Synthesis, reactivity and catalytic activity in transfer hydrogenation of ketones of ruthenium(II) and ruthenium(IV) complexes containing the novel N-thiophosphorylated iminophosphorane-phosphine ligands Ph2PCH2P{=NP(=S)(OR)2}Ph2(R = Et, Ph)

Iminophosphorane-phosphines Ph2PCH2P{=NP(=)(OR)2}Ph2(R = Et 1a, Ph 1b) have been prepared by treatment of bis (diphenylphosphino)methane with an equimolar amount of thiophosphorylated azides (RO)2P(=S)N3. Dimers [{Ru((eta)^6-p-cymene)(µCl)Cl}2] and [{Ru((eta)^3:(eta)^3-C10H16)(µ-Cl)Cl}2] react with a two-fold excess of 1a,b yielding the neutral complexes [Ru((eta)^6-pcymene)Cl2((kappa)^1-P-Ph2PCH2P{=NP(=S)(OR)2}Ph2)](R = Et 2a, Ph 2b) and [Ru((eta)^3:(eta)^3-C10H16)Cl2((kappa)1-PPh2PCH2P{=NP(=S)(OR)2}Ph2)](R = Et 5a, Ph 5b), respectively. Treatment of 2a,b and 5a,b with one equivalent of AgSbF6 affords the cationic species [Ru((eta)^6-p-cymene)Cl((kappa)^2-P,S-Ph2PCH2P{=NP=(S)(OR)2}Ph2)][SbF6](R = Et 3a, Ph 3b) and [Ru((eta)^3: (eta)^3-C10H16)Cl((kappa)2-P,S-Ph2PCH2P{=N=P(S)(OR)2}Ph2)][SbF6](R = Et 6a, Ph 6b), respectively. The structure of the cation of complex 6a has been confirmed by X-ray crystallography. The preference observed for the (kappa)^2-P,S- vs. (kappa)^2-P,Ncoordination of 1a,b seems to be sterically controlled since theoretical calculations on the models [Ru((eta)^6-C6H6)Cl((kappa)^2-P, N-H2PCH2P{NP(S)(OH)2}H2)]+A and [Ru((eta)^6-C6H6)Cl((kappa)^2-P,S-H2PCH2P{=NP=(S)(OH)2}H2)]+B show that isomer A is ca. 5.0 kcal mol–1 more stable than B. Dicationic complexes [Ru((eta)^6-p-cymene)((kappa)^3-P,N,S-Ph2PCH2P{=NP=(S)(OR)2}Ph2)][SbF6]2 (R = Et 4a, Ph 4b) and [Ru((eta)^3:(eta)^3-C10H16)((kappa)^3-P,N,S-Ph2PCH2P{=N=P(S)(OR)2}Ph2)][SbF6]2(R = Et 7a, Ph 7b) have been obtained by treating 2a,b and 5a,b, respectively, with two equivalents of AgSbF6. The reactivity of [Ru((eta)^6-p-cymene) ((kappa)^3-P,N,S-Ph2PCH2P{=NP=(S)(OEt)2}Ph2)][SbF6]24a towards neutral and anionic ligands has been explored allowing the synthesis of complexes [Ru(6-p-cymene)(L)((kappa)^2-P,S-Ph2PCH2P{=NP=(S)(OEt)2}Ph2)][SbF6]2(L = N(identical)CMe 8, PMe39, PMe2Ph 10, PMePh211) and [Ru((eta)^6-p-cymene)X((kappa)^2-P,S-Ph2PCH2P{=NP=(S)(OEt)2}Ph2)][SbF6](X = Br 12, I 13, N314), respectively. The catalytic activity of complexes 2-7a,b in transfer hydrogenation of ketones by propan-2-ol has been also studied.