OLIGOPHOSPHANE LIGANDS .33. INTERMOLECULAR AND INTRAMOLECULAR CLEAVAGES OF SP2-C-H BONDS AND SP3-C-H BONDS IN L4RU(0) COMPLEX-CORES WITH P(ORTHO-C6H4PME2)3, N(CH2CH2PME2)3, MEP(CH2CH2CH2PME2)2/PR3 AND MESI(CH2PME2)3/PR3 (P=ME, OME) AS SUPPORTING LIGANDS

While attempts at the preparation of complexes of composition (pp3)RuH(Ar) (pp3 = P(o-C6H4PMe2)3) by reduction of (pp3)RuCl2 (1) with Na(Hg) in benzene, toluene, and xylenes remained unsuccessful, sodium amalgam reduction of the osmium homologue (pp3)OsCl2 (2) in C6H6 proceeded smoothly at room temperature to afford (pp3)OsH(C6H5) (7). The hydrido phenyl derivatives (pp2)[(MeO)3P]RuH(C6H5) (13) and (sip3)(Me3P)RuH(C6H5) (14) (pp2 = MeP(CH2CH2CH2PMe2)2, sip3 = MeSi(CH2PMe2)3) were similarly obtained by reduction with Na(Hg) of benzene solutions of (pp2)[(MeO)3P]RuCl2 (5) and (sip3)(Me3P)RuCl2 (6), respectively. Treatment of (np3)RuCl2 (3) (np3 = N(CH2CH2PMe2)3) with sodium amalgam in refluxing benzene afforded a 1:4 mixture of (np3)RuH(C6H5) (8) and [(Me2 activated PCH2CH2)2NCH2CH2P(Me)CH2]RuH (9). When the reaction temperature was decreased, the portion of complex 8, formed by intermolecular oxidative C-H addition, was observed to increase. Interaction of (pp2)(Me3P)RuCl2 (4) with Na(Hg) in mesitylene produced (pp2)(Me3P)RuH(CH2C6H3Me2-3,5) (10) together with (pp2)(Me2 activated PCH2)RuH (12), presumably via (pp2)(Me3P)Ru0 and (pp2)Ru0 as reactive intermediates: Reduction of 4 in 1,3,5-Me3C6H3/PMe3 (1:1) yielded metallacycle 12 as the only product of C-H-cleavage, while (pp2)(4-MeC5H4N)RuH(CH2C6H3Me2-3,5) (11) was isolated when dichloride 4 was treated with sodium amalgam in mesitylene under a stream of argon (to remove any PMe3) in the presence of 4-picoline. Cyclometallated (sip3)(Me2 activated PCH2)RuH (15) resulted from Na(Hg) reduction of 6 in p-xylene.