Coordination properties of novel hemilabile acetamide-derived P,O phosphine ligands. Crystal structures of Ph2PNHC(O)Me and [PdMe{PPh2NHC(O)Me}{PPh2NHC(O)Me}][O3SCF3] †
作者:Pierre Braunstein、Céline Frison、Xavier Morise、Richard D. Adams
DOI:10.1039/b002386h
日期:——
Cationic methyl Pd(II) complexes are described in which the new heterofunctional phosphine ligands Ph2PNHC(O)Me 1 or Ph2PN(Me)C(O)Me 3 behave as rigid and/or hemilabile P,O chelates. The chelating ability of 3 is higher than that of 1 and both are compared to that of other P,O ligands, such as the keto- and amido-phosphines Ph2PCH2C(O)Ph and Ph2PCH2C(O)NPh2, respectively. The crystal structure of 1 reveals the presence in the solid-state of an intermolecular hydrogen-bonded network N–H⋯O and that of [PdMePPh2NHC(O)Me}PPh2NHC(O)Me}][O3SCF3] 12b establishes the presence of both a chelating and a monodentate ligand 1 in the same complex. Carbonylation of the cationic methyl complexes 8a, 17, 18a and 20a afforded the corresponding acetyl complexes in which this ligand occupies a position cis to phosphorus, irrespective of that of the alkyl ligand in the precursor complex.
本研究描述了阳离子甲基钯(II)配合物,其中新的杂功能膦配体 Ph2PNHC(O)Me 1 或 Ph2PN(Me)C(O)Me 3 表现为刚性和/或半稳定的 P,O 螯合物。Ph2PNHC(O)Me 1 和 Ph2PN(Me)C(O)Me 3 的螯合能力高于 Ph2PNHC(O)Me 1 和 Ph2PN(Me)C(O)Me。1 的晶体结构显示固态中存在分子间氢键网络 N-H⋯O,而[PdMePPh2NHC(O)Me}PPh2NHC(O)Me}][O3SCF3] 12b 的晶体结构则确定了同一配合物中同时存在螯合配体和单齿配体 1。对阳离子甲基络合物 8a、17、18a 和 20a 进行羰基化处理,可得到相应的乙酰基络合物,在这些络合物中,该配体占据磷的顺式位置,与前体络合物中烷基配体的位置无关。