Ab initio crystal structure determination, thermal behaviour, and magnetic characterization of a new nickel coordination polymer based on carboxyethylphosphonic acid and 4,4′-bipyridine

Abstract

Crystalline powder aggregates of a new nickel coordination polymer with 2-carboxyethylphosphonic acid (HPPAH) and 4,4′-bipyridine, Ni(HPPA)(4,4′-bipy)(HO), has been obtained by hydrothermal synthesis, and their crystal structure has been ab initio determined from synchrotron powder data. The compound shows a layer structure in bc plane, with Ni atoms in two different environments. The loss of the coordinated water by heating leads to the apparition of an anhydrous phase, which remains stable when cooling down to room temperature. Synthesized material presents a paramagnetic behaviour with weak antiferromagnetic interactions and zero-field splitting at low temperature (T < 50 K).