US3064024A

US3064024A - Cycloheptatrienyl cycloheptatriene metal compounds and process of making the same

Info

Publication number: US3064024A
Application number: US856348A
Authority: US
Inventors: Wilkinson Geoffrey
Original assignee: Ethyl Corp
Current assignee: Ethyl Corp
Priority date: 1958-12-08
Filing date: 1959-12-01
Publication date: 1962-11-13
Anticipated expiration: 1979-11-13
Also published as: GB894852A

Description

United States Patent @fifice 3,%4 ,24 Patented Nov. 13, 1962 This invention relates to new organometallic compounds and a method for their preparation. More specifically, this invention relates to organometallic compounds in which metallo carbonyl moieties are bonded to both of the cycloheptatrienyl rings present in a l-cycloheptatrienyl cyeloheptatriene compound.

An object of this invention is to provide new organometallic compounds and a method for their preparation.

A more specific object is to provide compounds in which metallocorbonyl moieties are bonded to each of the cycloheptatrienyl rings present in a l-cycloheptatrienyl cycloheptatriene compound. Further objects will become apparent from a reading of the specification and claims which follow.

The compounds of my invention are best described by reference to their generic structural formula:

M and M in the above formula, are metal atoms selected from groups ViB-VIII of the periodic table of the elements shown in the Handbook of Chemistry and Physics, 39th edition, The Chemical Rubber Publishing Company, Cleveland, Ohio, 1957. The group VIB metals are molybdenum, chromium and tungsten. The group VIIB metals are manganese, technetium and rhenium, and the group VIII metals are iron, ruthenium, cobalt, rhodium, platinum, iridium, osmium, palladium and nickel. The metals of groups VB and VIIB are preferred in forming the compounds of my invention. Further preferred are my compounds in which M and M are molybdenum since these compounds are generally more stable than other of my compounds. b and c are integers ranging from zero to six and may be the same or different while d and f are integers ranging from one to three and may be the same or different. if is an integer ranging from zero to one.

In the above formula, the metal atoms M and M have an electron configuration ranging from two less than up to and including the electron configuration of the next higher rare gas. Preferred compounds are those in which each of the metal atoms has achieved the electron configuration of the next higher rare gas. As an example, in the compound 1-cycloheptatrienyl cycloheptatriene bis(molybdenum tricarbonyl) both molybdenum atoms have the electron configuration of xenon. Tins is accomplished by donation of 12 electrons to each of the metal atoms M and M In this case, the 1-cycloheptatrienyl cycloheptatriene compound contributes l2 electrons, six of which go to M and six of which go to M All 12 electrons from the l-cycloheptatrienyl cycloheptatriene compounds come from their double bonds with each double bond contributing two electrons. Each carbonyl group, of which there are three for each of the two molybdenum atoms, contributes two electrons to the molybdenum atom. This gives a total of six electrons donated by the three carbonyl groups to each molybdenum atom.

.As exemplified in l-cycloheptatrienyl cycloheptatriene bis(molybdenum tricarbonyl), the integers d and f are such that the above enumerated requirements of the 2 metal atoms as to their electron configuration are satisfied.

R and R are monovalent hydrocarbon groups which may be the same or diiferent. They are substituents on the two cycloheptatrienyl rings comprising the l-cycloheptatrienyl cycloheptatriene compound. They may contain from one to twenty carbon atoms and may be such radicals as, for example, alkyl, aryl, alkaryl, and aralkyl.

Typical of the compounds of my invention are: 1- methyl-7 (2 methyl-2,4,6 cycloheptatrien-l-yl) 1,3,5- cycloheptatriene bis(chromium tricarbonyl), 2-eicosyl-7- (2-methyl-2,4,6 cycloheptatrien-l-yloxy)-l,3,5-cycloheptatriene bis(tungsten tricarbonyl), 7-(2-tert-butyl-2,4,6- cycloheptatrienl-yloxy l ,3,5-cycloheptatriene bis (nickel carbonyl), 7 (2-ethyl-2,4,6 cycloheptatrien-l-yl)-1,3,5- cycloheptatriene bis(molybdenum tricarbonyl), 7-3-npropyl-2,4,6-cycloheptatrien-l-yl)-1,3,5 cycloheptatriene bis (cobalt carbonyl), 7-(3-isopropyl-2,4,6-cycloheptatrien- 1 yl) 1,3,5 cycloheptatriene molybdenum tricarbonyl chromium tricarbonyl (121:1 complex) in which the chromium tricarbonyl moiety is bonded to the isopropylsubstituted cycloheptatrienyl ring, 3-ethyl-7-(3-ethyl- 2,4,6-cycloheptatrienl -y1 -l ,3 ,5 -cycloheptatriene bis (iron dicarbonyl), 3-ethyl-7(3-phenyl-2,4,6 cycloheptatrien-lyl)-l,3,5-cycloheptatriene bis(manganese dicarbonyl).

