摘要:

2094 J.C.S. DaltonChemistry of the Metal Carbonyls. Part L X W Reactions BetweenDodecacarbonyltriruthenium and Tertiary Phosphines or ArsinesBy M. 1. Bruce, G. Shaw, and F. G. A. Stone,* Department of Inorganic Chemistry, The University, BristolThe preparation of trinuclear ruthenium complexes of the type Ru,(CO),,-,L, (L = tertiary phosphine or arsine;n = 1-4) is described. Their i.r. and l H n.m.r. spectra are discussed and possible structures suggested.The complexes RU,(CO)~L, [L = PPh,, P(rn-C,H,Me),, P(p-C,H,Me), or PMePh,] undergo controlledpyrolytic reactions in boiling decalin, affording complexes of the type Ruz(C0),(PAr,), (Ar = Ph or rn-MeC,H,),Ru,(CO),[PPhR(C,H,)](PPhR) (R = Ph or Me), Ru~(CO),[PP~,(C,H~)]~, and Ru,(CO),(PAr,)(PAr,) (Ar =Ph, rn-MeC,H,, or p-MeC,H,).Spectroscopic data suggest structures containing bridging phosphido-ligands,and ortho-metallated phenyl rings.BS8 ITSSINCE the discovery of a high-yield route to dodeca- Some of these accounts are notable for the discrepanciescarbonyltrir~thenium,~~~ a number of reports have in physical properties claimed; the most commonappeared describing reactions between this carbonylwith a variety of substituted phosphines or arsines. J . ’”. (A)p lg6‘>Part LXIV, M. I. Bruce, G. Shaw, and F. G. A. Stone, J. L. Dawes and J. D. Holmes, Inorg. Nuclear Chem. Lettevs,J.C.S. Dalton, 1972, 1781.12;8.M* I. Bruce and F. G. A.1971, 7, 8471972 2095explanation being a ready formation of isomers (of un-specified configuration). Up to the present time, mostauthors have described the reactionas proceeding without the isolation of mono- or di-substituted derivatives.Indeed, a kinetic study * ofthis reaction has suggested that formation of Ru,(CO),,Lis the rate-determining step, the subsequent formationof the complexes Ru,(CO),,-,L, (ryc = 2 and 3) beingfast. Table 1 summarises the compounds which havebeen reported, together with their v(C0) bands.L ?JPPh 333P(OPh),PEt, 3PMe,CH,Ph 3AsPh, 2As;Lle,CH,Ph 3PBun,disubstituted complex, Ru3( CO) ,,(AsPh,) 2, is formedwith triphenylarsine, with no evidence for the formationof a tris-derivative. In contrast, however, otherarsines, such as AsMe,Ph and ASM~,CH,P~,~ affordedthe trisubstituted compounds. A single product, shownto be Ru,(CO),,(diphos), in which the ligand probablychelates one metal atom, was obtained using Ph2PCH,-CH,PPh2 (diphosj.The absolute stereochemistries of these products aredifficult to determine unless recourse to X-ray diffractionmethods is made, but some conclusions may be drawnfrom the i.r. and lH n.m.r.data. Thus, in no case wereTABLE 1Reported complexes of the type Ru,(CO),, - %LnColour M.p. v(CO), cm-lDeep red 160-165" d. 2060, 2040, 2020, 1980, 1965, 1958Dark violet 1980s. 1969s, 1945sh1982, 1969s, 1935s2046vw, 1978sh, 1970s, 1933s, 1929s,1920sh1983, 1971Dark violet 174-176Orange 77-78 2001s, 1986s, 1970m, 1945shDark red 62-63 2035vw, 1960s, 1927shOrange redReddish-purple 171-172 2043w, 2017w, 1973% 1937mRed-purple 158-160d 2100vw, 208Ow, 2048w, 2027% 2017s,Purple 217-218 2043vw, 