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• Spontaneous and precise assembly of compounds into giant, well-defined, functional superstructures are attractive for their novel structures^[1-4] and promising applications in molecular recognition, catalysis, guest inclusion, luminescence, anion complexation and so on^[5-9]. Over the last decade, numerous novel metal-organic molecules have been constructed by metal-directed self-assembly^[10-14]. The Fujita group has estab-lished a series of complexes that can be self-assembled by simply mixing ligands and bare square-planar Pd(Ⅱ) ions^[15-16]. And in our previous research, we have reported an array of well-defined metallic supramolecular structures formed by quantitatively assembling^[17-18]. More recently, transition metals with specific coordination geometries have been employed for the rational design and construction of highly ordered supramolecular structures^[19].

  Owing to the fact that the aryl-aryl structure motif is an important building block in organic chemistry, the Suzuki reaction is widely applied in academic research as well as in industrial synthesis of fine chemicals and highly complex pharmaceuticals^[20]. A representative Suzuki-Miyaura cross-coupling reac-tion is shown in Scheme 1. In the Suzuki reaction, Pd-based catalysts coordinated with organophosphorus ligands are frequently used in Suzuki-crossing reactions. Since the organophosphorus ligands are poisonous, from the environmental point of view, making the Suzuki reaction green is a continuous process pursued by organic chemists. In the past few years, considerable attention has been paid to functional metal-organic assemblies that show promise in catalysis with environment-friendly^[21]. Especially, palladium and platinum were employed in the Suzuki coupling reactions for their high stability and remarkable efficiency^[22].

  图Scheme 1 Representative Suzuki-Miyaura cross-coupling reaction Scheme1. Representative Suzuki-Miyaura cross-coupling reaction

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  In this work, we designed and synthesized three mononuclear complexes using the self-assembly appr-oach, namely [(bpy)Pd(L)]NO₃ (1·NO₃·H₂O), [(bpy)Pt(L)]NO₃ (2·NO₃·H₂O), and [(phen)Pd(L)]NO₃ (3·NO₃·H₂O), respectively. All of these three complexes have been intensively studied by NMR and ESI-MS, and X-ray single-crystal diffraction analysis have been empl-oyed for complex 1·PF₆·CH₃CN. In addition, consid-ering the structural characteristics and the palladium and platinum (Ⅱ, Ⅱ) properties, these three well-defined complexes have been developed and applied into Suzuki-coupling reactions, as expected, all of these three complexes show excellent catalysis properties.

  1   Experimental

  1.1   Materials and instruments

  All chemicals for synthesis and analysis were obtained commercially with analytical grade and used without further purification. All solvents were of reagent pure grade and were purified according to conventional methods.

  The ESI-MS were performed on a JEOL Accu-TOF mass spectrometer. ¹H and ¹³C NMR spectra were performed on a Bruker AV 400 MHz spectrometer.

