Carbazole-based D-π-A molecules: Determining the photophysical properties and comparing ICT effects of π-spacer and acceptor groups

• Two different D -π-A molecules were synthesised by varying acceptor groups. Carbazole-benzylidenemalononitrile shows one of the highest solvatochromism (153 nm). Carbazole-benzaldehyde also high (86 The dicyanovinyl group is a more effective than formyl group. A pyridine linker leads to larger Stokes shift benzene ring. 4-(9′-Hexylcarbazol-3′-yl)benzaldehyde (Cz-Ph-CHO: 4 ) and 4-(9′-hexylcarbazol-3′-yl)benzylidenemalononitrile (Cz-Ph-CN: 5 with structure -π-A, where carbazole, phenylene formyl/dicyanovinyl groups act as electron donor (D), pi-spacer (π) (A) units, respectively. thermal, electrochemical, optical intramolecular charge transfer (ICT) properties compounds investigated. Compounds , in particular their ICT behaviour, compared closely related structure, 2-(9′-hexylcarbazol-3′-yl)-5-pyridinecarbaldehyde (Cz-Py-CHO: 7 ). For purpose tuning chemical obtain targeted properties, electrochemical data absorption emission measurements suggest that unit compound better 4, π-spacer exerting characteristics such fluorosolvatochromism shifts. based fully characterised. Compound very nm) which makes it an ideal candidate for biosensing applications.