Reactions of binuclear ruthenium–platinum μ-allenyl complexes with nucleophilic and electrophilic reagents. The characterization of two 1:1 adducts of L(PPh 3)Pt(μ-η 1:η 2α,β-C(Ph)CCH 2)Ru(CO)Cp (L=PPh 3, t-BuNC) and p-toluenesulfonyl isocyanate

Abstract

Reactions of (PPh 3) 2Pt(μ-η 1:η 2 α,β-C(R)CCH 2)Ru(CO)Cp (R=H ( 1), Ph ( 2)) with Ph 2PCH 2CH 2CH 2PPh 2, PEt 3 and t-BuNC in THF at −78°C to room temperature afforded the substitution products L 2Pt(μ-η 1:η 2 α,β-C(R)CCH 2)Ru(CO)Cp (R=H, L 2=Ph 2PCH 2CH 2CH 2PPh 2 ( 3), R=Ph, L 2=Ph 2PCH 2CH 2CH 2PPh 2 ( 4), R=H, L 2=2PEt 3 ( 5), R=Ph, L 2=PPh 3 and t-BuNC ( 6)). No reaction was observed for 1 with Et 2NH or C 6H 11NH 2 and 2 with p-TolS(O) 2NH 2 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 (PPh 3) 2Pt(μ-η 1:η 2 α,β-C(Ph)CCHC(O)NHS(O) 2Tol- p) ( 7) and the [3+2] cycloadduct (PPh 3) 2Pt(μ-η 1:η 2-CC(Ph)N(S(O) 2Tol- p)C(O)CH 2)Ru(CO)Cp ( 8). Complexes 4 and 6 afforded with TSI, under essentially similar conditions, only [3+2] cycloadducts, L 2Pt(μ-η 1:η 2-CC(Ph)N(S(O) 2Tol- p)C(O)CH 2)Ru(CO)Cp (L 2=Ph 2PCH 2CH 2CH 2PPh 2 ( 9), PPh 3 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·C 3H 6O) 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 MeO 2CCCCO 2Me, MeO 2CCCMe, PhCCH and PhCCPh (L) resulted in the formation of the mononuclear metal complexes Cp(CO) 2RuC(R)CCH 2 (R=H, Ph) and (PPh 3) 2PtL. The reverse of this fragmentation reaction occurred when Cp(CO) 2RuCHCCH 2 was treated with (PPh 3) 2Pt(PhCCPh). No reaction was observed between 2 and each (CN) 2CCPh 2 and MeS(O) 2NSO in benzene or toluene on heating. The η 1-allenyl Cp(CO) 2RuC(Ph)CCH 2, obtained in this study, is a new compound.