  1.2   Syntheses and characterization of mononuclear complexes^[23]

  The self-assembly of mononuclear Pd complex 1·NO₃·H₂O was shown in Scheme 2. Ligand L (11.2 mg, 0.05 mmol) was treated with [(bpy)₂Pd₂(NO₃)₂](NO₃)₂ (19.3 mg, 0.025 mmol) in a mixture of water and acetone with 2:1 molar ratio. The mixture was stirred at 60 ℃ for 7 h to give 1·NO₃·H₂O. ¹H NMR of 1·NO₃·H₂O (400 MHz, DMSO-d₆, 298 K, TMS): δ 8.27 (m, J=7.9 Hz, 4H), 8.11 (t, J=7.7 Hz, 2H), 7.83 (d, J=7.5 Hz, 4H), 7.61 (m, J=7.4 Hz, 4H), 7.39 (t, J=7.8 Hz, 4H), 6.76 (s, 1H). ¹³C NMR for 1·NO₃·H₂O (400 MHz, DMSO-d₆, 298 K, TMS): δ 181.32, 155.96, 147.28, 142.56, 135.15, 133.30, 129.30, 128.48, 124.62, 96.84, 49.07. ESI-MS (CH₃CN, m/z): Calcd. for [(bpy)Pd(L)]⁺ 485.05, Found 485.01. Elemental analysis calculated for 1·NO₃·H₂O (C₂₅H₂₁N₃O₆Pd, %): C: 53.06, H: 3.74, N: 7.43. Found(%): C: 53.03, H: 3.76, N: 7.42. A ten-fold excess of KPF6 was added to the solution, the yellow precipitation were collected by centrifugation, washed with minimum amount of water and dried in vacuum to give 1·PF₆·H₂O as pale yellow solid (32.1 mg, 0.049 mmol, 97% yield). Single crystals of 1·PF₆·CH₃CN were obtained by the slow vapor diffusion of diethyl ether into their acetonitrile solutions over two weeks. The needle-shaped pale yellow crystals were collected by filtration, washed with water several times and dried in vacuum. ¹H NMR of 1·PF₆·H₂O (400 MHz, DMSO-d₆, 298 K, TMS): δ 8.38 (d, J=7.8 Hz, 2H), 8.35 (d, J=7.8 Hz, 2H), 8.19 (t, J=7.8 Hz, 2H), 7.93 (d, J=7.4 Hz, 4H), 7.70 (t, J=6.6 Hz, 2H), 7.62 (t, J=7.3 Hz, 2H), 7.43 (t, J=7.8 Hz, 4H), 6.86 (s, 1H). ¹³C NMR for 1·PF6 (400 MHz, DMSO-d₆, 298 K, TMS): δ 181.14, 155.83, 147.13, 142.48, 134.98, 133.28, 129.24, 128.41, 124.57, 96.70, 31.15. ESI-MS (CH₃CN, m/z): Calcd. for [(bpy)Pd(L)]⁺ 485.05, Found 485.03. Elemental analysis calculated for 1·PF₆·H₂O (C₂₅H₂₁F₆N₂O₃PPd, %): C: 46.28, H: 3.26, N: 4.32. Found(%): C: 46.30, H: 3.30, N: 4.29. Elemental analysis calculated for 1·PF₆·CH₃CN (C₂₇H₂₂F₆N₃O₂PPd, %): C: 48.27, H: 3.30, N: 6.25. Found(%): C: 48.25, H: 3.32, N: 6.23.

  图Scheme 2 Self-assembly of complexes 1·NO₃·H₂O, 2·NO₃·H₂O and 3·NO₃·H₂O Scheme2. Self-assembly of complexes 1·NO₃·H₂O, 2·NO₃·H₂O and 3·NO₃·H₂O

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  Ligand L (11.2 mg, 0.05 mmol) was treated with [(bpy)₂Pt₂(NO₃)₂](NO₃)₂ (23.7 mg, 0.025 mmol) in a mixture of water and acetone with 2:1 molar ratio at 60 ℃ for 7 h to give 2·NO₃·H₂O. ¹H NMR of 2·NO₃·H₂O (400 MHz, DMSO-d₆, 298 K, TMS): δ 8.64 (d, J=5.5 Hz, 2H), 8.42 (d, J=8.0, 2H), 8.24 (t, J=7.8 Hz, 2H), 8.03 (d, J=7.8 Hz, 4H), 7.73 (m, J=7.4 Hz, 4H), 7.49 (t, J=7.8 Hz, 4H), 6.94 (s, 1H). ¹³C NMR (400 MHz, DMSO-d₆, 298 K, TMS): δ 178.37, 156.39, 146.50, 141.87, 134.79, 133.25, 129.39, 128.11, 124.78, 97.32, 49.07. ESI-MS (CH₃CN, m/z): Calcd. for [[(bpy)Pt(L)]]⁺ 574.11, Found 574.07. Elemental analysis calculated for 2·NO₃·H₂O (C₂₅H₂₁N₃O₆Pt, %): C: 45.87, H: 3.23, N: 6.42. Found(%): C: 45.85, H: 3.26, N: 6.40. A ten-fold excess of KPF6 was added to the above solution, the yellow precipitation were collected by centrifuga-tion, washed with minimum amount of water and dried in vacuum to give 2·PF₆·H·H₂O as yellow solid (35.6 mg, 0.048 mmol, 95% yield). ¹H NMR confirmed the quantitative formation of 2·PF₆·H·H₂O. ¹H NMR (400 MHz, DMSO-d₆, 298 K, TMS): δ 8.63 (d, J=5 Hz, 2H), 8.41 (d, J=7.8 Hz, 2H), 8.23 (t, J=7.8 Hz, 2H), 8.02 (d, J=7.4 Hz, 4H), 7.72 (m, 4H), 7.48 (t, J=7.9 Hz, 4H), 6.93 (s, 1H). ¹³C NMR (400 MHz, DMSO-d₆, 298 K, TMS): δ 178.80, 156.66, 146.77, 142.06, 135.10, 133.29, 129.47, 128.32, 128.21, 124.87, 97.67. ESI-MS (CH₃CN, m/z): Calcd. for [(bpy)Pt(L)]⁺ 574.11, Found 574.09. Elemental analysis calculated for 2·PF₆·H·H₂O (C₂₅H₂₁F₆N₂O₃PPt, %): C: 40.71, H: 2.87, N: 3.80. Found: C: 40.69, H: 2.88, N: 3.78.