As described above, my invention involves compounds in which metallocarbonyl moieties are bonded to each of the cycloheptatrienyl rings in a l-cycloheptatrienyl cycloheptatriene compound. My invention is not limited to such compounds, however, and is intended to include all chemical equivalents thereof. Typical of such chemically equivalent compounds are those of the formula in which M M R R b and 0 have the meaning as set forth above. Z and Z are electron donating groups which may be the same or difierent and are each capable of donating from one to six electrons to the metal atoms M and M p and g are integers ranging from one to six and may be the same or different- The metal atoms M and M have, as previously defined, an electron configuration ranging from two less than up to and including the electron configuration of the next higher rare gas.

Various combinations of the above groups can also be used as the bridging groups X." Thus, X can be:

The above examples of groups meeting the requirement of X are solely'by Way of illustration and are not intended to llmit the scope ofthe term X in the above formula.

R, in the above examples of bridging groups, denotes a hydrocarbon radical which may be alkyl, aryl, alkaryl or aralkyl, and can also be hydrogen.

Z groups capable of sharing a single electron with the metal atom include monovalent inorganic groups such as hydrogen, the halogens and the cyanide group, CN. Such a Z group may also be a monovalent organic radical containing up to about 16 carbon atoms. These radicals include alkyl, aryl, alkaryl, aralkyl radicals and the like. Also included are acyclic unsaturated radicals such as the alkenyl and alkynyl radicals.

Z groups capable of sharing two electrons with the metal atom include ammonia, primary-, secondary-, and tertiary-amines, cyclic nitrogen compounds in which the nitrogen is in the trivalent state, monoolefin molecules, organophosphine compounds, phosphine halides, arsines, stibines, and bismuthines, isonitriles and the like. The nitrosyl group, NO, is an example of an electron donor capable of donating three electrons to either of the metal atoms, M or M in the above formula.

Four electron donor groups include organic diamines, diphosphines, diarsines, distibines, aliphatic diolefins, and alkyne molecules. Groups capable of donating five electrons to the metal atoms of my compounds are groups containing a cyclopentadienyl moiety. Examples of such groups are cyclopentadienyl, 1-methyl-cyclopentadienyl; indenyl radicals such as indenyl or 2-methyl-indenyl; fluorenyl radicals such as fiuorenyl, S-ethyl-fiuorenyl; and radicals such as 4,5,6,7-tetrahydroindenyl, 1,2,3,4,5,6,7,8- octahydrofluorenyl, 3 methyl 4,5,6,7 tetrahydroin denyl and the like.

Examples of electron donating groups capable of donating six electrons to the metal atom are benzene and substituted benzenes. These groups may contain from six to 18 carbon atoms. Examples of typical donating groups are benzene, mesitylene, toluene, biphenyl, tetralin, m-hexyl-biphenyl and the like.

