Generation of metal formyl complexes using nickel and platinum hydrides as reducing agents

Abstract

The five-coordinate nickel hydride complex [Ni(dmpe)[sub 2]H]PF[sub 6] (1) [dmpe = 1,2-bis-(dimethylphosphino)ethane] was synthesized by protonation of Ni(dmpe)[sub 2] with NH[sub 4]PF[sub 6]. The platinum analog, [Pt(dmpe)[sub 2]H]PF[sub 6] (2), and [Pt(depe)[sub 2]H]PF[sub 6] (3) [depe = 1, 2-bis(diethylphosphino)ethane]RB were synthesized by reduction of the corresponding Pt(II) complexes with NaBH[sub 4] on alumina. Complexes 1 and 3 can also be synthesized electrochemically. Reduction of Ni-(dmpe)[sub 2][sup 2+] by two electrons in the presence of ammonium ion generates 1, and reduction of Pt(depe)[sub 2][sup 2+] in methanol or wet acetonitrile produces 3. These hydrides react with a variety of cationic metal carbonyl complexes to produce known metal formyl complexes. The structure of 3 was determined by X-ray diffraction. Complex 3 crystallizes in a monoclinic unit cell with P2[sub 1]/c symmetry with a = 14.258 (4) [angstrom], b = 9.648 (3) [angstrom], c = 21.898 (5) [angstrom], [beta] = 91.17 (2)[degrees], V = 3011.7 (14) [degrees][sup 3], Z = 4, and d[sub calcd] = 1.662 g/cm[sup 3]. Full-matrix least-squares refinement converged with residuals R = 4.52% and R[sub w] = 5.90%. 21 refs., 1 fig., 4 tabs.