Syntheses, structures and properties of three cobalt coordination polymers based on flexible bis(triazole) and 5-nitroisophthalate coligands

Three coordination polymers {[Co(bte)(NO2-1,3-bdc)(H2O)]⋅H2O}n (1), {[Co(btp)(NO2-1,3-bdc)(H2O)]⋅2H2O}n (2) and {[Co2(btb)2(NO2-1,3-bdc)2]⋅2H2O}n (3) were synthesized by the different spacer lengths and conformational flexibilities bte, btp, btb and the rigid NO2-1,3-bdc. 1 forms an independent 1D MONT and a (1D → 2D) interdigitated array. In 2, two identical undulated (4,4) networks are parallel stacking to give a double-layer. In 3, the btb ligands connect the [Co2(NO2-1,3-bdc)2]n ladders to construct an unusual 3D network with point symbol 46⋅67⋅82 based on [Co2(COO)2] unit. The thermal stability and the UV–vis spectra of 1, 2 and 3 were investigated.