2016vw, 1982s, 1971s, 1935m,2035w, 1964s, 1930m1998vs, 1979s, 1958m1921mSolventCH,C1,NujolC6H12C6HllMe-C6H,NujolCH,C1,Nu j olC6H12Ref.abbCffos (2) 2087m, 2027m(sh), 2019% 2007s, C6H12 h1989m(sh), 1974w, 196Ow, 1960w(sh)1 944m (sh) , 1 8 9 8w (sh)1980w(sh), 1967w, 1950w(sh),193 8w (sh)1948m(sh), 1844wffos ( 4) Dark red 200-202 20481x1, 1996m(sh), 1978s(sh), 1972% CS, iLff ars (2) Dark red 191-192 2087m, 2024m(sh), 2014s, 2007s(sh), C,H,, hff ars (4) Dark red 173-176 2045m, 1991m(sh), 1978s, 1971% C6H12 hI n addition t o the above examples, the complexes Ru,(CO),L, [L = PPh,Et, PPhEt,, PBun,, AsPh,, SbPh, (ref.a) ; L = PPh&e,PPhMe, (ref.i)], Ru,(CO),(PH,), (ref. j ) , and Ru,(CO),(L,), (L, = diphos, diars) (ref. i) have been mentioned cursorily, but nodetails are available.b F. Piacenti, M. Bianchi, E. Benedetti, andG. Sbrana, J. Inorg. Nuclear Chem., 1967,29,1389. 0 B. F. G. Johnson, R. D. Johnston, P. L. Josty, J. Lewis, and I. G. Williams,Nature, 1967, 213, 901. I Ref. 6. * Mentioned in R. D. Johnston, Adv. Inorg. Chem.Radiochem., 1970, 13, 471. j F. Klanberg and E. L. Muetterties, J . Amer. Chem. Sac., 1968, 90, 3296.0 J. P. Candlin, K. K. Joshi, and D. T. Thompson, Chem. and Ind., 1966, 1960.Ref. 5.d Ref. 4. 6 F. Piacenti, M. Bianchi, E. Benedetti, and G. Braca, Inorg. Chem., 1968, 7, 1816. * W. R. Cullen and D. A. Harbourne, Inorg. Chern., 1970, 9, 1839.In the course of an investigation into the reactionsbetween Ru,(CO),, and a variety of substituted-phosphineplatinum complexes, during which the derivativesRU~(CO),,_~L, (ryc = 1-3) were isolated, it becameevident that serious discrepancies existed between thepublished data and our own results.Accordingly wehave reinvestigated the reactions of Ru,(CO),, with arange of substituted phosphines and arsines.Generally, we have confirmed the ready formation oftrisubstituted complexes, Ru,(CO),L,. However, inseveral cases, chromatographic separation of the reactionproducts (in contrast with the crystallisations previouslyused) has enabled us to isolate in addition severalcomplexes Ru,(CO),,-,L, (n = 1 or 2), together with atetrasubstituted complex with L = PPh(OMe),.We have also confirmed our original finding that theJ.P. Candlin and A. C. Shortland, J. Organometallic Chem.,1969, 16, 289.any bands characteristic of bridging carbonyl groupsfound, although as might be expected with the morebasic phosphines, the lowest v(C0) bands occurred ca.1940 cm-l (Table 2).Comparison of the i.r. spectra of the disubstitutedcomplexes also does not provide any information con-cerning the positions of substitution. The configurationof only one complex is known, namely that of(ffars)Ru3(CO),, (ffars = Me,As*d=C(AsMe,)*CF,&,),in which the ligand bridges two metal atoms. Thev(C0) pattern reported for this complex closely re-sembles those of OS,(CO)~,(PP~~)~ (presumably con-taining the two ligands attached to different metal5 M. I.Bruce, C. W. Gibbs, andF. G. A. Stone, 2. Naturforsch.,6 M. I. Bruce, R. L. Bennett, and F. G. A. Stone, J. Organo-1968, 23b, 1543.metallic