(p-cymene)Ruthenium(II)(diphenylphosphino)alkyne Complexes: Preparation of (mu-Cl)(mu-PPh2C=CR) Bridged Ru/Pt Heterobimetallic Complexes.

Abstract

The neutral complexes [n6-p-cymene)RuCl2(PPh 2C≡CR)] (R = Ph 1, tBu 2, (4-CH3)C 6H4 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 T1PF6 and the corresponding PPh 2C≡CR allows the preparation of cationic bis(diphenylphosphino) compounds [(n6-p-cymene)RuCl(PPh2C=CR)2]X (X = OTf; R = Ph 6, tBu 7, (4-CH3)C6H4 8, (4-C≡CPh)C6H4 9, X = PF6; R = (4-CN)C6H410). 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 [(n6-p-cymene)Cl-Ru(μ-Cl)(μ-1KP:n2-PPh 2C=CR)Pt(C6F5)2] (R = Ph 11a, tBu 12a, (4-CH3)C6H413a, (4-C≡CPh)-C6H4 14a) and cationic [(n 6-p-cymene)(PPh2C≡CR)Ru(μ-Cl)(μ-1K:P:n 2-PPh2C≡CR)Pt(C6F5) 2]-(OTf) (R = Ph 15, tBu 16, (4-CH3)C 6H4 17) derivatives stabilized by a mixed Cl/PPh 2C≡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 [(n 6-p-cymene)ClRu(μ-Cl)(μ-1kP:n2-PPh 2C≡CR)Pt(C6F5)2] (a) and [(n6-p-cymene)(PPh2C≡CR)Ru-(μ-Cl) 2Pt(C6F5)2] (b), respectively.