(η5-pentamethylcyclopentadienyl)rhodium and -iridium complexes with weakly and strongly coordinating anions:: Isolation and first X-ray molecular structures of the tris(solvent) complexes [(C5Me5)M(acetone)2(H2O)][BF4]2 (M = Rh, Ir)

Several novel pentamethylcyclopentadienyl complexes of general formula [(C5Me5)IrL3][BF4](2) were prepared including the tris(solvent) precursors [(C5Me5)M(acetone)(2)(H2O)][BF4](2) (M = Rh, Ir) (1a,b). The X-ray molecular structures of 1a,b were determined at low temperature. Complexes lab are isostructural, and both compounds crystallize in the monoclinic space group P2(1)/c with a 10.157(3) Angstrom, b = 14.038(9) Angstrom, c = 16.335(2) Angstrom, beta = 99.73(2)degrees, and Z = 4 for 1a and with a = 10.107(9) Angstrom, b = 13.994(16) Angstrom, c = 15.996(34) Angstrom, beta = 99.61(12)degrees, and Z = 4 for 1b. The coordinated water molecule is hydrogen bonded to both BF4- anions, Reaction of la,b with pyridine (py) afforded the related tris(pyridine) complexes [(C5Me5)M(eta(1)-(N)-py)(3)][BF4](2) (M = Rh, Ir) (2a,b), Complex 2b was characterized by X-ray crystallography, monoclinic space group P2(1)/c with a = 8.665(3) Angstrom, b = 19.687(7) Angstrom, c = 18.408(5) Angstrom, beta = 94.17(3)degrees, and Z = 4. Moreover, we prepared the novel neutral compounds (C5Me5)M(eta(2)-NO3)(eta(1)-NO3) (M Rh, Ir) (4a,b) where the anions are bonded to the metal center instead of a coordinating solvent as confirmed by X-ray study on the iridium complex Q. The latter crystallizes in the orthorhombic space group Pcab with a 13.032(4) Angstrom, b = 14.370(11) Angstrom, c = 14.839(18) Angstrom, and Z = 8.