  Ligand L (11.2 mg, 0.05 mmol) was treated with [(phen)₂Pd₂(NO₃)₂](NO₃)₂ (20.5 mg, 0.025 mmol) in a mixture of water and acetone with 2:1 molar ratio at 60 ℃ for 7 h to give 3·NO₃·H₂O. ¹H NMR of 3·NO₃·H₂O: (400 MHz, DMSO-d₆, 298 K, TMS): δ 8.93 (d, J=8.2 Hz, 2H), 8.87 (d, J=5.2 Hz, 2H), 8.23 (s, 2H), 8.15 (m, J=4.7 Hz, 6H), 7.69 (t, J=7.3 Hz, 2H), 7.55 (t, J=7.6 Hz, 4H), 7.02 (s, 4H). ¹³C NMR (400 MHz, DMSO-d₆, 298 K, TMS): δ 180.27, 147.95, 145.69, 140.94, 134.31, 133.23, 130.46, 129.09, 128.33, 126.65, 49.07. ESI-MS (CH₃CN, m/z): Calcd. for [(phen)Pd(L)]⁺ 509.05, Found 509.01. Elemental analysis calculated for 3·NO₃·H₂O (C₂₇H₂₁N₃O₆Pt, %): C: 54.97, H: 3.59, N: 7.12. Found(%): C: 55.00, H: 3.56, N: 7.11. A ten-fold excess of KPF6 was added to the solution, the yellow precipitation were collected by centrifugation, washed with minimum amount of water and dried in vacuum to give pale yellow solid of 3·PF₆·H₂O. (33.2 mg, 0.049 mmol, 97% yield). ¹H NMR confirmed the quantitative formation of 3·PF₆·H₂O. ¹H NMR of 3·PF₆·H₂O: (400 MHz, DMSO-d₆, 298 K, TMS): δ 8.56 (d, J=8.1 Hz, 2H), 8.48 (d, J=4.4 Hz, 2H), 7.98 (s, 2H), 7.86 (m, 2H), 7.80 (d, J=7.4 Hz, 4H), 7.59 (t, J=7.3 Hz, 2H), 7.37 (t, J=7.8 Hz, 4H), 6.61 (s, 1H). ¹³C NMR (400 MHz, DMSO-d₆, 298 K, TMS): δ 180.46, 148.01, 145.86, 141.00, 134.46, 133.26, 130.52, 129.13, 128.36, 126.66, 96.02. ESI-MS (CH₃CN, m/z): Calcd. for [(phen)Pd(L)]⁺ 509.05, Found 509.04. Elemental anal-ysis calculated for 3·PF₆·H₂O (C₂₇H₂₁F₆N₂O₃PPd, %): C: 48.20, H: 3.15, N: 4.16. Found: C: 48.18, H: 3.15, N: 4.17.

  1.3   X-ray crystallography of complex 1·PF₆· CH₃CN

  X-ray diffraction data of the crystals of complex 1·PF₆·CH₃CN was collected at 150(2) K by using Bruker Smart Apex CCD area detector equipped with a graphite monochromated Mo Kα radiation (λ=0.071 073 nm). The structure of 1·PF₆·CH₃CN was solved by direct method and refined by employing full matrix least-square on F² by using SHELXTL (Bruker, 2000) program and expanded using Fourier techniques^[24-25]. All non-H atoms of the complex 1·PF₆·CH₃CN were refined with anisotropic thermal parameters. The hydrogen atoms were included in idealized positions with isotropic displacement parameters constrained to 1.5 times the U_equiv of their attached carbon atoms for methylene hydrogens, and 1.2 times the U_equiv of their attached carbon atoms for all others. SQUEEZE option was employed to treat the disordered counter anions. The crystallographic data of complex 1·PF₆·CH₃CN were listed in Table 1 and the selected hydrogen bond lengths and bond angles of complex 1·PF₆·CH₃CN were listed in Table S1 and S2.

