Preparation of ruthenium silanethiolato complexes and their reactions withsulfur dioxide; possible models for the activation of SO2 in the homogeneously catalyzed Claus reactions

CpRu(PPh3)(2)(SSiPr3)-Pr-i (6a) was prepared by reacting [CpRu(PPh3)(2)(ace tone)]BF4 and (NaSSiPr3)-Pr-i. Complex 6a is substitution-labile and readil y gave the mixed-ligand derivatives CpRu(PPh3)(L)(SSiPr3)-Pr-i, where L = C O (6b), PMe3 (6c), P(OMe)(3) (6d), upon treatment with the corresponding li gands. CpRu(dppe)(SSiPr3)-Pr-i (6e) was obtained from complex 6a and dppe v ia the intermediate formation of CpRu(PPh3)(eta(1)-dppe)(SSiPr3)-Pr-i. Trea tment of complex 6a with one equivalent of SO2 gave primarily unstable CpRu (PPh3)(SO2)(SSiPr3)-Pr-i (6f). However, complexes 6b-e inserted one equival ent of SO2 solely at their S-(SiPr3)-Pr-i function to give the unstable O-s ilyl thiosulfito complexes CpRu(PPh3)(L)SS(O)(OSiPr3)-Pr-i (L = CO (8b), PM e3 (8c), P(OMe)(3) (8d)) as well as CpRu(dppe)SS(O)(OSiPr3)-Pr-i (8e). The S-H bonds of CpRu(PPh3)(2)SH (7a) and CpRu(dppe)SH (7b) added to PhNSO to g ive CpRu(PPh3)(2)SS(O)NHPh (9a) and CpRu(dppe)SS(O)NHPh (9b), respectively. The crystal structure of complex 6a was determined. Crystallographic data for 6a: triclinic, P (1) over bar, a = 10.642(6) Angstrom, b = 11.068(8) An gstrom, c = 21.994(10) Angstrom, alpha = 79.27(5)degrees, beta = 89.22(5)de grees, gamma = 62.32(4)degrees, V = 2246(2) Angstrom(3), Z = 2. (C) 2000 El sevier Science S.A. All rights reserved.