US 3378569 A
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United States Patent 3,378,569 ARENE METAL CARBONYLS Roy L. Pruett, Charleston, and John E. Wym'an, St. Albans, W. Va., and Donald R. Rink and Leo Parts, Buffalo, N.Y., assignors to Union Carbide Corporation, a corporation of New York No Drawing. Filed Sept. 12, 1958, Ser. No. 760,558 5 Claims. (Cl. 260-3403) This invention relates to organo-metallic carbonyls. More particularly, this invention relates to arene metal carbonyl wherein the metal is chromium, molybdenum or tungsten.
Bis(arene)organo-metallic compounds in which two aromatic hydrocarbon groups are bonded to each metal atom, for example bis(benzene)chromium and bis(benzene)molybdenum, have been described. Such compounds and a method for their preparation are disclosed in several published articles by E. O. Fischer and coworkers. See, for example, Z. Naturforshung, (b), 665 (1955); Chem. and Ind, 1956, 153; Z Anorg. Allgem. Chem, 286, 142 (1956); ibid., p. 146; Ber., 89, 1805 (1956); ibid., p. 1809; and Angew. Chem, 68, 462 (1956). The organic groups of the bis(arene)metal compounds of the published articles include only hydrocarbon groups, such as benzene, mesitylene and tetrahydronaphthalene.
We have now discovered a new and useful class of organo-metallic compounds wherein only one arene organic group is bonded to each metal atom and wherein the arene organic group may contain any of a wide variety of chemical elements and functional groups.
These novel organo-metallic compounds are arene metal carbonyls, for example benzene chromium tricarbonyl.
We have further discovered a. process by which the organo-metallic compounds of this invention may be produced.
The compounds of this invention may be represented by the formula ArM(CO) where M is selected from the group consisting of chromium, molybdenum and tungsten and Ar is an arene organic compound containing the benzenoid ring system. The benzenoid ring system is the six-carbon, unsaturated ring which may be represented by the structural formula The simplest members of the class of compounds represented by the above formula are benzene chromium tricarbonyl, benzene molybdenum tricarbonyl and benzeue tungsten tricarbonyl. Additional examples of compound of this invention which illustrate the above formula are the following:
Alltyl substituted compounds such as toluene chromium tricarbonyl, mesitylene chromium tricarbonyl, cumene chromium tricarbonyl, toluene molybdenum tricarbonyl, toluene tungsten tricarbonyl, 9,10-dihydroanthrocene chromium tricarbonyl, and hexamethyl benzene chromium tricarbonyl.
Aryl substituted compounds such as biphenyl chromium tricarbonyl, terphenyl chromium tricarbonyl, quaterphenyl chromium tricarbonyl, biphenyl molybdenum tricarbonyl, biphenyl tungsten tricarbonyl, and alphanaphthyl benzene chromium tricarbonyl.
Aralkyl substituted compounds such as diphenyl methane chromium tricarbonyl, alpha-naphthyl phenyl methane chromium tricarbonyl, diphenyl ethane chromium tricarbonyl, diphenyl methane molybdenum tricarbonyl, and diphenyl methane tungsten tricarbonyl.
Alkoxy substituted compounds such as anisole chromium tricarbonyl, phenetole chromium tricarbonyl, 1,3- dimethoxybenzene chromium tricarbonyl, anisole molybdenum tricarbonyl, and anisole tungsten tricarbonyl.
Aryloxy substituted compounds such as diphenyl ether chromium tricarbonyl, 1,3-diphenoxybenzene chromium tricarbonyl, 1,4-diphenoxybenzene chromium tricarbonyl, diphenyl ether molybdenum tricarbonyl, and diphenyl ether tungsten tricarbonyl.
Alkenyl substituted compounds such as allylbenzene chromium tricarbonyl, styrene chromium tricarbonyl, alphamethylstyrene chromium tricarbonyl, allylbenzene molybdenum tricarbonyl and allylbenzene tungsten tricarbonyl.
Alkhydroxy substituted compounds such as benzyl alcohol chromium tricarbonyl, beta-phenyl ethyl alcohol chromium tricarbonyl, beta-B-tolylethyl alcohol chromium tricarbonyl, benzyl alcohol molybdenum tricarbonyl, and benzyl alcohol tungsten tricarbonyl.
Hydroxyl substituted compounds such as phenol chromium tricarbonyl, resorcinol chromium tricarbonyl, phloroglucinol chromium tricarbonyl., phenol molybdenum tricarbonyl, and phenol tungsten tricarbonyl.
