TDDFT-calculations of Vis/NIR absorbing compounds

To examine the strengths and limitations of the time-dependent density functional theory in calculating the absorption wavelengths of dye, 130, non-radical, radical and biradical coloured organic compounds, including perylenimide, porphyrin, azobenzene, quinone, croconaine, squaraine and push–pull-type colorants, were randomly selected. The first intense electronic transitions were satisfactorily calculated using time-dependent density functional theory. Whilst polymethine dyes behaved exceptionally, the calculated transition energies for cyanines, oxonols and various related dyes were systematically too large. Broken-symmetry unrestricted density functional calculations revealed the biradical character of several quinoid compounds derived from p-quinodimethane as well as that of some non-Kekulé-type structures.     

Synthesis of Reactive Condensation Products of Acetylacetone and Their Transformation into Deeply Coloured Methine Dyes

Starting from acetylacetone 1 , boric acid and a diol, or a 2‐aminothiazole 16 and perchloric acid several dimethyl‐substituted 1,3,2‐dioxaborines 5 and thiazolo[3,2‐a]pyrimidinium salts 17 , resp., have been prepared and transformed by raction with 4‐N,N‐dimethylamino‐benzaldehyde 3a or 3‐methyl‐2‐methylmercapto‐benzthiazolium perchlorate 13 into deeply colored polymethine dyes 11, 12, 14, 15, and 18—21 , and 23—24 their spectroscopic data were recorded.