Analysis of the applicability of the particle-in-a-box model to conjugated systems of cyanine dyes

The particle-in-a-box model was used to analyze the conjugated bonds and π electrons of several cyanine dyes. Analysis by UV-Vis spectrophotometry led to calculation of λmax values for each dye, and values were compared to electronic spectra generated with the HyperChem program. The effective box length, a, was determined for six cyanine dyes and compared to the expected geometric box length, and the lengths of C-C bonds in each conjugated system was analyzed and compared to tabulated values. The applicability of the particle-in-a-box model to extract electronic and structural information is discussed and was deemed less than ideal for usage with cyanine dyes to predict spectral properties. 5