Amino substituted compounds such as aniline chromium tricarbonyl, p-phenylene diamine chromium tricarbonyl, 1,3,5-triaminobenzene chromium tricarbonyl, aniline molybdenum tricarbonyl, and aniline tungsten tricarbonyl.
N-alkylamino substituted compounds such as N-methylaniline chromium tricarbonyl, N-ethylaniline chromium tricarbonyl, N-n-butylaniline chromium tricarbonyl, N- methylaniline molybdenum tricarbonyl, and N-methylaniline tungsten tricarbonyl.
N,N-dialkylamino substituted compounds such as N,N- dimethylaniline chromium tricarbonyl, N,N-diethylaniline chromium tricarbonyl, N,N-di-n-butylaniline chromium tricarbonyl, N,N-dimethylaniline molybdenum tricarbonyl, and N,N-dirnethylaniline tungsten tricarbonyl.
Halogeno substituted compounds such as chlorobenzene chromium tricarbonyl, bromobenzene chromium tricarbonyl, iodobenzene chromium tricarbonyl, fluorobenzene chromium tricarbonyl, chlorobenzene molybdenum tricarbonyl, and chlorobenzene tungsten tricarbonyl.
Aldehydo substituted compounds such as benzaldehyde chromium tricarbonyl, o-methylbenzaldehyde chromium tricarbonyl, p-methylbenzaldehyde chromium tricarbonyl, benzaldehyde molybdenum tricarbonyl, and benzaldehyde tungsten tricarbonyl.
Nitro substituted compounds such as nitrobenzene chromium tricarbonyl, m-dinitrobenzene chromium tricarbonyl, rn-nitrotoluene chromium tricarbonyl, nitrobenzene molybdenum tricarbonyl, and nitrobenzene tungsten tricarbonyl.
Cyano substituted compounds such as benzonitrile chromium tricarbonyl, 4-cyanobiphenyl chromium tricarbonyl, o-dicyanobenzene chromium tricarbonyl, benzonitrile molybdenum tricarbonyl, and benzonitrile tungsten tricarbonyl.
Acyl substituted compounds such as acetophenone chromium tricarbonyl, benzophenone chromium tricarbonyl, propiophenone chromium tricarbonyl, acetophenone molybdenum tricarbonyl, and acetophenone tungsten tricarbonyl.
Sulfhydryl substituted compounds such as benzenethiol chromium tricarbonyl, o-methyl sulfhydrylbenzene chromium tricarbonyl, p-methylsulfhydrylbenzene chromium tricarbonyl, benzenethiol molybdenum tricarbonyl, and benzenethiol tungsten tricarbonyl.
Alkylsulfonyl substituted compounds such as methylsulfonyl-benzene chromium tricarbonyl, ethylsulfonylbenzene chromium tricarbonyl, propylsulfonylbenzene chromium tricarbonyl, methylsulfonylbenzene molybdenum tricarbonyl, and methylsulfonylbenzene tungsten tricarbonyl.
Arylsulfonyl substituted compounds such as benzenesulfonyl benzene chromium tricarbonyl, p-diphenylsulfonyl benzene chromium tricarbonyl, o-tolylsulfonylbenzene chromium tricarbonyl, benzene suifonyl benzene molybdenum tricarbonyl, and benzenesulfonyl benzene tungsten tricarbonyl.
Carboalkoxy substituted compounds such as carbomethoxybenzene chromium tricarbonyl, carbcethoxybenzene chromium tricarbonyl, dibutylphthalate chromium tricarbonyl, carbomethoxybenzene molybdenum tri carbonyl, and carbomethoxybenzene tungsten tricarbonyl.
Carboxamido substituted compounds such as benzamide chromium tricarbonyl, N-methylbenzamide chromium tricarbonyl, o-toluamide chromium tricarbonyl, benzamide molybdenum tricarbonyl, and benzamide tungsten tricarbonyl.
Carboxyl substituted compounds such as benzoic acid chromium tricarbonyl, phthalic acid chromium tricarbonyl, toluic acid chromium tricarbonyl, benzoic acid molybdenum tricarbonyl, and benzoic acid tungsten tricarbonyl.
Sulfonamido substituted compounds such as benzenesulfonamide chromium tricarbonyl, o-methylbenzenesulfonamide chromium tricarbonyl, p-methy1benzenesulfonamide chromium tricarbonyl, benzenesulfonamide molybdenum tricarbonyl, and benzencsulfonamide tungstcn tricarbonyl.
