Metameric Brooker's versus Reichardt's zwitterions: Conformational metamorphosis on optoelectronic properties, using coupled-perturbed and finite field theories

This contribution reports influences of unusual conformational metamorphosis shown by Reichardt's and Brooker's metameric zwitterions by an earlier work, on various intrinsic electronic and optoelectronic properties. Detailed quantum mechanical investigations were carried out using HF, B3LYP, CAM-B3LYP, and ωB97xD methodologies. Observations suggest that whereas certain properties were directly and strongly influenced by the conformation preferences (twisted vs. planar), others were not strongly inclined to such conformational transformations. Interestingly, even with inherent conformational differences, observed properties were found to have only one major contributing component in each molecule and can be beneficial in one dimensional (1D) or pseudo-1D chromophore design strategies. Both coupled perturbed (CP) and finite field (FF) theories were used to compute dipole moments, polarizabilities, and hyperpolarizabilities, and so on, and excellent agreements (or exact matching results) were observed between the two theories. Reichardt's metamer was found to be more efficient in many aspects than Brooker's metamer. The direct and strong influences of metameric manipulations on structure–property correlations shown in this work can be adopted as a useful strategy for efficient chromophore design. Such a strategy is useful in the field of nonlinear optics, and may also find applications in various other areas of material sciences.