Solid-state structural transformation of two-dimensional coordination polymers

Abstract

The solid state structural transformation with loss of 4,4'-bipyridine of the two-dimensional coordination polymer phyllo-diaquacobalt(II){4-α,α-xylenediylbis(phenylphosphinate)-4,4'-bipyridine} dihydrate 1 or phyllo-diaquanickel(II){4-α,α-xylenediylbis(phenylphosphinate)-4,4'-bipyridine} dihydrate 2 to phyllo-cobalt(II){4-α,α-xylenediylbis(phenylphosphinate)} 1' or phyllo-nickel(II){4-α,α-xylenediylbis(phenylphosphinate)} 2', respectively, either by heating or, just for 1, by solvent washing is presented.For 1 → 1', the coordination polymer goes from light pink to deep blue, indicating a change in the Co II coordination environment from octahedral to tetrahedral.For 2→ 2', the color changed from light green to violet.In the single crystal structures of 1 and 2, the bipyridine ligands are stacked along the crystallographic x direction.The loss of 4,4'-bipyridine from 1 and 2 to form 1' and 2', respectively, was followed by thermogravimetric analysis and powder X-ray diffraction studies.Nitrogen adsorption studies show that 2' from solvent washing is porous, with a Brunauer-Emmett-Teller surface area of 190 m 2 g -1 .The compounds were further characterized by infrared and Raman spectroscopy, diffuse reflectance spectroscopy, X-ray fluorescence spectroscopy, elemental analysis and scanning electron microscopy.