REACTIVITIES OF BIS(2-BROMOETHYL)SELENIUM DIBROMIDE AND ITS RELATED-COMPOUNDS - FORMATION OF HYPERVALENT T-SHAPED COORDINATED SELENIUM-COMPOUNDS BY REACTION WITH PYRIDINE AND ITS DERIVATIVES

The reaction of bis(2-bromoethyl)selenium dibromide 1 with pyridine 2a and its derivatives 2b-2d gave hypervalent T-shaped coordinated selen ium compounds 3a-3d with two halogen atoms in the trans positions in m oderate to good yields. Also, 2-pyridiniumethylselenol bromide 10 was obtained by the reaction of (2-bromoethyl)phenyl selenium dibromide 9 with 2a in 9.8% yield. The X-ray analysis of 10 revealed that the two conformers about the CH2-CH2, bond existed in one crystal unit, althou gh the H-1-NMR spectra at room temperature showed relatively free rota tion about the CH2-CH2 bond.