Mono- and dinuclear copper(I) complexes with methyl-substituted pyrimidinethiones

The reaction of 4,6-dimethylpyrimidine-2(1H)-thione (dmpymtH) or its corresponding N-methylated form (dmpymt-NMe) with the parent complex [Cu(MeCN)4][BF4] (1) affords the mono- and dinuclear copper(I) complexes [Cu(dmpymt-NMe)3][BF4] (2) and [Cu(dmpymtH)3]2[BF4]2 · 2H2O (3), respectively. The reaction of Cu2O and the hydrochloride salt of dmpymtH gives the dinuclear complex [CuCl(dmpymtH)2]2 (4). The X-ray crystal structure reveals that 2 is coordinatively unsaturated and weak intermolecular interactions between Cu(I) and H atoms from methyl groups are involved. The complexes 3 and 4 are dinuclear in the solid state in which the copper atoms adopt distorted tetrahedral geometry. In both cases, the neutral dmpymtH is acting as a bridging ligand.

The mononuclear complex [Cu(dmpymt-NMe)3][BF4] is tricoordinated and subjected to weak intermolecular interactions between the Cu atom and H atoms from the ligand’s methyl groups. When the less demanding ligand dmpymtH was used instead of dmpymt-NMe, the dinuclear complexes [Cu(dmpymtH)3]2[BF4]2 · 2H2O and [CuCl(dmpymtH)2]2 were obtained. In this cases, the copper(I) atoms adopt a distorted tetrahedral geometry.Figure optionsDownload as PowerPoint slide