86392-65-6Relevant academic research and scientific papers
Nucleophilic, electrophilic, and homolytic reaction chemistry of transition-metal carbonyl trihalomethyl (X = F, Cl, Br) complexes
Richmond, Thomas G.,Crespi, Ann M.,Shriver, Duward F.
, p. 314 - 319 (2008/10/08)
The nucleophilic, electrophilic, and homolytic reaction chemistry of transition-metal carbonyl trihalomethyl complexes (X = F, Cl, Br) has been surveyed. The complexes CpFe(CO)2CX3 (X = F, Cl, Br) were found to readily react with electrophiles to afford cationic carbene complexes [CpFe(CO)2(CX2)]+ that were characterized by NMR and IR spectroscopic methods. These carbenes are extremely moisture sensitive, and hydrolysis affords [CpFe(CO)3]+. Difluorocarbene complexes are also implicated in the proton acid induced hydrolysis of MCF3 to afford [MCO]+ (M = CpFe(CO)2, CpMo(CO)3, Mn(CO)5). The trihalomethyl complexes CpFe(CO)2CX3 (X = Cl, Br) are much more reactive with nucleophiles than the corresponding trifluoromethyl complexes. Treatment of CpFe(CO)2CCl3 with NH3, i-PrNH2, or H2O at room temperature affords high yields of CpFe(CO)2CN, [CpFe(CO)2(CN-i-Pr)]+, or [CpFe(CO)3]+, respectively. In contrast, CpFe(CO)2CF3 is inert to these reagents. Reaction of Mn(CO)5CBr3 with olefins, cumene, or toluene takes place by a radical process to afford a large number of products including Mn(CO)5CHBr2, Mn(CO)5Br, CH2Br2, CHBr3, C2HBr3, and C2Br4. Carbon-bromine bond cleavage is proposed to be the major initiation step for these reactions. Accordingly, Mn(CO)5CCl3 is much less reactive with these reagents and Mn-(CO)5CF3 is completely inert. Addition of 2 equiv of HSn(n-Bu)3 to a solution of Mn(CO)5CBr3 results in a rapid exothermic reaction to afford Mn(CO)5CHBr2 and Mn(CO)5CH2Br. The latter complex is converted to Mn(CO)5CH3 by reaction with HSn(n-Bu)3 for 1 h at 60°C.