Typical of those chemical compounds which are equivalent to my compounds as defined above are: 1-ethyl-7- [p (6 ethyl 2 methyl 2,4,6 cycloheptatrien 1 yloxy) phenyloxy] 6 methyl 2 n propyl 1,3,5 cycloheptatriene manganese dicarbonyl molybdenum tricarbonyl in which the manganese atom is coordinated with the di-substituted cycloheptatrienyl ring and the molybdenum atom is coordinated with the tri-substituted ring, 7 (2,4,6 cycloheptatrien 1 ylcarbonyl) 1,3,5 cycloheptatriene cobalt carbonyl manganese dicarbonyl (1:1:1) complex, bis(2,4,6-cycloheptatrien-1-yl) methane bis(manganese dicarbonyl cyanide), 1 methyl 7 [(2 ethyl 2,4,6 cycloheptatrien 1 yl) thio] 1,3,5 cy cloheptatriene bis(chromium tricarbonyl), 1-methyl-7- [(4 methyl 2,4,6 cycloheptatrien 1 yl) methyl] 1,3,5-cycloheptatriene bis(chromium tricarbonyl), 1,2,3, 4,5,6 hexamethyl 7 (2,4 ,6 cycloheptatrien l ylcar bonyl) 1,3,5 cycloheptatriene bis(molybdenum tricarbonyl), methyl bis(2-methyl-2,4,6,-cycloheptatrien-l-yl) amine chromium tricarbonyl molybdenum tricarbonyl (1:1:1 complex) 2-methyl-7-[dimethyl-(3-ethyl-2,4,6-cycloheptatrien 1 yl) silyl] 1,3,5 cycloheptatriene bis(tungsten tricarbonyl), methyl bis-(2,4,6-cycloheptatrienyl) phosphine bis(manganese dicarbonyl), 7-{ {[(2, 4,6 cycloheptatrien 1 yl) diethylsilyl] methyl} diethylsilyl}-2-p-tolyl-1,3,5-cycloheptatriene bis(nickel carbonyl), and bis-(2,4,6-cycloheptatrien-1-yl) selenium bis(cobalt carbonyl).

My compounds are prepared by reacting a l-cycloheptatrienyl cycloheptatriene compound having the formula with R R b, c and t having the meanings previously defined carbonyl compounds in which the metal or metals are chosen from groups VIBVIII of the periodic table. In this reaction the l-cycloheptatrienyl cycloheptatriene compound displaces either two or three carbonyl groups from each molecule of the metal carbonyl reactant so that a metallocarbonyl moiety containing either two or three less carbonyl groups than the original reactant is bonded to each of the cycloheptatrienyl rings in the final product. In the formation of a mixed metal compound, this reaction may be carried out stepwise to form an intermediate compound in which a metallocarbonyl moiety is bonded to only one of the cycloheptatrienyl rings. This intermediate is then reacted with an additional quantity of a metal carbonyl compound so as to bond a metallocarbonyl moiety to the remaining cycloheptatrienyl ring.

In general, the process may be carried out at temperatures between about 75 to about 200 C. Preferably, however, temperatures in the range from about to about C. are employed since, within this range, relatively higher yields are obtained with a minimum of undesirable side reactions. The pressure under which the process is carried out is not critical. Preferably, however, the process is conducted at atmospheric pressure or slightly higher although higher pressures, up to 500 atmospheres, can be employed if desired.

The process is generally conducted under a blanketing atmosphere of an inert gas such as nitrogen, helium, argon and the like.

The process is preferably conducted in the presence of a non-reactive solvent. Typical of reaction solvents which may be employed in my process are high boiling saturated hydrocarbons such as n-octane, n-decene, and other paratlinic hydrocarbons having up to about 20 carbon atoms such as eicosane, pentadecane, and the like. Typical ether solvents are ethyl octyl ether, ethyl hexyl ether, diethylene glycol methyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, trioxane, tetrahydrofuran, ethylene glycol dibutyl ether and the like. Ester solvents which may be employed include pentyl butanoate, ethyl decanoate, ethyl hexanoate, and the like. Silicone oils such as the dimethyl polysiloxanes, bis(chlorophenyl) polysiloxanes, hexapropyldisilane, and diethyldipropyldiphenyldisilane may also be employed. Other ester solvents are those derived from succinic, maleic, glutaric, adipic, pimelic, suberic, azelaic, sebacic and pinic acids. Specific examples of such esters are di-(Z-ethylhexyl) adipate, di-(Z-ethylhexyl) azelate, di-(2-ethylhexyl) sebacate, di-(methylcyclohexyl) adipate and the like. Of these enumerated solvents, those which are preferred for use in the process are the high boiling ethers and saturated aliphatic hydrocarbons. All of the above solvents will not be suitable for all of the specific embodiments of the invention since certain of the metal carbonyl reactants are relatively insoluble in some of the above solvents. Thus, care should be used in selecting the specific solvent for the specific reaction.

