100701-29-9Relevant academic research and scientific papers
Diazoalkane activation by iridium phosphine compounds. 1. Complexes containing the intact dibenzoyldiazomethane ligand and interconversion between the η1-N-bound and a chelated N,O-bound form of the ligand accompanied by hydride migration
Cowie, Martin,Loeb, Stephen J.,McKeer, Ian R.
, p. 854 - 860 (2008/10/08)
The reaction of dibenzoyldiazomethane (N2C(C(O)Ph)2) with trans-[IrCl(N2)(PPh3)2] yields the four-coordinate species [IrCl(N2C(C(O)Ph)2)(PPh3)2] (1) in which the intact diazoalkane molecule is coordinated in a η1, singly bent geometry. Compound 1 reacts with donor ligands, L, to give five-coordinate adducts of formulation [IrCl(N2C(C(O)Ph)2)(L)(PPh3)2] (L = PMe2Ph, t-BuNC, and NO+). The reaction of 1 with 1 equiv of HCl yields an equilibrium mixture of [IrHCl2(N2C(C(O)Ph)2)(PPh3) 2] and [IrCl2(HN2C(C-(O)Ph)2)(PPh3) 2] in which hydride migration from Ir to the coordinated nitrogen atom occurs; the latter species is present in an approximate 15:1 excess. An X-ray structure determination of the second (more abundant) species was undertaken. It crystallizes in the space group P21/c with a = 10.165 (2) A?, b = 17.422 (2) A?, c = 25.653 (5) A?, β = 93.66 (2)°, V = 4533.7 A?3, and Z = 4. The structure has refined to R = 0.044 and Rw = 0.050 based on 190 variables and 1869 unique observations. The compound is a six-coordinate Ir(III) species in which the reduced diazoalkane ligand is coordinated to Ir through the terminal nitrogen atom, which also is bound to the H atom, and a benzoyl oxygen atom.
Diazoalkane activation by iridium phosphine compounds. 2. Unusual products resulting from N2 loss from the dibenzoyldiazomethane ligand: Structures of [IrCl(HC(C(O)Ph)2)(PC6H4Ph 2)(PPh3)]·1/2C6H5CH 3 and [IrCl((C6H ...
Cowie, Martin,McKeer, Ian R.,Loeb, Stephen J.,Gauthier, Michele D.
, p. 860 - 868 (2008/10/08)
Full title: Diazoalkane activation by iridium phosphine compounds. 2. Unusual products resulting from N2 loss from the dibenzoyldiazomethane ligand: Structures of [IrCl(HC(C(O)Ph)2)(PC6H4Ph 2)(PPh3)]·1/2C6H5CH 3 and [IrCl((C6H4)C(O)CC(Ph)OPPh2)(PPh 3)2]·C6H5CH3. Refluxing [IrCl(N2C(C(O)Ph)2)(PPh3)2] in toluene results in N2 loss and ortho metalation of one of the phosphine phenyl groups, yielding the β-diketonate complex [IrCl(HC(C(O)Ph)2)(PC6H4Ph 2)(PPh3)] (2). The diketonate group, which chelates through both oxygen atoms, is formed by hydride transfer from the metal to the carbene carbon, generated by N2 extrusion. When dibenzoyldiazomethane is reacted with [IrCl(PPh3)3] in refluxing THF, a geometric isomer of 2 is formed as the major product. A minor product in this reaction is [IrCl((C6H4)C(O)CC(Ph)OPPh2)(PPh 3)2] (5), a species containing a highly unusual tridentate ligand which has formed by the condensation of the carbene fragment, resulting from the diazoalkane molecule, and PPh2 which has resulted from phosphorus-aryl bond cleavage in PPh3. The X-ray structures of 2 (as the hemitoluene solvate) and 5 (as the toluene solvate) have been determined. Compound 2 crystallizes in the space group P1 with a = 12.396 (2) A?, b = 19.272 (3) A?, c = 10.742 (1) A?, α = 97.845 (6)°, β = 115.594 (9)°, γ = 78.772 (7)°, and Z = 2. The structure has refined to R = 0.050 and Rw = 0.068 on the basis of 223 parameters refined and 5140 observations. Compound 5 crystallizes in space group P1 with a = 12.1972 (8) A?, b = 10.163 (1) A?, c = 11.761 (1) A?, α = 103.609 (8)°, β = 95.059 (7)°, γ = 96.619 (7)°, and Z = 1 and has refined to R = 0.028 and Rw = 0.037 on the basis of 266 parameters refined and 4387 observations.
