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:η2αβ-C-(Ph)=C=CH2)Ru(CO)Cp (L = PPh3, t-BuNC) and p-toluenesulfonyl isocyanate

Reactions of (PPh3)(2)Pt(mu-eta(1):eta(alpha,beta)(2)-C(R)=C=CH2)Ru(CO)Cp (R = H (1), Ph (2)) with Ph2PCH2CH2CH2PPh2, PEt3 and t-BuNC in THF at -78 degrees C to room temperature afforded the substitution products L2Pt(mu-eta(1):eta(alpha,beta)(2)-C(R)=C=CH2)Ru(CO)Cp (R = H, L-2 = Ph2PCH2CH2CH2PPh2 (3), R = Ph, L-2 = Ph2PCH2CH2CH2PPh2 (4), R = H, L-2 = 2PEt(3) (5), R = Ph, L-2 = PPh3 and t-BuNC (6)). No reaction was observed for 1 with Et2NH or C6H11NH2 and 2 with p-TolS(O)(2)NH2 in THF at reflux temperature. Complex 2 reacted with p-TolS(O)(2)NCO (TSI) in toluene at -78 degrees C to room temperature to yield two 1:1 addition products of the reactants: the gamma-carbon substituted mu-allenyl (PPh3)(2)Pt(mu-eta(1):eta(alpha,beta)(2)-C(Ph)=C=CHC(O)NHS(O)(2)Tol-p) (7) and the [3 + 2] cycloadduct (PPh3)(2)Pt(mu-eta(1):eta(2)-C=C(Ph)N(S(O)(2)Tol-p)C(O)CH2)Ru(CO)Cp (8). Complexes 4 and 6 afforded with TSI, under essentially similar conditions, only [3 + 2] cycloadducts, L2Pt(mu-eta(1):eta(2)-C=C(Ph)N(S(O)(2)Tol-p)C(O)CH2)Ru(CO)Cp (L-2 = Ph2PCH2CH2CH2PPh2 (9), PPh3 and t-BuNC (10)). All products were characterized by a combination of IR and NMR (H-1, C-13{H-1} and P-31{H-1}) 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)(2)RuC(R)=C=CH2 (R=H, Ph) and (PPh3)(2)PtL. The reverse of this fragmentation reaction occurred when Cp(CO)(2)RuCH=C=CH2 was treated with (PPh3)(2)Pt(PhC=CPh). No reaction was observed between 2 and each (CN)(2)C=Ph-2 and MeS(O)(2)NSO in benzene or toluene on heating. The eta(1)-allenyl Cp(CO)(2)RuC(Ph)=C=CH2, obtained in this study, is a new compound. (C) 2000 Elsevier Science S.A. All rights reserved.