Metal derivatives of thiosemicarbazones: crystal and molecular structures of mono- and di-nuclear copper(I) complexes with N¹-substituted thiosemicarbazones

Abstract

The reactions of copper(II) chloride with a series of N¹-substituted thiosemicarbazones, {R¹(H)C²=N³–N²(H)–C¹(=S)–N¹HMe, R¹ = furan, Hftsc-N-Me; thiophene, Httsc-N-Me; phenyl, Hbtsc-N-Me} in 1 : 2 molar ratio yield copper(I) complexes : sulfur-bridged dinuclear complexes, [Cu₂Cl₂(μ-S-Hftsc-N-Me)₂(η¹-S-Hftsc-N-Me)₂] (1), [Cu₂Cl₂(μ-S-Httsc-N-Me)₂(η¹-S-Httsc-N-Me)₂] (2), and a mononuclear complex [CuCl(η¹-S–Hbtsc-N-Me)₂] (3). Complexes 1–3 have been characterized by elemental analysis (C, H, N), spectroscopy (IR, ¹H NMR) and X-ray crystallography. The Cu(μ-S)₂Cu cores in 1 and 2 form parallelograms with unequal bond distances {Cu–S, 2.2831(3), 2.5955(4) Å (1); 2.2641(9), 2.8006(10) Å (2)}. Bond angles at sulfur and copper are, Cu–S–Cu, S–Cu–S, 69.86(11), 110.12(17)° (1); 75.84(3), 104.16(3)° (2), respectively. The Cu ··· Cu separations are 2.806 Å (1) and 3.141 Å (2) with each copper center a distorted tetrahedron (96.67–119.28°). Bond parameters of 3, Cu–S, 2.227(3), 2.224(3) Å, and 118.97–121.11° are different.

Keywords:

• Copper(I)
• Furan-2-carbaldehyde-N-methyl thiosemicarbazone
• Thiophene-2-carbaldehyde-N-methyl thiosemicarbazone
• Benzaldehyde-N-methyl thiosemicarbazone

Acknowledgment

Financial support from CSIR {Scheme no. 01(1993)/05/EMR II}, New Delhi is gratefully acknowledged.