The particular solvent employed in any embodiment of the process should be selected from those solvents having the requisite boiling and/ or freezing point. Frequently the boiling point of the solvent is used to control the reaction temperature when the process is carried out at atmospheric pressure. In such cases, the reaction mixture is heated at reflux, and the reflux tempertaure is determined by the boiling point of the solvent. The ease of separating the product from the solvent depends on the degree of difference between the boiling and/or freezing points of the product and the solvent. If the product is a liquid having the boiling point close to that of the solvent, it is obvious that separation will be difiicult. In order to avoid this, it is preferable to select a solvent whose normal boling point varies by at least 25 C. from the normal boiling point of a liquid product. If, on the other hand, the product is a solid, it is desirable that the freezing point of the solvent be at least 25 less than the tem Mo, 35.5 percent.

perature at which separation of the product has been affected through crystallization. Obviously, if the solvent freezes before the solid product precipitates, it will be impossible to make a separation through crystallization.

The above criteria, as to physical properties of the solvent, are not unique to this process. In any chemical process, it is necessary to pick a solvent whose physical properties make it readily separable from the product being formed. It is deemed, therefore, within the skill of .the art to select the most suitable solvent for use in any particular embodiment of the process of the invention.

The process is preferably conducted with agitation of the reaction mixture. Although agitation is not critical to the success or failure of the process, its use is preferred since it accomplishes a smooth and even reaction rate.

The time required for the process varies depending on the other reaction variables. In general, however, a time period from about two to about 40 hours is sufficient.

In some cases, the process is advantageously carried out in the presence of an ultraviolet light source. This tends in some cases to decrease the reaction time and give a higher yield of product.

It is desirable to use an excess quantity of the metal carbonyl reactant in order to insure formation of the bis(metallocarbonyl) l-cycloheptatrienyl cycloheptatriene compound as opposed to formation of a mono metallocarbonyl l-cycloheptatrienyl cycloheptatriene compound.

Generally, a total quantity of from about two to about moles of the metal carbonyl reactant are employed for each mole of the l-cycloheptatrienyl cycloheptatriene reactant. Within this range, it is found that the his- (metallocarbonyl) l cycloheptatrienyl cycloheptatriene compound is formed in relatively good yield.

In some cases, hydroquinone or other free radical reaction inhibitors can be employed in the reaction to prevent any polymerization of the l-cycloheptatrienyl cycloheptatriene reactant. Their presence is not critical, however, to the success of the reaction. Typical of other applicable free radical inhibitors are p-tert-butyl catechol, p-hydroxy anisole, 4-amino-l-naphthol, chloranil, 2,4-dinitro-chlorobenzene, dithiocarbamate and the like.

To further illustrate the compounds of the invention and their mode of preparation, there are presented the following examples in which all parts and percentages are by weight unless otherwise indicated.

Example I Nineteen parts or l-cycloheptatrienyl cycloheptatriene and 56 parts of molybdenum hexacarbonyl were refluxed for 36 hours under nitrogen at a temperature of 100120 C. in approximately 3,500 parts of petroleum ether. The ether was then removed by heating the reaction mixture at 20. C. and a pressure of'0.5 millimeter. Excess molybdenum carbonyl and l-cycloheptatrienyl cycloheptatriene were sublimed from the residue at 60 C./0.l mm. The remaining solid was washed with light petrol to remove the l-cycloheptatrienyl cycloheptatriene bis- (molybdenum tricarbonyl) formed in the reaction. The light-brown residue was extracted with hot chloroform. The extracts were combined and concentrated and on 'cooling to 20 C. gave three parts of 7-(2,4,6-cycloheptatriene-l-yl)-1,3,5-cycloheptatriene bis-(molybdenum tricarbonyl). The theoretical analysis for this compound is: C, 44.3 percent; H, 2.6 percent; 0, 17.7 percent, and

Found: C, 43.5 percent; H, 3.1 percent; O, 17.7 percent; Mo, 35.5 percent. When Example I is repeated under slight pressure at a temperature of 150 C., good yields of product are obtained.

