Thiobenzoates of lead (II) and bismuth (III). The crystal and molecular structures of (AsPh4) [Pb(SOCPh)3] and Pb(SOCPh)2(S2CP{c-C6H11}3)

Abstract

The compounds M(SOCPh)n (M = Pb, n = 2; M = Bi, n = 3) have been prepared by the reaction of M(OAc)n or M(SPh)n with a slight excess of PhCOSH in MeOH. The ligands PhCOS−, (c-C6H11)3PCS2 and (c-C6H11)3PO solubilize Pb(SOCPh)2 in solvents in which it is otherwise poorly soluble. Neither Ph3P nor Ph3P increase the solubility of Pb(SOCPh)2 and none of the above five ligands enhance the solubility of very poorly soluble Bi(SOCPh)3. Solubilization of the Pb(II) compound is due in each case to a 1:1 reaction as shown by the isolation of (Ph4As)(SOCPh)3] (1) and Pb(SOCPh)2(S2CP{c-C6H11}3) (2), and by a multi-NMR (31P, 207Pb) study of the system Pb(SOCPh): (c-C6H11)3PO (in which unidentified more ligand-rich species are also formed). 1 and 2 have been characterized by multi-nuclear magnetic resonance spectroscopy (13C, 31P, 207Pb, as appropriate) and by single crystal X-ray diffractometry techniques at −50 °C. The compound 1•CH2Cl2(=1′) crystallizes in the triclinic space group [Formula: see text] with Z = 2. The crystal data for 1′ are a = 13.395(4), (b) = 16.585(3), c = 11.582(3) Å, α = 88.03(2), β = 112.34(2), γ = 113.00(2)°, V = 2171(1) Å3, ρcalcd(ρobsd) = 1.663 (1.65(3)) g cm−3, RF = 0.038, Rw = 0.035. In the [Pb(SOCPh)3]− anion the Pb—S distances are in the range 2.703(3)–2.763(2) Å. The primary coordination geometry around Pb is trigonal pyramidal (PbS3 kernel). There are four additional weaker interactions with oxygen atoms, one from each ligand and one a bridging interaction that links the anions in a centrosymmetric dimer. The Pb—O distances are in the range 2.879(6)− 3.298(7) Å. Compound 2 crystallizes in the monoclinic space group, P21/c with Z = 4. The crystal data for 2 are, a = 17.039(2), b = 11.834(2), c = 18.965(3) Å, β = 116.44(1)°, V = 3424(1) Å3 ρcalcd ρ(obsd) = 1.621 (1.61(3)) g cm−3RF = 0.034, Rw = 0.029. The (c-C6H11)3PCS2 ligand binds in an anisobidentate manner and the primary coordination geometry around Pb in the neutral molecule is trigonal pyramidal, the primary Pb—S distances in the PbS3 kernel being 2.626(2), 2.755(2), and 2.885(2) Å. The weakly bound sulfur of the (c-C6H11)3PCS2 acts as a bridge, again producing a centrosymmetric dimer. In addition to the two weak interactions to sulfur (3.350(2), 3.639(2) Å) there are also two involving the oxygens of the PhCOS− ligands (2.626(5), 3.002(5) Å).2 is the first complex containing a ligand of the type R3PCS2 bound to a Main Group element.