Benzene rings substituted with mixed substituents such as alkyl, alkoxy benzene: for example, anethole, may also form the compounds of this invention. Still other examples are p-cresol chromium tricarbonyl, salicylaldehyde chromium tricarbonyl, anisaldehyde chromium tricarbonyl, m-nitroaniline chromium tricarbonyl, p-chlorophenol chromium tricarbonyl, para-chlorotoluene chromium tricarbonyl, o-N,N-dimethylaminotoluene chromium tricarbonyl, and p-dimethylaminobenzaldchyde chromium tricarbonyl.
Therefore, the compounds of this invention may also be represented by the formula (CO)a wherein M is selected from the group consisting of chromium, molybdenum and tungsten and the R groups may be the same or mixed and may be hydrogen and other benzenoid ring system substituents such as alkyl, aryl, aralkyl, alkaryl, alkenyl, alkoxy, aryloxy, alkhydroxy, hydroxyl, amino, N-alkyl amino, N,N-dialkylamino, halogeno, aldehydo, acyl, carboalkoxy, carboxamido, and carboxyl.
The bonding between the metal atom and the arene organic group takes place through six electrons of the benzenoid ring system of the arene organic group. This type of bonding is discussed in more detail in an article by E. O. Fischer and H. P. Kogler, Angew. Chem. 68, 462 (1956). The substituents on the benzenoid ring system must therefore be of such size and number that the benzenoid ring may approach the metal atom sufiiciently closely to permit stable bond formation to take place. For example, tertiary-butylbenzene chromium tricarbonyl and hexamethylbenzene chromium tricarbonyl are stable compounds, but 1,3,S-tritertiary-butylbenzene chromium tricarbonyl is too unstable to permit isolation because the three bulky tertiary butyl groups do not permit the henzenoid ring system to approach the chromium atom sulficiently closely for stable bond formation to take place.
The organo-metallic compounds of the present invention may be characterized as addition compounds in contrast to organo-metallic substitution compounds. In the latter, a hydrogen or other substituent in the organic nucleus is substituted or removed in the formation of the organometallic compound. However, no hydrogen, alkyl or other substituent is removed from or replaced on the arene organic moiety in the formation of the arene metal carbonyls of this invention.
The compounds of this invention should be distinguished from addition compounds such as the hexapyridine chromium cation, Cr(NC I-I wherein bonding between the metal and the organic group results from a conventional covalent (two electron) bond between the metal atom and one other atom in the organic group.
According to the process for producing the compounds of this invention, an arene organic compound and a metal carbonyl are reacted either in solution or in the vapor phase. This process may be represented by the equation or, representing the arene organic group in more detail, by the equation wherein Ar, M and R have the meanings defined hereinabove.
The embodiment of the process wherein the reaction takes place in the vapor phase may be conveniently carried out by passing vapors of metal carbonyl and arene organic compound through a glass, ceramic or metal tube heated to an elevated temperature. It is preferable to use a stoichiometric excess of the arene organic compound.
The temperatures may vary over wide limits from the vaporization temperatures of the reactants up to the decomposition temperature of the product. Temperatures in the range from about 200 C. to about 300 C. give good yields of product and relatively rapid rates of reaction.
The reactant vapors may be undiluted or may be carried through the reaction zone in a stream of inert gas, such as nitrogen or argon. A total pressure of about one atmosphere is most convenient but higher or lower pressures may be used.
In the embodiment of the process wherein the reaction takes place in the liquid phase, it is preferable to employ an excess of the aromatic reactant as a solvent for the metal carbonyl. However, the reaction between the aromatic compound and the metal carbonyl may be carried out in an inert hydrocarbon solvent, such as heptane, petroleum ether or .an aromatic compound which does not form an arene metal carbonyl under the particular reaction conditions.
In the preferred form of the liquid phase reaction, a basic catalyst is added to the reaction mixture. The basic catalysts of this invention are basic, nitrogen-containing liquid organic compounds, preferably alkyl-substituted pyridines or tertiary amines such as N,Ndimethylaniline, tributylamine, 2 methylpyridine, 2,6 dimethylpyridine, 2,4,6-trimethylpyridine and triethyl amine. When aniline or a derivative thereof is a reactant, no additional catalyst is necessary. The catalyst increases the rate of reaction and thus makes it possible to carry out the reaction at a lower temperature than that required in the absence of a catalyst. Trace amounts of catalyst are effective, but larger amounts are preferred, as described hereinbelow.
