摘要:

610 J.C.S. DaltonOrganometallic Complexes containing Phosphorus(v) bonded to aTransition Metal : Derivatives of Dicarbonyl(q-cyclopentadieny1)ferrate-(1 -)By P. Piraino and F. Faraone,' lstituto di Chimica Generale dell'Universit8,98100 - Messina, ItalyThe complexes [Fe(q-C5H5)(CO),(PR,E)] [E = S, R = Me (I) ; E = S, R = OEt (11) ; E = Se, R = Ph (111)] havebeen synthesized by the reaction of Na[Fe(q-C5H6) (CO),] with PBrMe,S, PCI(OEt),S. or PPh,CISe. The methodseems to be valid for the preparation of a variety of the title complexes and suitable for a wider series of carbonyl-metallate anions. On the basis of i.r. and l H n.m.r. data, the complexes are believed to contain an Fe-P rather thanFe-E bond. On treating tertiary phosphines, L (PPh3 or PMe,Ph), with the complexes (1)-(111), no evidencehas been obtained for formation of phosphido-complexes and only substitution products of carbon monoxide havebeen obtained ; using Me1 or [OMe,] [BF,] as reagents, the cations [Fe(q-C5H5) (CO),{PR,(EMe))]+ are obtainedby S- or Se-methylation ; Etl and [OEt,] [BF,] react only with complex (I).The structure of the cationic complexeshas been established by i.r. and l H n.m.r. spectroscopy.M. C. Aversa, lstituto di Chimica Organica dell'Universit8, 981 00 - Messina, ItalyMETAL-CARBONYL complexes containing phosphorus(v)bonded directly to a transition metal are very few innumber.l-3 Complexes of the type [Fe(q-C,H,) (CO),-{P(CF,),E)] (E = 0, S, or Se) have been preparedrecently by the action of nitrogen mono-oxide (E = 0),sulphur, or selenium on the monomeric phosphido-complex [Fe(q-C,H,) (CO),{P(CF,),)J ; the complex[Fe(q-C,H5)(CO)2{P(CF,),S)] can be also obtained * bytreating P(CF,),(SH) with [Fe(q-C,H,) (CO),Cl].Reaction of S[P(CF,)d, and of Se[P(CF,)J, with [{Fe-(Y~C,HJ(CO),}~] gives equimolar amounts of theR.J. Haines and C . R. Nolte, J . Organometallic Chem.,1970, 24, 725.R. J. Haines, A. L. Du Preez, and I. L. Marais, J . Organo-metallic Chem., 1971, 28, 97.phosphido-complex [Fe(q-C,H,) (CO),{P(CF,),}] and of[Fe(?-C,H,) (Co) 2{p(CF&s11 or [Fe(?-C5H5) (co)z(p-(CF,),Se)]. In each case, the method of preparationappeared to be specific for the complex containing CF,groups bonded to the phosphorus and the authors madeno claims as to the generality of the synthetic procedure.We found that carbonyl complexes containing P Vbonded to a transition metal can be prepared in one step,by treating carbonylmetallate anions with dialkyl- ordiaryl-phosphinot hioic halogenides, dialkyl- or diaryl-3 R.J. Haines, A. L. Du Preez, and I. L. Marais, J, Organo-* R. C. Dobbie and P. R. Mason, J.C.S. Dalton, 1973, 1124.R. C. Dobbie and M. J . Hopkinson, J.C.S. DuZtoH, 1974,metallic Chem., 1971, 28, 406.12801976 611phosphinoselenoic halogenides, 00-dialkyl or 00-diary1 structure (B) were isolated when R=CF3 on U.V.halogenothioyhosphates. This method is most suitable irradiation, in non-polar solvents, of the correspondingfor the preparation of a variety of the title complexes. isomers of structure (A), and their lH n.m.r.spectrumThis paper reports the preparation and reactivity ofcomplexes [Fe(r,-C,H,)(CO),(PR,E)] (E = S, R = Me orOEt; E = Se, R = Ph). The synthesis and thereactions of analogous complexes derived from othercarbonylmetallate anions will be discussed in forth-coming papers.RESULTS AND DISCUSSIONOn adding to a tetrahydrofuran (thf) solution ofNa[Fe(q-C,H,) (C0)J a slight excess of PBrMe,S,PCl(OEt),S, or PPh,ClSe, a reaction occurred, withoutany evolution of carbon monoxide. After evaporationof the solvent, separation of the reaction products