Two Novel Cobalt(Ⅱ)/nickel(Ⅱ) Metal-organic Coordination Polymers Based on Flexible Polycarboxylic Acids and Rigid Bis(imidazole) Mix Ligands

Two novel metal-organic coordination compounds, [Co2(OH)(chdc)1.5(bibp)]n(1) and [Ni(chdc)(bib)]n·2nH2O(2, H2chdc=1,4-cyclohexanedicarboxylic acid, bibp=4,4’-bis(1-imidazolyl)biphenyl, bib=1,4-bis(1-imidazolyl)benzene), were synthesized and characterized. Compound 1 crystallizes in monoclinic system, space group PI with a=10.591(3), b=11.146(3), c=12.264(3) ?, α=89.009(6), β=88.397(4), γ=87.823(3)°, V=1446.0(6) ?3, Dc=1.554 g/cm3, C30H30Co2N4O7, Mr=676.44, F(000)=696, μ(MoKα)=1.202 mm-1, Z=2, R=0.0278 and wR=0.0718. In 1, it contains an interesting tetranuclear Co(Ⅱ) cluster. The neighboring {Co4} clusters are linked by chdc2-ligands to generate a 2D network. The bibp ligands connect adjacent layers to form an open 3 D metal-organic framework. Compound 2 crystallizes in monoclinic system, space group P21/n with a=8.8110(1), b=19.369(1), c=12.7379(4) ?, β=102.952(5)o, V=2118.5(2) ?3, Dc=1.490 g/cm3, C20H24N4NiO6, Mr=475.14, F(000)=992, μ(MoKα)=0.961 mm-1, Z=4, R=0.0306 and wR=0.0738. In 2, each deprotonated chdc 2-ligand links two Ni(Ⅱ) atoms to generate a 1 D chain along the a axis. The adjacent chains are further connected by bib ligands to build up an interesting two-dimensional network. Compound 1 shows antiferromagnetic property.