  Table 1.  Crystallographic data for complex 1·PF₆·CH₃CN

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  Formula	C27H22F6N3O2PPd		F(000)	1 344
  Formula weight	671.84		Index ranges	-8 ≤ h ≤ 8, -21 ≤ k ≤ 21≤k, -23 ≤l ≤ 23
  Crystal system triclinic	Monoclinic		θ range / (°)	2.360~25.246
  Space group	P21/n		Reflection collected	12 779
  a / nm	0.711 28(6)		Observed reflection with [I > 2σ(I)]	3 521
  b/ nm	1.807 66(19)		Number of parameter	356
  c / nm	1.970 19(15)		Independent reflection	4 436 (Rint=0.060 1)
  β/(°)	94.296(5)		Goodness-of-fit on F2	1.096
  Volume / nm3	2.526 1(4)		Final R indices [I > 2σ(I)]	R1=0.041 1, wR2=0.100 6
  Z	4		R indices (all data)	R1=0.052, wR2=0.104 3
  Dc / (g·cm-3)	1.767		Largest diff. peak and hole / (e·nm-3)	1 415 and -1 274
  μ/ mm-1	0.875

  CCDC: 1566337, 1·PF₆·CH₃CN.

  2   Results and discussion

  2.1   Characterization of 1·PF₆·H₂O, 2·PF₆·H·H₂O and 3·PF₆·H₂O

  NMR were fully carried out to characterize the complexes of 1·PF₆·H₂O, 2·PF₆·H·H₂O and 3·PF₆·H₂O. Analysis by ¹H NMR spectroscopy of 1·NO₃·H₂O in DMSO-d₆ solutions clearly showed an array of well-defined resonance and suggested the self-assembly of [(bpy)₂Pd₂(NO₃)₂](NO₃)₂ and L to form a single product (Fig.S1~S2). Upon replaced by PF₆^-, a series of peaks shifted downfield as shown in Fig. 1. The results of ¹H NMR spectroscopy indicated that the formation of a 1:1 complex of 1·PF₆·H₂O. Detailed analysis of ¹H NMR spectra belonged to the complex 1·PF₆·H₂O was disc-ussed as below: for complex 1·PF₆·H₂O, the featured single peak at 6.86 corresponded to methylene-H, the triplet at 7.43 were assigned to aromatic-H2, aromatic-H2′, aromatic-H4 and aromatic-H4′, the triplet at 7.62 with integral of 2 H assigned to pyridine-H7 and pyridine-H7′, and the triplet at 7.70 with integral of 2 H assigned to pyridine-H8 and pyridine-H8′, the doublet at 7.93 with integral of 4 H assigned to aromatic -H1, aromatic-H1′, aromatic-H5 and aromatic-H5′, the triplet at 8.19 with integral of 2 H assigned to aromatic-H3 and aromatic-H3′, the downfield 4 H assigned to pyridine-H6, pyridine-H6′, pyridine-H9 and pyridine-H9′, respectively. And the results of ¹³C NMR spectroscopy as shown in Fig.S8 agreed well with the analysis results of ¹H NMR spectroscopy. These results were consistent with those of the complexes 2·NO₃·H₂O, 2·PF₆·H·H₂O, 3·NO₃·H₂O and 3·PF₆·H₂O (Fig.S3~S6 and Fig.S9~S12).

  图1 ¹H NMR spectrum of complex 1·NO₃·H₂O and 1·PF₆·H₂O in DMSO-d₆ Figure1. ¹H NMR spectrum of complex 1·NO₃·H₂O and 1·PF₆·H₂O in DMSO-d₆

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  ESI-MS studies also confirmed the structure of 1·NO₃·H₂O, 1·PF₆·H₂O, 2·NO₃·H₂O, 2·PF₆·H·H₂O, 3·NO₃·H₂O and 3·PF₆·H₂O in solution (Fig. 2, S13~S17). Isotope patterns matched those simulated and peak separations consistent with the charges. When an acetonitrile solution of 1·PF₆·H₂O was subjected to the ESI-MS, prominent peaks for [(bpy)Pd(L)]⁺ were clearly observed at 485.03, indicating the complete formation of metal-organic complexes. Additionally, the striking peak at 485.03 also confirmed the spontaneous deprotonation of 1, 3-diphenylpropane-1, 3-dione (L) in solution driven by coordination effect. Similarly, the ESI-MS study of 2·PF₆·H·H₂O and 3·PF₆·H₂O afforded a series of peaks at m/z 574.09 and 509.04 were similar to that of complex 1·PF₆·H₂O.

