Crystalline potassium boryl dithiolate and diselenolate

Both the B-S and S-S bonds of 1,2,4,3,5-trithiadiborolane 1 could be cleaved by potassium graphite (KC₈) to give the first isolable boryl dithiolate DmpB(SK)₂3, whereas the reduction of 1,2,4-triselena-3,5-diborolane 2 with KC₈ afforded the boryl diselenolate DmpB(SeK)(SeSeK) 4, showcasing the unprecedented structural authentication of ligand substituted diselenolate.