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Coordination chemistry of [C(PPh2)(P(S)Ph2)2]−: 31P NMR of rhodium, iridium and platinum complexes, and the crystal and molecular structures of [Rh(cod){C(PPh2)(P(S)Ph2)2-P,S}] · CH2Cl2 and [RhI2(tBuNC)2{C(PPh2)(P(S)Ph2)2-P, S}]

1993; Elsevier BV; Volume: 460; Issue: 1 Linguagem: Inglês

10.1016/0022-328x(93)80367-k

1872-8561

Jane Browning, Keith R. Dixon, Neil J. Meanwell, Fang Wang,

Catalytic C–H Functionalization Methods

Complexes of the anionic ligand, [C(PPh2)(P(S)Ph2)2]−, are readily prepared under mild conditions by reactions of CH(PPh2)(P(S)Ph2)2, in the presence of base (NHEt2), with chlorobridged complexes, [M2Cl2(cod)2], M  Rh or Ir, cod = cycloocta-1,5-diene, [Pt2Cl4(PEt3)2], and [Pt2Cl2(MeOcod)2], MeOcod = 8-methoxy-cyclooct-4-ene-1-yl. The products are [M(cod){C(PPh2)(P(S)Ph2)2-P,S}], [PtCl(PEt3){C(PPh2)(P(S)Ph2)2-P,S}], and [Pt(MeOcod){C(PPh2)(P(S)Ph2)2-P,S}] respectively, and the platinum complexes are both mixtures of the two possible isomers. Subsequent reactions of [Rh(cod){C(PPh2)(P(S)Ph2)2-P,S}] with tBuNC followed by oxidative addition of I2 or benzyl bromide give [Rh(tBuNC)2{C(PPh2)(P(S)Ph2)2-P,S}], and isomeric mixtures of [RhI2(tBuNC)2{C(PPh2)(P(S)Ph2)2- P, S}] and [RhBr(Bz)(tBuNC)2{C(PPh2)(P(S)Ph2)2-P, S}]. The complexes were characterized primarily by 31P nuclear magnetic resonance (NMR) studies and by two crystal structure determinations. Complex 1a, [Rh(cod){C(PPh2)(P(S)Ph2)2-P,S}]·CH2Cl2 crystallized in the P21/c (No. 14) space group (Z = 4) with a = 12.294(3), b = 16.063(5), c = 21.384(5), Å, β = 91.60(3)°. Complex 4a(i), [RhI2(tBuNC)2{C(PPh2)(P(S)Ph2)2-P,S}] crystallizes in the P421/c (No. 114) space group (Z = 8) with a = b = 30.174(3), c = 11.317(2) Å. Both complexes contain bidentate P, S bonded ligands with the second PS group non-coordinated (“dangling”). In 1a, approximate square planar coordination about rhodium is completed by the two double bonds of a cod ligand, and in 4a(i), the P,S ligand and two cis iodides comprise the equatorial plane of an octahedron which is completed by two tBuNC ligands.