The temperatures at which the liquid phase reaction may be carried out may vary over a considerable range of from 0 C. to 300 C. Temperatures up to about 100 C. are often satisfactory but in the interest of increasing the rate of reaction, higher temperatures are preferred. Temperatures in excess of the decomposition temperature of the products in the reaction medium employed should be avoided. Generally, it is preferred to employ temperatures in the range of 100 C. to 250 C.
The time necessary to carry out the reaction varies over wide limits depending on the temperature employed. The yields are not materially reduced by long time maintenance of reaction mixture under reaction conditions. Carbon monoxide gas is evolved during the course of the reaction, and it is generally preferred to maintain the reactants under the desired reaction conditions until carbon monoxide evolution essentially ceases.
The ratio of reactants is not critical and such ratios may he varied over wide limits. However, it is preferable to use the aromatic reagents in considerable stoichiometric excess, although stoichiom-etric amounts may be used. Further, for good yields, at least equal amounts of the metal carbonyl and catalyst should be used, although small quantities of the catalyst may also be used with success. The best yields are obtained when a considerable excess of both the catalyst and aromatic reactant are used.
When a metal carbonyl is reacted with a mixture of arene reactants, an arene metal carbonyl will form preferentially with the arene compound having the stronger electron donating group or weaker electron withdrawing group, as a substituent. In Example 9 hereinbelow, molybdenum hexacarbonyl was heated with equal volumes of N,N-dimethylaniline and toluene. Since the dimethylamino group is a stronger electron donor than the methyl group, N,N-dimethylaniline molybdenum tricarbonyl was produced rather than toluene molybdenum tricarbonyl. Similarly, from a reaction mixture containing chromium hexacarbonyl, chlorobenzene and benzaldehyde, the compound produced would be chlorobenzene chromium tricarbonyl, not benzaldehyde chromium tricarbonyl, because the chloro group is a weaker electron withdrawing group than the aldehyde group.
The compounds of this invention and the process for producing them are illustrated by the following examples:
Example 1.p-Xylene chromium tricarbonyl One hundred milliliters of 2,4,fi-trimethylpyridine, 100 ml. of p-xylene and 2.0- g. of chromium hexacarbonyl were placed in a 500 ml. round bottom flask equipped with a condenser. The reaction mixture was heated at a reflux temperature of 147 C. for a period of six hours. After cooling to room temperature, the solution was filtered and evaporated to an oily residue by heating under partial vacuum in an oil bath at 110 C. The oily residue was then crystallized by chilling. The solid was then taken up in boiling n-heptane and 1.56 grams of yellow crystals of p-xylene chromium tricarbonyl were isolated. This represents a yield of 71% of theoretical amount based on chromium hexacarbonyl. The melting point of the product, p-xylene chromium tricarbonyl is 9798 C. and the infrared spectrum is consistent with the assigned structure.
Following the same procedure, 50 milliliters of pxylene, 2 grams (0.009 mole) of chromium hexacarbonyl and 1.87 grams (0.01 mole) of tri-n-butylamine were reacted to yield 0.8 gram of yellow crystals of p-xylene chromium tricarbonyl. This represents a yield of 36% based on Cr(C0) Example 2.--Tetrahydronaphthalene chromium tricarbonyl Tetrahydronaphthalene (150* ml.), 50 milliliters of 2,4, G-trimethylpyridine, and 3.0 grams of chromium hexacarbonyl were placed in a SOD-milliliter round bottom flask equipped with a reflux condenser and heated at 150 to 160 C. for four hours. The reaction was carried out under an argon atmosphere. An additional 50 milliliters of tetrahydronaphthalene were added and the solution refluxed for eight hours. The solution was cooled to room temperature and evaporated to dryness under a partial vacuum. The yellow residue was dissolved in boiling nheptane and chilled to crystallize the crude product. The yellow crystals were collected and twice; recrystallized from n-heptane affording a 2.2 gram yield of yellow crystals of tetrahydronaphthalene chromium tricarbonyl, M.P. 11S-l16 C. This represents a 60% yield based on Cr(CO) Example 3.Toluene chromium tricarbonyl A mixture of milliliters of toluene, 100 milliliters of Z-methylpyridine, and 2.0 grams of chromium hexacarbonyl was placed in a SOO-ml. flask and the reaction was carried out by the process of Example 1. Yellow crystals of toluene chromium tricarbonyl, M.P. 79-81 C., were obtained.
