Thermal stability and crystallochemical analysis for CoII-based coordination polymers with TPP and TPPS porphyrins

Abstract

Two new CoP–bipy compounds have been synthesised and characterised, where P is TPP for compound 1 (TPP = meso-tetraphenylporphyrin) and TPPS for compound 2 (TPPS = meso-tetraphenylporphine-tetrasulfonic acid tetrasodium salt), and bipy is 4,4′-bipyridine. Compound 1 consists of 1D polymers packed in a network where isolated porphyrin units are immobilized by an extended π-bond system. On the other hand, as we are aware, compound 2 is the first Co–TPPS compound in literature. It also consists of 1D polymers that are formed by the alternation of two distinct metal centres. These unprecedented polymers are packed forming cavities where crystallization molecules of water are located. The robustness of the hydrogen bond system and a topology based on interpenetrated nets are responsible for the high thermal stability of compound 2. Additionally, a crystallochemical study confirmed the existence of a correlation between the degree of ruffled distortion of the porphyrin macrocycle and some selected dihedral angles and distances for Co^II porphyrins in literature.