Synthesis and characterization of dinuclear trihydride complexes of platinum with chelating ligands. Crystal and molecular structure of [Pt2H3(Ph2P(CH2)2PPh 2)2][BPh4]

A series of cationic dinuclear trihydride complexes of platinum have been prepared and isolated as the different salts [Pt2H3(L-L)2][A]: 1a, L-L = Ph2P(CH2)2PPh2 (dpe), A = BF4; 1b, L-L = dpe, A = I; 1c, L-L = dpe, A = NO3; 1d, L-L = dpe, A = BPh4; 1a-d3, L-L = dpe, A = BF4; 2a, L-L = Ph2P(CH2)3PPh2 (dpp), A = BF4; 3a, L-L = Ph2P(CH2)4PPh2 (dpb), A = BF4; 3c, L-L = dpb, A = NO3; 4a, L-L = cis-Ph2PCH=CHPPh2 (dpet), A = BF4; 5a, L-L = Ph2P(CH2)2AsPh2 (dpae), A = BF4. Raman spectroscopic data (for 1a) indicate the presence of both terminally bonded and bridge-bonded hydride while only the terminal hydride absorptions are seen in the IR spectra. 1H, 31P, and 195Pt NMR studies indicate fluxional behavior down to -95°C. Crystal and molecular structure determination of 1d was undertaken at 115 K. The salt crystallizes in the monoclinic space group C2h5-P21/n with cell dimensions a = 11.107 (2) Å, b = 29.118 (4) Å, c = 19.646 (2) Å, and β = 97.62 (1)°. There are four [Pt2H3Ph2P(CH2)2PPh 2] cations and four BPh4 anions per unit cell. The bidentate phosphine groups are chelated each to a separate metal atom, and two hydrogen atoms are observed to be bridging between the two metal atoms. If the bridging hydrogen atoms are ignored, coordination around one of the two metal atoms, Pt(1), is close to a square plane while that around Pt(2) is trigonal. The square plane around Pt(1) consists of two cis-coordinated phosphorus atoms, Pt(2), and the terminally bonded hydrogen atom. The trigonal coordination around Pt(2) is composed of two cis-coordinated phosphorus atoms and Pt(1). The Pt-Pt distance (bridged by two hydrogen atoms) is 2.728 Å with Pt-Hμ distances estimated to be in the range 1.4 (1)-2.0 (1) Å. © 1983 American Chemical Society.