摘要:

J.C.S. CHEM.COMM.,1974 Synthesis and Crystal Structure of An Unusual Trinuclear Ferracyclobutene Complex, Fe,(CO),[Ph,PC,(CF,),] (PPh,) By MATHAIMATHEWand Gus J. PALENIK* (Centre for Molecular Structure, Department of Chemistry, University of Florida, Gainesville, Florida 326 1 1) and ARTHURJ. CARTY*and HANG N. PAIK (Department of Chemistry, University of Waterloo, Waterloo, Ontario,, Canada) Summary The molecular structure of a ferracyclobutene iron complexes are major components in the mixture of complex Fe,(CO),(Ph,PC,(CF,),) (PPh,), obtained from the products obtained from the reaction of Fe3(CO)12 with room-temperature reaction of Fe,(CO)la with Ph,- alkynes. Metallocyclopentadienes have also been charac- PC =CCF,, has been determined by X-ray crystallographic terized for rhodium,a iridium,, and palladium.* A few techniques. six-membered metallocyclic rings are known and, recently, a seven-membered nickelacycloheptatriene complex Ni-A FASCINATING and recurring feature of the reactions of [C, (CF,),] [AsPhMe,], has been described.6 alkynes with metal carbonyls is the formation of organo- We have characterized the first example of a ferracyclo- metallic ring systems via oligomerization of the acetylene. butene complex, Fe,(CO),[Ph,PC,(CF,),] (PPh,) (I) as one Thus l,l,l-tricarbonylferracyclopentadiene-r-tricarbonyl-of several products from the reaction of Fe,(CO),, with l’Ii,l’C =CCF3.Compound (I) is a rare example of a coni-plcs containing an acyclic dimerized acetylene. Careful chromatography of the inisture obtained from the reaction of Fe,(CO),, with Ph,PC =CCF3 (L), in benzene at room temperature affords small amounts of (I) as well as thc following products : 17e3(CO),,L, Fe, (CO) ,0L2,Fe(CO)&,, I~c3(CO)8(l~1121~)[l’h,T’C,(Cl~,),]~ (11) axid two, as yet, un-characterized tritiuclear complexes.The complexes (I) and (11)can also be obtaincd by warming Fe,(CO),,L, in benzene. Physical measurements (i.r., n.m.r., mass spectra and XIijssbauer spectra) on (I) and (11) suggest a marked similarity in the structures of the two complexes. An X-ray structure determination was undertaken ancl has revealed the isomeric nature of the two compounds. C?’Jlstd data : ~;c~(CO)~[P~,PC~(CI;,)~](1’I’h2),C6H6, hf = 1026.2.Red triclinic crystals, space group Pi, a = 11.738(6), b = 14.110(6), c = 14.753(4) A, a = 97-26(3), = 92*35(4),y = 112*31(4)’, U = 2231*9(1*6)Hi3, D, = 1-5g ctn-”, Z = 2, I), = 1.527. The structure has been rcfined to R = 0.079 for the 4059 observed reflections measured with a computer-controlled diffractometer, using graphite-monochromatized Mo-K,-radiation. o!2@ C FIGGRF:.11 view of the Fe,(CO),[Ph,PC,(CF,),](Ph,P) moleculc showing Lhc niolcculnr shnpc, atomic numbering, and thc thcrnial ellipw,ids. ‘I‘he structurc and atomic numbering are illustrated in the 1;igurc. ’lhc dinierization of two phosphino-acetylene nwlcxulcs has produced a tvnns-butadiene unit. The carlion atoms C(11) and C(13) of the butadiene unit are co-ordinatetl to l?c( 3) forming a nearly planar ferracyclo- butcnc ring.Tlie Fe-C distances [Fe(3)-C( 11) of 2.021( 13) ant1 Fc(3)-C(13) of 1.050(12) A] are comparable to the Fe-C distancvs in (TI) (av. 1.964 A) and othcr ferracyclopentadiene com~~l~scs.