waseffected by means of column chromatography, usingas eluant methylene dichloride-diethyl ether (3 : 1 ) ;1 -showed a single sharp peak due to the resonance of theC5H5 ring and no coupling to the distant phosphorusatom was detected.Organic substituents bonded tophosphorus should be equivalent as inferred from the1H n.m.r. spectrum of (I) which shows the methylresonance as a doublet at 7 8.10 [J(P-CH,) 10.0 Hz].Spectroscopic data aComplex q(C0) /ern-' 7(C5H5) J(P-C,H,) r(P-R) J(P-Me) T(E-Me) b J(P-Elk)[1:e(q-C6H5) (CO),(Phfe,S)l,,fI) 1 978vs. 2 028vs 4.86(d) G 8.10(d) 10.01 996vs, 2 045vs 4.88( d) 1.0 5.83(m)8.63 (t)rw?-C,H,) (CO),{P(OEt),5)18 (11)[l;e(r,-C,H,) (CO),(PPh,Se)], (111) 1 986vs, 2 035vs 4.89( d) 1.5[Fe(q-C,H,) (CO) ,{Phie,(SMe)}] I 2 025vs, 2 065vs 4.48 (d) 1.6 7.88(d) 10.0 7.67(d) 11.5[Fe(q-C,H,) (CO),{P(OEt),(SMe)}]I 2 023vs, 2 065vs 4.63(d) 1.0 5.82(m) 7.63(d) 14.0[Fe(r,-C,H,) (Co) ,(PPh,(SeMe))] I 2 018vs, 2 068vs 4.42(d) 1.5 7.9(d) ca.101 930vs G G1 9 1 8 ~ s [Fe(q-C,H,) (CO) (PMe,Ph) (PMe,S)] G c1 9 3 2 ~ s C c1 925vs [Fe(q-C,H,) (CO) (PMe,Ph) {P(OEt),S)] G GI Fe(q-C,H,) (CO) (PPh,) (PPh,Se)] 1 9 3 8 ~ s G G8.67 (t):Fe(q-C,H,) (CO) ,{PMe,(SEt)}]I 2 015vs, 2 058vs 4.54 (d) 1.5 7.87(d) 9.0LFe(?-C,H,) (CO) (PPh,) (PMe2S)I!Fe(?-C5H6) (Co) (PPh3) {P(0Et)2S}1LFe(q-C,H,) (CO) (PMe,Ph) (PPh,Se)) 1935vs c G(1 1.r. spectra in CH,Cl, solution, n.ni.r. spectra in [,H6] acetone; coupling constants, J, are in Hz. a E=S or Se. c See text.the first product eluted from the column was [{Fe(q-C,H,)(CO),),] followed by a yellow fraction which, asreported in the Experimental section, gave a productformulated as rFe(q-C,H,) (CO),(PR,E)] on the basis ofthe analytical data [E = S, R = Me (I); E = S, R =OEt (11); E = Se, R = Ph (HI)].The complexes aresolids, not electrolytes, and are monomers in benzenesolution.The structure of the products was established fromtheir spectroscopic properties, which are collected in theTable. In the carbonyl-stretching region of the i.r.spectrum two very strong bands were observed, whichunderwent a slight change on varying the substituentsbonded to phosphorus; a band at ca. 620 cm-l can betentatively assigned to the v(P=S). In the lH n.m.r.spectrum, in [2H,]acetone coupling between the hydrogenatoms of the cyclopentadienyl ring and phosphorus wasdetected LJ(HP) ca 1.2 Hz], giving a sharp doublet atca. 7 4.9 for the cyclopentadienyl resonance.In com-plex (I), the phosphorus coupling of the C5H5 resonanceseemed beyond the resolution of the spectrometerbut, in the alkylated derivatives of the sameproduct (see below), the doublet was observed. Suchcoupling is consistent with a structure (A) rather thanwith (B) where Fe-S-P or Fe-Se-P linkages are presentand consequently there is a larger distance between theC,H, ring and the phosphorus atom. Complexes withThe extent of the Fe P x bonding in phosphine-oxide, phosphine-sulphide, and phosphine-selenide com-plexes having structure (A) has been discussed on thebasis of spectroscopic data and, as far as phosphine-oxide complexes are concerned, on the basis of the bonddistances as determined by X-ray crystallography,6~iWe observe that the v(C0) values in our complexes arelower than those previously reported for the analogouscomplexes [Fe(q-C,H,) (CO),(P(CF,),E)] and are coni-parable to those reported for the phosphido-complex[Fe( q-C5H5) (CO),(P(CF,) ,}I.Furthermore, the V( CO)stretching frequencies increase with the electron-with-drawing power of the organic substituents bonded tophosphorus; thus, the highest values were observed forcomplexes where R = CF,, whereas the complex containingMe groups showed the lowest v(C0) values suggesting ahigher electron-density donation d, + $,* from themetal to carbon monoxide in the methyl derivative thanin the CF3-containing complex. According to i.r. data,the highest q-C,H, resonance in the lH n.m.r.spectrumwas observed when R = Me (T 4.95, compared with thevalue of T 4.36 observed for the CF3 derivative 4). Asimilar spectroscopic trend was also observed in thephosphine-selenide complexes.M. J. Barrow, G. A. Sim, R. C. Dobbie, and P. R. Mason,R i . J. Barrow and G. -4. Sim, J.C.S. Dalton, 1976, 291.J . Organotnetallic Chem., 1974, 69, C4612 J.C.S. DaltonTervalent phosphorus has a high affinity for free andbonded sulphur, which has led to many useful syntheticreactions.* Accordingly we tried to prepare newphosphido-complexes [Fe(q-C,H,) (CO),(PR,)] by treat-ing (I) and (11) with PPh, or PMe,Ph; at room tempera-ture, in ligroin (80-120 "C) solution, no reaction wasobserved, whereas on heating the reaction mixture underreflux the complexes [Fe(q-C,H,) (CO)L(PR,S)] (LzPPh,or PMe,Ph) were obtained.Complex (111) reacted withligands L giving [Fe(q-C,H,) (CO)L(PPh,Se)]. Qualita-tively, we observe that the better cr donor PMe,Ph reactsmore rapidly than PPh, and that the phosphine-selenidecomplex reacts easier than phosphine-sulphide complexes.Satisfactory lH n.m.r. spectra for complexes containingtertiary phosphines could not be obtained because oftheir low solubility; the i.r. spectra of these complexesshowed, in the w(C0) stretching region, only one band atlower wavenumbers than their precursors, indicating thebetter a-donor ability of the tertiary phosphines comparedwith CO.Complexes (1)-(111), at room temperature and inCH,Cl, solution, reacted with [OMeJ[BF,] or Me1 byS- or Se-methylation to give the ionic complexes [Fe(q-C,HJ (CO),{PR,(EMe)}] + which were also isolated astetraphenylborate salts. The assumption that themethylation occurs at the sulphur or selenium atom isbased on spectroscopic data and on some examples re-ported in the literat~re.~ Methylation at the carbonatom of the co-ordinated carbon monoxide would seem tobe ruled out by the i.r.spectrum, which showed, for allthe cationic complexes, two very strong w(C0) bandsshifted to higher frequency compared to the precursor, asexpected from the overall charge of the complex, and noband attributable to w(C0) of an acetyl group. Hydro-gen-1 n.m.r. spectra of methylation products showed anew methyl resonance, as a doublet; some other slightdifferences from the spectra of the precursors wereobserved, mainly a shift towards low field of the C,H,resonance and of organic groups bonded to phosphorus,in accordance with the higher formal charge on thephosphorus atom.Alkylation at the sulphur or seleniumatom would not be expected to substantially influenceeither the geometry or the electronic structure of thecomplex. The only apparent alternative to methylationat sulphur or selenium would be methylation at phos-phorus; this would yield a metal complex of the ligandPMeR,E (R r= Me or OEt, E = S ; R = Ph, E = Se), whichcan form stable complexes having the chalcogen asdonor atom.1° In this case, however, an isomerizationprocess, leading to an Fe-E-P bond, is to be expected andin the lH n.m.r.spectrum the C,H, resonance would be asingle sharp peak, and not a doublet as observed. In8 J. I. G. Cadogan and R. K. Mackie, Chem. SOC. Rev., 1974,3, 87. * W. K. Dean and P. M. Treichel, J . Orgaitometallic Chem.,1974, 66, 87.lo E. W. Ainscough, A. &I. Brodie, and E. Mentzer. J.C.S.Dalton, 1973, 