Copper(II) Complexes with Ethyl [(Pyrazolo-1-carbothioyl)-amino]acetate Derivatives: Synthesis and Structure

Abstract

Optically active derivative of the natural monoterpene (+)-3-carene, namely, ethyl (3bS,4aR)-[(3,4,4-trimethyl-3b,4,4a,5-tetrahydrocyclopropa[3,4]cyclopenta[1,2-c]pyrazole-1-carbothioyl)-amino]acetate (HL1) and ethyl [(3,5-dimethyl-pyrazole-1-carbothioyl)-amino]acetate (HL2) were synthesized. Paramagnetic complexes [CuL1Cl] n (I) and [Cu2L22Cl2] (II) were prepared. According to X-ray diffraction data, complex Iwith anion of (+)-3-carene derivative has chain structure, whereas complex IIwith anion of HL2, which has no carbocyclic fragments, is a pseudodimer. Organic anions act as tetradentate bridging, cyclic ligands forming five-membered CuN3C and CuNOC2metal cycles. Coordination polyhedron of Cu(ClN2O + S) in complexes Iand IIis a square pyramid. The values of μefffor complexes Iand II(1.88 and 1.84 μB, respectively) are constant in the temperature interval 78–300 K, which means that the unpaired electrons of Cu(II) ions do not exhibit any noticeable exchange interactions.