TD-DFT calculations and MCD spectroscopy of porphyrin and phthalocyanine analogues: rational design of photosensitizers for PDT and NIR region sensor applications

Abstract

Geometry optimizations and TD-DFT calculations have been carried out on series of fused-ring-expanded phthalonitriles, phthalocyanines, and aza-dipyrromethene boron difluoride (aza-BODIPY) dyes and trends in their optical and redox properties have been analyzed. The potential utility of fused-ring-expanded phthalocyanine and aza-BODIPY analogues for photodynamic therapy and near infrared region sensor applications is assessed on this basis. Recent attempts to prepare fused-ring-expanded aza-BODIPY analogues with benzene, pyrazine, and naphthalene rings have demonstrated that the properties of aza-BODIPYs vary markedly when different fused ring systems are added to the β -carbons of the pyrrole rings. A comparison of the TD-DFT calculations demonstrates that, as has previously been postulated, trends in the optical spectra, redox properties, and electronic structures of aza-BODIPYs follow those observed for the phthalonitrile precursors and the analogous phthalocyanines despite the absence of a fully conjugated macrocyclic perimeter that obeys Hückel's rule.

A 3,5‐DistyrylBODIPY Dye Functionalized with Boronic Acid Groups for Direct Electrochemical Glucose Sensing

“…The p-conjugation system of BODIPY dyes can be extended by structurally modifying the 3,5-positions of the BODIPY core in this manner. The introduction of the styryl substituents at the 3,5-positions results in a relative destabilization of the HOMO and a stabilization of the LUMO thus narrowing the HOMO-LUMO gap [41,42]. The reasons for this have been rationalized by using TD-DFT calculations [41,42].…”

“…Styrylation is a convenient means to red-shift the main spectral band of BODIPY dyes on this basis [39,40]. The reasons for this have been rationalized by using TD-DFT calculations [41,42]. The introduction of the styryl substituents at the 3,5-positions results in a relative destabilization of the HOMO and a stabilization of the LUMO thus narrowing the HOMO-LUMO gap [41,42].…”

π-Extended BODIPY Analogues: Synthesis, Electronic Structure, Potential Utility for in vivo Imaging Applications and Cytotoxicity

“…TD-DFT calculations were carried out by using CAM-B3LYP functional, which includes a long-range correction of the exchange potential, since this provides more accurate results for complexes that have excited states with significant intramolecular charge transfer character. [11,12]…”

An analysis of the photophysical and optical limiting properties of a novel 1,3,5-tristyrylBODIPY dye

“…Bromination of BODIPY 1 via nucleophilic addition of bromine with NBS was used to form BODIPY 2, while a Knoevenagel condensation reaction of (4methylthio)benzaldehyde and BODIPY 2 resulted in the synthesis of 1,3,5tri(4methylthio)styryl BODIPY 3 (BOTTOM) potential and incorporates an increasing fraction of HartreeFock exchange as the interelectronic separation increases. This has been demonstrated to provide more accurate predictions of trends in the optical properties of BODIPY and porphyrinoid dyes when excited states have significant charge transfer character [17,[55][56][57][58].…”