Syntheses, structures and magnetic properties of three Co(Ⅱ)coordination architectures based on a flexible multidentate carboxylate ligand and different N-donor ligands

Three new cobalt complexes,{[Co5(tci)2(bimb)3(3-O)2(H2O)2]·3DMF·4H2O}n(1),{[Co3(tci)2(bib)]·2DMF·2H2O}n(2)and{[Co(Htci)(bpea)0.5]·H2O}n(3)(H3tci=tris(2-carboxyethyl)isocyanurate,bimb=4,4′-bis(imidazol-1-yl)biphenyl,bib=1,4-bis(imidazol-1-yl)benzene,bpea=1,2-bis(4-pyridyl)ethane,DMF=N,N′-dimethylformamide),have been successfully synthesized through the assembly of Co(II)ions,H3tci and different N-donor ligands,respectively.All complexes were structurally characterized by single crystal X-ray diffraction,elemental analyses,IR spectra,thermogravimetric(TG)analyses and X-ray powder diffraction(XRPD).Complex 1 exhibits a 3D three-fold parallel interpenetrated 3D→3D structure with(65·8)CdSO4topology.Complex 2 is built from[Co3(2-Ocarboxyl)2(CO2)4]clusters and linear bib ligands,displaying a two-fold parallel interpenetrated(3,8)-connected(43)2(46·618·84)topology,while complex 3 is a 3D pillar-layered structure involving an infinite–Co–(2-Ocarboxyl)(CO2)–Co–chain.The diverse structures of the three complexes indicate that the skeletons of different N-donor ligands play an important role in the assembly of such different frameworks.In addition,magnetic investigation indicates that besides spin-orbit coupling of Co(II)ions,there exist antiferromagnetic exchange interactions in Co5and Co3clusters of 1 and 2,respectively.

Three new cobalt complexes, {[Co5（tci）2（bimb）3（μ3-O）2（H2O）2]·3DMF·4H2O}n（1）, {[Co3（tci）2（bib）]·2DMF·2H2O}n （2） and {[Co（Htci）（bpea）0.5]-H2O}n （3） （H3tci = tris（2-carboxyethyl）isocyanurate, bimb = 4,4＇-bis（imidazol-l-yl）biphenyl, bib = 1,4-bis（imidazol-l-yl）benzene, bpea = 1,2-bis（4-pyridyl）ethane, DMF = N,N＇-dimethylformamide）, have been successfully synthesized through the assembly of Co（If） ions, H3tci and different N-donor ligands, respectively. All complexes were structurally characterized by single crystal X-ray diffraction, elemental analyses, IR spectra, thermogravimetric （TG） analyses and X-ray powder diffraction （XRPD）. Complex 1 exhibits a 3D three-fold parallel interpenetrated 3D · 3D structure with （65.8） CdSO4 topology. Complex 2 is built from [Co3（μ/2-Ocarboxyl）2（CO2）4] clusters and linear bib ligands, displaying a two-fold par- allel interpenetrated （3,8）-connected （4^3）2（4^6.6^18·8^4） topology, while complex 3 is a 3D pillar-layered structure involving an in- finite -Co-（μ2-Ocarboxyl）（CO2）-Co-chain. The diverse structures of the three complexes indicate that the skeletons of different N-donor ligands play an important role in the assembly of such different frameworks. In addition, magnetic investigation indi- cates that besides spin-orbit coupling of Co（II） ions, there exist antiferromagnetic exchange interactions in Co5 and Co3 clus- ters of 1 and 2, respectively.