Example 4.-Mesitylene chromium tricarbonyl One hundred milliliters of mesitylene, 100 ml. of 2- methylpyridine, and 2.0 grams of Cr(CO) were reacted by the process of Example 1, to yield 1.4 grams of mesitylene chromium tricarbonyl, M.P. 174175 C. This represents a yield of 60% based on Cr(C0) Example 5.-p-Chlorotoluene chromium tricarbonyl Following the procedure of Example 1, 2.0 grams of chromium hexacarbonyl, 100 milliliters of Z-methylpyridine, and 100 milliliters of p-chlorotoluene were reacted to yield 1.4 grams of yellow crystals of p-chlorotoluene chromium tricarbonyl, M.P. 89-91 C. This represents a yield of 60% based on Cr(CO) Example 6.-Anisole chromium tricarbonyl Following the procedure of Example 1, 100 milliliters of redistilled anisole, 100 milliliters of Z-methylpyridine, and 2.0 grams of chromium hexacarbonyl were reacted to yield 1.52 grams of yellow crystals of anisole chromium tricarbonyl M.P. 8486 C. This represents a yield of 70% based on Cr(C0) Example 7.-Bromobenzene chromium tricarbonyl Following the procedure of Example 1, 100 milliliters of 2-methylpyridine, 100 milliliters of bromobenzene, and 2.0 grams of chromium hexacarbonyl were reacted to yield 0.16 gram of dark yellow crystals of bromobenzene chromium tricarbonyl, M.P. 117-120 C. This represents a yield of 6% based on Cr(CO) Following the procedure in Example 1, 50 milliliters of N,N-dimethylaniline, 50 milliliters of toluene and 3 grams of molybdenum hexacarbonyl were reacted to yield pale yellow crystalline N,N-dimethylaniline molybdenum tricarbonyl which decomposes without melting at C.
Found: C, 44.6%; H, 3.6%; M0, 32.8%; N, 4.5%. Calculated for C H N(CH Mo(CO) C, 43.9%; H, 3.7%; Mo, 31.9%; N, 4.7%.
Example 10.--Mesitylene molybednum tricarbonyl Following the procedure of Example 1, 2 grams of molybdenum hexacarbonyl, 4.4 grams of tri-n-butylamine and 50 milliliters of mesitylene were reacted to yield pale yellow crystalline mesitylene molybdenum tricarbonyl which decomposes without melting at C. Example 11.N,N-Dimethylaniline tungsten tricarbonyl Following the procedure of Example l, 50 milliliters of N,N-dimethylaniline, 50 ml. of toluene and 3 grams of tungsten hexacarbonyl were reacted to yield bright yellow crystalline dimethylaniline tungsten tricarbonyl which turns green at 160 C. and melts at 180 C. with gas evolution.
Following the same procedure but without the use of toluene as a solvent, 50 milliliters of N,N-dimethylaniline and 3 grams of tungsten hexacarbonyl were reacted to yield 2.5 grams of dimethylaniline tungsten tricarbonyl. This represents a yield of 76% based on W(CO) Example 12.Aniline chromium tricarbonyl Following the procedure of Example 1, 50 milliliters of aniline, 50 milliliters of toluene and 3 grams of chromium hexacarbonyl were reacted to yield bright yellow crystals of aniline chromium tricarbonyl which melts without decomposition at 156-158 C.
Found: C, 47.3%; H, 3.2%; Cr, 23.6%; N, 5.9%. Calculated for C H NH Cr(CO) C, 47.2%; H, 3.1%; Cr, 22.7%; N, 6.1%.
Preparation of the hydrochloride of (l) N,N-dimethylaniline tungsten tricarbonyl and (2) aniline chromium tricarbonyl: Each of the above compounds was treated in the following manner: about 0.2 gram was dissolved in toluene and gaseous hydrogen chloride was bubbled through the solutions. The bright yellow, crystalline hydrochlorides precipitated. These hydrochlorides were hygroscopic and reverted to the toluene-soluble free amine metal tricarbonyls on contact with a mixture of toluene and water. The hydrochloride of N,N-dimethylaniline or aniline does not ordinarily revert to the free amine on contact with water. This shows that the complexing of the benzenoid ring :by the M(CO) unit decreases the base strength of the free amine.
Example 13.--p-Xylene tungsten tricarbonyl Following the procedure of Example 1, 75 milliliters of p-xylene, 2 grams of tungsten hexacarbonyl and 3 grams of tri-n-butylamine were reacted to yield bright yellow crystalline p-xylene tungsten tricarbonyl which melts with decomposition at 160162 C.
Found: C, 34.9%; H, 3.1%; W, 50%. Calculated for C H.,(CH W(CO) C, 35.3%; H, 2.7%; W, 49%.
