X-Ray Structural Characterization of (Cr(CNPh)6) (CF3SO3), (Cr(CNPh6)(PF6)2 and (Cr(CNPh)6) (SbCl6)3.CH2Cl2, Completion of a Unique Series of Complexes in Which the Metal Attains Four Different Oxidation States While Maintaining I

摘要

The crystal structures of (Cr(CNC6H5)6)(CF3O3) (A) (Cr(CNC6H6)6)(SbCl6)3) CH2Cl2 have been determined by single-crystal X-ray diffraction techniques. Compound A crystallizes in the P2 sub 1/n space group. Full-matrix least-squares refinement converged to give R and R sub w values. The structure of A consists of discrete (Cr(CNC6H5)6) cations and disordered (CF3SO3) anions. A minot Jahn-Teller distortion is observed in the Cr-C bond lengths, which average 1.975 A. Compound B crystallizes in the P2 sub a/n space group. The ligands show a pronounced C sub 2V angular distortion with the C-Cr-C bond angles ranging from 83.7 to 97.0 deg. The Cr-C bonds average 2.1014A. Compound C crystallizes in the Cccn (No. 66) space group. The four crystallography related equatorial ligands exhibit Cr-C bonds of 2.049 A relative to the long Cr-C axial bonds of 2.091 814) A. Changes in the Cr-C and C triple bond lengths are discussed in relation to the d-electron configuration of the central metal. The origin of the large position value previously obtained for the Cr(CNPh)5(3+)/Cr(CNPh)6(2+) reduction potential is discussed in relation to the large negative value reported for the Cr(CN6(3=)/Cr(CN)6(4-) couple.