Vanadium complexes carbonyl

Several anionic metal carbonyl hydrides stoichiometrically convert acyl chlorides to aldehydes. The anionic vanadium complex [Cp(CO)3VH] reacts quickly with acyl chlorides, converting them to aldehydes [44]. Although no further reduction of the aldehyde to alcohol was observed, the aldehydes reacted further under the reaction conditions in some cases, so a general procedure for isolation of the aldehydes was not developed. 

Acetic acid is formed when methane reacts with CO or C02 in aqueous solution in the presence of 02 or H202 catalyzed by vanadium complexes.327 A Rh-based FeP04 catalyst applied in a fixed-bed reactor operating at atmospheric pressure at 300-400° C was effective in producing methyl acetate in the presence of nitrous oxide.328 The high dispersion of Rh at sites surrounded by iron sites was suggested to be a key factor for the carbonylation reaction. 

Heteroalkenes, with iron, 6, 132 Heteroannulation, allylic benzylamines, 10, 156 Heteroarene chromium carbonyls, preparation and characteristics, 5, 260 Heteroarenes borylation, 10, 242 C—H functionalizations, 10, 127 as metal vapor synthesis milestone, 1, 237 with titanium, 4, 246 vanadium complexes, 5, 48 7]6-Heteroarenes, with platinum, 8, 664 Heteroaromatic compounds... 

The formation of the 17-electron paramagnetic vanadium complex is not surprising in view of the known corresponding carbonyl complex, however the 16-electron titanium derivative is unexpected in view of the ready formation of the 18-electron biscarbonyl and bistrifluorophos-phine metal complexes containing the 5-cyclopentadienyl ligand. The solid-state structure of the PF3 adduct of bis[2,4-dimethyl-(pentadienyl)]titanium has recently been determined (111) and is shown in Fig. 20. The corresponding vanadium complex is isomorphous. The metal-PF3 distances are 2.326(Ti) and 2.275(V) A. 

Table 2 Some isotope shifts ( A and/or A in ppm per isotopic substitution) and temperature gradients (tg in ppm deg ) for carbonyl vanadium complexes [32,33]...

OjNSCyH, 1,2-Benzi othiazol-3(2H)one, 1,1-dioxide, chromium and vanadium complex, 27 307, 309 OjNjWCijHis, Tungsten, tricarbonyltris-(propanenitrile)-, 27 4 0jNaWC,H,2C4Hi 02, Tungstate(l -), tri-carbonyl(n -cyclopentadienyl)-, sodium, compd. with 1,2-dimethoxy-ethane(l 2), 26 343... 

The low-valency cyclopentadienyl vanadium complexes are usually stabilized by carbon monoxide, and VCp(CO)4 is the most useful precursor to various low-valency organovanadium complexes. There are a number of synthetic routes to VCp(CO)4. One convenient method is to carry out the reaction between NaCp and VCl3 in THF in situ and then to carbonylate under 60 atm CO pressure at 120 °C [19]. Reduction of preformed vanadocene by potassium, and subsequent carbonylation also gives rise to VCp(CO)4 [20]. These methods, however, cannot be applied to alkyl-substituted cyclopentadienyl derivatives. It is necessary to treat alkyl-substituted cyclopentadiene... 

The analogous chromium and tungsten complexes can be prepared by the same procedure, and the vanadium complex from a carbonyl complex. 

---