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（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.