Force Constants for MC, CN Interaction in Metal—Cyanide Complexes

Accurate measurements of the Raman-active CN stretching frequency, v1, and the infrared-active CN stretching frequency, v3, have been made for aqueous KAu(CN)2 and the disubstituted 13C and 15N species. The results are 2164.0, 2133.6, and 2115.6 cm−1 for v1 of Au(CN)2−, Au(C15N)2−, and Au(13CN)2−, respectively. The respective values for v3 are 2145.7, 2115.3, and 2099.3 cm−1. From the results it was possible to to calculate the stretch—stretch interaction constants. It is found that for adjacent MC, CN interactions, FMC, CN≈0.3 mdyn/Å while for nonadjacent interaction, FMC, C'N≈0.