INFRARED SPECTRA AND NORMAL COORDINATE ANALYSIS OF METAL-OLEFIN COMPLEXES .2. ZEISES DIMER AND ITS PALLADIUM(2) ANALOG

The infrared spectra of Ziese's dimer, [Pt(C2H4)CI2]2, and its deuterated and Pd(II) analogs have been obtained from 4000 to 50 cm−1. The Raman spectrum of crystalline Zeise's dimer has also been obtained. A normal coordinate analysis has been carried out on the planar [MXYR]2 system of C2h symmetry where M is Pt(II) or Pd(II), R is C2H4, and X and Y are terminal and bridging CI atoms, respectively. The bands at 408 and 427 cm −1 of Zeise's dimer and its Pd(II) analog have been assigned to the Pt-ethylene and Pd-ethylene stretching modes, respectively. The corresponding force constants (mdyn/Å) are: Pt-ethylene stretching, 2.25, and Pd-ethylene stretching, 2.14, including repulsive force constants between nonbonded atoms. All the other bands in the low-frequency region have been assigned based on potential energy distribution. © 1968, American Chemical Society. All rights reserved.