Syntheses of rod-shaped fluorescent 1,3,2-benzodiazaboroles with phosphonium, and phosphane chalcogenide acceptor functions

A series of 1,4-phenylenes X-C(6)H(4)-BDB with a 1,3,2-benzodiazaborolyl (BDB) and a phosphorus based end group [X = PPh(2) (2), P(O)Ph(2) (3), P(S)Ph(2) (4), P(Se)Ph(2) (5), P(AuCl)Ph(2) (6) and P(Me)Ph(2) (7)] as well as 2-(2')thienyl-1,3,2-benzodiazaboroles with a second end group X [X = PPh(2) (8), P(S)Ph(2) (9), P(Se)Ph(2) (10) and P(Me)Ph(2) (11)] in the 5' position were synthesised using established methodologies. Molecular structures of 2-9 and 11 were determined by X-ray diffraction. Compounds 3, 4, 6, 7, 9 and 11 show intense blue luminescence in cyclohexane, toluene, chloroform, dichloromethane and tetrahydrofuran with pronounced solvatochromism. Thereby Stokes shifts in the range of 8950-10,440 cm(-1) and quantum yields up to 0.70 were observed in dichloromethane solutions. In contrast to this, for the selenides 5 and 10 quantum yields are small (