The vibrational frequencies of the tetrakis(amminemercurio)methane cation, [C(HgNH3)4]4+ (1), in both aqueous ammonia buffer solutions and in solid [C(HgNH3)4](PF6)4 have been used in an all-atom normal coordinate analysis for 1. A similar analysis has been carried out for the isoelectronic tetrakis(methylmercurio)methane, C(HgCH3)4 (2). 1 and 2 respectively exhibit the highest (2.016 N/cm) and lowest (1.509 N/cm) valence force constants K(CHg) in the central CHg4 entity so far observed for tetramercuriomethanes. The force constants for the peripheral HgNH3 and HgCH3 bonds in 1 and 2 are 2.461 N/cm and 2.183 N/cm, respectively. Both the electronic properties of the peripheral ligands and the total charge on the molecule are shown to influence the force constants. The potential energy distributions indicate that the valence vibrations of the NH CH and HgNH3 HgCH3 bonds in 1 and 2, and the breathing vibrations of the central CHg4 units are almost independent of all other vibrations, which in turn are more or less strongly coupled.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry
- Materials Chemistry