Spectiioscopic study of the mutual effect of atomic groups, connected through different types of bridges

Conclusions

• 1. Among the compounds of type$X - \begin{array}{*{20}c} { / / } \\ \setminus \\ \end{array} \begin{array}{*{20}c} {\_\_\_} \\ {\underline {\_\_\_} } \\ \end{array} \begin{array}{*{20}c} { \setminus \setminus } \\ / \\ \end{array} - M - \begin{array}{*{20}c} { / / } \\ \setminus \\ \end{array} \begin{array}{*{20}c} {\_\_\_} \\ {\underline {\_\_\_} } \\ \end{array} \begin{array}{*{20}c} { \setminus \setminus } \\ / \\ \end{array} - Y$, where the substituents X and Y axe adjacent to a system ofπ-bonds, it is possible to isolate the following types of intermediate links: interaction of X and Y is not observed in the spectra when M=CH₂ or CH₂-CH₂, and it is slight when M=O, S, NH or NR. If the intermediate links are a system of conjugatedπ-bonds, then important interaction of the donor and acceptor groups is observed, exerting an effect on the frequencies (and, probably, on the rigidity of the bonds in X and in Y), on the dipole moments, on the optical parameters, etc. The mutual effect when the X and Y groups are of the same type is small.

• 2. The donor-acceptor properties of the groups can change under electronic excitation and dependon the vibrational coordinates. Besides this, these properties depend on the medium.