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Absorption maxima study of chromophores of indigoid dyes
Author(s) -
Chen P. C.
Publication year - 1996
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1996)60:2<681::aid-qua6>3.0.co;2-t
Subject(s) - bathochromic shift , chromophore , hypsochromic shift , chemistry , bond length , absorption (acoustics) , single bond , bond order , photochemistry , computational chemistry , crystallography , group (periodic table) , fluorescence , crystal structure , materials science , organic chemistry , physics , composite material , quantum mechanics
Molecular structure of 21 chromophores of indigoid dyes were studied by an ab initio MP2/6–31 + G*/ /HF/6–31 + G* method. Bond lengths and bond angles were affected by π‐electron conjugation. The difference between molecular structures of chromophores and indigoid dyes indicated that benzene rings and five‐membered rings in indigoid dyes are structurally important. Absorption maxima of chromophores were successfully calculated by the CI‐singles‐MP2/6–31 + G* theory. Like indigoid dyes, absorption maxima of the chromophores are affected by the positions of the donor and acceptor groups on the trimethine group. Bathochromic shifts of the absorption maxima were observed with the best donor group of (SINGLE BOND)NH among (SINGLE BOND)NH, (SINGLE BOND)O, and (SINGLE BOND)S groups. Appropriate substitution of longer‐chain polymethines brought about chromophoric systems having hypsochromic shifts. From these calculations, the absorption maxima of some indigoid dyes could be explained by their chromophores qualitatively. © 1996 John Wiley & Sons, Inc.