Example II 79 parts of 7-(2,4,6-cycloheptatriene-1-yloxy)-1,3,5- cycloheptatriene and 210 parts of molybdenum hexacarbonyl were heated at reflux for hours under nitrogen at a temperature ranging between 100 and 120 C. The reflux was carried out using approximately 3,500 parts of petroleum ether as a solvent. The solvent was then removed by heating at 20 C./0.5 mm. The unreacted molybdenum hexacarbonyl and 7-(2,4,6-cycloheptatrienl-yloxy)-1,3,5-cycloheptatriene were sublimed from the residue by heating at 75 C./ 0.1 mm. The residue was then washed with light petrol and extracted with hot chloroform. The chloroform extracts were concentrated by means of evaporation and cooled to -20 C. At this point, 7 (2,4,6 cycloheptatrien-l-yloxy)-1,3,5-cycloheptatriene bis-(molybdenum tricarbonyl) crystallized from the solution. A theoretical analysis of this compound is as follows: C, 42.9 percent; H, 2.5 percent; 0, 20.1 percent, and Mo, 34.4 percent. Found: C, 44.3 percent; H, 2.4 percent; 0, 20.4 percent, and Mo, 34.2 percent.

Example III Example IV A solution comprising 0.30 mole of tungsten hexacarbonyl, 0.10 mole of l-ethyl-7-(2,4,6-cycloheptatrienl-yl)-1,3,5-cycloheptatriene in petroleum ether is heated under nitrogen for 10 hours at reflux. The reaction product is then filtered, and solvent and unreacted starting materials are removed from the filtrate by heating in vacuo. The residue is dissolved in low-boiling petroleum ether and chromatographed on alumina. On removing the solvent from the eluate by heating under vacuum, there is obtained 1-ethyl-7-(2,4,6-cycloheptatrienl-yl)- 1,3,5-cycloheptatriene bis(tungsten tricarbonyl).

Example V A solution comprising 0.03 mole of l-benzyl-7-(2,4,6- cycloheptatrienl-yloxy)1,3,5-cycloheptatriene and 0.15 mole of manganese carbonyl in diethylene glycol dimethylether solvent is heated at reflux for 40 hours under nitrogen. The reaction mixture is then filtered, and solvent and unreacted starting materials are removed by heating under vacuum. The residue is dissolved in low-boiling petroleum ether and chromatographed on alumina. The product band is heated in vacuo to give a good yield of 1-benzyl-7-(2,4,6-cycloheptatrien-1-yloxy) 1,3,5 cycloheptatriene bis(manganese dicarbonyl).

Example VI A solution is formed by dissolving 0.20 mole of iron 'pentacarbonyl and 0.01 mole of 1-p-tolyl-7-(2,4,6-cycloheptatrien-l-yl)-l,3,5-cycloheptatriene in tetrahydrofuran. The resulting solution is heated at reflux for 20 hours under nitrogen after which the reaction mixture is filtered, and solvent and unreacted starting materials are removed by heating in vacuo. There is obtained from the residue, by means of chromatographic separation as in the previous examples, a good yield of l-p-tolyl-7- (2,4,6-cycloheptatrien-1-yl) 1,3,5 cycloheptatriene bis- (iron tricarbonyl).

Example VII One-tenth mole of molybdenum hexacarbonyl and 0.10 mole of 7-(2,4,6-cycloheptatrien-1-y1)-1,3,5-cycloheptatriene are dissolved in n-nonane and the resulting solution is heated at reflux for two hours under nitrogen. The reaction mixture is discharged from the reaction vessel,

'filtered' and heated under vacuum to remove solvent and unreacted starting materials. The residue is dissolved in low-boiling petroleum ether and chromatographed on alumina to yield an eluate which when heated in vacuum gives 7-(2,4,6-cycloheptatrie n-1-yl)-1,3,5-cycloheptatriene Example VIII A solution comprising 0.20 mole of nickel carbonyl and 0.02 mole of 1-eicosyl-7-(2,4,6-cycloheptatrien-1-yl)- 1,3,5-cycloheptatriene in di-(Z-ethylhexyl) adipate is heated with an ultraviolet light source for five hours at reflux under nitrogen. The reaction product is discharged, filtered, and the filtrate is heated under vacuum to remove unreacted starting materials and solvent. The residue is dissolved in low-boiling petroleum ether and chromatographed on alumina to give a good yield of 1-eicosyl-7-(2,4,6-cycloheptatrien-l-yl) 1,3,5-cycloheptatriene bis(nickel carbonyl).

