in triclinic space group P1 (crystal data a=7.5574, b=8.2683, c=9.0056 Å, α=73.010, β=69.698, γ=66.51°) and exhibits a distorted octahedral coordination sphere. Most interesting point in its structure is the involvement of sulphur atom of thiocyanate moiety in the trifurcated hydrogen bonding to build up the hydrogen-bonded self assembly. The magnetic behavior as determined by squid magnetometer (2~300 K temp. range) reveals dominating antiferromagnetic interaction followed by spin canting behavior below 20 K.
2015, 34(5): 786-793
doi: 10.14102/j.cnki.0254-5861.2011-0576
Abstract:
A new inorganic-organic hybrid cadmium(II) complex [Cd2(H1/2C4BIm)2(CH3COO)]n has been prepared by a hydrothermal reaction, and characterized by fluorescence, IR, TGA, and single-crystal X-ray diffraction analysis. In its crystal structure, there are two kinds of coordinating forms for those Cd(II) ions. One is that the Cd(II) ion is coordinated by one carboxylate oxygen atom from one acetate oxygen ligand and three benzimidazole nitrogen atoms from three 2,2'-(1,4-butanediyl)bis (1H-benzimidazole) (H2C4BIm) ligands, and the other is that the Cd(II) ion is coordinated by four benzimidazole nitrogen atoms from four H2C4BIm ligands to furnish two distorted tetrahedral coordination geometries. It exhibits a beautiful structure for a 2D layer and a 3D network, with its four-connecting nodes provided by the H2C4BIm ligands. Furthermore, this complex shows intense luminescent property at room temperature. In [Cd2(H2C2BIm)2(C9H6O4)2]n, the H2C2BIm ligand lost the role as a bridging ligand because of the shorter alkyl chain compared with that of H2C4BIm ligand.
A new inorganic-organic hybrid cadmium(II) complex [Cd2(H1/2C4BIm)2(CH3COO)]n has been prepared by a hydrothermal reaction, and characterized by fluorescence, IR, TGA, and single-crystal X-ray diffraction analysis. In its crystal structure, there are two kinds of coordinating forms for those Cd(II) ions. One is that the Cd(II) ion is coordinated by one carboxylate oxygen atom from one acetate oxygen ligand and three benzimidazole nitrogen atoms from three 2,2'-(1,4-butanediyl)bis (1H-benzimidazole) (H2C4BIm) ligands, and the other is that the Cd(II) ion is coordinated by four benzimidazole nitrogen atoms from four H2C4BIm ligands to furnish two distorted tetrahedral coordination geometries. It exhibits a beautiful structure for a 2D layer and a 3D network, with its four-connecting nodes provided by the H2C4BIm ligands. Furthermore, this complex shows intense luminescent property at room temperature. In [Cd2(H2C2BIm)2(C9H6O4)2]n, the H2C2BIm ligand lost the role as a bridging ligand because of the shorter alkyl chain compared with that of H2C4BIm ligand.
2015, 34(5): 794-798
doi: 10.14102/j.cnki.0254-5861.2011-0780
Abstract:
A new copper(II) complex [Cu2(MNA)2(2,2'-bipy)2]·2.5H2O with methy-5-norbornene-2,3- dicarboxylic acid (MNA) and 2,2'-bipyridine as ligands has been synthesized in the mixed solvents of DMF and water. It crystallizes in monoclinic, space group P1, with a=10.4191(11), b=12.8883(13), c=16.1114(16) Å, α=70.8090(10), β=80.568(2), γ=77.440(2)°, V=1984.3(4) Å3, Dc=1.551 g/cm3, Z=2, F(000)=962, the final GOOF(000)=1.051, R=0.0431 and wR=0.0980. The crystal structure shows that the whole molecule consists of two independent dinuclear units, in which two copper ions are bridged by two μ2-η1:η0 3-carboxylate groups of MNA2-. The coordination environment of Cu(II) ion is CuO3N2, giving a distorted square pyramidal geometry. The spectroscopic characterization, thermal stability and magnetic properties of the complex were investigated.
A new copper(II) complex [Cu2(MNA)2(2,2'-bipy)2]·2.5H2O with methy-5-norbornene-2,3- dicarboxylic acid (MNA) and 2,2'-bipyridine as ligands has been synthesized in the mixed solvents of DMF and water. It crystallizes in monoclinic, space group P1, with a=10.4191(11), b=12.8883(13), c=16.1114(16) Å, α=70.8090(10), β=80.568(2), γ=77.440(2)°, V=1984.3(4) Å3, Dc=1.551 g/cm3, Z=2, F(000)=962, the final GOOF(000)=1.051, R=0.0431 and wR=0.0980. The crystal structure shows that the whole molecule consists of two independent dinuclear units, in which two copper ions are bridged by two μ2-η1:η0 3-carboxylate groups of MNA2-. The coordination environment of Cu(II) ion is CuO3N2, giving a distorted square pyramidal geometry. The spectroscopic characterization, thermal stability and magnetic properties of the complex were investigated.
2015, 34(5): 799-806
doi: 10.14102/j.cnki.0254-5861.2011-0580
Abstract:
First-principles calculations based on density functional theory are performed to investigate the structural, electronic and optical properties of monoclinic α-CoV2O6. Firstly, the geometry structures obtained by geometry optimization are consistent with the experimental values. Then, the energy band structure is studied using both GGA and GGA+U methods. It is found that the on-site Coulomb repulsion of the Co 3d orbital plays a key role in describing the electronic properties of α-CoV2O6, and is necessary to open the energy band gap. According to the partial density of states (PDOS), significant Co-O and V-O hybridizations are observed in the valence and conduction bands, respectively. Furthermore, the Co-O and V-O bonds are found to have significant covalent characters. Below the absorption threshold ~1.9 eV, no absorption can be detected. However, there exists a strong and wide absorption band in the energy range from 1.9 to 11 eV. Such novel optical properties imply that the α-CoV2O6 may have some potential optical applications.
First-principles calculations based on density functional theory are performed to investigate the structural, electronic and optical properties of monoclinic α-CoV2O6. Firstly, the geometry structures obtained by geometry optimization are consistent with the experimental values. Then, the energy band structure is studied using both GGA and GGA+U methods. It is found that the on-site Coulomb repulsion of the Co 3d orbital plays a key role in describing the electronic properties of α-CoV2O6, and is necessary to open the energy band gap. According to the partial density of states (PDOS), significant Co-O and V-O hybridizations are observed in the valence and conduction bands, respectively. Furthermore, the Co-O and V-O bonds are found to have significant covalent characters. Below the absorption threshold ~1.9 eV, no absorption can be detected. However, there exists a strong and wide absorption band in the energy range from 1.9 to 11 eV. Such novel optical properties imply that the α-CoV2O6 may have some potential optical applications.
