Ligand substitution in cis-bis(acetonitrile)tetrachlororhenium(IV) complex with N,N-dimethylformamide and N,N-dimethylacetamide

Abstract

The preparation, crystal structures, and magnetic properties of two novel mononuclear ReIV complexes of formula cis-[ReIVCl4(dmf)2] (1) and cis-[ReIVCl4(dma)2] (2) (dmf = N,N-dimethylformamide and dma = N,N-dimethylacetamide) have been studied. Both ReIV systems were synthesized through ligand substitution reactions from the cis-[ReIVCl4(MeCN)2] precursor, upon heating in the employed solvent. 1 and 2 crystallize in the monoclinic crystal system with space group C2/c. Each ReIV ion exhibits a distorted octahedral environment, being bonded by two oxygen atoms from two dmf (1) and dma (2) molecules and four chloride ions. In the crystal lattice of 1 and 2, the mononuclear ReIV complexes are placed generating short intermolecular ReIV-Cl⋯Cl-ReIV contacts. The magnetic properties of 1 and 2 were investigated through variable-temperature magnetic susceptibility measurements, which reveal significant antiferromagnetic exchange interactions between neighboring ReIV ions. In 1, these interactions account for a maximum in the magnetic susceptibility curve at ca. 5.0 K.