  图2 ESI-MS spectrum of complex 1·PF₆·H₂O in acetonitrile Figure2. ESI-MS spectrum of complex 1·PF₆·H₂O in acetonitrile

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  2.2   Crystal structure of 1·PF₆·CH₃CN

  The molecular structure of complex 1·PF₆·CH₃CN was unambiguously determined by reliable methods of X-ray diffraction analysis. As shown in Fig. 3, complex 1·PF₆·CH₃CN crystallizes in monoclinic space group P2₁/n. The crystal structure of 1·PF₆·CH₃CN displays a mononuclear palladium(Ⅱ) complex with planar conformation, and a parallel pattern is formed between planes. A dimeric crystal structure is formed by the efficient π-π stacking interactions and the metal-metal interactions, which make the complex of 1·PF₆·CH₃CN be an efficient catalyst. The central palladium(Ⅱ) is coordinated by two N atoms (the two N atoms of bpy) and two O atoms (the two O atoms of L) in a square coordination mode. The distances of Pd(1)-O(1) and Pd(1)-O(2) are 0.200 7 and 0.197 8 nm, respectively. And the distances between Pd(1) and the two N atoms are 0.201 6 and 0.198 5 nm, respectively. While the intermolecular Pd(Ⅱ)…Pd(Ⅱ) distance is about 0.322 4 nm, which indicates that the interactions exist between them, and the interaction may be suitable for the catalysis applications of the complex 1·PF₆·CH₃CN. The angles of O(1)-Pd(1)-O(2) and N(1)-Pd(1)-N(2) were 93.06° and 82.10°, respectively. The dihedral angle, defined by planes O(1)-Pd(1)-O(2) and N(1)-Pd(1)-N(2), is 5.48°. Extending a, b and c axes with PF₆^- anions and acetonitrile molecules frozen inside as shown in Fig. 3 and S18. The structure determined by X-ray crystallographic analysis agreed well with the NMR and ESI-MS analysis. We had tried many times to obtain the crystals of 2·PF₆·CH₃CN and 3·PF₆·CH₃CN, but failed.

  图3 Molecular structure (left) and the dimeric crystal structure (right) of 1·PF₆·CH₃CN Figure3. Molecular structure (left) and the dimeric crystal structure (right) of 1·PF₆·CH₃CN

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  2.3   Catalytic activity

  For the importance of the Suzuki cross-coupling reaction and the structural characteristics of palladium and platinum (Ⅱ, Ⅱ) complexes, 1·PF₆·H₂O, 2·PF₆·H·H₂O and 3·PF₆·H₂O were devoted to explore the catalyst activity. In our previous work, we have discussed the catalyst activity of pyrazolate-based dipalladium(Ⅱ) complexes^[26]. In this work, different solvents, temperature, reaction time and reagents were examined to optimize the process conditions.

  Firstly, effects of different solvents were investigated, and the optimum conditions were shown in Table 2. According to previous experiments records^[27], 1, 4-dioxane and ethanol were prepared for the catalyst activity, and it was observed that different solvents are suited for different reactions. Meanwhile, the temperature and the reaction time were adjusted to achieve the optimal strategy.

  Table 2.  Catalytic activity of complexes 1·PF₆·H₂O, 2·PF₆·H·H₂O and 3·PF₆·H₂O

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  Entry	Catalyst	Co-catalyst	Solvent	T / ℃	Time / h	Yield / %
  1	1·PFc·HeO	K3PO4	1, 4-dioxane	100	12	94
  2	2·PF6·H2O	K3PO4	1, 4-dioxane	100	36	87
  3	3·PF6·H2O	K3PO4	1, 4-dioxane	100	24	89
  4	1·PB6·H2O	K3PO4	ethanol	80	12	91
  5	2·PF6·H2O	K3PO4	ethanol	80	24	88
  6	3·PF6·H2O	K3PO4	ethanol	80	12	92

