Substituted Esters of Coumarin-3-phosphonic Acid—Linear-Polarized IR-Spectroscopic Elucidation.

Correlation between the structure and IR-spectroscopic properties of two halogen and one amino substituted esters of coumarin-3-phosphonic acid has been studied by means of linear-polarized IR-spectroscopy of oriented colloid suspensions in nematic host. The influence of the ester group on the peak positions of the IR-characteristic bands of these derivatives and in particular, on phosphorus group is investigated by a comparison with the data for corresponding coumarin-3-phosphonic acids. Theoretical quantum chemical DFT calculations (B3LYP/6-311++G**) are carried out, thus supporting the experimental assignment of the IR-bands and predicting the electronic structure of all of the compounds studied. [ABSTRACT FROM AUTHOR]