Mark A. Andrews

Metal formyl and hydroxymethyl metal compounds

Abstract Metal formyl anions are produced by reaction of borohydrides with metal carbonyls. The resulting metal formyl anions have moderate kinetic stability but are thermodynamically less stable than the corresponding metal hydrides. Anionic metal formyl compounds can react as hydride donors. Reaction of (C5H5)Re(CO)2(NO)+ with HB (OR)−3 produces the neutral metal formyl complex (C5H5)Re(CO)(NO)(CHO) which undergoes disproportionation as a neat oil to give the metallo ester (C5H5)(CO)(NO)ReCO2CH2(CO)-(NO) (C5H5). Indirect hydrolysis of this metallo ester produced (C5H5Re-(CO) (NO)(CH2OH), the first authentic hydroxymethyl metal compound. Reduction of (C5H5)Re(CO)2(NO)+ with H2Al(CH2CH3−2 provides a more convenient synthesis of (C5H5Re(CO)(NO)(CH2OH). (C5H5)Re(CO)(NO)-(CH2OH) does not react with CO below 90 °C, the temperature at which the hydroxymethyl compound loses H2O to form an ether dimer [(C5H5)Re-(CO) NO)CH2]2O. At room temperature, (C5H5)Re(CO)(NO)CH3 reacts with two equivalents of P(CH3)3 to produce (η1-C5H5)Re(CO)-(NO) [P(CH3)3]2CH3.