First heterodifunctional ligand derived from a tetradentate phosphine: synthesis and characterization of cis,trans,cis-1,3-bisdiphenylphosphino/ 2,4-bisdiphenylphosphinothioyl/ cyclobutane and its complex with PdCl2

Cis,trans,cis-1,2,3,4-tetrakisdiphenylphosphino.cyclobutane dppcb. can be selectively oxidized by S in toluene to the disulfide cis,trans,cis-1,3-bisdiphenylphosphino.-2,4-bisdiphenylphosphinothioyl.cyclobutane dppcbS2.. DppcbS2 is the first heterodifunctional ligand derived from a tetradentate phosphine obtained with good yield and high purity. It reacts with two equivalents of PdCl2 producing wPd2Cl4dppcbS2.x 1.. Both dppcbS2 and 1 have been fully characterized by X-ray structure analyses, NMR spectroscopy 31P1H4, 13C1H4, 1H., FAB mass spectrometry, elemental analyses and melting points. The possible catalytic applications of the versatile heterodifunctional ligand dppcbS2 are discussed in view of the two X-ray structures of dppcbS2 and 1.