Chemoselective Reactions of the Phosphino Enolate Li[Ph2PCH C( O)NPh2] with Ph2P−Cl and M−Cl Bonds (M = Pd, Pt). Coordination Properties of the New Functional Diphosphine Ligand (Ph2P)2CHC(O)NPh2. Hemilabile Behavior of [Cu2{(Ph2P)2CHC(O)NPh2-P,P,O}2](BF4)2. Reactivity and Molecular Structure of [(8-mq)Pd{Ph2PCH C( O)NPh2}]

The functional phosphine Ph 2 PCH 2 C(O)NPh 2 ( L 1 ) was obtained by P−C selective coupling of Ph 2 PCl with Li[CH 2 C( O)NPh 2 ] and we have studied the influence of the −NPh 2 substituent on the reactivity of the corresponding enolate Li[Ph 2 PCH C( O)NPh 2 ] toward Ph 2 P−Cl and M−Cl bonds (M = Pd, Pt). A selective P−C coupling reaction with Ph 2 PCl allowed the synthesis of the new diphosphine ligand (Ph 2 P) 2 CHC(O)NPh 2 [bis(diphenylphosphino)- N, N -diphenylacetamide] ( L 2 ). The dicationic dinuclear complex [Cu 2 {(Ph 2 P) 2 CHC(O)NPh 2 - P, P, O } 2 ](BF 4 ) 2 ( 3 ) has been obtained from the reaction of [Cu(NCMe) 4 ](BF 4 ) with L 2 . A preliminary X-ray diffraction study revealed a μ 2 -η 3 tripod-like bonding for L 2 in this centrosymmetric dimeric complex: each copper atom is P,O-chelated by one ligand and P-bonded to the other ligand. An eight-membered Cu 2 P 4 C 2 ring is thus formed with the functional diphosphine ligand. The dynamic behavior has been studied in CHCl 3 solution of mono- and binuclear copper(I) complexes of L 1 and L 2 . Reversible oxygen-metal dissociation occurs in the presence of donor solvents such as NCMe or SMe 2 . The reaction of Li[Ph 2 PCH C( O)NPh 2 ] with [(C N)Pd(μ-Cl) 2 ] afforded the complexes [(C N)Pd{Ph 2 PCH C( O)NPh 2 }] [( 9 ) (C N) = dimethylbenzylamine (dmba); ( 10 ) (C N) = 8-methylquinoline (8-mq)]. The molecular structure of [(8-mq)Pd{Ph 2 PCH C( O)NPh 2 }] has been determined by single-crystal X-ray diffraction: it crystallizes in the monoclinic space group P 2 1 / c with Z = 4 in a unit cell of dimensions a = 8.801(2) Å, b = 31.483(6) Å, c = 10.939(2) Å, β = 101.37(2)°. The structure has been solved from diffractometer data by Patterson and Fourier methods and refined by full-matrix least-squares methods on the basis of 2863 observed reflections to R and R w values of 0.0268 and 0.0338, respectively. A temperature dependence of the reaction of Li[Ph 2 PCH C( O)NPh 2 ] with [PtCl 2 (NCPh) 2 ] has been observed which leads to cis -Pt[Ph 2 PCH C( O)NPh 2 ] 2 ( 11 ) at −60 °C and to trans -Pt[Ph 2 PC{ C(NH)Ph}{C(O)NPh 2 }] 2 ( 12 ) at 0 °C. The high reactivity of cis -Pt[Ph 2 PCH C( O)NPh 2 ] 2 toward p -MeC 6 H 4 NCO leads to two diastereoisomeric products cis -Pt[Ph 2 PCH{C(O)N( p -MeC 6 H 4 )}{C(O)NPh 2 }] 2 ( 16a,b in a 1:1 ratio), which contain new chiral heterodifunctional phosphines.