Synthesis of NIR naphthyl-containing aza-BODIPYs and measure of the singlet oxygen generation

With 1-(6-methoxynaphthalen-2-yl)ethanone as the starting material, aza-BODIPYs bearing naphthyl groups were successfully prepared. Effect of extended pi-conjugation by attaching the naphthyl group on photophysical properties was noticeable. The absorption and emission maxima of aza-BODIPY 4 (lambda(abs)=706 nm, lambda(em)=733 nm) bearing the naphthyl group were bathochromically shifted compared to these of 1 (lambda(abs)=688 nm, lambda(em)=715 nm) bearing the phenyl group. Moreover, the main computed photophysical data at the best level of calculation, i.e., cLR-PCM(CHCl3)-M06-2X/6-311+G(2d,p)/SOS-CIS(D), were in agreement with the experimental data. Aza-BODIPY 5 as a photosensitizer (lambda(abs)=704 nm in toluene) had moderate singlet-oxygen production having about 2.0-fold rate enhancement when compared to that of methylene blue, and it is thought to be a photosensitizer to be potentially used for the singlet oxygen generation. (C) 2015 Elsevier Ltd. All rights reserved.