Theoretical investigation of luminescence behavior as a function of alkyl chain size in 4-aminobenzonitrile alicyclic derivatives.

摘要: There is still controversy about the structure of intramolecular charge transfer (ICT) emitting species in pi-electron donor-acceptor systems that show dual fluorescence. Although twisted ICT model quite generally accepted, planar not ruled out because firm experimental evidence supports it. Among these it fact some rigidized such as bicyclic 4-aminobenzonitrile derivatives exhibit We present here an ab initio CASSCF/CASPT2 study a series compounds with alicyclic chain ranging from 5 to 7 carbon atoms and compare their mechanism more flexible (ABN) 4-(dimethylamino)benzonitrile (DMABN). energetics, geometries, valence bond structures critical points potential-energy surfaces ground, local excited (LE), states. Our results photophysical differences studied may be rationalized by two factors: position LE at first stages reaction relative energies excited-state minima. Computational presented can adopted molecules NXC6 NXC7 anomalous band fluorescence spectra emitted species.