Cationic and Betaine-Type Boronated Acridinium Dyes: Synthesis, Characterization, and Photocatalytic Activity

Abstract

A series of isomeric boronated acridinium dyes were obtained by reactions of 10-(4′-octyloxyphenyl) functionalized 9(10 H )-acridanone derivative with lithiated phenylboronic azaesters followed by aromatization with perchloric acid. The effect of the position of boronic group attached at ortho, meta, and para positions of the 9-phenyl ring on the photophysical properties was investigated. Conversion to related betaine trifluoroborato-substituted compounds was successfully performed, and the effect of this structural change on UV–vis absorption and fluorescence spectroscopy characteristics was established. Furthermore, cyclic voltammetry studies revealed that electrochemical behavior of cationic versus betaine structures is different in terms of redox potential values as well as stability. The theoretical calculations revealed a different scheme for molecular excitation processes in B(OH) 2 versus BF 3 – -substituted compounds as charge transfer to acridinium core is observed from N -aryl or B -aryl moiety, respectively. Obtained compounds were active as photocatalysts in selected visible-light-promoted addition reactions to unsaturated substrates.

Oxazoline scaffold in synthesis of benzosiloxaboroles and related ring-expanded heterocycles: diverse reactivity, structural peculiarities and antimicrobial activity

“…Overall, the process is analogous to chelation of boronic derivatives with various ethanolamine and diethanolamine derivatives which is well documented and used for protection of boron atom against nucleophilic attack. 43,44 The DFT calculations confirm the higher stability of 4c over other hypothetical tautomeric structure comprising siloxaborole ring and pendant N -(1-hydroxy-2-methylprop-2-yl)aminomethyl arm (Δ G ° = 34.2 kJ mol −1 ), 4b′ , i.e. , the neutral form of 4b (Fig.…”

Radiolabeled Silicon-Rhodamines as Bimodal PET/SPECT-NIR Imaging Agents

“…The synthesis plan of boronic acid functionalized SiRs is shown in Scheme 1. Initially, the commercially available regioisomers of the brominated phenyl boronic acids 1a-c were converted in yields of 86% to 91% into the N-butyldiethanolamine func-tionalized phenyl boronates 2a-c to protect the boronic acid groups against the harsh conditions of the subsequent lithiation reaction [69].…”

Benchmarking Computational Approaches to Predict the UV-Vis Spectra of Organic Photocatalysts

“…34 Nevertheless, with the increasing number of In this work, we benchmark several exchange-correlation functionals against handpicked reference data that consists of experimental spectra extracted then digitized from recent literature. [35][36][37][38][39][40][41][42][43][44][45] The main novelties in our strategy are: i) the spectral fitting procedure takes into account full spectral shapes, not only individual excitations; ii) during the fitting we scale the excitation energies instead of shifting them resulting in proportional changes throughout the fitted range; iii) the benchmark focuses on organic photocatalysts. The molecules in the dataset are shown in Scheme 1.…”