The hydrosilylation/reduction of tertiary and secondary phosphine oxides to phosphines is catalyzed by B­(C6F5)3 or electrophilic fluorophosphonium cations (EPCs). B­(C6F5)3 is an effective catalyst for phosphine oxide reduction using (EtO)3SiH, PhSiH3, and Ph2SiH2 at elevated temperature (105 °C), while EPCs effect the same reduction at significantly lower temperature with PhSiH3 as reducing agent, allowing for good functional-group tolerance.

Allenylidene complexes [Ru(η 5 -C 9 H 7 )(C CCPh 2 ){P(OR) 3 }(PPh 3 )][PF 6 ] (R = Et (1), Me (2)) have been synthesized by the reaction of the complexes [Ru(η 5 -C 9 H 7 )Cl{P(OR) 3 }(PPh 3 )] with 1,1-diphenyl-2-propyn-1-ol in the presence of NaPF 6 . Addition of different nucleophiles to complex 1 allows the synthesis of new allenyl or alkynyl ruthenium complexes depending on the regiochemistry of the reaction. Unexpected complexes [Ru(η 5 -C 9 H 7 ){κ 3 (C,C,C)-C-(R 2 PCH 2 CHCH 2 )CCPh 2 }{P(OEt) 3 }][PF 6 ] (R = i Pr (9a), Ph (9b)), containing an unusual κ 3 (C,C,C)-ligand have been obtained from the reaction of the allenylidene complex 1 with alkenylphosphane Ph 2 PCH 2 CHCH 2 (ADPP) or i Pr 2 PCH 2 CHCH 2 (ADIP). The formation of these complexes is proposed to proceed through an intermediate, [Ru(η 5 -C 9 H 7 )(CCCPh 2 ){P(OR) 3 }{κ 1 (P)-R 2 PCH 2 CHCH 2 }][PF 6 ].

The reaction of the dimeric complex [RuCl(μ-Cl)(η6-C10H14)]2 (C10H14 = p-cymene) with an excess of allyldiisopropylphosphane (ADIP) leads to the complex [RuCl(η6-C10H14){κ2(P,C)-iPr2PCH2CH(iPr2PCH2CHCH2)CH2}] + (1 + ), which presents a new bidentate κ2(P,C) ligand. The same cationic complex can be prepared by nuclephilic attack of 1 equiv of the free ADIP at the coordinated κ3(P,C,C)-iPr2PCH2CHCH2 ligand in [RuCl(η6-C10H14){κ3(P,C,C)-iPr2PCH2CHCH2}] + (3 + ). Addition of different phosphane ligands to complex 3 + allows to the synthesis of ruthenium complexes with new bidentate ligands κ2(P,C). The unusual complexes [Ru{κ3(P,C,S)-iPr2PCH2CH(SR)CH2}(η6-C10H14)] + (11a–c + ) containing new κ3(P,C,S) ligands can be obtained by the reaction of 3 + with anionic nucleophiles RS–. For comparative purposes, the indenyl complex [Ru(η5-C9H7){κ3(P,C,C)-iPr2PCH2CHCH2}(PPh3)] + (8 + ) has been also prepared and differences in the reactivities of cationic complexes 3 + and 8 + toward nucleophiles are pointed out.

Nucleophilic attack on complex [RuCl(η6‐C10H14){κ3(P,C,C)‐Ph2PCH2CH=CH2}][BPh4] (2) takes place, either to the metal or to the coordinated olefin depending on the nucleophile and the reaction conditions. The nucleophilic attack of phosphanes on the coordinated olefin leads diastereoselectively to complexes [RuCl(η6‐C10H14){ĸ2(P,C)‐Ph2PCH2CH(PR3)CH2}]+ bearing κ2(P,C)‐ligands obtained as a racemic mixture of the enantiomers RRuSc/SRuRC. These kinetically stable isomers, undergo an isomerization process leading to the thermodynamically stable products isolated as the diastereoisomer RRuRC/SRuSC. 31P{1H} NMR monitoring experiments on the isomerization processes have been carried out.