In order to take advantage of the known volatility of actinide borohydride complexes, attempts were made to prepare half-sandwich borohydrides (RCOT)M(BH/sub 4/)/sub 2/, where COT is cyclooctatetraene and M is Th or U. The borohydrides were formed as complexes with THF solvent. Spectra and chemical reactions of these compounds were investigated. (DLC