Syntheses and Properties of meso‐Substituted Porphyrin Mesogens with Triazole Linkages and Peripheral Alkyl Chains

Abstract

Discotic mesogens P/n-M (n=12, 16, 18, M=2 H, Zn and Cu) bearing a porphyrin core, triazole linkages and peripheral 3,4,5-trialkoxybenzyl units have been synthesized by a click-chemistry approach. The thermal behavior, photophysical properties and morphologies of these compounds were investigated by polarized optical microscopy (POM), differential scanning calorimetry (DSC), XRD, UV and PL, SEM and TEM. These compounds can self-assemble into hexagonal columnar phases in their pure states and form organogels in 1,4-dioxane with unusually flower-like sphere morphology. The supramolecular complexes of P/18-Zn with C or 4,7-di-4-pydriyl-2,1,3-benzothadiazole can display hexagonal columnar phases too. Additionally, zinc porphyrin compounds P/n-Zn show binding selectivity to Cu among a series of cations in THF/H O.

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

“…The research group of Cheng [ 63 ] designed a click inspired synthesis of novel discotic mesogen bearing a porphyrin unit, a triazole linkage, and a peripheral 3,4,5-trialkoxybenzyl unit ( Scheme 32 ). Firstly, free-base porphyrin conjugates 151a–c were obtained by the CuAAC reaction between metal free tetraalkynylporphyrin 149 and benzyl azides 150a–c .…”

Azides and Porphyrinoids: Synthetic Approaches and Applications. Part 1—Azides, Porphyrins and Corroles

“…Photophysical studies supported by density functional theory (DFT) calculations showed strong evidence of efficient energy transfer (~40%) between the porphyrin and fluorescein moieties [30]. The research groups of Cheng [31] and Serrano [32] used the porphyrin-propargyl derivative P26 to prepare porphyrin-based dendrimers peripherally functionalized with alkyl chains linked by triazolyl rings and exhibiting liquid crystal behavior. Both groups developed synthetic routes using porphyrin P26 as the starting reagent for the CuAAC reaction with azide derivatives 7a-d (Scheme 10).…”

“…Cheng [31] prepared porphyrin derivatives P27a,b bearing four 1,2,3-triazole moieties with three terminal alkyl chains (n = 16 or 18) in each one of the meso positions that self-assembled into a columnar hexagonal packaging. When the chemosensorial ability of derivative P27b (n = 18) was evaluated in solution towards a series of metal(II) cations, that compound showed a selective emission quenching in the presence of Cu 2+ ions.…”

“…However, the films obtained with 4,7-di-4-pyridyl-2,1,3-benzothiadiazole present an unordered morphology, while with C 70 a uniform alignment of columns in a columnar hexagonal grid was attained that might lead to anisotropic charge carrier transport along the molecular stacking. Due to the properties presented by compound P27b, it can be investigated for different applications in organic electronic devices or as a chemosensor [31]. Serrano and co-workers prepared porphyrin-core dendrimer derivatives P27c,d with three or six alkyl chains with a terminal coumarin moiety at each one of the meso positions.…”