Triphenylborane (BPh3) has been successfully coordinated to five Ï-conjugated aromatic systems containing a Nâ§O bidentate 2-(2â²-hydroxyphenyl)benzoxazole (HBO) ligand. Complexes 6â8 are directly substituted on the phenolic side of the HBO core while the structure of derivatives 9â10 includes a 4-dibutylaminophenyl module linked through an ethynyl fragment, at position 4 or 5. The crystal structure of complexes 8 and 10 reveals different solid-state molecular packing depending on the substitution, a herringbone molecular packing being observed for complex 8 while the dibutylamino fragment present in complex 10 is in favour of a lamellar structure. The optical properties are highly dependent on the nature and the position of substituents. Solvatochromic charge-transfer emissions are observed for substitution at position 3 or 5 while singlet emission is favoured when position 4 is functionalized. Solid-state fluorescence reveals that complex 8 possesses red-shifted emission when dispersed in a KBr matrix.
三苯基
硼烷(BPh3)已成功配位到五个Ï-共轭芳香族体系中,其中包含一个 Nâ§O 双齿 2-(2â²-羟基苯基)
苯并恶唑(HBO)
配体。络合物 6â8 在 HBO 核心的
酚侧被直接取代,而衍
生物 9â10 的结构包括一个通过
乙炔基片段连接的 4-二丁
氨基苯基模块,位于第 4 或第 5 位。络合物 8 和 10 的晶体结构显示出不同的固态分子堆积,这取决于取代情况,络合物 8 的分子堆积为人字形,而络合物 10 中的二丁
氨基片段则有利于形成片层结构。光学特性与取代基的性质和位置有很大关系。当第 3 位或第 5 位被取代时,可观察到溶变色电荷转移发射,而当第 4 位被官能化时,则有利于单色发射。固态荧光显示,当复合物 8 分散在 KBr 基质中时,会产生红移发射。