Chem., 1972, 38, 3252096 J.C.S. Daltonatoms), and the complexes Ru3( CO) [PPh (CMe) ,I2,Ru3(CO),,(AsPh3),, and R~~(CO)~,(diphos) reported here.Of mostinterest were the methyl resonances of the appropriate1H N.m.r. parameters are listed in Table 3.TABLE 2Carbonyl stretching bands for some trinuclear rutheniumcarbonyl derivativesCompound v(CO), cm-l (cyclohexane)2097m, 2046s, 2030sh, 2023sh,2014s, 1996sh, 1986m, 1972sh,1960shRu3(CO) Q(PPh3) 3 2044vw, 1978sh, 1967s,brRus(CO) ,{P( m-MeC,H,) 313a= 2044vw, 1979sh, 1967s,brRu3(CO),(P(p-MeC,H,)3}3 2039vw, 2017w, 1977sh, 1966s,br2070m, 2016s, 1993s,br, 1969sh2042w, 1966s, 1939shRu3(CO) io(PMePhz) aRu3(CO),( PMePh,) b2092m, 2039s, 2026s, 2010s,1998sh, 1991sh, 1980m, 1973sh,Ru3(CO) 11(PMe2Ph)1956sh2069w, 2013s, 1989s,br, 1969sh2040w, 1972sh, 1966s, 1938m1987sh, 1975s, 1937w2099w, 2075w, 2047w, 2026s,ZOlSs, 1996s, 1979sh, 1959shRu3(CO) ,(AsMe,Ph), 2050w, 1988sh, 1976s, 1943sRu3(CO) ,,(Ph,PCH2CH2PPh2) 2082m, 202 lsh, 201 6s, 200 1 s,1983sh, 1965w, 1935w,br2054w, 2001sh, 1988s, 1963sh2080m, 2029s, 2005s, 1984sh,1972sh2031w, 1983s, 1966s, 1913shb Measured in chloroform.Ru3(C0)11PPh3R'3(C0)10(PMe2Ph)2Ru3(c0) 9 (PMe2Ph) 3Ru3(CO),{P(NMea)3}3Ru3 (CO) lO(ASPhS) a33u3(CO),{P(OMe)313Rus(C0) 10{PPh(OMe) 232RuS(Co) dPPh(OMe) 214a Measured in benzene.TABLE 31H N.m.r. data for some tnnuclear ruthenium carbonylderivatives ItCompound Tphenyl Tmethyl (JPH, Hz)2.76m 7.732.76m 7.632.66m 7.93d (8.6)2.72m 7-98d (8.6)2-69m 8-08d (9.6)Ru,(CO) ,(PMePh,) 3Rus(CO) 11PMe2Ph2-61m 8.lld (9.26)2.66m 8-20d (9.26)Ru3(CO) io(PMe2Ph) a7-36d (10.26)2-67m 8-32Rus(CO),(P(NMeJ 31sRu,(CO),(AsMe,Ph),Ru,(CO),,(P~,PCH~CH~PP~~) 244m 7-79m (CH,)Rus(CO),{P(OMe) 313Rus(CO),,{PPh(OMe)2~2Ru,(CO) * P P h (OM4 a*RuS(Co) 9(P(m-MeC6H4) 833Ru8(C0)9(P(p-MeC6H4)S}3Ru3(C0)10(PMePh2) 2Ru8(C0)9(PMe2Ph) 36.36d (12.0)2.5Om 2.52m {z& [':i!/0 Spectra determined in CDC13-Me,Si at 100 MHz.phosphine complexes , which enable some observationsconcerning relative stereochemistries to be made.Thus, in the spectra of Ru,(CO),,- .(PMe,Ph),, simpledoublet resonances are found at T ca.8.0, suggesting thateach phosphine is attached to a different metal atom,with a stepwise replacement of CO groups. Similarspectra are exhibited by the PMePh, complexes.The phosphonite, PPh(OMe),, forms di- and tetra-substituted derivatives. The spectrum of the formerexhibits an apparent doublet at 'C 6-39, with separation12.5 Hz, which shows the additional central structurepreviously found in cis-bis-phosphite complexe~.~ TheM. J. Church and M. J. Mays, J. Inorg. Nuclear Cham., 1971,33, 263.tetrasubstituted complex gives two signals, of equalintensity at T 6-48 and 6-92. The low-field resonance is asimple doublet (JpH 12.0 Hz), whereas the other signalhas a similar pattern to that found in the disubstitutedcomplex.The disubstituted complex may have either0 1-L" (CO I& ' K U ( CPh P,I( 0 C13R u -R u (CO l3 \ I@PPh2Ar Ar1-40 13LPh R' - 4i\ Ar Ar (& 'PhR(VI) Ar = Ph, m-MeC6H4, p-MeC6H4R = H or M eof the structures (Ia) or (Ib), neither the lH n.m.r. orthe v(C0) spectra (above) distinguishing between these.It seems likely, however, that the tetrasubstitutedcomplex has structure (11), with two ligands attachedin a relative cis-configuration on one metal atom.Controlled Pyrolysis Reactions.