Structure and spectrum investigation of the effect of substuiant on possibility of the formation of non-classical bound Rh(2η –Si-H) using density functional theory

Abstract

In this research structure and spectrum was investigated using DFT/B3LYP of the

complexes Rh(III) CpRh(SiR₂R^')(H)(C₂H₃Y)   where R₂R^'= H₃, Me₃, (OH)₃ and

Y=H; C₂H₃Y = PH₃, SiH₄. This is in order to find possible formation of the bound Rh(²η –Si-H)  in the complexes. This is in order to find possible formation of the bound Rh(²η –Si-H) in the complexes.

Hence it was found that each of the complexes exist in two isomeric forms of comparable energy. Theoretical results pointed out there are weak interaction between Si atom and one of the hydrogen atoms which is bound with it. Studying the geometric structure of these compounds does not refer to the existence of the bound of kind  Rh(²η –Si-H). The effects of donors and acceptors electrons on Si atom and on formation of Rh(²η –Si-H) . One can notice that the interaction increases between Si atom and hydrogen when donor group exist. On the other hand, the role of C₂H₃Y associated with the metal center was studied. It was found that the presence of carboxyl group Y= -COOH lead to better interaction between Si and H than SiH₄ or PH₃ group. It allowed us to study patterns of vibration theory to obtain infrared spectra IR and accurately vibration patterns. It can be noticed that there are three elongation of the Association of Si-H patterns ranging from 2146 to 2136 , and in return it was found only one single pattern elongation of the Association of Si-H up to 600  and this shows the weakness of the bound between hydrogen atom and Si.