Patent GB-868650-A (GB)
Title: Organic compounds of metals of group vi and production thereof
IPC: C07F17/00
Filed: 1957-10-16
Abstract: Synthetic resins containing chromium may be obtained from bis(arene) chromium compounds of formula:  <FORM:0868650/IV (a)/1> in which the chromium is attached to the benzene rings by non-localized covalent bonds and R is hydrogen or a non-interfering substituent (see Group IV(b)).  Condensation products may be obtained when R is hydroxyl by reaction with formaldehyde.  Polyamide, polyester and polyanhydride resins may be obtained from compounds in which R is carboxyl, amino or -MgBr. p   Polymerization products of either linear or three-dimensional type may be obtained when R is vinyl, e.g. from bis(vinylbenzene) chromium, by conventional styrene polymerization procedures. Divinyl benzene may be used as a cross-linking agent to obtain cross-linked structures.  Bis(arene) chromium compounds in which the arene group contains two or more vinyl substituents, e.g. bis (2, 4-divinylbenzene) chromium, will give rise to cross-linked homopolymers.  The compounds of the formula above may be used as polymerization catalysts in the polymerization of vinyl and other type monomers.ALSO:The invention comprises bis(arene) complexes of Group VIb metals viz. chromium, tungsten and molybdenum.  The term 'arene' is held to include substituted and unsubstituted aromatic hydrocarbons, the substituent being such that it will not destroy or react with Grignard reagents.  Compounds included in the invention include bis(benzene) chromium, bis (diphenyl) chromium, bis(p-chlorobenzene) chromium, bis(p-sec.butylbenzene) chromium, bis(vinylbenzene) chromium, bis (2,4-divinylbenzene) chromium, bis (naphthalene) chromium and bis(bromomagnesiumbenzene) chromium.  The metal is in a non-ionic state: the compounds however will form salts with anions such as chloride, iodide, sulphate, bisulphate, acetate, benzoate, picrate, perchlorate, tetraphenylboron and [Cr(CNS)4(NH3)2]-.  They may be prepared by treating an aryl metallic agent with an anhydrous halogen compound of a Group VIb metal, hydrolysing the resulting complex and isolating a water soluble complex of said metal from the hydrolysate.  Aryl Grignard reagents are the preferred metallic agent, though lithium, zinc and cadmium aryls may be used.  The Grignard reagent may be prepared from bromobenzene, 1,4-dibromobenzene, 1,2-dibromobenzene, p-bromotoluene, p-iodotoluene, p-bromostyrene, p-bromo-a -methylstyrene, bromomesitylene, chlorobenzene, a -bromonaphthalene, b -bromonaphthalene, a -bromoanthracene, b -bromophenanthrene, p-diethylamino-bromobenzene, m-bromotoluene, o-bromotoluene, 1-bromo-4-chlorobenzene, a -bromotetralin, pentamethyl-bromobenzene, m-fluorobromobenzene, p-ethylbromobenzene, p-butylbromobenzene, p-isobutylbromobenzene, p-sec.butylbromobenzene, p-tert.butylbromobenzene, p-hexylbromobenzene and p-phenylbromobenzene.  The Grignard reagent may be prepared in the usual solvents such as ethers, dioxane, benzene, toluene, ethylene glycol diethyl ether, tetrahydrofuran and tertiary amines, air and moisture being excluded.  Specified anhydrous metallic halides include chromyl chloride, chromous chloride, chromic chloride, chromium bromides and iodides, molybdenum tribromide, molybdenum pentachloride and tungsten hexachloride.  The reaction is carried out at temperatures from the temperature of dry ice to 0 DEG C., or up to room temperature.  The metal halide is added in small increments to the solution of the Grignard reagent, and after hydrolysis, the water-soluble complexes may be converted to water-insoluble salts which are separated.  The salts may be reduced to the bis(arene) metal complexes by reduction e.g. with benzene and 50% aqueous hypophosphorous acid, benzene and alkaline hydrosulphite or electrolytically.  The example gives a detailed method of preparing bis(benzene) chromium and its picrate and tetraphenylboron salts.ALSO:Bis (arone) Group VI metal compounds of formula <FORM:0868650/II/1> in which the chromium (or molybdenum or tungsten) is attached to the benzene rings by non-localized covalent bonds and R is hydrogen or a non-interfering substituent (see Group IV (b)) may be used as plating agents.  The metal, glass, ceramic or polysiloxane to be coated may be heated to a temperature above the decomposition temperature of the compound and then contacted with the compound in the vapour phase e.g. by passage of a stream of the vaporized compound in nitrogen or other inert gas over the hot surface.  The coating compound may also be placed in the liquid or solid state in contact with the heated surface.