Contributions to the Chemistry of Silicon‐Sulfur Compounds. 65 synthesis, crystal and molecular structure of cyclo ‐tetrakis[tri‐ tert ‐butoxysilanethiolatogold(I)], [( t ‐C 4 H 9 O) 3 SiSAu] 4 , the first example of an Au 4 S 4 ring System

The preparation of the first silanethiolate complex of gold, cyclo ‐tetrakis[tri‐ tert ‐butoxysilanethiolatogold(I)] from tri‐ tert ‐butoxysilanethiol and tetrachloroauric acid is described. The compound forms colorless orthorhombic crystals, and the molecular structure was determined at 200 K by single crystal X‐ray diffraction. At 187 K, a possible, reversible phase transition is observed. The center of the molecule is a distinctly folded eight‐membered Au 4 S 4 ring of alternating three‐fold coordinated sulfur and two‐fold coordinated gold atoms. The relevant bond lengths and angles are: AuS 228.4 and 229.6 pm, SiS 216.9 pm, SAuS 178.8° and 178.3°, AuSAu 90.3°, SiSAu 103.7° and 101.9°. The gold atoms are separated by 324.8 pm.