LAUSR

Abstract Two dinuclear phosphonate-based transition metal complexes, [Co2(H6tpmb)2(2,2′-bipy)2(H2O)2] (1) and [Zn2(H6tpmb)2(2,2′-bipy)2] (2), have been synthesized at 60 °C by the reactions of 1,2,4,5-tetrakis(phosphorylmethyl)benzene (H8tpmb) and 2,2′-bipyridine (2,2′-bipy) ligands, with CoCl2·6H2O and Zn(NO3)2·6H2O, respectively. These two complexes are characterized by single-crystal X-ray diffraction, XRD, IR and elemental analysis. Complexes 1 and 2 both adopt dinuclear macrocycle structures in which the Co(II) center in the former has an octahedral coordination geometry of {CoN2O4} while the Zn(II) center in the latter shows a square pyramidal coordination geometry of {ZnN2O3} with a τ value of 0.01. The H8tpmb ligand adopting the cis,trans,cis,trans conformation was partially deprotonated to be the H6tpmb2− dianion in both complexes 1 and 2. TG analysis shows that complexes 1 and 2 both are thermally stable upon heating to 250 °C.