33708-11-1Relevant academic research and scientific papers
Structures of Diarylcarbenes and Their Effect on the Energy Separation between Singlet and Triplet States
Gilbert, B. C.,Griller, D.,Nazran, A. S.
, p. 4739 - 4742 (2007/10/02)
Theory indicates that expansion of the central C-C-C angle in a diarylcarbene should lead to an enhancement of its triplet-singlet energy gap.The series of carbenes diphenyl, mesitylphenyl, mesityl-o-tolyl, and dimesityl was used to test this hypothesis.Electron paramegnetic resonance (EPR) spectra of the triplet states of these carbenes showed that increasing ortho substitution at the aryl groups led to an expansion of the C-C-C angle.Product and kinetic studies, on reactions which reflected the singlet-triplet energy gap, showed that this expansion led to an enhanced triplet-singlet energy separation thus substantiating the theoretical prediction.The results establish a relationship between structure and the energy separation between the triplet and singlet states of simple diarylcarbenes.
