Expanding the 2,2′-bipyrimidine bridged 1D homonuclear coordination polymers family: [MII(bpym)Cl2] (M = Fe, Co) magnetic and structural characterization

Abstract

One pot reaction of hydrated chloride salts of Fe(II) and Co(II) with stoichiometric amounts of 2,2′-bipyrimidine (bpym) in a methanol–acetonitrile mixture afforded the corresponding 1D homonuclear coordination polymers, [μ-(bpym)MCl₂]_n. Crystal structures of both complexes are isomorphous in the highly symmetric orthorhombic space group Fddd. The 1D coordination polymers are composed of almost orthogonal alternating bipyrimidine bridges linking the {MCl₂} units. The magnetic behaviour of the Fe(II) compound can be well understood as a uniform S = 2 chain with an antiferromagnetic exchange interaction between metal ion sites. In the case of the Co(II) ion, also an antiferromagnetic interaction is operative along the uniform chain, while at low temperatures a long range-ordering is observed due to spin canting originating from the anisotropic behaviour of the Co(II) lowest energy Kramers doublets.