New Molecules for Chemistry with LEDs

This paragraph introduces photoredox chemistry, a field that uses light to drive chemical reactions with the aid of photocatalysts. It highlights the ability of photoredox reactions to selectively synthesize complex molecules, especially those with sensitive functional groups. The paragraph details the use of a new class of compounds, alkylbis(catecholato)silicates, in photoredox reactions, noting their improved efficiency and selectivity in processes like thioetherification, arylation, and vinylation. The speaker describes setting up a chemical reaction using specific quantities of pentane, pyridine, methanol, and cyclohexyltrichlorosilane, leading to the formation of cyclohexyltrimethoxysilane through a series of steps including stirring, heating, and extraction.

The second paragraph focuses on the synthesis of diisopropylammonium bis(catecholato)cyclohexylsilicate, a reagent for the photoredox reaction. It begins with the preparation of a mixture containing catechol, THF, diisopropylamine, and cyclohexyltrimethoxysilane, which is then heated to reflux for a day. The reaction involves the formation of a salt through the interaction of hydroxyl and methoxy groups, and the balance of charges. The speaker notes the challenges of methanol formation during the reaction and the subsequent steps taken to remove it, including vacuum distillation and the addition of more solvent. The purification process includes cooling, extraction with diethyl ether, filtration, and drying, resulting in a white powder with an 85% yield.

This paragraph describes the preparation of two catalysts for the photoredox reaction: a nickel complex and a ruthenium complex. The nickel catalyst is synthesized by refluxing nickel(II)chloride hexahydrate with 1,2-dimethoxyethane and trimethyl orthoformate, resulting in a green-yellow product. The ruthenium catalyst involves heating a mixture of Tris(bipyridine)Ruthenium(II) chloride, ethanol, and potassium hexafluorophosphate, yielding a dark red product. The speaker then constructs a makeshift photoreaction chamber using an RGB LED strip and a container, setting the stage for the photoredox reaction.

The final paragraph details the execution of the photoredox reaction, where a mixture of ligands, nickel complex, silicate reagent, and the ruthenium photocatalyst is prepared in a flask and exposed to light from the LED setup for two days. The reaction involves a complex cycle of electron transfers, aiming to produce 4-cyclohexylanisole. After the reaction, the mixture is filtered, and the solvents are removed through vacuum distillation. The product is then isolated using column chromatography, with fractions containing the product combined and the solvent removed to obtain a small amount of clear liquid. The yield and purity of the product are discussed, with the speaker noting a lower yield than expected, possibly due to the LED setup and the lack of an inert atmosphere during the reaction.