Novel Supramolecular Photocatalyst Based on Conjugation of Cucurbit[7]uril to Non‐Metallated Porphyrin for Electrophotocatalytic Hydrogen Generation from Water Splitting

Abstract

Visible‐light triggerable, stable, organic material‐based photocatalysts that can function in alkaline media without the necessity of sacrificial agent for hydrogen production are highly sought after. Here, we report a novel supramolecular photocatalyst that confers the aforementioned features. This supramolecular photocatalyst (TPP‐4CB7) is synthesized through the conjugation of monohydroxylated cucurbit(7)uril (CB7) hosts to a suitably substituted tetraphenyl porphyrin. Although TPP‐4CB7 by its own preforms as an efficient visible light triggered photocatalyst, the hydrogen production efficiency is significantly enhanced upon mixing with TiO2. The resulting nanocomposite (TPP‐CB‐TiO2@Pt) is observed to exhibit remarkable electrophotocatalytic activity under visible light and produces hydrogen (onset potential −10 mV, turn over frequency (TOF) 0.202 s−1, 24.5 mmol h−1 g−1) from water splitting without any significant degradation during four runs (5 h each) in alkaline media and in the absence of sacrificial agent.

Covalent Organic Framework Constructed by Clicking Azido Porphyrin with Perpropargyloxy-Cucurbit[6]uril for Electrocatalytic Hydrogen Generation from Water Splitting

“…Under optimal conditions, 12%Ni@COF-TPP-CB­[6] catalyst exhibited high performance and good durability for HER and produced 18.7 mmol g –1 h –1 of hydrogen (Faradaic efficiency of 85%), which is comparable and even better than other porphyrin-based HER electrocatalysts reported in the literature (Table S3). ,,,,− …”

“…Another CB [ n ]-porphyrin conjugation was then reported by our group in 2019 in which the monohydroxyl- CB [7] was conjugated to 4­(TEG-OH)-TPP core. The as-prepared assembly was employed for electrophotocatalytic hydrogen generation from water splitting as well as photodynamic antibacterial and cancer therapy. , In the present paper, we report a CB[6] and porphyrin-based covalent organic framework. We first synthesized CB6­(O–P) n by direct functionalization of CB­[6] and then it was covalently attached to porphyrin core ( TPP-Zn-4N 3 ) through Cu-AAC click reaction to construct TPP-CB­[6] covalent organic framework.…”

Orthogonal Supramolecular Assembly Triggered by Inclusion and Exclusion Interactions with Cucurbit[7]uril for Photocatalytic H2 Evolution

“…[35][36][37][38] Notably, the unique structural feature of CB[n]p rovides an opportunity for building novel photocatalytic H 2 evolution systems. [39][40][41][42][43] However, supramolecular systems in which the photosensitizers and catalysts are directly linked with CB[n]t hrough hostguest self-assembly have never been reported.…”

Photodynamic Antimicrobial Chemotherapy: Advancements in Porphyrin-Based Photosensitize Development

“…To further potentiate the antibacterial activity, the system could be loaded effectively with drug molecules. As illustrated in Figure 5 , the system was synthesized by conjugation of cucurbit ( Omolo et al, 2018 ) uril shell, which acted as host for loaded drugs, to a free-base porphyrin core via suitable linkers ( Kumar et al, 2019 ; Özkan et al, 2019 ). While the resulting system exhibited no dark activity towards E. coli (gram-negative bacteria), it showed relatively high cytotoxicity on B. subtilis (gram-positive bacteria).…”