2167; E. W. Ainscough, A. M. Brodie, and A. R.Furness, ibid., p. 2360 and refs. therein.11 R. 8. King and F. G. ,4. Stone, Inorg. Syntlz., 1966, 7, 110.the absence of any kinetic data, we observe that methyl-ation is easier for complex (I) than (11).Ethyl iodide or [OEtJCBF,] reacted only with (I) togive an S-alkylated cationic complex; in this case thereaction is slower than with Me1 or [OMeJ[BF&, and thereaction product shows spectral characteristics verysimilar to those of the methylated complexes.The sulphur 01 selenium atom in complexes (1)-(111)has a lone pair which may be available for a-bondformation with a metal; because of this, such complexescould be used as ligands.We are now investigating thispossibility and the results will be discussed in a forth-corning paper.EXPERIMENTALThe starting materials Na[Fe(r)-C,H,) (CO),J,llPC1(OEt),S,12 and PPh,ClSe l3 were prepared by literaturemethods; PBrMe,S was a Strem product. Alkyl iodideswere purified before use by distillation from sodium thio-sulphate. Other reagents were used as obtained fromcommercial sources. The chromatographic separationswere effected on an alumina column. Infrared spectra wererecorded with a Perkin-Elmer 467 spectrometer using apolystyrene film for calibration. A Varian A60 MHzspectrometer was used to obtain lH n.m.r.spectra. Mole-cular weights were determined with a Knauer vapour-pressure osmometer. A conductivity meter WTW LBRwas used for conductivity measurements. Elementalanalyses were by Bernhardt Mikroanalytisches Labora-torium, Elbach uber Engelskirchen, Germany. All reactionswere carried out under an atmosphere of oxygen-freenitrogen.Preparation of Dicarbonyl (q-cyclopentadienyl) (dirurefhyl-phosphinothioato)iron, (I). To a solution of Na[Fe(r)-C,H,)-(CO)J, obtained from [(Fe(r)-C,H,)(C0),},](0.50 g, 1.4 mmol)in freshly distilled tetrahydrofuran solution, PBrMe,S(0.50 g, 3.0 mmol) was added and the mixture was left a troom temperature for ca.4 h. After filtration, the resultingred solution was evaporated to dryness and the crudeproduct chromatographed on an alumina column, elutingwith methylene dichloride-diethyl ether (3 : 1). The firstproduct eluted from the column was [{ Fe(y-C,H,) (CO),],]followed by a yellow fraction which, after evaporationof the solvent at reduced pressure and crystallization frommethylene dichloride-hexane, gave the product as brightyellow crystals (yield 32%) (Found: C, 40.5; H, 4.15; S,11.85. C,H,,FeO,PSrequiresC, 40.2; H, 4.10; S, 11.95%).DicarbonyZ(r)-cyclopentadie92yl) (OO-diethyl thiophosphato) iron,(11), was prepared in the same way from Na[Fe(r)-C,H,)-(CO),] and PCl(OEt),S and was isolated as a yellow-brownfiowder (yield 67%) (Found: C, 40.1; H, 4.60; S, 9.65.C,,H1,Fe04PS requires C, 40.0; H, 4.60; S, 9.70%).Preparation of Dicarbonyl(r)-cyclopentadie.iyl) (diphenyl-phosphinoselenoato)iron, (111).A thf solution (ca. 100 cm3)of Na[Fe(q-C,H,) (CO),], obtained from [{ Fe(r)-C,H,)-(CO)2}2] (1 g), was added to a filtered benzene solution ofPPh,ClSe, freshly prepared from PPB,Cl (1.5 g, 6.8 mmol)and selenium red powder. The resulting solution wasstirred for ca. 4 h and filtered. On evaporation of the solventto dryness, a red solid was obtained. This was chromato-l2 L. Maier, Topics PhosphorusChem., 1965,2,76; J. H. Fletcher,J. C. Hamilton, I. Hechenbleikner, E. I. Hoegberg, B. J. Sertl,and J. T. Cassaday, J. Amer.Chem. SOC., 1950. 