A simple and efficient method to synthesize metal salts of M[-BH] (M = Li, Na, K, and Cu).

The synthesis of [-BH] from [-BH] based on redox principles has been developed but is still limited. Using different oxidants often leads to various by-products and affects yields. This paper presents a facile and efficient method for synthesizing [-BH] by directly using the alkali metal salt of [-BH] as the precursor. This approach enables the synthesis of the metal salts of [-BH]. When Cu(OTf) is used as the oxidant, Cu[-BH] is formed with a yield exceeding 94%. On the other hand, when HP(MoO)·HO is used as the oxidant, alkali metal salts of [-BH] (M = Li, Na, and K) are obtained with a yield of up to 85%. All synthesized compounds were characterized by IR, TGA-DSC, and NMR spectroscopy, and M[-BH] (M = K, Cu) was characterized by X-ray single crystal diffraction. Both methods allow for the rapid completion of the reaction in a short time. This synthesis method offers promising potential for further applications, particularly as an all-solid-state electrolyte in battery technology.