Metallacarboranes as Photoredox Catalysts in Water

Abstract

Metallacarboranes with the shape of the Greek letter q,s uch as [Co(C 2 B 9 H 11 ) 2 ] À ,w ere tested, for the first time, as efficient photoredox catalysts in the oxidation of aromatic and aliphatic alcohols in water.T heir efficiency is linked to their high solubility in water,t heir high oxidizing power (Co 4 + /3 + ), and their absence of fluorescenceo ne xcitation, among others. In most of the studied examples, using ac atalystl oad of 0.4 mol %g ave high yields of 90-95 %w ith selectivity greater than 99 %. By reducing the cata-lyst load to 0.01 mol %, quantitative conversion of reactants to products was achieved, in some cases with greater than 99 %y ield, high catalyst efficiency reaching at urnover number of 10 000, and ah igher yield with a4 5t imes lower concentrationo fc atalyst. The metallacarboranes can be recoverede asily by precipitation on addition of [NMe 4 ]Cl.A pathway for the photoredox-catalyzed oxidation of alcohols is proposed.[a] I.

Preparing (Metalla)carboranes for Nanomedicine

“…COSAN and its derivatives can stabilise nanoemulsions, [152] are effective antimicrobial and antibiofilm agents, [155] interact with DNA, [156] are potent and highly selective inhibitors of tumour-specific carbonic anhydrase IX [157] and form robust shields on proteins. [158] They are not only potent in medical applications, but also capable of performing photo-redox catalysis in water, [159] tune the properties of conducting organic polymers [160] or selectively extract lanthanide and actinide cations from solutions. [161] However, some interpretations and predictions about COSAN in general should be treated with caution.…”

Free three-dimensional carborane carbanions

“…[17][18][19] The unusual steric and electronic properties of boron cluster derivatives have been utilized in coordination chemistry, catalysis, luminescent materials, metal-organic frameworks, polymers, medicine, and energy storage. [20][21][22][23][24][25][26][27][28][29][30][31][32][33] The most commonly studied icosahedral anionic [CB 11 H 12 ] − and neutral C 2 B 10 H 12 clusters contain relatively acidic C−H bonds (for example, pK a of ortho-dicarbaborane is ca. 23).…”

Photoredox-Catalyzed Reduction of Halogenated Arenes in Water by Amphiphilic Polymeric Nanoparticles

“…Traditionally, photoredox-catalyzed reactions have been performed in organic solvents, as this permits good mixing between the catalyst, the substrates and the products. More recently, photoredox catalysis has also become feasible in water by using micellar systems, water compatible ligands, or water-soluble counter ions for the metal-based catalysts [ 6 , 7 , 8 , 9 , 10 ]. Water is considered a green solvent, making reactions more environmentally benign.…”