Example 14.-Mesitylene tungsten tricarbonyl Following the procedure of Example 1, 50 milliliters of mesitylene, 2 grams of tungsten hexacarbonyl and 10 cc. of triethylamine were reacted to yield 0.2 gram of yellow crystals of mesitylene tungsten tricarbonyl which sublimes at 150 C. at 1 atmosphere and decomposes above 186 C.
Example .N,N-Dimethylaniline chromium tricarbonyl Example 16.-2-Aminobiphenyl chromium tricarbonyl Following the procedure in Example 1, 10 grams of Z-amino-biphenyl, 2 grams of chromium hexacarbonyl and 3 milliliters of toluene were reacted to yield bright yellow crystals of Z-aminobiphenyl chromium tricarbonyl.
Example 17.Biphenyl chromium tricarbonyl Following the procedure in Example 1, 10 grams of biphenyl, 2 grams of chromium hexacarbonyl and milliliters of tri-n-butylamine were reacted to yield dark yellow crystals of biphenyl chromium tricarbonyl which melts at 8081 C.
8 Found: C, 59.7%; H, 3.5%; Cr, 18.3%. Calculated for (C H Cr(CO) C, 62.0%; H, 3.5%; Cr, 17.9%.
Example l8.Aniline molybdenum tricarbonyl Following the procedure of Example 1, 2 grams of molybdenum hexacarbonyl, 50 milliliters of aniline and 5 milliliters of toluene were reacted to yield yellow crystals of aniline molybdenum tricarbonyl.
Example 19.Aniline tungsten tricarbonyl Following the procedure of Example 1, 2 grams of tungsten hexacarbonyl and 50 milliliters of aniline were reacted to yield yellow crystals of aniline tungsten which melt at 120121 C. with decomposition and which were identified by infrared analysis.
Example 20.Cumene chromium tricarbonyl Following the procedure of Example 1, 2 grams of chromium hexacarbonyl, 25 ml. of tri-n-butylamine and 100 milliliters of cumene were reacted to yield 1.5 grams of yellow crystals of cumene chromium tricarbonyl. This represents a yield of based on Cr(CO) Example 2l.Toluene chromium tricarbonyl Vapors of Cr(CO) and toluene were passed through a Pyrex tube heated to a maximum temperature of 340 C. Yellow crystals of toluene chromium tricarbonyl began to collect at the downstream end of the reaction tube when the temperature reached 220 C. The rate of reaction appeared to increase up to 250 C. where a chromium mirror began to form on the walls of the reaction tube. A total of 1.3 grams of Cr(CO) was vaporized and passed through the tube, yielding 0.8 gram of yellow toluene chromium tricarbonyl. This represents a yield of 59% based on Cr(CO) Example 22.Alpha-methyl styrene chromium tricarbonyl Fifty (50) milliliters of alpha-methyl styrene inhibited with tertiary butyl catechol, 50 milliliters of tri-n-butylamine and 2 grams of chromium hexacarbonyl were placed in a 200 milliliter boiling flask which had been purged with argon. The reaction was carried out under a protective atmosphere of argon throughout. The reaction mixture was heated to boiling (170 C. and allowed to reflux 1 /2 hours until carbon monoxide evolution ceased. The dark yellow solution was then stripped to dryness under a partial vacuum. A yellow crystalline solid was obtained which was recrystallized from n-heptane to obtain 0.7 gram of yellof alpha-methyl styrene chromium tricarbonyl which has a melting point of 77-78 C. with no apparent decomposition. The structure and composition of this compound were confirmed by intrared and elemental analysis. A 30% yield based on chromium was obtained.
Example 23.-Durene chromium tricarbonyl Two hundred (200) milliliters of Z-methylpyridine, 2.0 grams of chromium hexacarbonyl and 25 grams of durene were reacted by the process of Example 1, to yield 0.7 gram of durene chromuim tricarbonyl, melting point 97 98 C. This represents a yield of 39% based on chromium hexacarbonyl.
Example 24.Tertiary-butylbenzene chromium tricarbonyl One hundred milliliters (100 ml.) of Z-methylpyridine, 100 milliliters of tertiary-butyl benzene, and 2.0 grams of chromium hexacarbonyl were reacted by the process of Example 1, to yield 1.53 grams of tertiary-butylbenzene chromium tricarbonyl, melting point 7879 C. This represents a yield of 63% based on chromium hexacarbonyl.
