Reactivities of π-electron-rich phosphorusnitrogen ligands toward Groups VIB and VIIB metal carbonyl complexes

The interaction of (Ph2PN)C(Ph)[N(SiMe3)2] (L1) with one equivalent of Mn(CO)5Br afforded cis-Mn(CO)4Br{(Ph2PN)C(Ph)[N(SiMe3)2]} (1), which upon boiling in THF gave fac-Mn(CO)3Br[(Ph2PNH)C(Ph)(NSiMe3)] (2), and with one equivalent of Re(CO)5X (X=Br or Cl) gave fac-Re(CO)3X[(Ph2PNH)C(Ph)(NH)] [X=Br (3) or Cl (4)] in good yield. Reaction of 1,4-C6H4{C(NPPh2)[N(SiMe3)2]}2 (L2) with two equivalents of Mn(CO)5Br gave the symmetric dimer [cis-Mn(CO)4Br]2{(Ph2PN)[N(SiMe3)2]C}2C6H4-1,4 (5), and with two equivalents of Re(CO)5Br gave the cyclic dimer cyclo-[fac-(Me2NCHO)Re(CO)3(μ-Ph2PO2)]2 (6) upon recrystallization in DMF. Treatment of (NC5H4){(Ph2PN)C[N(SiMe3)2]}-4 (L3) with one equivalent of (nbd)M(CO)4 (M=Mo or Cr, nbd=norbornadiene) in THF produced cis-M(CO)4{(NC5H4)[(Ph2PNH)C(NSiMe3)]-4} [M=Mo (7) or Cr (8)], and with excess Mn(CO)5Br led to the trinuclear complex fac-{cis-Mn(CO)4Br[(NC5H4){(Ph2PN)C[N(SiMe3)2]}-4]}2Mn(CO)3Br (9) in good yield. Compound 7, in the presence of CdCl2, hydrolyzed to cis-Mo(CO)4{(NC5H4)[(Ph2PNH)C(NH)]-4} (10). Compound 8 reacted with half an equivalent of Mn(CO)5Br to give the trinuclear complex fac-[cis-Cr(CO)4{(NC5H4)[(Ph2PNH)C(NSiMe3)]-4}]2Mn(CO)3Br (11). All the new compounds were characterized by spectroscopic and analytical methods and the structures of compounds 1, 3, 6, 9 and 10 were established by X-ray crystallography.