Syntheses and Structures of Donor-Acceptor Complexes of Selenium Dioxide with Pyridine and Trimethylamine

Abstract

Donor-acceptor (DA) complexes of pyridine (py)·SeO2 and trimethylamine (TMA)·SeO2 were prepared by direct reactions of solid selenium dioxide with the amines. Both are white solids decomposing slowly at room temperature. The former complex decomposes into its components, while the latter one undergoes a redox reaction. The single-crystal structure determination of py·SeO2 has revealed that the chain-like structure of (SeO2)n is destroyed during the formation of the DA bond and the py·SeO2 molecule is bound to the nearest neighbouring molecule through two weak Se···O interactions. More labile TMA·SeO2 complex could not be prepared as single crystals. Analogous molecular structure of both complexes was proved by their Raman spectra. A modified general valence force field was used for the interpretation of Raman spectra of TMA·SeO2 and TMA·SO2.