Reactions of binuclear ruthenium–platinum μ-allenyl complexes with nucleophilic and electrophilic reagents. The characterization of two 1:1 adducts of L(PPh3)Pt(μ-η1:η2α,β-C(Ph)CCH2)Ru(CO)Cp (L=PPh3, t-BuNC) and p-toluenesulfonyl isocyanate

Reactions of (PPh3)2Pt(μ-η1:η2α,β-C(R)CCH2)Ru(CO)Cp (R=H (1), Ph (2)) with Ph2PCH2CH2CH2PPh2, PEt3 and t-BuNC in THF at −78°C to room temperature afforded the substitution products L2Pt(μ-η1:η2α,β-C(R)CCH2)Ru(CO)Cp (R=H, L2=Ph2PCH2CH2CH2PPh2 (3), R=Ph, L2=Ph2PCH2CH2CH2PPh2 (4), R=H, L2=2PEt3 (5), R=Ph, L2=PPh3 and t-BuNC (6)). No reaction was observed for 1 with Et2NH or C6H11NH2 and 2 with p-TolS(O)2NH2 in THF at reflux temperature. Complex 2 reacted with p-TolS(O)2NCO (TSI) in toluene at −78°C to room temperature to yield two 1:1 addition products of the reactants: the γ-carbon substituted μ-allenyl (PPh3)2Pt(μ-η1:η2α,β-C(Ph)CCHC(O)NHS(O)2Tol-p) (7) and the [3+2] cycloadduct (PPh3)2Pt(μ-η1:η2-CC(Ph)N(S(O)2Tol-p)C(O)CH2)Ru(CO)Cp (8). Complexes 4 and 6 afforded with TSI, under essentially similar conditions, only [3+2] cycloadducts, L2Pt(μ-η1:η2-CC(Ph)N(S(O)2Tol-p)C(O)CH2)Ru(CO)Cp (L2=Ph2PCH2CH2CH2PPh2 (9), PPh3 and t-BuNC (10)). All products were characterized by a combination of IR and NMR (1H, 13C{1H} and 31P{1H}) spectroscopy, FAB MS and elemental analysis. The structures of 7 (as 7·C3H6O) and 10 were determined by single-crystal X-ray diffraction analysis. Reactions of 2 with trans-NCCHCHCN (L) and of 1 with the alkynes MeO2CCCCO2Me, MeO2CCCMe, PhCCH and PhCCPh (L) resulted in the formation of the mononuclear metal complexes Cp(CO)2RuC(R)CCH2 (R=H, Ph) and (PPh3)2PtL. The reverse of this fragmentation reaction occurred when Cp(CO)2RuCHCCH2 was treated with (PPh3)2Pt(PhCCPh). No reaction was observed between 2 and each (CN)2CCPh2 and MeS(O)2NSO in benzene or toluene on heating. The η1-allenyl Cp(CO)2RuC(Ph)CCH2, obtained in this study, is a new compound.