Two novel coordination compounds,1[Zn4(L1)4(NO3)2(H2O)2](NO3)2·2H2O and 2[Mn2(L2)2(DMF)(H2O)3](ClO4)2·DMF(HL1 = N'-[(1E)-pyridine-2-ylmethylidene]pyrazine-2-carbohydrazide,H2L2 = 2-hydroxy-3-methoxybenzaldehyde(pyrazin-2-ylcarbonyl)hydrazone),based on the N-N bridged ligands were prepared and structurally characterized.Compound 1represents the[2*2]molecular squares,in which both N atoms belonging to the N-N bridged ligands are connected to the Zn centers.The emission of compound 1 exhibits a blue shift,which can be assigned to strong electrostatic interaction between Zn^Ⅱ ions and the L1^-1.Compound 2represents a rare phenol-O bridged Mn2^Ⅱ complex.The magnetic investigation indicates weak antiferromagnetic interactions between the Mn^Ⅱ centers.
Temperature dependent assembly of two novel Cd coordination polymers with the phen and H2MIP ligands (phen = 1,10-phenanthrolion and H2MIP = 5-methyl-isophthalic acid), formulated as Cd2(MIP)2(phen)2 (1) and Cd3(MIP)3(H2MIP)(phen)2 (2). They have been structurally characterized by single-crystal X-ray diffraction, elemental analysis, FT-IR spectra and TGA. 1 crystallizes in the monoclinic space group P2/n, while 2 crystallizes in the triclinic space group P1. 1 shows a 2D (two-dimensional) plane and 2 shows a 1D (one-dimensional) chain. In addition, their solid-state luminescent properties have also been investigated.
A new 2Fe2 S complex[(2-C5H4N)N(μ-CH2S)2Fe2(CO)6](1) related to the active site of[FeFe]-hydrogenase was obtained by treating(HS)2Fe2(CO)6 with(pyridin-2-ylazanediyl)dimethanol.Protonation occurred at the pyridine nitrogen atom when two equivalents of HBF4·OEt2acid were added to the toluene solution of 1,leading to the formation of[(2-C5H4NH)N(μ-CH2S)2Fe2(CO)6]·BF4·OEt2(1H~+),whose molecular structure was further established by singlecrystal X-ray analysis.Complex 1 crystallizes in the monoclinic system,space group P21/n with α=7.728(3),b = 11.825(4),c = 17.888(6) A,β= 92.968(5)°,while complex 1H~+ crystallizes in the triclinic system,space group P1 with a = 7.672(4),b = 10.382(5),c = 16.480(10) A,α=106.575(13),β= 93.18(3),γ=104.262(17)°.
Two homochiral enantiomorphic 3D coordination polymers: (D-HAPA)2[Cd2Cs(D- HAPA)(m-BDC)4]'(EtOH) (1D) and (L-HAPA)2[Cd2Cs(L-HAPA)(m-BDC)a]'(EtOH) (1L) (APA = 2-amino-l-propanol, m-H2BDC = 1,3-benzenedicarboxylate), have been assembled solvothermally respectively with the induction of enantiomorphic organic small molecules (D,L-APA). 1L and 1I) crystallize in chiral space group P21 with Flack parameters of-0.012(13) and -0.07(3), respectively, and have been characterized by satisfactory elemental analysis, FT-IR spectra, CD-spectra and single-crystal X-ray diffraction. They both exhibit sqp topological net, purple fluorescence and SHG activity.
Solvothermal reactions of Zn(NO3)2·6H20 with isophthalic acid in the presence of potassium nitrate lead to an acentric three-dimensional (3D) hereto-metallic inorganic-organic hybrid framework [ZnK2(m-BDC)ffH20)2]n (1, m-H2BDC = benzene-l,3-dicarboxylic acid). The crystal was characterized by elemental analysis, IR spectroscopy, TGA and single-crystal X-ray diffraction analysis. Complex 1 is of orthogonal crystal system, acentric space group Cmc2j with a = 19.764(6), b = 19.948(6), c = 12.039(4) A, V = 4746(3) A3, Z = 4, C32H20019KaZn2, Mr = 995.66, Dc= 1.393 g/cm3, F(000) = 2000 andp = 1.426 mm-1. The final R = 0.0761 and wR = 0.1841. The crystal exhibits remarkable blue luminescence emissions with high quantum yield of 56.02% and displays modest powder SHG efficiency of about 0.7 times that produced by a potassium dihydrogen phosphate (KDP) powder. In addition, it also exhibits potential ferroelectric property.