  Next, the influence of reagents was explored in the controlled experiments. Different yields but satisfactory results were obtained for the aryl-aryl reactions (Table 3). But for the heterocyclic-based reactions, since the previous set of experiments have consistently use unprotected starting pyrazol-based, the palladium or platinum ions in 1·PF₆·H₂O, 2·PF₆·H·H₂O and 3·PF₆·H₂O complexes could coordinate with the unprotected starting pyrazole, leading to side-products and yield decreasing. Then a series of protected starting pyrazol-based were employed for the cross-coupling reactions, as expected, the yields of adducts were higher. With the optimized reaction conditions in hand, a broad substrate listed in Table 3 is observed. The results of control experiment and blank experiment show that good catalytic effect would be found only when main catalysts and sub-catalysts coexist simultaneously. It seems that the electronic effect of metal-metal interaction and the steric effect of the catalysts make the reaction efficiency.

  Table 3.  Catalytic activity of complexes 1·PF₆·H₂O, 2·PF₆·H·H₂O and 3·PF₆·H₂O

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  Entry	Catalyst	Co-catalyst	Substrate A	Substrate B	Solvent	T/℃	Yield/%
  1	1·PF6·H2O	None			ethanol	100	11.4
  2	None	K3PO4			ethanol	100	7.3
  3	None	None			ethanol	100	7.8
  4	1·PF6·H2O	K3PO4			1, 4-dioxane	100	92
  5	2·PF6·H2O	K3PO4			ethanol	80	88
  6	3·PF6·H2O	K3PO4			ethanol	80	89
  7	1·PF6·H2O	K3PO4			1, 4-dioxane	100	86
  8	2·PF6·H2O	K3PO4			ethanol	80	79
  9	3·PF6·H2O	K3PO4			1, 4-dioxane	100	81
  10	1·PF6·H2O	K3PO4			1, 4-dioxane	100	83
  11	2·PF6·H2O	K3PO4			ethanol	80	73
  12	3·PF6·H2O	K3PO4			ethanol	80	75
  13	1·PF6·H2O	K3PO4			1, 4-dioxane	100	88
  14	2·PF6·H2O	K3PO4			ethanol	80	75
  15	3·PF6·H2O	K3PO4			ethanol	80	82
  16	1·PF6·H2O	K3PO4			ethanol	80	35
  17	2·PF6·H2O	K3PO4			ethanol	80	26
  18	3·PF6·H2O	K3PO4			ethanol	80	29
  19	1·PF6·H2O	K3PO4			ethanol	80	25
  20	2·PF6·H2O	K3PO4			ethanol	80	27
  21	3·PF6·H2O	K3PO4			ethanol	80	22
  22	1·PF6·H2O	K3PO4			ethanol	80	72
  23	2·PF6·H2O	K3PO4			ethanol	80	68
  24	3·PF6·H2O	K3PO4			ethanol	80	69
  25	1·PF6·H2O	K3PO4			ethanol	80	67
  26	2·PF6·H2O	K3PO4			ethanol	80	64
  27	3·PF6·H2O	K3PO4			ethanol	80	73

  3   Conclusions

  In summary, we have synthesized three mono-metallic complexes in quantitative yields by a directed self-assembly of diketone-based ligands with [(bpy)Pd(NO₃)]NO₃, [(bpy)Pt(NO₃)]NO₃ and [(phen)Pd(NO₃)]NO₃ in a 2:1 molar ratio. The assemblies have been chara-cterized by NMR and ESI-MS, and the complex of 1·PF₆·CH₃CN was fully defined by single-crystal X-ray diffraction method. These characterizations show the structural similarity of these assemblies. The single-crystal structures show that weak intramolecular Pd…Pd interactions exist in 1·PF₆·CH₃CN. More signifi-cantly, these metal-organic species with metal-metal interaction have potential application in the field of Suzuki cross-coupling reaction.

