Reaction of the lithium-bis(iminophosphorany1)methanide compounds Li[CH(PPh2=N-C&-R'-4)21 (2a, R' = CH3; 2b, R' = CH3 and NO2; 2c, R' = NO21 with [ML2C112 (M = Rh, L2 = COD, L = CO; M = Ir, L2 = COD) yields the novel bis(iminophosphorany1)methanide complexes [M CHComplex 3a (M = Rh, R' = CH3, La = COD) has also een synthesized in the reaction of CH2-(PPhyN-C&CH3-4)2 (la) with [Rh(COD)(OMe)l2. The COD li and in the Ir-COD com ounds 4a-c can be substituted by reaction with CO to give [ I~( C H ( P P~~~-C B H~-R ' )~) ( C O )~~ (ad-6. The solid-state structure of 4a (M = Ir, R' = CH3, L2 = COD) has beendetermined by an X-ray diffraction stud Compound 4a crystallizes in the triclinic space group P1 with a = 10.633 (2) A, b = 11.766 (2) t c = 17.366 (2) A, a = 99.73 ( 1 ) O , j3 = 90.59 (3)O, y = 95.42 (2)O, and 2 = 2. The structure was refined to R = 0.055 (R, = 0.060) using 4065 independent observed reflections. The bis-(imino hosphorany1)methanide ligand is coordinated in a a-N,a-C chelate mode toward the square moiety. g p o r t a n t bond distances and angles are Pl-Nl = 1.55 (1) A, P2-N2 = 1.62 (1) f, Pl-Cl (4)O, Cl-Pl-NI = 119.3 (6)", and C~-P~-NP = 96.4 (5)". In solution the bis(iminophos horany1)-coligands become equivalent. The exchan e processes for 3a, 3b, 4a, and 4d have been studied by intermediate five-coordinate complex that is formed via intramo ecular attack of the pen antiminophosphorane entity. Additional structural information has been acquired from IR and 13C, lo3Rh, and solid state 31P{1HJ CP/MAS NMR spectroscopy. Complexes 3a, 3b, 4a, and 4d react with C02 in an aza-Witti reaction to ive the (iminophosphoranyl)(oxophosphoranyl)methyl complexesThe inertness of the four membered M-N-P-C rin toward C02 stresses the nonreactivity of this atom of t h e free iminophosphorane moiety, affording t h e complexes [M{CH-(11). Reaction with HC1 leads to a net protonation of either the methanide or the nitrogen atoms with formation of the known coordination com lexes of bis(iminophosphoranyl)methane, in which the li and is either coordinated as a a-N,a-C cherate ( i n 11) o r a s a a-N,a-N' c h e l a t e in [M~(4-CH3-CsH4-N=PPh2)2CH2 -and a subsequent hydrogen-migration reaction from the metal to either the methanide C atom or the N atom of the coordinated iminophoaphorane entity. This has been evidenced by the observation of Ir-hydride complexes (lH NMR) in the reaction of 4a with 1 equiv of HCl at 193 K. These complexes react further to ive I1 and I11 upon raisin the temperature to 233 K. Addition of excess [ M L z X ]~ and the amino[ (aminop osphonio)methyl]phosphonium compounds [ H2-(PPh~N-CsH4-R'-4)2)Lzl (3a-d, 4a-c), in which the li and is coordinated as a a-N,u-C che \ ate. planar P r, 'ving rise to a four-membered M-N-P-C metallacycle and one pendant iminophoa horane methanide complexes undergo a dynamic process, in which both halves of the ligan a and both using variable-temperature lH and 31P N If R they occur via a Ber pseudorotation, involvin an [M{CH(PPhl=N-~H4-CH3-4)( P, P h d ) ) L 2 ] (Sa-d),...
