A preparative and multinuclear nuclear magnetic resonance spectroscopic study of As(SPh)_<i>x</i>(SePh)_3−<i>x</i><i>(x</i> = 0−3), Sb(SPh)_<i>x</i>(SePh)_3−<i>x</i> (<i>x</i> = 0−3), Bi(SPh)₃, Bi(SePh)₃, [Sn(SPh)_<i>x</i>(SePh)_3−<i>x</i>]⁻<i>(x</i> = 0−3), Pb(SePh)₃⁻, and Pb(SPh)₃⁻ and some related thiolatoplumbates(II)

Abstract

The phenyl selenolates of tin(II), lead(II), arsenic(III), antimony(III), and bismuth(III), M(SePh) n (M = Sn(II) or Pb(II), n = 2; M = As(III), Sb(III), or Bi(III), n = 3), have been synthesized by acid–base reaction of the appropriate metal acetate (for M = Sn(II) or Pb(II)) or thiophenolate (for all five elements) with PhSeH, and characterized by elemental analysis and, for the Group V elements, 77 Se and 13 C nmr spectroscopy.M(SPh) 2 and M(SePh) 2 (M = Sn(II) or Pb(II)) are poorly soluble in MeOH but dissolve in the presence of an equimolar or greater amount of PhS − or PhSe − . The soluble stannate(II) complexes are triligated as shown by the slow exchange 119 Sn and, where appropriate, 77 Se nmr spectra of the series [Sn(SPh) x (SePh) 3−x ] − (x = 0−3) measured for the supernatant liquor of mixtures in which {Sn(EPh) 2 } total /PhE − total &gt; I. The corresponding plumbate(II) complexes are probably triligated also, but are labile on the nmr timescale; the parent complexes Pb(Eph) 3 − have been characterized in solution by 207 Pb and 13 C (E = S and Se) and 77 Se (E = Se) nmr spectroscopy. For both Pb(II) and Sn(II), the order of chemical shifts in the metal nmr spectra is δ(MSe 3 ) &gt; 5(MS 3 ). The metal nmr spectra of the mixtures M(SePh) 2 :PhSe − :PhS − ≈ 1:2:4 (M = Sn(II) or Pb(II)) show that the coordination of PhSe − occurs in preference to coordination of PhS − for both tin(II) and lead(II).Thiolatoplumbates(II) might be formed during some antidotal treatments for lead poisoning, so "fingerprint" 207 Pb nmr spectra have been measured for a range of model soluble species formed in Pb(SR) 2 −(excess)RS − mixtures in MeOH, including some mixtures containing newly synthesized and characterized lead thiolates derived from dithiolate anions. For RS − = MeS − , EtS − , PhS − , C 6 H 11 S − (for which "Pb(SR) 2 " has been shown to be Pb(SC 6 H 11 )(OAc)), − S(CH 2 ) 2 S − /2, − SCH 2 CHS − Me/2, and − SCH 2 CHS − CH 2 OH 2 , δ Pb (from PbMe 4 in toluene as reference) falls in the comparatively short range 2518–2999 ppm.The redistribution of ligands between M(SPh) 3 and M(SePh) 3 in chloroform to give equilibrium mixtures of M(SPh) x (SePh) 3−x , occurs slowly on the preparative timescale for M = As, rapidly on the preparative timescale but slowly on the 13 C and 77 Se nmr timescales for M = Sb, and rapidly on the 13 C and 77 Se nmr timescales for M = Bi. Thus 13 C and, where appropriate, 77 Se nmr data are reported for M(SPh) x (SePh) 3−x (M = As or Sb) and Bi(EPh) 3 (E = S or Se). In addition, it has been possible, using 13 C nmr assessment of species distribution in the systems Sb(SPh) 3 –As(SePh) 3 and Bi(SPh) 3 –As(SePh) 3 , to deduce that for the trivalent Group V elements the order of preference for PhSe − over PhS − as ligands is Bi &gt; Sb &gt; As.Trends in the 13 C nmr data for M(SPh) x (SePh) 3−x (M = As or Sb) and 77 Se nmr data for a range of metal complexes of PhSe − have been discussed. The selenium chemical shifts are influenced primarily by the acceptor atom and are in the order Cd(II) &lt; Zn(II) &lt; Pb(II) &lt; Sn(II) &lt; As(III) &lt; Bi(III) &lt; Sb(III).