Two new dicyanovinyl (DCV) functionalized triarylboranes (Mes2B-π-spacer-DCV, for 1: π-spacer = C6H4, for 2: π-spacer = 2,3,5,6-tetramethyl-phenyl) are reported. The molecular structures of 1 and 2 are similar except for the spacer which connects the boryl and DCV units. This small structural perturbation induces drastic changes in the optical properties of 1 and 2. Compound 2 shows weak dual fluorescence emission in nonpolar solvents and a stronger emission in polar solvents. Compound 1 is weakly fluorescent in polar environments but shows an intense single luminescence peak in less polar environments. Compound 1 exhibits a turn-off fluorescence response for both fluoride and cyanide: in contrast, 2 shows a turn on fluorescence response for both anions with different fluorescence signatures. The NMR titration studies reveal that for compound 2, fluoride binds to the boron centre and cyanide binds to the DCV unit. For compound 1, the fluoride ion binds to the boron center, whereas the CN− binds to both the Ar3B and DCV units.
报告了两种新的二
氰乙烯基(DCV)官能化三芳基
硼烷(Mes2B-π-spacer-DCV,其中1:π-间隔物=
C6H4,2:π-间隔物= 2,3,5,6-四甲基苯基)。1和2的分子结构相似,除了连接
硼基和DCV单元的间隔物。这种小的结构扰动导致1和2的光学性质发生巨大变化。化合物2在非极性溶剂中显示弱双荧光发射,在极性溶剂中显示强发射。化合物1在极性环境中显示弱荧光,但在非极性环境中显示强单发光峰。化合物1对
氟化物和
氰化物表现出关闭荧光响应:相反,2对两种阴离子表现出开启荧光响应,并具有不同的荧光特征。核磁共振滴定研究表明,对于化合物2,
氟化物与
硼中心结合,
氰化物与DCV单元结合。对于化合物1,
氟离子与
硼中心结合,而CN-与Ar3B和DCV单元结合。