Example 25.4-Methyl-2-phenyl-1,3-dioxolane chromium tricarbonyl Fifty (50) milliliters of 4-methyl-2-phenyl-1,3-dioxolane, milliliters of 2-rnethylpyridine, and 2.0
grams of chromium hexacarbonyl were reacted by the process of Example 1 to give 4-methyl-2-phenyl-1,3-dioxolane chromium tricarbonyl as an intractable oil.
Example 26.-Benzaldehyde diethylacetal chromium tricarbonyl A mixture of 3.0 grams of chromium hexacarbonyl, 50 milliliters of benzalde-hyde diethylacetal, and50 milliliters of Z-methylpyridine were reacted by the process of Example 1 to give 2.1 grams of benzaldehyde diethylacetal chromium tricarbonyl, melting point l-52 C. This represents a yield of 50% based on chromium hexacarbonyl.
Example 27.Benzaldehyde chromium tricarbonyl A mixture of 1.5 grams of benzaldehyde diethylace-tal chromium tricarbonyl and 35 milliliters of Water containing 3 drops of concentrated hydrochloric acid was placed in a stoppered test tube under argon and allowed to react with occasional shaking for a six-hour period. The resulting orange solid was filtered in a dry box using argon as the inert atmosphere. The solid material was a mixture of benzaldehyde chromium tricarbonyl and benzaldehyde diethylacetal chromium tricarbonyl. This mixture was then shaken continuously for six hours with 30 milliliters of water containing 3 drops of concentrated hydrochloric acid in a stoppered test tube under an argon atmosphere. The following operations were conducted in a dry box using argon as the inert atmosphere. The resulting red aqueous solution containing some red oil was extracted with toluene until the aqueous layer was colorless. 'I he toluene layer was dried over sodium sulfate, filtered and evaporated to dryness under a partial vacuum. The resulting mixture of a red oil and red crystals was recrystallized from 100 milliliters of boiling heptane, cooled in a Dry Ice bath, and filtered aifording 1.0 gram of benzaldehyde chromium tricarbonyl. This represents a yield of 83%, based on benzaldehyde diethylacetal chromium tricarbonyl.
Example 28.-N-methylaniline chromium tricarbonyl Following the procedure of Example 1, 100 milliliters of N-methylaniline and 3.0 grams of chromium hexacarbonyl were reacted to yield 2.65 grams of yellow crystals of N-methylaniline chromium tricarbonyl which melts without decomposition at 120l2l C. This represents an 80% yield, based on chromium hexacarbonyl. The infrared spectrum was consistent with the assigned structure.
Example 29.Acetophenone diethylketal chromium tricarbonyl Following the procedure of Example 1, 50 milliliters of 2-methylpyridine, 50 milliliters of acetophenone diethylketal, and 3.0 grams of chromium hexacarbonyl were reacted to give 2.13 grams of yellow platelets of acetophenone diethylketal chromium tricarbonyl, melting point 4143 C. This represents a yield of 46% based on chromium hexacarbonyl.
Example 30.Ace-tophenone chromium tricarbonyl A stoppered test tube containing 1.5 grams of acetophenone diethylketal chromium tricarbonyl, 35 milliliters of water, and 3 drops of concentrated hydrochloric acid was mechanically shaken for six hours. The reddish orange solid remaining in the test tube was dissolved in toluene and the aqueous layer extracted with toluene. The combined toluene extracts were dried over sodium sulfate, and evaporated to dryness in a partial vacuum at 40 C. The red crystalline solid was recrystallized twice from heptane alfording 0.8 gram of golden yellow crystals of acetophenone chromium tricarbonyl. This represents a yield of 64%, based on acetophenone diethylketal chromium tricarbonyl.
The sample of the material melted at 48-50 C. after shaking with 40 ml. of water containing 3 drops of concentrated hydrochloric acid, washing, and drying.
Example 31.-Benzyl alcohol chromium tricarbonyl A mixture of 50 milliliters of benzyl alcohol, 50 milli liters of Z-rnethylpyridine and 2.0 grams of chromium hexacarbonyl were reacted by the process of Example 1 to give 0.8 gram of benzyl alcohol chromium tricarbonyl, melting point 96-98 C. This represents a yield of 63% based on chromium hexacarbonyl.
Example 32.-Diphenylmethane chromium tricarbonyl A mixture of 50 milliliters of diphenylmethane, 150 milliliters of Z-methylpyridine and 2.0 grams of chromium hexacarbonyl were reacted by the process of Example 1 to give 1.52 grams of diphenylmethane chromium tricarbonyl, melting point 99-1 01 C. This represents a yield of 56% based on chromium hexacarbonyl.
