Electronic spectra of organic molecules and their interpretation—IV : Effect of terminal atoms with lone electron pairs on the K-bands of conjugated systems

摘要: Abstract The effect of the hydroxyl, methoxyl, mercapto, methylmercapto, and amino groups as well charged O− S− atoms (X) at ends conjugated systems (1) (2) on position corresponding K-bands is discussed. conclusions earlier investigations are confirmed. “effective” electron migration in one direction along absorbing system (indicated by long arrow) determines almost exclusively stability observed excited state. displacement a K-band to longer wavelengths introduction terminal group can be due either an shift substituted coinciding with effective transition or increased polarisability itself. A consistent qualitative, but very detailed, theoretical interpretation these observations possible consideration electronic perturbations state Heisenberg resonance, if molecules accepted being built up localised bonds involving inductive (inductomeric) shifts only.