Synthesis and multinuclear NMR study of Hg(II), Cd(II), and Pd(II) complexes with biphenylmethylenetriphenylphosphorane: X-ray crystal structure of [{C6H5C6H4CO{(C6H5)3P}CH}HgI2]2

Reactions of title ylide, {(C₆H₅)₃PCHCOC₆H₄C₆H₅)} (BPPPY), with mercury(II) halides in equimolar ratios in methanol yielded dinuclear complexes (BPPPY)HgCl₂]₂ (1), (BPPPY)HgBr₂]₂ (2), and (BPPPY)HgI₂]₂ (3). Reactions of BPPPY with CdCl₂ in equimolar ratios gave (BPPPY)CdCl₂]₂ (4). Reaction of PdCl₂ with BPPPY (1/2) in acetonitrile at room temperature gave cis/trans PdCl₂{CH(PPh₃)COC₆H₄C₆H₅}₂] (5). The same reaction at reflux gave the orthopalladated complex Pd{CH{P(2-C₆H₄)Ph}(COC₆H₄C₆H₅)}(μ-Cl)]₂ (6) along with the phosphonium salt Ph₃PCHCOC₆H₄C₆H₅]Br. The compounds were characterized by elemental analysis, IR-, ¹H-, ¹³C-, and ³¹P-NMR spectroscopy. Single crystal X-ray analysis of 3 reveals the centrosymmetric dimeric structure containing the ylide and HgI₂. Crystallographic data for 3 are: crystal system, monoclinic; space group, P 2₁/n, a = 15.7744(7), b = 23.0288(9), c = 20.2867(9) Å, β = 112.237(3)°, V = 6821.4(5) ų, and Z = 1.