A rational design of catechol-based compounds: an experimental and theoretical study of optical properties.

The synthesis and optical properties of 4,5-disubstituted (tert-butyldimethylsilyloxy)-protected catechol derivatives are reported. One or two carbon-carbon triple bond functions were introduced through the Sonogashira cross-coupling reaction. The effects on the optical properties of monosubstitution at the 4-position or disubstitution at the 4- and 5-positions of these catechol derivatives with electron-withdrawing or -donating substituents have been investigated. The experimental chemical-structure-polarisability relationship has been studied by using the Lippert-Mataga correlation and compared with the results of a theoretical study carried out with DFT calculations. These compounds are promising candidates for the fine-tuning of internal charge transfer, but also as potential non-linear chromophores and ligands within multifunctional coordination complexes.