Vibrational and Quantum-Chemical Study of Push–Pull Chromophores for Second-Order Nonlinear Optics from Rigidified Thiophene-Based π-Conjugating Spacers
作者:Mari Carmen Ruiz Delgado、Víctor Hernández、Juan Casado、Juan T. López Navarrete、Jean-Manuel Raimundo、Philippe Blanchard、Jean Roncali
DOI:10.1002/chem.200204542
日期:2003.8.4
types of push-pull chromophores built around thiophene-based pi-conjugating spacers rigidified by either covalent bonds or noncovalent intramolecular interactions have been analysed by means of IR and Raman spectroscopical measurements in the solid state as well as in a variety of solvents. Comparison of the Raman features of NLO-phores based on a covalently rigidified dithienylene (DTE) spacer with those
已通过固态和多种溶剂中的IR和拉曼光谱测量方法分析了围绕通过噻吩基pi共轭间隔基(通过共价键或非共价分子内相互作用刚性化)构建的两种类型的推挽生色团。比较基于共价刚性二亚噻吩基(DTE)间隔基的NLO-phor的拉曼特征与其开链DTE类似物的拉曼特征,表明DTE的中心双键与噻吩基单元的最接近β位的桥连度为两个乙烯桥显着改善了分子内电荷转移。与基于2,2'-双(3,4-乙撑二氧噻吩)(BEDOT)间隔基的NLO-phor及其基于未取代联噻吩(BT)间隔基的相应母体化合物相比,这种情况也会发生。对于基于BEDOT间隔基的NLO-phores,硫和氧原子之间的非共价分子内相互作用负责间隔基的刚性化。在稀溶液中以溶质形式获得的这些NLO-phors的拉曼光谱显示出两种不同的行为:i)基于共价桥接或开链DTE间隔基的发色团在溶液中显示的拉曼光谱特征与相应固体的相似,其中ii)从固体到溶液,围绕BED