β-Functionalized Push–Pull opp-Dibenzoporphyrins

Abstract

The synthesis of a series of β-functionalized push-pull dibenzoporphyrins was realized. These porphyrins display subtle push-pull effects, demonstrating the exceptional tunability of their electronic and electrochemical properties. The UV-vis spectra of these porphyrins show unique absorption patterns with shouldered Soret bands and extra absorptions in the Q-band region. Stronger electron-withdrawing groups display more significant bathochromic shifts of the Soret bands. The fluorescence spectra of these porphyrins show strong near-IR emission bands (600-850 nm). In particular, fluorescence quenching effect was observed for pyridyl carrying push-pull porphyrin 4c in the presence of an acid. TFA titration study of 4c using UV-vis and fluorescence spectroscopy reveals that the fluorescence quenching can be mainly attributed to the protonation of the pyridyl groups of 4c. The versatile synthetic methods developed in this work may open a door to access a large number of functionalized organic materials that are currently unavailable. The structure-property studies provided in this work may provide useful guidelines for the design of new generations of materials in dye-sensitized solar cells, in nonlinear optical applications, as fluorescence probes, as well as sensitizers for photodynamic therapy.

Synthesis and Spectroscopic Investigation of a Series of Push–Pull Boron Dipyrromethenes (BODIPYs)

“…Cresyl violet perchlorate (0.55 in methanol) and methylene blue (0.03 in methanol) were used as external standards for BODIPYs 2 , 6a , 6b , 4 and 3 , 7 , 8 , respectively. The relative fluorescence quantum yields (Φ f ) were determined using the following equation (1), 4c $${\varphi }_x={\varphi }_R\left[\frac{\mathit{Gra}{d}_X}{\mathit{Gra}{d}_R}\right]\left[\frac{{\eta }_X^2}{{\eta }_R^2}\right]$$where Φ represent the fluorescence quantum yields; ƞ represent the refractive indexes of solvents; Grad represent the gradient from the plot of integrated fluorescence intensity vs absorbance at λ ex ; Subscripts X and R represent the tested sample and standard sample respectively.…”

Synthesis and Photophysical Properties of Hexabenzocoronene‐Tetrabenzoporphyrin Architectures

“…[ 23 ] For the synthesis of TATBP 5 , 4,7‐dihydro‐5,6‐dimethoxycarbonyl‐4,7‐ethano‐2 H ‐isoindole 2 , which was prepared by a modified literature procedure [ 24 ] (see Supporting Information) was utilized for the acid‐catalyzed condensation with 4‐ tert ‐butylbenzaldehyde yielding the desired TATBP 5 in 49 %. Jinadasa et al [ 25 ] demonstrated the post‐functionalization of such ester substituted porphyrins with anilines to the corresponding N ‐phenyl‐phthalimido derivatives. Hence, the reported reaction conditions were modified for the condensation of the two building blocks 5 and HAB‐NH 2 to the corresponding tetrakis‐ N ‐HAB‐phthalimido‐porphyrin 6 , which was obtained in 64 % yield.…”

β‐Functionalized Push–Pull opp‐Dibenzoporphyrins as Sensitizers for Dye‐Sensitized Solar Cells

“…Dibromobenzoporphyrins 3a and 3b were obtained throughr egioselective bromination of 2a and 2b by using N-bromosuccinimide( NBS)i nd ry CHCl 3 . [15] Pushpull opp-dibenzoporphyrins 4a and 4b were generated from methyl acrylate and 3a and 3b,r espectively, by using aH eckbased cascade reactioni nt he presence of aP d 0 catalyst formed in situ. We also tried the Pt[P(tBu) 3 ] 2 /Pd 2 (dba) 3 catalyst system for this reaction; however,itd id not lead to the desired product.…”