[Cu(men)2(BF4)2] (men = N-methyl-1,2-diaminoethane): Preparation, crystal structure, spectroscopic and magnetic properties

Single crystals of [Cu(men)2(BF4)2] (men = N-methyl-1,2-diaminoethane) (1) were isolated from an aqueous-ethanolic system Cu2+–men–BF4−. The crystal structure of 1 consists of [Cu(men)2(BF4)2] molecules. Copper ion exhibits usual distorted octahedral coordination; there are two coordinated men ligands in the equatorial plane with Cu–N bonds of 2.0451(12) and 2.0035(12) Å, while the axial positions are occupied by fluorine atoms from BF4− anions with Cu–F bond of 2.5091(11) Å. The packing of the [Cu(men)2(BF4)2] molecules is governed by N–H⋯F type hydrogen bonds. The measured ESR spectrum corroborated the presence of Jahn–Teller anisotropy of Cu(II) with g|| = 2.20 and g⊥ = 2.06. The magnetic studies in the temperature range 300–2 K reveal that 1 follows the Curie–Weiss law with parameters g = 2.1612(1) and θ = −0.233(1) K suggesting the presence of weak antiferomagnetic interactions.