72, 2461.Is A. Mfiller, P. Christophliemk, and V. V. K. Rao, Chem. Ber.,1971, 104, 19061976 613graphed on an alumina column, eluting with methylenechloride-diethyl ether (3 : 1). The pure product wasobtained from the yellow-orange fraction, by partial evapor-ation of the solvent and adding hexane (yield 53%) (Found:C, 51.9; H, 3.55; Se, 17.3. C,,H,,FeO,PSe requiresC, 51.75; H, 3.40; Se, 17.2%).Reactions with Tertiary Phosphines.-Complex (I) (0.50 g,1.85 mmol) in ligroin (b.p. 80-120 "C) was treated withexcess of PPh, and the reaction mixture was heated underreflux. The progress of the reaction was followed by i.r.spectroscopy. After ca. 40 h, the red-brown precipitatewhich formed [Fe(q-C,H,) (CO) (PPh,) (PMe,S)], was separ-ated by filtration, washed several times with diethyl ether,and dried (Found: C, 61.75; H, 5.20; S, 6.30.C,&t,,-FeOP,S requires C, 61.9; H, 5.20; S, 6.35%). The follow-ing complexes were prepared and isolated similarly :[Fe (q-C,H,) (CO) (PMe,Ph) (PMe,S)], red solid, reaction timeca. 15 h (Found: C, 50.6; H, 5.95; S, 8.45. C,,H,,FeOP,Srequires C, 50.55; H, 5.85; S, 8.46); [Fe(q-C,H,)(CO)-(PPh,){ P(OEt),S)], red-brown solid, reaction time cu. 30 h(Found: C, 59.6; H, 5.40; S, 5.60. C,8H,oFe0,P,Srequires C, 59.6; H, 5.35; S, 5.70); [Fe(q-C,H,)(CO)-(PMe,Ph)(P(OEt),S}], brown solid, reaction time cu. 10 h(Found: C, 49.15; H, 6.00; S, 7.30. Cl8H2,FeO,P,Srequires C, 49.1; H, 5.95; S, 7.30%); [Fe(q-C,H,)(CO)-(PPh,)(PPh,Se)], yellow solid, reaction time ca.8 h (Found:C, 64.2; H, 4.50; Se, 11.5. C,,H,,FeOP&e requires C,64.0; H, 4.45; Se, 11.7%); and [Fe(q-C,H,)(CO)(PMe,Ph)-(PPh,Se)], yellow solid, reaction time ca. 2 h (Found: C,56.45; H, 5.05; Se, 14.3. C,,H,,FeOP,Se requires C,56.55; H, 4.90; Se, 14.3%).,4 solution of com-plex (I) (0.52 g, 1.85 mmol) in Me1 (4 cm3) was left, withvigorous stirring, for ca. 1 h. A pale yellow solid wasobtained, [Fe [q-C5H5) (CO) ,(PMe, ( SMe) }] I, which wasAZkyZation Reactions.-Method (a).separated by filtration, washed several times withpentane, and dried (Found: C, 28.95; H, 3.50;S, 7.90. C,,H,,FeIO,PS requires C, 29.15; H, 3.40; S,7.80%). The following complexes were prepared andisolated similarly, using the appropriate alkylating agent :[Fe(q-C,H,)(CO),{P(OEt),(SMe)~]I, yellow solid (Found:C, 30.7; H, 3.90; S, 6.80.C1,H,,FeI04PS requires C,30.55; H, 3.85; S, 6.gOx) ; [Fe(q-C,H,)(C0)2{PPh,-(SeMe))]I, yellow-brown solid (Found: C, 41.3; H, 3.15;Se, 13.6. C,,H,,FeIO,PSe requires C, 41.2; H, 3.10; Se,13.55%) ; and [Fe(q-C,H,)(CO),{ PMe,(SEt)}]I, brown(Found: C, 31.2; H, 3.7; S, 7.70. C,,H,,FeIO,PS re-quires C, 31.0; H, 3.80; S, 7.50%).To a solution of complex (I) in dichloro-methane, a slight excess of [OMe,][BFJ was added and themixture was left with vigorous stirring. The progress of thereaction was followed by i.r. spectroscopy. The brownsolution was evaporated to dryness ; extraction withmethanol gave, after partial evaporation of the solvent, theproduct [Fe(q-C,H,)(CO),(PMe,(SMe) )][BF,] (Found : C,32.45; H, 3.85; S, 8.75. Cl0H,,BF,FeO,PS requires C,32.3; H, 3.80; S, 8.60%). Working-up as above andusing the appropriate alkylating agent, the complexes( PPh,( SeMe) )] [BFJ, [Fe(q-C,H,) (CO) ,{ PMe,( SEt) 13-[BFJ were obtained.TetrufihenyZbovate Salts. The complexes [Fe (q-C,H,) -(CO),(PR,(ER) )][BPhJ were prepared by adding Na[BPh,l,dissolved in methanol, to a solution of [Fe(q-C,H,)(CO),-(PR,(ER)}]Y (Y = I or BF,) in the same solvent. Theyclosely resemble the corresponding iodide or tetrafluoro-borate salts except for a lower solubility in organic solvents.Method ( b ) .[Fe(rl-C,H,) (CO),P(OEt),(SMe) IIPF41, [Feh-C,H,) (W,-andWe thank the C.N.R. for support.[6/1237 Received, 23rd June, 1976

ISSN:1477-9226    

DOI:10.1039/DT9760000610

出版商:RSC    

年代:1976

数据来源: RSC