Hydridoiron complexes

Nitroarenes are reduced to anilines (>85%) under the influence of metal carbonyl complexes. In a two-phase system, the complex hydridoiron complex [HFe,(CO)u]2-is produced from tri-iron dodecacarbonyl at the interface between the organic phase and the basic aqueous phase [7], The generation of the active hydridoiron complex is catalysed by a range of quaternary ammonium salts and an analogous hydrido-manganese complex is obtained from dimanganese decacarbonyl under similar conditions [8], Virtually no reduction occurs in the absence of the quaternary ammonium salt, and the reduction is also suppressed by the presence of carbon monoxide [9], In contrast, dicobalt octacarbonyl reacts with quaternary ammonium fluorides to form complexes which do not reduce nitroarenes. 

Binding energy, pentacarbonyliron, 6, 3 Binuclear complexes bis-Cp titanium halides, 4, 522 with Ni-M and Ni-C cr-bonds heterometallic clusters, 8, 115 homometallic clusters, 8, 111 Binuclear dicarbonyl(cyclopentadienyl)hydridoiron complexes, with rand C5 ligands, 6, 178 Binuclear iridium hydrides, characteristics, 7, 410 Binuclear monoindenyl complexes, with Ti(IV), 4, 397 Binuclear nickel(I) carbonyl complexes, characteristics, 8, 13 Binuclear osmium compounds, with hydrocarbon bridges without M-M bonds, 6, 619... 

Mononuclear dicarbonyl(cyclopentadienyl)hydridoiron complexes, characteristics, 6, 173 Mononuclear a-donor ligands, in molybdenum carbonyls,... 

The hydridoiron complex has also been used in the alkylation of active methylene compounds by formaldehyde or benzaldehyde (equations II and III). 

The reductive dehalogenation of haloalkanes has also been achieved in high yield using polymer supported hydridoiron tetracarbonyl anion (Table 11.15). In reactions where the structure of the alkyl group is such that anionic cleavage is not favoured, carbonylation of the intermediate alkyl(hydrido)iron complex produces an aldehyde (see Chapter 8) [3]. 

Alkenylboron compounds cyclopropanations, 9, 181 haloetherification, 9, 182 hydrogenation and epoxidation, 9, 182 metal-catalyzed reactions, 9, 183 metallic reagent additions, 9, 182 via radical addition reactions, 9, 183 5-Alkenylboron compounds, cross-coupling reactions, 9, 208 Alkenyl complexes with cobalt, 7, 51 with copper, 2, 160, 2, 174 with Cp Re(CO) (alkene)3 , 5, 915-916 with dicarbonyl(cyclopentadienyl)hydridoirons, 6, 175 with gold, 2, 255... 

Selective hydrogenation ofx,p-nnsatwated carbonyl compounds. Japanese chemists have effected selective hydrogenation of ,/7-unsaturated carbonyl compounds by a wine-red hydridoiron carbonyl complex generated in situ from iron pentacarbonyl and a small amount of base in moist solvents. Three different procedures can be used ... 

Anionic hydridoiron species undergo selective addition to a, -unsaturated earbonyl compounds in methanol to give reduction products (Noyori et al., 1972c). Under an atmosphere of carbon monoxide, carbonylation takes place. Methylmalonate is selectively obtained from acrylate by treatment of the reaction mixture with alcoholic iodine (Masada et al., 1970). The organo-iron complexes are readily acylated by treatment with alkyl iodides in an aprotic solvent (Mitsudo et al., 1974). 

---