‘ amam‘ nited States Patent ‘"0 " Patented Aug. 26, 1958 1 2 It is an object of .this'invention to provide a new class 2,849,471 of organometallic compounds. A’ further object is to pro vide new~organometalliccarbonyl halide compounds of ORGANOMETALLIC CARBONYL HALIDE COM POUNDS OF A GROUP VIII METAL DIRECTLY ‘group VIII metals and processes for-their preparation. BONDED TO ONE CYCLOPENTADIENYL Other objects will appear hereinafter. NUCLEUS AND TO HALOGEN AND (IO-ORDI These objects are accomplished by the following inven -NATELY BONDED TO AT ‘LEAST TWO CAR tion of new organometallic compounds of group VIII BONYL GROUPS, AND THEIR PREPARATION metals of Mendeleef’slPeriodic Table in which the metal is’bonded to ‘at least two-carbonylrgroups and to at least John C. Thomas, Wilmington, Del., assignor to E. I. du 10 one halogen atom, >an'diis Ffurth'er bonded directly to a Pont de Nemours and Company, Wilmington, Deh, a carbocyclic hydrocarboniradicalcontaining one cyclopen corporation of Delaware tadiene ‘ring ‘through "nuclear {carbon of said ring. The .No Drawing. Application January 28, .1955 preferred class of compounds of thisinvention are those Serial No. 484,830 in which the‘metal isof-the *fourth‘period of group 'VIII of theIperiodic>table,-i. e.,ra-metalof'the iron family, and 17 Claims. 1(Cl.‘260-—439) 'isl-b'on‘de'd v‘to =;( a) va cyclopentadienyl rradical I‘ through nu clear ‘carbon thereof, ‘(12) two :carbonyl groups, and This invention relates to a new class of organometallic (c) i’halogenlo‘fa tornic number ‘1710135, i. e., chlorine derivatives and their preparation. Moreparticularly, this or'bromine. invention relates to new organometallic carbonyl‘halide "The'newloompounds of this‘invention arev generally ob derivatives of group'VIII metalsand processes ‘for their ‘.tained ?by 5the:halogenation, ‘either :with free ‘haogen or preparation. with ~a=mercuric halide:of,ve.=g., a cyclopentadienyl group Organometallic compounds, wherein the metal atom is VIII metal carbonyl. bonded directly to carbon of organic radicals,,hav.e "found Thef‘following-‘examples illustrate‘ speci?c embodiments utility in ‘catalytic and synthetic processes. ‘For example, 125 vof thei‘preparation-of the ~new'compouu'ds-of this inven tetraethyllead is used as an antiknock agent in'spark ig tion. nition engines; organomercury compounds are used in‘ the ‘EX’AMPBE ‘I fungicide ?eld, particularly as seed disinfecetants; and organomagnesium, organosodiurn and organolithium com :Prep‘aralion 0f cyclopenmu/ienylimn dicarbonyl chloride pounds are used inorganic syntheses. 'Carbonyls‘of'var by 1chl0i'inati0n 0f.7bis(cyclopentadienyliron) tetracar ious metals, and'in particular of those ofgroup "VIII, rlzanyl ' ‘ have found‘importance in-synthetic reactions-and as cat alysts. Recently [Kealy and‘Paus-onjNature1168,'1039 ("1951) ] Theientirerpreparation as described below was carried "there has been disclosed a compound-"having‘two’cyclo out under a nitrogen atmosphere. A solution of ‘3.6 g. ‘pentadienyl radicals directly attached to ‘an ‘iron ‘atom. (0.05 mole) of chl0rine_in.5.0_ml.,of deoxygenated carbon This compound has beenconsidered unique "in'that, ac tetrachloride was added‘dropwise’with stirring to a solu cording to Wilkinson ‘et al. in I. Am. Chem. Soc. 74, . tion- of 117.7 rg.- (0.05tmole) {of :bis ( cyclopentadienyliron) ‘2125 (1952), all ?ve positionsof thecyclopenta'diene .tetraoarbonyl .in ‘.280 (ml. rot [methylene-chloride over a ring‘in dicyclopentadienylmetallics areiequivalent 'and‘no ‘.period. of .27 .:-minutes. ‘:The :temperature. of the ‘ mixture isomerism with respect to anyone cyclopentadiene ring was kept at 20-25 ° C. by periodicecooling with an ice is possible. Other group ‘VIII organometallics dicyclo bath. The mixturewasstirredfopBO minutes after com pentadiene have been‘reporte'd. 'For example, the- cobalt pletion of . the. addition. arid was pressure-?ltered. compound has been prepared by Wilkinsonj] ‘Chem. The-solid on-the'?lter vwa‘s'washed‘three times with de ‘Soc. 74, ’6146—9 (1952), and‘theniékelderivative-is the . woxygenated -::ca.rb.on itetraehloride. 1The ?nal washings subject of my U. S.‘Patent2,‘680,‘758, issued June '8, 1954. were‘ colorless. 'll‘he: combined ?ltrate and'washings were "Wilkinson has also reported the preparation otcorre evaporated at-about 25.<mm..pressure in'a water bath ‘at ‘sponding dicyclopentadienyl derivativees ‘of ruthenium, "ZS-‘309C. The-residuewas adarkrred solid. that weighed ‘rhodium and iridium. In these organornetallic “com l713rg. :Itzwas:groundinasmortarrandshaken with 900 ‘pounds of the'group VIII elements, there'are two l‘cyclo- . ml. ‘of; deoxygenated water :for >“3O1‘minutes. Themixture “pentadienyl radicals directly‘ linked through‘ carbonr‘there was pressure-?ltered; andithe solidwvas washed once with of to the metal atom. Many investigators‘ have attempted deoxygenated Water. tTheJcombined ?ltrate .aud'washing ‘to explain ‘the unusual stability of these lcompoun'ds-as were extracted with three successive 100.:ml. portions of I'due not only to the particular type of>organicradical methylene chloride. - bonded to the metal, but due also to the fact that there are , ‘The extractszwerexdried.oversanhydrous magnesium sul two: radicals 'so linked. fate ‘and evaporated at:room temperature or "below in a The preparation and properties of thegrouptVllli deriv "stream .of.;nit1'ogen. ‘:The residual, fred, crystalline solid :atives of cyclopentadienes are- not completely predictable. ‘ was ‘dried. furtherJ-at ?275 ° ‘l C:/ 2-5 mm. There was thus ob~ ‘As an example, dicyclopentadienyliron'has:been obtained :tained 118.