Two novel coordination compounds,1[Zn_4(L_1)_4(NO_3)_2(H_2O)_2](NO_3)_2·2H_2O and 2[Mn_2(L_2)_2(DMF)(H_2O)_3](ClO_4)_2·DMF(HL_1 = N'-[(1E)-pyridine-2-ylmethylidene]pyrazine-2-carbohydrazide,H_2L_2 = 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 L_1^(-1).Compound 2represents a rare phenol-O bridged Mn_2~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 H2 MIP ligands(phen = 1,10-phenanthrolion and H2 MIP = 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-C_5H_4N)N(μ-CH_2S)_2Fe_2(CO)_6](1) related to the active site of[FeFe]-hydrogenase was obtained by treating(HS)_2Fe_2(CO)_6 with(pyridin-2-ylazanediyl)dimethanol.Protonation occurred at the pyridine nitrogen atom when two equivalents of HBF_4·OEt_2acid were added to the toluene solution of 1,leading to the formation of[(2-C_5H_4NH)N(μ-CH_2S)_2Fe_2(CO)_6]·BF_4·OEt_2(1H^+),whose molecular structure was further established by singlecrystal X-ray analysis.Complex 1 crystallizes in the monoclinic system,space group P2_1/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[Cd_2Cs(DHAPA)(m-BDC)_4]·(EtOH)(1D)and(L-HAPA)_2[Cd_2Cs(L-HAPA)(m-BDC)_4]·(EtOH)(1L)(APA=2-amino-1-propanol,m-H_2BDC=1,3-benzenedicarboxylate),have been assembled solvothermally respectively with the induction of enantiomorphic organic small molecules(D,L-APA).1L and 1D crystallize in chiral space group P2_1 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)2·6H2O with isophthalic acid in the presence of potassium nitrate lead to an acentric three-dimensional(3D) hetero-metallic inorganic-organic hybrid framework [ZnK2(m-BDC)2(H2O)2]n(1, m-H2 BDC = benzene-1,3-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 Cmc21 with a = 19.764(6), b = 19.948(6), c = 12.039(4) , V = 4746(3) 3, Z = 4, C32H20O19K4Zn2, Mr = 995.66, Dc = 1.393 g/cm3, F(000) = 2000 and μ = 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.
Two new europium-based metal-organic-frameworks(MOFs),namely[NMe4][Eu(mBDC)_2](1) and[Eu_3(p-BDC)_4(C1O_4)(H_2O)_4](2),have been synthesized and structurally characterized.Single-crystal X-ray diffraction studies reveal that 1 crystallizes in the monoclinic system,space group P2_1/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 [Fe2(μ-pdt)(CO)5(3,5-Me2Pz)](1,3,5-Me 2Pz=3,5-dimethylpyrazole) was prepared as a biomimetic model for the active site of [FeFe]-hydrogenase by CO-substitution of all-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 P1 with a=9.108(7), b=9.743(8), c=11.192(9), α=109.235(5), β=101.914(9), γ=96.605(6)o. In CH3CN solution, reversible transformation between 1 and the acetonitrile-substituted species [Fe2(μ-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 CH2Cl2.
Two new coordination polymers, [Cd(N3)2(Baep)1/2]n(1) and [Cd2(N3)4(CH3OH)(Bapp)1/2]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), β=93.925(13)°, V=891.8(11)3 , Z=4, μ(MoKα)=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), α=72.91(2), β=77.10(2), γ=73.95(2)°, V=820.0(8)3 , Z=2, μ(MoKα)=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)4(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 {Cd4(N3)8(CH3OH)2(Bapp)}, in which the azido anions exhibit four different bridging modes (μ-1,1, μ-1,3, μ-1,1,1 and μ-1,1,3). The thermal stability and fluorescent property of 1 and 2 have also been investigated.
