Structure, spectroscopic and magnetic properties of a novel 1-D coordination copper(II) polymer containing BIMAM ligand [BIMAM = bis(imidazol-2-yl)methylaminomethane] and μ-1,3 squarato bridges

This paper reports the synthesis and complete characterization (structural, spectroscopic and magnetic) of [Cu(HBIMAM)Cl(C4O4)]n · (H2O)n [BIMAM = bis(imidazol-2-yl)methylaminomethane]. This compound is made of infinite chains – running along c axis – built from [CuCl(HBIMAM)]+ units bridged together by μ-O1,O3-bis(monodentate) squarate anions. Non-covalent interactions (H-bonds and π–π) drive the build-up of an infinite three-dimensional array. The coordination polyhedron about the copper(II) ion is distorted square pyramidal. The EPR spectrum is indicative of a dz2-y2dz2-y2 ground state for the Cu(II) ions with significant contribution of dz2dz2. Magnetic susceptibility measurements in the range 1.8–200 K show weak antiferromagnetic exchange interactions (2J = −3.5(1) cm−1). The observed magnetic behaviour is discussed in terms of the crystal structure and compared with that observed in related copper(II) complexes containing μ-O1,O3-squarato bridges.