  Supporting information is available at http://www.wjhxxb.cn

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  Scheme 1  Representative Suzuki-Miyaura cross-coupling reaction

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  Scheme 2  Self-assembly of complexes 1·NO₃·H₂O, 2·NO₃·H₂O and 3·NO₃·H₂O

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  Figure 1  ¹H NMR spectrum of complex 1·NO₃·H₂O and 1·PF₆·H₂O in DMSO-d₆

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  Figure 2  ESI-MS spectrum of complex 1·PF₆·H₂O in acetonitrile

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  Figure 3  Molecular structure (left) and the dimeric crystal structure (right) of 1·PF₆·CH₃CN

  Counter ions and solvent molecules are omitted for clarity

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  Table 1.  Crystallographic data for complex 1·PF₆·CH₃CN

  Formula	C27H22F6N3O2PPd		F(000)	1 344
  Formula weight	671.84		Index ranges	-8 ≤ h ≤ 8, -21 ≤ k ≤ 21≤k, -23 ≤l ≤ 23
  Crystal system triclinic	Monoclinic		θ range / (°)	2.360~25.246
  Space group	P21/n		Reflection collected	12 779
  a / nm	0.711 28(6)		Observed reflection with [I > 2σ(I)]	3 521
  b/ nm	1.807 66(19)		Number of parameter	356
  c / nm	1.970 19(15)		Independent reflection	4 436 (Rint=0.060 1)
  β/(°)	94.296(5)		Goodness-of-fit on F2	1.096
  Volume / nm3	2.526 1(4)		Final R indices [I > 2σ(I)]	R1=0.041 1, wR2=0.100 6
  Z	4		R indices (all data)	R1=0.052, wR2=0.104 3
  Dc / (g·cm-3)	1.767		Largest diff. peak and hole / (e·nm-3)	1 415 and -1 274
  μ/ mm-1	0.875

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  Table 2.  Catalytic activity of complexes 1·PF₆·H₂O, 2·PF₆·H·H₂O and 3·PF₆·H₂O

  Entry	Catalyst	Co-catalyst	Solvent	T / ℃	Time / h	Yield / %
  1	1·PFc·HeO	K3PO4	1, 4-dioxane	100	12	94
  2	2·PF6·H2O	K3PO4	1, 4-dioxane	100	36	87
  3	3·PF6·H2O	K3PO4	1, 4-dioxane	100	24	89
  4	1·PB6·H2O	K3PO4	ethanol	80	12	91
  5	2·PF6·H2O	K3PO4	ethanol	80	24	88
  6	3·PF6·H2O	K3PO4	ethanol	80	12	92

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  Table 3.  Catalytic activity of complexes 1·PF₆·H₂O, 2·PF₆·H·H₂O and 3·PF₆·H₂O

  Entry	Catalyst	Co-catalyst	Substrate A	Substrate B	Solvent	T/℃	Yield/%
  1	1·PF6·H2O	None			ethanol	100	11.4
  2	None	K3PO4			ethanol	100	7.3
  3	None	None			ethanol	100	7.8
  4	1·PF6·H2O	K3PO4			1, 4-dioxane	100	92
  5	2·PF6·H2O	K3PO4			ethanol	80	88
  6	3·PF6·H2O	K3PO4			ethanol	80	89
  7	1·PF6·H2O	K3PO4			1, 4-dioxane	100	86
  8	2·PF6·H2O	K3PO4			ethanol	80	79
  9	3·PF6·H2O	K3PO4			1, 4-dioxane	100	81
  10	1·PF6·H2O	K3PO4			1, 4-dioxane	100	83
  11	2·PF6·H2O	K3PO4			ethanol	80	73
  12	3·PF6·H2O	K3PO4			ethanol	80	75
  13	1·PF6·H2O	K3PO4			1, 4-dioxane	100	88
  14	2·PF6·H2O	K3PO4			ethanol	80	75
  15	3·PF6·H2O	K3PO4			ethanol	80	82
  16	1·PF6·H2O	K3PO4			ethanol	80	35
  17	2·PF6·H2O	K3PO4			ethanol	80	26
  18	3·PF6·H2O	K3PO4			ethanol	80	29
  19	1·PF6·H2O	K3PO4			ethanol	80	25
  20	2·PF6·H2O	K3PO4			ethanol	80	27
  21	3·PF6·H2O	K3PO4			ethanol	80	22
  22	1·PF6·H2O	K3PO4			ethanol	80	72
  23	2·PF6·H2O	K3PO4			ethanol	80	68
  24	3·PF6·H2O	K3PO4			ethanol	80	69
  25	1·PF6·H2O	K3PO4			ethanol	80	67
  26	2·PF6·H2O	K3PO4			ethanol	80	64
  27	3·PF6·H2O	K3PO4			ethanol	80	73

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