A bi‐butterfly W‐Cu‐S cluster compound: Synthesis and crystal structure of ( n ‐Bu 4 N) 2 [W 2 Cu 4 S 8 (S 2 CNC 4 H 8 ) 2 ]

The compound ( n ‐Bu 4 N) 2 [W 2 Cu 4 S 8 (S 2 CNC 4 H 8 ) 2 ] was obtained by the reaction of Bu 4 NBr, (NH 4 ) 2 WS 4 , NaS 2 NCC 4 H 8 and CuCl in CH 3 CN and CH 3 OH. It crystallizes in the monoclinic space group P2 1 / c with unit cell parameters: a =21.875(5), b =16.843(4), c =17.745(5)Å, β = 101.69(6)°, V =6402(6)Å 3 , Z =4, D c =1.718 g·cm −3 . The final R and R w values converged to 0.055 and 0.060 respectively. The structure consists of two ‘butterfly’ units [WS 4 Cu 2 ] linked together by two weak Cu—S bonds and two bridging S 2 CNC 4 H 8 ligands. Infrared spectra gave characteristic absorptions at 495 cm −1 for W=S and 450, 435, 412 cm −1 for W—μ‐S.