-There is currentlyconsiderable interest in intramolecular metallation re-actions involving co-ordinated tertiary phosphine an1972 2097triaryl phosphite ligands.8-lO Some of the resultingcomplexes are active catalysts for the hydrogenation ofolefins.No tertiary phosphine complexes of rutheniumresulting from ortho-metallation of a phenyl phosphineligand have been isolated, but deuteriation studies haveshown that RuHCl(PPh,), and RuH,(N,) (PPh,), undergointramolecular aromatic substitution reactions-l1 Theequilibria for these reactions lie well over on the side ofthe non-metallated complex. A related reaction hasbeen reported for Ru[Me2PCH,CH2PMeJ2, in whichmetallation of one of the P-Me groups affords a six-co-ordinate ruthenium(I1) hydride complex.12R%(CO),(PAr,)(PAr,) (Ar = Ph, m-MeC,H,, or $-M&,H,) (VI) were isolated. Similar pyrolytic reactionswere carried out with complexes containing otherphosphines, and also with Rrg(CO),o(AsPh3),, andalthough other complexes were formed, they could notbe isolated in a pure state.These derivatives arepresumably analogous to the new compounds describedin detail below.The lH n.m.r. spectrum (Table 5) of the yellowair-stable crystalline binuclear compound RU,(CO),-[PPh2(C6H4)I2 exhibits three complex resonances a t7 2-68, 3.04, and 3-25, with relative intensities 11 : 1 : 2.TABLE 4Analytical data and other physical properties for some polynuclear ruthenium carbonyl complexes aCompound ColourYellowRedRedRedRedRedOrange-redRedRedRedRedRedRedRedWhiteWhiteYellow06 Yield1686958717831719661.5473145723198Iii610M.p. ("C)131-133178-181 d172-173182-183129-130176-177108-109145-147142-144255-258170-172 d130-132>190 d120-122165-168111-114218-222122-123184-186204-206195-197193-196C40.2 (39.35)66-15 (56.4)58.6 (58.9)58-5 (58-9)44.1 (43.95)49.85 (49.8)36-65 (36.3)40.95 (40.85)31.3 (31.05)46.65 (46-2)35-6 (35.95)44.05 (44.05)33.3 (33.8)23.55 (23.3)46.9 (47.05)39-5 (39.75)49.9 (49.7)49-35 (49.7)51-25 (51.25)44-85 (45.0)56.6 (56.5)H1.85 (1.75)3.25 (3.35)4.15 (4.3)2-8 (2.65)4.3 (4.3)3.35 (3.4)3.4 (3.45)3.0 (2.6)5-5 (5.2)2-35 (2.55)3.0 (3.0)2.55 (2.45)2.35 (2.4)3.85 (3.65)2.95 (2.95)2.55 (2.45)3-7 (3.45)3.35 (3.45)3.15 (3.55)2.9 (3.05)3.15 (3.15)011.2 (9.8)9.75 (9.8)13.6 (13.4)20.9 (21.2)11.65 (11.85)11.6 (11.0)11.4 (11.0)12.1 (12.05)14.25 (13.85)12-1 (10.75)As or P6.5 (6.35)6.15 (6.35)11.15 (12-55)10.7 (10.25)6.55 (6-55)5.85 (6.1)5-95 (6.1)7.75 (7.76)7.7 (6.95)Ru20.5 (20.65)25.45 (25.35)26.35 (26.1)32.1 (32.1)28.95 (29.8)28.85 (29.8)25.5 (25.4)29.4 (29.15)M b1211 (1469)820 (984)210 860)1015 (1196)I90 1970)770 (946)678 (1018)639 (694)a Calculated figures in parentheses.b Determined in chloroform solution using a Mechrolab Osmometer. 