New iridium(I) complexes with labile ligands: reactivity and structural characterization by atmospheric pressure mass and tandem mass spectrometry

Reaction of diphosphine complexes [IrCl{(C6F5)2P(CH2)2P(C6F5)2}]2 (I) and [IrCl(dppe)]2 (II) with coordinating solvents (acetonitrile, acetone, DMSO) leads to several square-planar complexes of the type [IrCl(diphosphine)(solvent)] which are stable only in solution ([IrCl{(C6F5)2P(CH2)2P(C6F5)2}(NCCH3)] (III) and [IrCl{(C6F5)2P(CH2)2P(C6F5)2}(acetone)], IV) and/or can be detected only under APCI-MS/MS conditions ([IrCl(dppe)(solvent)]). When III is allowed to react with CO for at least 30 min, the unusual five coordinated trans-dicarbonyl complex [IrCl{(C6F5)2P(CH2)2P(C6F5)2}(CO)2] (Vb) is formed, as characterized by 1H and 31P NMR, FT-IR, TGA and APCI-MS/MS. A new and stable square-planar complex [Ir(OCH3)(cod)(PClPh2)] (IX) was also synthesized. Its APCI-MS/MS spectrum is simple and unique as it shows exclusively the loss of a neutral C3H2 species. Along with the APCI-MS and APCI-MS/MS analyses, whenever it was possible all complexes were also characterized by 1H and 31P NMR spectroscopy.