72905-56-7Relevant academic research and scientific papers
Novel bonding modes of α-diimines. Synthesis and characterization of [MCl2L(α-diimine)] and [MCl2(α-diimine)n] (M = Pd, Pt; L = phosphine, arsine; n = 1, 2) containing σ,σ-N,N′, σ-N, or σ-N ? σ-N′ bonded α-diimines
Van Der Poel, Henk,Van Koten, Gerard,Vrieze, Kees
, p. 1145 - 1151 (2008/10/08)
Compounds of the type [PdX2(RN=CHCH=NR)n] (n = 1, 2; X = Cl, Br, I) and [MIICl2L(RN=CHCH=NR)] (L = monodentate phosphine or arsine; M = Pd, Pt; R = alkyl) have been synthesized starting from the α-diimine (R-dim) and [PdCl2(PhCN)2] or [(MIICl2L)2], respectively. Three types of metal - α-diimine interactions have been established: (i) σ,σ-N,N′ chelate bonded R-dim in [PdX2(R-dim)]; (ii) σ-N monodentate bonded R-dim in monomeric trans-[PdX2(R-dim)2] (1H and 13C NMR spectroscopy reveals that the R-dim ligand has the anti conformation with the C-C and Pd-N bonds of the coordinated part of the ligand in the cis configuration. This brings the β-imine proton (δ(CH) 9.70) in the proximity of the palladium atom.); (iii) σ-N ? σ-N′ bonded R-dim in the monomeric complexes, trans-[MIICl2L(R-dim)], which contain monodentate (σ-N) bonded R-dim in the slow-exchange limit (-55°C). At 120°C (fast-exchange limit) the complexes are fluxional by an intramolecular process which involves a pentacoordinate intermediate containing σ,σ-N,N′ bonded R-dim. These novel bonding modes for the R-dim ligand in these palladium and platinum complexes are a clear indication of the versatile coordination properties of the R-dim ligand compared with ligands such as bpy and phen, which also contain the N=CC=N skeleton.
