Halogenation of Dibenzoselenophene and Dibenzo[1,2]diselenine

Abstract

AbstractThe syntheses of the selenium containing heterocycles dibenzoselenophene (1 ≡ biphenSe) and dibenzo[1,2]diselenine (2 ≡ biphenSe2) were optimized. The halogenation reactions of 1 and 2 with XeF2, SO2Cl2, Br2 and I2 were performed and the corresponding products characterized. In the case of 1, the selenium(IV) dihalogenides, biphenSeF2 (3), biphenSeCl2 (4), biphenSeBr2 (5), and the adduct biphenSe·I2 (6), were isolated and identified. The extremely sensitive selenium(IV) difluoride 3 slowly formed significant amounts of an adduct with HF of the corresponding selenium(IV) oxide biphenSeO·HF (3a) upon storage in glass vessels at low temperatures. In the case of 2, the selenium(IV) trihalogenides, biphen(SeHal3)2 (Hal = F, Cl, Br), were found to be extremely labile (Hal = F) or not detectable (Hal = Cl, Br). Instead, as decomposition products, the selenium chloride species Se2Cl2, SeCl4 and 1 were detected. In the case of Hal = I, the stable adduct biphenSe2·I2 (7) was isolated. In addition to characterization by multinuclear NMR spectroscopy, several molecular structures of biphen‐selenium substituted halogenides were determined.