SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF (C5ME5)ZR(R)2(L)N+ COMPLEXES

The reaction of (C5Me5)Zr(CH3)3 with [(C5H4Me)2Fe][BPh4] in THF yields [(C5Me6)Zr(CH3)2-(THF)2][BPh4] (1) via oxidative cleavage of a Zr-CH3 bond. X-ray diffraction reveals that the cation of 1 adopts a square-pyramidal/four-legged piano-stool structure with cis CH3 groups. The orientations of the THF ligands and the Zr-O bond distances suggest that Zr-O 7 π-bonding is important for at least one of the THF ligands. Data for 1: a = 14.551 (2) Å, b = 15.191 (4) Å, c = 17.852 (19) Å, β= 92.26 (3)°, V = 3943 (6) Å3, Z = 4 in space group P21/c. Reaction of 1 with excess dmpe in THF solution yields [(C5Me5)Zr(CH3)2(dmpe)(THF)][BPh4] (2), which also has been characterized by X-ray diffraction. The cation of 2 has a distorted-octahedral structure with the Cp* ligand in an axial position and equatorial/axial coordination of the dmpe ligand. The two CH3 groups are equatorial and mutually trans. The THF ligand is equatorial and trans to the dmpe ligand and lies in the square plane in an orientation that precludes Zr-O 7 π-bonding. Data for 2: a = 10.110 (3) Å, b = 14.701 (8) Å, c = 17.190 (4) Å, α = 70.14 (3)°, β = 78.72 (2)°, γ = 84.68 (4)°, V = 2355.6 (1.9) Å3, Z = 2 in space group P1. The reaction of (C5Me5)Zr(CH2Ph)3 with [(C5H4Me)2Fe][BPh4] in THF at 0 °C yields the thermally sensitive compound [(C5Me5)Zr-(CH2Ph)2(THF)][BPh4] (3). The benzyl ligands of 3 are distorted, most likely as a result of weak donor interactions between the Ph rings and the cationic Zr center. © 1990, American Chemical Society. All rights reserved.