Example [X A solution comprising 0.30 mole of dicobalt octacarbonyl, 0.04 mole of 3-ethyl-7-(3-ethyl-6-methyl-2,4,6- cycloheptatrien-l-yloxy)-5,6-dimethyl 1,3,5-cycloheptatriene in ethyloctylether is heated for 15 hours at reflux under nitrogen. The reaction product is discharged, filtered, and the filtrate is heated under vacuum to remove solvent and unreacted starting materials. The residue is dissolved in low-boiling petroleum ether and chromatographed on alumina to yield an eluate which, when heated in vacuo, gives a good yield of 3ethyl-7-(3-ethyl-6-methyl-2,4,6-cycloheptatrien-l-yloxy) -5,6-dirnethyl-1,3,5-cycloheptatriene bis(cobalt carbonyl).

As illustrated by the foregoing examples, my process involves reaction between a 7-(2,4,6-cycloheptatrien-1- yl)-l,3,5-cycloheptatriene compound and a group VIE- VIII metal carbonyl. Chemically equivalent processes involve reaction between a compound having the structural formula and a metal-ligand compound containing a group VIE- VIiI metal and a ligand Z to form a compound The compounds of my invention can be used in forming metallic mirrors comprising a layer or coating of a particular metal selected from groups VIE-VIII of the periodic table. These mirrors are formed by thermally decomposing one of the compounds of my invention at a temperature above 400 C. On the decomposition of the compound, the metal deposits on adjacent surfaces to form thereon a metallic mirror. These mirrors have useful and desirable properties of electrical conductance and further serve to protect the base material against corrosion. Also, they can be used to decorate the base material as by applying the mirror to a base material that is covered by a stencil. The compounds of the present invention can be deposited on glass, glass cloth, resins and other insulating supports. The resultant metal-coated material can then be used as a conductor or as an insulating tape for electrical applications. When the metals are deposited, through thermal decomposition on the support, a so-called printed electrical circuit can be obtained. It is prefeorred that inert gases, e.g., argon, be used to protect the base material from oxidation during the mirror-forming operation.

Deposition on glass cloth illustrates one form of the applied processes. A glass cloth band weighing one gram is dried for one hour in an oven at C. Then together with 0.5 gram of 7-(2,4,6-cycloheptatrien-l-yl)- 1,3,5-cycloheptatriene bis(molybdenum tricarbonyl), it is enclosed in a glass tube devoid of air and heated at 400 C. for one hour, after which time the tube is cooled and opened. The cloth has a uniform metallic appearance and exhibits a gain in weight of about 0.02 gram. The cloth has a greatly decreased resistivity. Each individual fibre proves to be a conductor. As would be expected, the application of a current to the cloth causes an increase in temperature. Thus, a conducting cloth has been prepared. This cloth can be used to reduce static electricity, for decoration, for thermal insulation by reflection, and as a heating element.

The compounds of my invention have further utility as additives to jet fuels, home heater fuels and diesel fuels to reduce smoke and soot. Further, they are excellent antiknocks when used in fuels and are lubricity improvers when used in lubricating oils. For example, my compounds in which manganese or iron are present in the molecule are particularly preferred antiknocks. My compounds in which molybdenum is present in the molecule are particularly preferred antiwear additives. My compounds may be used alone or in combination with other additives such as scavengers, deposit-modifying agents containing phosphorus or boron and with antiknock agents such as tetraethyllead. They may be used in fuels containing from about 0.01 to about 13.8 grams of lead antiknock per gallon.

When present in a liquid hydrocarbon fuel used in a spark ignition internal combustion engine, my compounds may be present in a concentration range from about 0.015 to about 10 grams per gallon based on the weight of metal. A preferred concentration range is from about 0.03 to about six grams of metal per gallon of fuel.

