Structures and electronic states of the electron donor-acceptor (EDA) complexes: Trimethylamine-halogen complex (CH 3) 3N…F 2

Abstract

Ab initio MO and direct dynamics calculations of the electron donor-acceptor (EDA) complex composed of trimethylamine (ME) 3N and F 2 molecules (D and A) have been carried out in order to elucidate the interaction between D and A molecules. The electronic states and structures of the EDA complex were determined for both ground and excited states by means of the singly excited configuration interaction (SE-Cl) and MP2 calculations. The ab initio calculations indicated that the interactions between D and A are composed of weak charge-transfer (CT) interaction at the ground state, whereas this becomes a strong CT interaction at the first excited state. The structure of the EDA complex was largely distorted at the first excited state, which strongly supports a model proposed previously by us (Tachikawa, Komatsu, Inorg. Chem. 34 (1995) 6546). The direct dynamics calculations for R 3N…F 2 system (R = H and Me) were carried out in order to include the temperature effect on the structures of the complexes. The large substitution effect of methyl group was found in the structure of the EDA complex. The geometric structures and the electronic states of the EDA complexes are discussed on the basis of the present results.