Mercury(II) complexes of new bidentate phosphorus ylides: synthesis, spectra and crystal structures

The reaction of dppm (1,1-bis(diphenylphosphino)methane) with 2-bromo-4-phenylacetophenone and benzyl bromoacetate in chloroform produces new phosphonium salts, [Ph2PCH2PPh2CH2C(O) C6H4Ph]Br (I) and [Ph2PCH2PPh2CH2COOCH2Ph]Br (II). By allowing the phosphonium salts to react with the appropriate base, the bidentate phosphorus ylides, Ph2PCH2PPh2=C(H)C(O)C6H4Ph (III) and Ph2PCH2PPh2=C(H)C(O)OCH2Ph (IV), were obtained. The reaction of these ligands with mercury(II) halides in dry methanol led to the formation of the mononuclear complexes {HgX2[(Ph2PCH2PPh2C(H)C(O)C6H4Ph)]} (X = Cl (V); X = Br (VI); X = I (VII)) and {HgX2[(Ph2PCH2PPh2C(H)COOCH2Ph)]} (X = Cl (VIII); X = Br (IX); X = I (X)). The FTIR and H-1, P-31 and C-13 NMR spectra were studied. The structure of compound III was unequivocally determined by the single-crystal X-ray diffraction technique. Single-crystal X-ray analysis of the {HgBr2[(Ph2PCH2PPh2C(H)C(O)C6H4Me)]} complex (XI) revealed the presence of a mononuclear complex containing the Hg atom in a distorted tetrahedral environment. In all complexes, the ylides referred to above were coordinated through the ylidic carbon and the phosphine atom. (C) 2013 Institute of Chemistry, Slovak Academy of Sciences