My compounds can be added directly to the hydrocarbon fuels or lubricating oils after which the mixture is agitated until a homogeneous fluid results. Also my compounds may be first blended into concentrated fluids containing solvents such as kerosene, antioxidants and other antiknock agents such as tetraethyllead. The concentrated fluid can then be blended with a hydrocarbon base material to form a fuel particularly adapted for use in a spark ignition internal combustion engine. When my compounds are employed in a concentrated fluid in combination with lead, my compounds are present in an amount so that for each gram of lead present there is a suflicient quantity of my compound to give about 0.01 to about 10 grams of a group VIBVIII metal. A preferred range comprises from about 0.1 to about six grams of a group VIB-VIII metal as a compound of the instant invention for each gram of lead as an organolead compound.

The scavengers employed in combination with my compounds are either phosphorus compounds or halohydrocarbons. The halohydrocarbon scavengers can be either aliphatic or aromatic with the halogen atoms being attached to carbon atoms either in the aliphatic or aromatic portion of the molecule. The scavenger compounds may also contain carbon, hydrogen and oxygen such as, for example, haloalkyl ethers, halohydrins, haloesters, halonitro compounds and the like. When used in forming an antiknock fluid, the atom ratio of metal to halogen ranges from about 50:1 to about 1:12. The halohydrocarbon scavengers normally contain from about two to about 20 carbon atoms in the molecule.

When a phosphorus scavenger is employed with my compounds in formulating an antiknock fluid, it can be present in an amount between about 0.01 to about 1.5 theories of phosphorus. A theory of scavenger is that amount of scavenger which will react completely with the metal present in the antiknock mixture. Reaction between a halide scavenger and lead gives the lead dihalide. Thus, a theory of halogen scavenger represents, in the case of lead, two atoms of halogen for each atom of lead. A phosphorus scavenger reacts with lead to form lead orthophosphate, Pb (PO Thus, a theory of phosphorus represents, in the case of lead, an atom ratio of two atoms of phosphorus to three atoms of lead. Theories of phosphorus or halohydrocarbon scavengers of other metals are computed in the same manner by stoichiometric calculations.

I claim:

1. New organometallic compounds selected from the class consisting of 7-(2,4,6-cycloheptatrien-1-yl)-l,3,5-cy cloheptatriene bis(moylbdenum tricarbonyl) and 7-(2,4, 6-cycloheptatrien-l-yl-oxy) 1,3,5 cycloheptariene bis (molybdenum tricarbonyl) 2. 7 (2,4,6 cycloheptatrien-l-yl)-1,3,5-cycloheptatriene bis-(moylbdenum tricarbonyl).

3. 7-(2,4,6 cycloheptatrien-l-yl-oXy)-1,3,5 cycloheptatriene bis(mo1ybdenum tricarbonyl).

4. Process for the preparation of the compounds of claim 1 comprising reacting a compound selected from the class consisting of 7-(2,4,6-cycloheptatrien-l-yl)-1,3,5- cycloheptatriene and 7-(2,4,6-cycloheptatrien-l-yl-oxy)- 1,3,5-cycloheptatriene, with molybdenum hexacarbonyl.

5. The process of claim 4 wherein the reaction is carried out in the presence of a non-reactive solvent.

6. The process of claim 5 wherein the process is carried out at temperatures ranging between about to 200 C.

7. The process of claim 5 wherein the reaction temperature ranges from about to about C.

8. The process of claim 7 wherein the process is conducted under a blanketing atmosphere of an inert gas.

9. Process of claim 8 wherein the compound reacted with molybdenum hexacarbonyl is 7-(2,4,6-cycloheptatrien-l-yl)-1,3,5-cycloheptatriene.

10. Process of claim 8 wherein the compound reacted with molybdenum hexacarbonyl is 7-(2,4,6-cycloheptatrienl-yl-oxy) -1,3, 5 -cycloheptatriene.

don, May 1958, pp. 152-153.

Burton et a1.: Chemistry and Industry, Nov. 29, 1958, p. 1592 relied on.

Claims

1. NEW ORGANOMETALLIC COMPOUNDS SELECTED FROM THE CLASS CONSISTING OF 7-(2,4,6-CYCLOHEPTATRIEN-1-YL)-1,3,5-CYCLOHEPTATRIENE BIS(MOYLBDENUM TRICARBONYL) AND 7-(2,4, 6-CYCLOHEPTATRIEN-1-YL-OXY) - 1,3,5 - CYCLOHEPTATRIENE BIS (MOLYBDENUM TRICARBONYL).