Disubstituted 1883 cm - ; M. O. Albers, N. J. Coville, T. V. Ashworth, E. J. Singleton,...

Disubstituted 1883 cm ^- ; M. O. Albers, N. J. Coville, T. V. Ashworth, E. J. Singleton, Organomet. Chem. , 1981 , 217 , 385.) is also formed in the reaction described in Problem 4.33 . Which of the following molecular geometries is supported by this spectrum? Support your decision by determining the number of IRactive CO stretching modes for these isomers. What does R. L. Keiter, E. A. Keiter, K. H. Hecker, C. A. Boecker, Organometallics 1988 , 7 , 2466 indicate about the infallibility of group theoretical CO stretching mode infrared spectroscopic prediction in the case of Fe(CO)₃(PPh₃)₂ ?

Reference of problem 33

Complexes of the general formula Fe(CO)_5-x(PR₃)_x are long known. The bimetallic Fe₂(CO)₉ reacts with triphenylphosphine in refluxing diethyl ether to afford a monosubstituted product Fe(CO)₄(PPh₃) that exhibits (CO) absorptions at 2051, 1978, and 1945 cm ^-1 in hexane. (N. J. Farrer, R. McDonald, J. S. McIndoe, Dalton Trans. , 2006 , 4570.) Can these data be used to unambiguously establish whether the PPh₃ ligand is bound in either an equatorial or axial site in this trigonal bipyramidal complex? Support your decision by determining the number of IR-active CO tretching modes for these isomers.