Substitution reactions of diphenyl-2-pyridylphosphine with [(h5-C5Me5)M(m-Cl)Cl]2 (M = Rh or Ir) dimers: Isolation of mono-,di- and chelating complexes

The reaction of [{(h5-C5Me5)M(m-Cl)Cl}2] {where M = Rh (1), Ir (2)} with functionalized phosphine viz., diphenyl-2-pyridylphosphine (PPh2Py) in dichloromethane solvent yield neutral k 1-Pcoordinated rhodium and iridium complexes [(h5-C5Me5)RhCl2(k1-P-PPh2Py)] 3 and [(h5-C5Me5) IrCl2(k1-P-PPh2Py)] 4. Reaction of complexes 1 and 2 with the ligand PPh2Py in methanol under reflux give bis-substituted complexes such as [(h5-C5Me5)RhCl(k1-P-PPh2Py)2]+ 5 and [(h5-C5Me5)IrCl(k1-PPPh2Py) 2]+ 6, whereas stirring in methanol at room temperature gives P-, N-chelating complexes of the type [(h5-C5Me5)RhCl(k2-P-N-PPh2Py)]+ 7 and [(h5-C5Me5)IrCl(k2-P-N-PPh2Py)]+ 8. Neutral k1-P-coordinated complexes [(h5-C5Me5)RhCl2(k1-P-PPh2Py)] 3 and [(h5-C5Me5)IrCl2(k1-P-PPh2Py)] 4 easily undergo conversion to the cationic P-, N-chelating complexes [(h5-C5Me5)RhCl(k2-P-N-PPh2Py)]+ 7 and [(h5-C5Me5) IrCl(k2-P, N-PPh2Py)]+ 8 on stirring in methanol at room temperature. These complexes are characterized by FT–IR and FT–NMR spectroscopy as well as analytical methods. The molecular structures of the representative complexes [(h5-C5Me5)RhCl2(k1-P-PPh2Py)] 3, [(h5-C5Me5)IrCl2(k1-P-PPh2Py)] 4 and hexafluorophosphate salt of complex [(h5-C5Me5)IrCl(k2-P-PPh2Py)2]+ 6 are established by singlecrystal X-ray diffraction methods.