‘. g. (38% yield) of <a'1brick-red,crystallinesolid ‘by reacting cyclopentadiene with<irontpentacarbonylat tempertaures of 220-500° (-C. ' under ‘pressure = (Anzilotti zt'rically heated block. rAsecond extraction ‘with water and ‘and Weinmayr, U. S. patent application :Serial -No. methylene chloride by the method just‘described gave van 292,388, ?led June 7, Y1952,‘n0W U. 18. ‘Patent 2,791,597, . additional‘0r8isga (additional 4% :yield) oft-Ya. product hav issued May 7, 1957). 'However, Awhenthe" temperature iing‘ithe ¢sarne appearance and *melting point. ‘The solid ‘iskept below 220°- C. an'dabove- 160°1C.,»new compounds 65 vcyclopenta'dienyliro‘n i‘dicarbonyl-lchloride ‘was soluble in are obtained which‘have-ironL bonded to.one cyclopenta organic solvents and moderately soluble in water. ' vdienyl group and 'to carbonyl groups. (Catlin rand “Analysis-.é'eCalcd.t-for1'C5H5Fe(CO)2Cl: C, 39159; H, ‘Thomas, ‘U. ‘ S. ‘Patentnapplication i'Serial 2N0. 1365;5'48, I?led July 1, 1953,>~nowiU.‘-S.1Patent?No...2;8l.0;73l6,iissued - QQtQbeIFZZ, 1957). i _ 2,849,471 , 3 4 EXAMPLE H pear as soon as the ?rst bromine was added. The solid was separated by ?ltration, washed with water, and dried. Preparation of cyclopentadienyliron dicarbonyl chloride There was obtained 14.5 g. of dicyclopentadienylcobalt by the reaction of bis(cycl0pentadienyliron)tetracar (III) tribromide. Recrystallization by dissolving the prod bonyl with mercuric chloride uct in methylene chloride and precipitating with benzene gave 10.5 g. of the tribromide. The monobromide as well as the corresponding triiodide are shown by Wilkinson, J. Am. Chem. Soc. 74, 6148 (1952). The entire preparation was carried out under nitrogen. The bis(cyclopentadienyliron) tetracarbonyl employed A solution of 32.6 g. (0.12 mole) of mercuric chloride in 10 300 ml. of deoxygenated, absolute ethanol was added in Examples I and II is prepared by the method of Catlin all at once to a solution of 42.6 g. (0.12 mole) of his ?led July 1, 1953, now Patent No. 2,810,736, issued (cyclopentadientyliron) tetracarbonyl in 900 ml. of de October 22, 1957, i. e., the reaction of iron petacarbonyl oxygenated, absolute ethanol with stirring at room tem at a temperature of preferably about 200° C. with cyclo pentadiene as follows: perature. The red color of the mixture lightened almost 15 immediately, and a crystalline precipitate came down. Ninety-eight grams (0.5 mole) of iron pentacarbonyl The mixture was stirred for 5 minutes at room tempera and 66 g. (1.0 mole) of cyclopentadiene in the form of its dimer were charged into a stainless steel bomb under ture and for 10 minutes at 40-45 ° C., chilled to 5° C., dry nitrogen. The bomb was closed, evacuated, vented and pressure-?ltered. with dry nitrogen to atmospheric pressure, and heated at The solid on the ?lter was washed two times with cold, 20 deoxygenated, absolute ethanol. This solid, which was 200° C. with rocking over a period of about 2 hours, crude chloromercuric derivative of cyclopentadienyliron and then allowed to cool to room temperature. The dicarbonyl hydride, could be puri?ed by recrystallization product was a dark brown mixture of a viscous liquid from deoxygenated, absolute ethanol. The combined ?l and a crystalline solid. The solid was broken up under 200 ml. of n-hexane, and the mixture was chilled in ice trate and washings were evaporated under about 25 mm. 25 and pressure-?ltered under dry nitrogen. The solid on pressure in a bath at 40-45” C. The residual, brick-red solid was shaken with 280 ml. of deoxygenated benzene, the ?lter was washed twice with cold n-hexane and dried and the mixture was pressure-?ltered. The solid on the in a stream of dry nitrogen. There was thus obtained 59 g. (67%) of a dark red, crystalline solid, which was ?lter was washed once with benzene. shown by analysis to be substantially pure bis(cyclopenta To the clear, dark red ?ltrate and washing was added 30 1120 ml. of deoxygenated n-hexane, and the mixture was dienyliron) tetracarbonyl. thoroughly chilled. The solid that precipitated was sep It will be understood that the above examples are arated by pressure ?ltration, washed three times with cold merely illustrative and that the invention broadly com hexane:benzene (4:1), and dried, ?rst in a stream of nitro prises the production of organometallic compounds in which a group VIII metal is co-ordinately bonded to at gen and then at 25° C./ 0.5 mm.