~Hon-ever, the Fe(3)-C( 1 l)-C(12)-C( 13) ring is J.C.S. CHEW Conmi., 1973 quite unsymnietrical [C(ll)-C(12) is 1+.535(16)A4and C(12)- C(13) is 1.240(14) A] because of the multiple cliaractcr of tlic C(12)-C(13) bond. Fe(3) is also linlced to l;c(2) Tii(t n iiictal -metal bond of 2-514(3) A which is similar to the l;c(3)-l;e(3) distance of 2-554(2) A in (11),and the distalices of 3.831(2) and 2-534(2) A reported for cis-and tvazzs-(rr-C51-15),~‘c,o,, respectively.8 The Fe(2) atom is also 1)onclcd in r-fashion to the truns-C(l0)-C(11) ancl C(12)-C(13) multiple bonds.The Fe(l)-Fe(2) and Fe( I)-Fe(3) tlistaiices are both greater than 3.45 A which precludes any nictal-Inctal bomliiig between these atoms. The presence of a bridging phosphido group between Fe(1) and Fe(2) implics a clcavagc of the l’-C.(sp) bond of the parent phosphino-acetylcne, which is somcwhat surpris- ing considering the mild reaction conditions. However, accumulating evidencee p9 suggests that 1’-C bond rupturc is a common feature of reactions bctwcen phosphino-acetylencs and iron carbonyls. Presumably, thc strain induced by attempting to co-ordinate both tlic phosphorus atom and the alkyne unit sini~~lta~ieously leads to 1’4: bond cleavage. A consideration of the molecular structurc leads to a valence-bond representation (A) for (I)\vhich is vcsy siniilar to that proposed for (II).6 The similarities of tlic chemical bonding in (I) and (11) raise the qiicstion of whether tho isomers might be in tcrconvertiblc und cr ripprop ria tc experimental conditions.Finally, it is notcn-orthy that while (I) and (11) are both formed in the reaction of l?c,-(CO) with Ph21’C =CCi;,, fcrracyclobutenc coniplescs analogous to (I)have not yet been isolated from tlic reaction of Fe,(CO) with other acetylenes. We thank the Department of Chcmistry, IJnivcrsity of Florida for a postdoctoral 1;cllowship (31.31.) am1 tlic North- east Regional Data Center, State University Systcm of Florida, University of Florida for a grant of coniputcr time (G.J.Y.) and the National Research Council of Canatla for financial support (A.J .C.).(Received, 1 lth October 1‘373; Coitz. 1403.) W. Hubcl, ‘Organic Synthescs via Mctal Carbonyls’, vol. I, eds. I. Wender and P.,Pino, Intcrscicncc, Ncw York, 19Gti, pp. 373 -342 and rcfcrcnces thcrein. rtntl G. Wilkinson, Inorg. Cliein., 1968, 7, 542; J. T. Mague, ibid., 1970, 9, 1610; J. T. Maguc, ,I. AWZPY.“ J. T. JI;L~uc Clicrrz. SM., 1971. 93. 3550. J. 1’. Colliiwn, J. W. Iiang, W. F. Little, ancl &I. F. Sullivan, Inovg. Chmrn., 1968, 7, 1208. I<. RIoselcy am1 P. M.hlaitlis, CAcm. Coinrn., 1971, 1604. J. 13rowniiiq,h1. Green. B. N.Yenfold, J. L. Spencer, and 1;. G. A. Stone, J.C.S. Citein. Co~n?.,1973, 31. T. J. O’Connor,A. J. Carty, AI. Mathew, and G. J. Palenil<,.I. Orgammptallic Chein., 1972. 38, Clt. i\. FTock and 0.S. Rlills, Acta Cvyst., 1961, 13, 139; Y. Degreve, J. Mcunier-Piret, hi. Van Rlccrsche, and P. Pirct, ibid., 1967,23,119; I<. 1’. Dodge and V. Schomaker, J. Ovgatrometallic Ckem., 1965, 3, 271. R. I?. 13ryan ant1 P. T. Grcene, J. Chem. SOC.(A), 1970, 3064; R. F. Bryan, P. T. Grccnc, 31. J. h’cwlantls, and 0. S. Fivld, ibid.,p. 3008. @ H. A. Patel, R. G. Fischer, A. J, Carty, D. V. Naik, and G. J. Palenik, J. Organornetallic Chem., 1973, 60, C49.

ISSN:0022-4936    

DOI:10.1039/C39740000025

出版商:RSC    

年代:1974

数据来源: RSC