INVESTIGATION OF LOW-TEMPERATURE FLUORESCENCE AND ABSORPTION SPECTRA OF HIGHLY STABLE MERO-CYANINES DERIVATIVES OF 2, 6-DI-TERT-BUTYL-4-[R]-CYCLOHEXA-2, 5-DIENONE

Abstract

This work presents the results of the investigation of the dependence of the fluorescence and absorption spectra of merocyanines, derivatives of the 2,6-di-tret-butyl-4-[R]-cyclohexa-2,5-dienone, on the nature of donor end groups (pyridinium, quinolinium, pyrilium, benzo[c,d]indolium, benzoimidindolium). Quantum-chemical calculation of the distribution was organized to electronic density and lengths of the relationships, which has shown that introduction tert-butyl groups in nucleus cyclohexa-2,5-dienone practically does not influence upon the general characteristic merocyanines in contrast with hydrogen. The stability merocyanines vastly increases when entering tert-butyl groups in cyclohexa-2,5-dienone. But such three-dementional groups vastly complicate the bands of the absorption, which become broader, have a complex oscillatory structure. So more suitable spectrums turned out to be for interpreting electronic transition to fluorescences, to measure at the temperature of the fluid nitrogen. As it is seen, spectral bands become more structuring with clearly marked by maximum of the transition. Well-defined 0`→ 0 vibronical transition was found at use of the low-temperature fluorescent spectra. Merocyanines with highly stable tert-butyl groups can be used as fluorescence probes and labels in chemistry and biology, active and passive components for tunable dye lasers, highly effective materials for non-linear optic.