CONTRIBUTIONS TO THE CHEMISTRY OF SILICON SULFUR-COMPOUNDS .57. SYNTHESIS, MOLECULAR-STRUCTURE AND PROPERTIES OF CYCLO-TETRAKIS-[TRI-TERT-BUTOXYSILANETHIOLATOCOPPER(I)], [(T-C4H9O)3SISCU]4, THE 1ST EXAMPLE OF A SQUARE-PLANAR CU4S4 RING

The preparation of cyclo-tetrakis[tri-tert-butoxysilanethiolatocopper(I)] from tri-tert-butoxysilanethiol and copper(II) acetate or CuCl or Cu2O is described. The com- pound crystallizes as colourless monoclinic rods. The molecular structure is characterized by a nearly planar alternating Cu4S4-eight-membered ring with three-fold coordinated sulphur and two-fold coordinated copper atoms. According to the mass spectrum the tetrameric molecule is also preserved in the vapour phase. The compound was characterized spectroscopically by 29Si, 13C, 1H NMR, IR and UV. Reactions with triphenylphosphine, 1,10-phenanthroline, and 2,2′-bipyridine afforded three adducts with formal stoichiometries RSCu·(PPh3)2, RSCu·phen and (RSCu)2·bipy, respectively. © 1990.