Patent GB-941061-A (GB)
Title: Improvements in or relating to organometallic carbonyl complexes
IPC: C23C16/16
Filed: 1959-01-29
Abstract: Aromatic compound-Group VIB metal tricarbonyl complexes are prepared by reacting an aromatic compound with a Group VIB metal hexacarbonyl in a polar solvent.  (Deming's revised Periodic Table is used throughout). Solvents specified include tetrahydrofuran, ethylene glycol dimethyl and diethyl ethers, diethylene glycol diethyl and dibutyl ethers, ethylene glycol monomethyl and monoethyl ethers, isoamyl alcohol, methyl alcohol, ethyl acetate, amyl acetate, acetic acid, dimethylformamide and acetonitrile.  The reaction is facilitated by the presence on the aromatic ring of electron-repelling substitutents such as dimethylamino, methoxy, butoxy, ethoxy, substituted and unsubstituted amines, hydroxyl and alkyl groups. These substituents should have a meta sigma constant (as defined) less than +0.50.  A list of typical complexes which may be prepared is given.  The aromatic residue in the complex may be reacted to produce aromatic derivative complexes, thus hydroxybenzene chromium tricarbonyl can be methylated or acetylated to the anisole and phenylacetate derivatives, aniline complexes may be converted to acetanilide complexes and complexes such as benzoic acid chromium tricarbonyl and phenylacetic acid chromium tricarbonyl can be prepared by alkaline hydrolysis of the corresponding esters. Where the aromatic ring is substituted, the substituents are more easily displaced by nucleophilic reagents than they are in the parent compound. Further the aromatic residue may be regenerated from the complex by thermal decomposition, by reaction with a more powerful ligand such as pyridine, triphenyl-phosphine, dimethyl-phenylarsine or other p-electron donors, or by reaction with carbon monoxide. Thus in Example XIV, chlorobenzene is reacted with chromium hexacarbonyl in dioxane to give chlorobenzene chromium tricarbonyl, which is reacted with sodium hydroxide and then with carbon monoxide to give phenol, chlorobenzene and chromium hexacarbonyl, Ex. XV describes the reaction of o-toluidine chromium tricarbonyl with carbon monoxide to give o-toluidine and chromium hexacarbonyl, and Ex. XVI the regeneration of p-dimethoxy benzene from p-dimethoxybenzene chromium tricarbonyl which was prepared from p-chloroanisole chromium tricarbonyl and sodium methoxide in tetrahydrofuran.  Tris - (dimethylphenylarsine) chromium tricarbonyl is prepared (Ex. X) by reacting methylbenzene chromium tricarbonyl with dimethylphenylarsine, methylbenzene being regenerated.ALSO:Aromatic compound-Group VIb metal (Deming) tricarbonyl complexes may be used as additives to hydrocarbon fuels and lubricating oils. Typical compounds are benzene chromium tricarbonyl, o-cresyl methyl ether chromium tricarbonyl, acetophenone chromium tricarbonyl-many others are specified. When used as antiknock agents, scavengers (phosphorus compounds, halohydrocarbons), deposit modifying agents containing phosphorus or boron and other antiknock agents, e.g. tetraethyl lead, may also be present.ALSO:Aromatic compound-Group VIb (Deming) metal tricarbonyl complexes may be decomposed at above 400 DEG C. by heating in an inert atmosphere e.g. argon in order to deposit a film of the metal on a support such as glass, glass cloth, resins or other insulating materials. The deposition of chromium upon a glass cloth band by decomposition of benzene chromium tricarbonyl is described.