Example 33.-Benzoic acid chromium tricarbonyl Ethyl benzoate chromium tricarbonyl, obtained from the reaction of 5.0 grams of chromium hexacarbonyl, 100 milliliters of triethylamine, 100 milliliters of Z-methylpyridine, and 100 milliliters of ethyl benzoate, was added to a solution of 5.0 grams of potassium hydroxide in 45 milliliters of water and the mixture allowed to stand for 3 days at room temperature. The yellow solution, which did not contain unreacted ethyl benzoate chromium tricarbonyl, was filtered and acidified with concentrated hydrochloric acid after the addition of about 20 grams of ice. The resulting cloudy orange solution was then extracted with ether (three 50 milliliter portions), the ether extracts dried after washing with distilled water (three 50 milliliter portions), and evaporated to dryness in partial vacuum. The resulting orange-yellow solid was dissolved in the minimum amount of ether and evaporated to dryness in a stream of argon to give benzoic acid chromium tricarbonyl. The compound was obtained as an orange-red solid, soluble in aqueous base, insoluble in heptane and water, difiicultly soluble in benzene and very soluble in ether.
The compounds of this invention may be used to deposit a metallic mirror on various substrates. All of the compounds of this invention can be decomposed by employment of temperatures in excess of 400 C. to form a metallic film or coating on materials such as glass, glass cloth, resins and metals. The metallic coatings provide electrically conducting coatings for such substances as glass cloth and provide corrosion resistant coatings for metals.
For coating glass cloth, a quantity of an arene metal tricarbonyl of this invention is sealed in an evacuated glass tube with a strip of glass cloth which has previously been dried in an oven at C. for one hour; the tube is then heated to about 400 C. for one hour, cooled and opened. The glass cloth increases in weight by up to about 0.01 gram per gram of glass cloth and has a resistivity of approximately 2 ohms per centimeter. Thus, a conducting cloth may be prepared which is useful for the reduction of static charge.
For example, a piece of thin copper wire about 43 millimeters long, a piece of sapphire rod 3 millimeters in diameter and 22 millimeters long, and a rectangular piece of glass cloth about 50 x 20 millimeters average dimension were placed in a 30 millimeter OD. glass tube 2 feet long. A glazed porcelain boat containing 1 gram of toluene chromium tricarbonyl was placed in the tube which was then purged with argon and heated to 300 C. The boat was then pushed into the hot zone. After 45 minutes, a chromium plate was deposited on the objects as well as on the walls of the tube, and toluene was condensing on the cool downstream end of the tube.
The glass cloth had attained a very dark metallic luster and would conduct an electric current. The copper Wire had a dull, even coating of chromium rnetal over its entire length. The sapphire rod had an even, bright, shiny 1 1 surface coating of chromium metal and this chromium plate had a resistance of 150 ohms from one end to the other.
The alkenyl substituted compounds of this invention may also be used to prepare light sensitive polymers. Such polymers are useful in preparing paper suitable for photo reproduction.
For example, alpha-methyl styrene chromium tricarbonyl (.3 gram, 0.001 mole), and .5 gram (0.005 mole) of styrene catalyzed with a few crystals of 1,1-azo-bisl-cyclohexane nitrile were placed in an argon purged reaction vessel. The reaction was carried out in an inert atmosphere of argon throughout. The reaction mixture was heated to 110 C. for three hours at which time the reaction mixture Was nearly solid. The styrene-alphamethyl styrene chromium tricarbonyl co-polymer was taken up in toluene. The toluene, styrene-alpha-methyl styrene chromium tricarbonyl co-polymer mixture was added to about 150 milliliters of methanol and the polymer filtered out. Analysis of the product corresponds to one alpha-methyl styrene chromium tricarbonyl molecule per 5.25 styrene molecules. The copolymer softens at about 140 C. and changes from yellow to green on exposure to light.
What is claimed is:
1. Alpha-methyl styrene chromium tricarbonyl.
12 2. 4-methyl-2-phenyl 1,3 dioxolane chromium tricarbonyl.
3. Benzaldehyde diethylacetal chromium tricarbonyl. 4. Acetophenone diethylketal chromium tricarbonyl. 5. A styrene polymer chromium tricarbonyl.
References Cited UNITED STATES PATENTS 12/1957 Brown et al. 260429 OTHER REFERENCES TOBIAS E. LEVOW, Primary Examiner.
ABRAHAM H. WINKELSTEIN, Examiner.
H. M. S. SNEED, W. J. VAN BALEN, L. C. BROWN,
B. D. WIESE, Assistant Examiners.