Syntheses, Reactions, and Molecular Structures of trans-Hydrido(phenylamido)bis(triethylphosphine)platinum(II) and trans-Hydridophenoxobis(triethylphosphine)platinum(II)

Article abstract of DOI:10.1021/ja00195a031

The reaction between trans-PtH(NO3)(PEt3)2 and NaNHPh in C6H6 yields the novel hydridoamido complex trans-PtH(NHPh)(PEt3)2 (I).This compound is stable in solution; however, crystals of I decompose within hours at room temperature.At -100 deg C a crystal of I belongs to the monoclinic space group P2₁/n with a = 11.445(2) Angstroem, b = 13.010(2) Angstroem, c = 14.888(2) Angstroem, β = 104.63(1) deg, V = 2144.9(6) Angstroem³, and Z = 4.Complex I adopts a trans structure, with Pt-N = 2.125(5) Angstroem, indicative of a single bond weakened by the trans-hydride ligand.The Pt-N-Ph angle of 125.5(4) deg and the observation of the H on N in a position expected for trigonal-planar coordination suggest sp² hybridization about nitrogen.SCF-DV-Xα calculations of the model complex PtH(NH2)(PH3)2 confirm the expected repulsive nature of the interaction between the nitrogen lone-pair orbital and filled d? orbitals on the metal.This interaction is minimized when the nitrogen lone pair lies in the coordination plane of Pt.The reaction between trans-PtH(NO3)(PEt3)2 and excess NaOPh produces trans-PtH(OPh)(PEt3)2 (II).Crystals of II belong to the triclinic space group PI, and at -50 deg C a = 9.477(3) Angstroem, b = 10.617(3) Angstroem, c = 11.641(3) Angstroem, α = 101.61(2), β = 98.28(2) deg, γ = 104.13(2), V = 1089.5(5) Angstroem³, and Z = 2.This complex is isostructural to I with Pt-O = 2.098(9) Angstroem and Pt-O-Ph = 123.6(7) deg.Complex I undergoes rapid insertion of electrophilic substrates such as CO2.COS, and PhNCO into the Pt-NHPh bond in preference to the metal hydride bond.These reactions in C6H6 solvent do not appear to involve free NHPh(1-) as evidenced by the reaction between PtH((15)NHPh)(PEt3)2, which exclusively yields PtH(PEt3)2 as the initial product.Crossover between PtH(NHPh)(PEt3)2 and PtD((15)NHPh)(PEt3)2 to form PtH((15)NHPh)(PEt3)2 and PtD(NHPh)(PEt3)2 occurs slowly (t_1/2 ca. 48 h) at room temperature.Electrophiles such aas CH3I and H2O directly attack bound aniline in PtD(NHPh)(PEt3)2 to produce trans-PtDI(PEt3)2 and trans-PtD(OH)(PEt3)2, along with NH(CH3)Ph and NH2Ph, respectively.The electrophilic olefin acrylonitrile inserts into the Pt-N bond to form trans-PtH(PEt3)2 (III).Crystals of III belong to the monoclinic space group P2₁/c and at 22 deg C a = 14.260(6) Angstroem, b = 14.021(6) Angstroem, c = 13.240(6) Angstroem, β = 107.96(3) deg, V = 2519(3) Angstroem³, and Z = 4.The structure shows a 3-anilinopropionitrile ligand trans to hydride ?-bound to platinum (Pt-C = 2.198(13) Angstroem) by the 2-carbon atom.Complex III undergoes C-H reductive elimination on heating to 70 deg C to produce 3-anilinopropionitrile.Methyl acrylate appears to undergo a similar insertion reaction; however, the organic product is unstable toward elimination in the presence of "Pt(PEt3)2"...