Reactions of Zn(NO3)E'6H20 and MNO3 (M = Na, K and Rb) with HEmip (HEmip = 5-methylisophthalic acid) in DMF (DMF = N,N'-dimethylformamide) resulted in the formation of novel heterometallic metal-organic frameworks (MeENHE)[ZnM(mip)2] (1: M = Na; 2: M = K; 3: M = Rb, mip = 5-methylisophthalate dianion for 1-3). These complexes belong to the monoclinic system, space group PE/c and have been fully characterized by satisfactory elemental analysis, FT-IR spectra, TGA and single-crystal X-ray diffraction. Single-crystal X-ray diffraction studies reveal that 1-3 are 3D isomorphic structures based on a trinuclear unit {ZD.ME(/d2-COO)E(μ3- COO)E} and exhibitpcu topological net and blue fluorescence.
Two new europium-based metal-organic-frameworks (MOFs), namely [NMen][Eu(m- BDC)2] (1) and [Eu3(p-BDC)4(ClO4)(H2O)4] (2), have been synthesized and structurally characte- rized. Single-crystal X-ray diffraction studies reveal that 1 crystallizes in the monoclinic system, space group P21/n with a 2D layer structure, while 2 crystallizes in the orthorhombic system, space group Pccn with a 3D net structure. Both 1 and 2 have strong characteristic Eu(Ⅲ) emissions at visible red region and the quantum yields can reach up to 78.1 and 46.0%, respectively. The high luminescent efficiency may be attributed to the efficient energy transition from the ligands to the Eu(Ⅲ) center.
A pyrazole-substituted diiron dithiolate complex [Fez(p-pdt)(CO)5(3,5-Me2Pz)] (1, 3,5-MezPz = 3,5-dimethylpyrazole) was prepared as a biomimetic model for the active site of [FeFe]-hydrogenase by CO-substitution of aU-carbonyl complex [Fe2(μ-pdt)(CO)6] with 3,5-Me2Pz. The molecular structure was confirmed by MS, IR, 1H NMR, elemental analysis and single-crystal X-ray analysis. Complex 1 crystallizes in the triclinic system, space group PI with a = 9.108(7), b = 9.743(8), c = 11.192(9)A, a = 109.235(5), fl = 101.914(9), y = 96.605(6). In CH3CN solution, reversible transformation between 1 and the acetonitrile-substituted species [Fe2(p-pdt)- (CO)5(NCCH3)] was detected by both IR and cyclic voltammetry (CV). The electrochemical proton reduction catalyzed by 1 in the presence of acetic acid was also studied in CH2C12.
Two new coordination polymers, [Cd(N3)2(Baep)l/2]n (1) and [Cd2(N3)4(CH3OH)(Bapp)I/.2]n (2) (Baep = 1,4-bis(2-aminoethyl)piperazine, Bapp = 1,4-bis(3-aminopropyl)piperazine) were synthesized. The crystal of 1 is of monoclinic system, space group P21/c with a = 9.341(7), b = 11.677(9), c = 8.195(6) A, fl = 93.925(13), V= 891.8(11) A3, Z= 4, μ(MoKa) = 2.42 mm-1, Mr = 280.58, Dc = 2.090 g/cm3, the final R = 0.0297 and wR = 0.0720. The crystal of 2 is of triclinic system, space group PI with a = 9.121(5), b = 9.666(5), c = 10.250(6) A, a = 72.91(2), β= 77.10(2), V = 73.95(2)°, V = 820.0(8)°, Z = 2,μ(MoKa) = 2.62 mm-1, Mr= 522.10, Dc = 2.114 g/cm3, the final R = 0.0251 and wR = 0.0632. Single-crystal X-ray diffraction studies reveal that 1 is a 3D structure based on a dinuclear unit {Cd2(N3)a(Baep)}, in which the Baep ligands formed in situ display two different bridging modes. Compound 2 also has a 3D structure based on a tetranuclear cluster {Cda(N3)8(CH3OH)2(Bapp)}, in which the azido anions exhibit four different bridging modes (μ-1,1, μ-1,3, μ-l,l,1 and μ-1,1,3). The thermal stability and fluorescent property of 1 and 2 have also been investigated.