(p-cymene)Ruthenium(II)(diphenylphosphino)alkyne Complexes: Preparation of (μ-Cl)(μ-PPh2C⋮CR)-Bridged Ru/Pt Heterobimetallic Complexes
摘要:
The neutral complexes [(eta(6)-p-cymene)RuCl2(PPh2C=CR)] (R = Ph 1, Bu-t 2, (4-CH3)C6H4 3, (4-C=CPh)C6H4 4, (4-CN)C6H4 5) have been synthesized by reacting [(p-cymene)RuCl2](2) with the respective alkynylphosphine. Treatment of 1-5 with AgOTf or TIPF6 and the corresponding PPh2C=CR allows the preparation of cationic bis(diphenylphosphino) compounds [(eta(6)-p-cymene)RuCl(PPh2C=CR)(2)]X (X = OTf; R = Ph 6, Bu-t 7, (4-CH3)C6H4 8, (4-C=CPh)C6H4 9, X = PF6; R = (4-CN)C6H4 10). All complexes have been characterized by analytical and spectroscopic methods, by cyclic voltammetry, and in several cases (3 and 7) by X-ray crystallography. Reactions of both neutral (1-4) and cationic (6-8) complexes with [cis-Pt(C6F5)(2)(thf)(2)] (thf = tetrahydrofuran) gave heterobimetallic neutral [(n(6)-p-cymene)Cl-Ru(mu-Cl)(mu-1kappaP:eta(2)-PPh2C=CR)Pt(C6F5)(2)] (R = Ph 11a, Bu-t 12a, (4-CH3)C6H4 13a, (4-C=CPh)-C6H4 14a and cationic [(eta(6)-p-cymene)(PPh2C=CR)Ru(rho-Cl)(mu-1kappaP:eta(2)-PPh2C=CR)Pt(C6F5)(2)]-(OTf) (R = Ph 15, Bu-t 16, (4-CH3)C6H4 17) derivatives stabilized by a mixed Cl/PPh2C=CR bridging system. The molecular structures of 12a and 17 have been confirmed by X-ray diffraction. However, the neutral complexes 11-14 existed in solution as a mixture of isomers [(eta(6)-p-cymene)ClRu(mu-Cl)(mu-Cl)(mu-1kappaP:eta(2)-PPh2C=CR)Pt(C6F5)(2)] (a) and [(eta(6)-p-cymene)(PPh2C=CR)Ru(mu-Cl)(2)Pt(C6F5)(2)] (b), respectively.