Vibrational spectra of square-planar tetrahalogeno-gold(III), -palladium(II), and -platinum(II) anions in solution

Abstract

I.r. and Raman spectra of the salts R₄N[AuX₄][R = Buⁿ or Pnⁿ(n-pentyl), X = Cl or Br] and (R₄N)₂[MX₄](R = Buⁿ or Pnⁿ; M = Pd, X = Cl; M = Pt, X = Cl or Br) in solution are reported, together with the i.r. spectrum of a solid containing (Buⁿ₄N)₂[PdBr₄] and Raman spectra of aqueous solutions containing the above anions and [PtI₄]^2–. Studies of the solvent dependence of the Raman frequencies of [AuCl₄]^– and the cation dependence of vibrational frequencies of solid R₄N[AuCl₄](R = Me, Et, Prⁿ, Buⁿ, or Pnⁿ) have also been made. The inactive B_2u mode has been deduced as 112 cm^–1 from a study of the combination bands of solid Cs[AuCl₄]. The most consistent sets of vibrational frequencies have been used to recalculate force constants.