8 Not isolated analytically pure. d With decomposition.4 N, 11.55 (12.05)TABLE 51H N.m.r. data for some ruthenium-carbonyl-phosphine complexes formed by pyrolysis of trinuclear complexesin decalinCompound Tphenyl %,thy 1R~a(c0) 7 (PPh2) aC13H.3Ru3(C0) 7{P(m-MeC6H4) 2}2MeC6H,Rua(CO) ~{P(P-M~CI~H~) ahMeCaH3Ru!2C0)6{P(m-MeCt3H4)2)z 3.13m (8) 7.82 (3), 8.02 (3)Ru2( CO) ,,(P(C,H,) PhMe}{PPhMe}2.38m (2), 2.70m ( 8 ) , 3.10m (l), 3.62 (1)247m ( 5 ) , 2.90m (13), 3*30m,br ( I ) , 3-71d (1)JHH = 8.02.60m (4), 3-08m (14), 3.75m (1)1.82d (l), 2.95m (12)3-56t (1)2.68m (11), 3.04~1 (I), 3.26m (2)7.68 (6), 7.77 (6), 8.20 (3)7.69 (6), 7-72 (6), 8.23 (3)7.86d (3), 8.70d (3)Jan = 7.0J H H = 8.0Jp = 8.75, Jp = 8-75Ru2(C0)6{P(C6H4) (C6H5)2]20 Measured in CDC1, solution at 100 MHz using TMS as internal standard.Relative intensities given in parentheses; m - multiplet, d = doublet, t = triplet, br = broad.Controlled pyrolytic reactions in an inert solvent, suchas decalin, have been found to be useful sources of thistype of complex.l2 Heating complexes of the typeor PMePh,] in refluxing decalin affords a variety ofcomplexes, which have been separated by extensivechromatography on alumina.Complexes with thecompositions (Table 4) Ru,(CO),[PPh,(C,H,)], (III),[PPhR(C,H,)](PPhR) (R = Me or Ph) (V), andRu,(CO)gL, [L PPha, P(W%-MeC,H,),, P($-MeC,H,),,RU,(CO),(PAI',), (Ar = Ph or W%-MeC,H,) (IV), RU,(co),-a G. W. Parshall, Accounts Chem. Res., 1970, 3, 139.S. D. Robinson and J. J. Levison, J . Chem. SOC. (A), 1970,lo ,4. J . Cheney, B. E. Mann, R. 111. Slade, and B. L. Shaw,639.J . Chem. SOC. ( A ) , 1971, 3833.Widely separated chemical shifts for the aromaticprotons is now a characteristic feature of co-ordinatedphosphorus- or nitrogen-containing ligands where themetal is bonded to an ortho-carbon atom of one of thephenyl groups, although overlapping resonances pre-cluded observation of the expected five resonances.The i.r.spectrum (Table 6) showed only terminal v(C0)bands, and the region 1600-650 cm-1 contained newabsorptions at 1585, 1200, 1170, and 895 cm-l, whichwere not present in the spectrum of RU,(CO)~(PP~,),.Bands at similar positions have been reported in thespectra of ortho-met allated phosphites or phosphines.lOl1 G. W. Parshall, W. H. Knoth, and R. A. Schunn, J . Amer.l2 J. Chatt and J. M. Davidson, J . Chem. SOL, 1965, 843.Chem. Soc., 1969, 91, 49902098 J.C.S.DaltonThe mass spectrum did not show a parent ion, but ionscorresponding to the loss of two phenyl groups, followedby the stepwise loss of six carbonyl groups, were foundat the high m/e end of the spectrum.The physical properties of this complex thus suggestTABLE 6Carbonyl stretching frequencies for some rutheniumphosphine coniplexes formed by pyrolysis of trinuclearcomplexes in decalinComplex v(CO), cm-lRu3(C0) 7(PPh2)2C6H4 2057s, 2020s, 2009vs, 1998s,Ru~(CO),{P(~-~I~C~H,),}~M~C~H, 2054% 2016s, 2006vs, 1996s,Ru,(CO),{P(~-M~C,H,)~),M~C~H, 2054s, 2017s 2006vs, 1996s,2072s, 2041s, 2011% 2007sh,RU,(CO)~(P(C,H,)P~~}(PP~,) 2071s, 2037s, 2010s, 1991w,Ru2(C0)6{P(’~2-MeC~H~)2~2 2070s, 2067sh, 2039s, 2009s,Ru2(CO),(P(C6H4)PhMe)(PPhMe) 2068s, 2033s, 2008% 2003sh,2028s, 1981s, 1968s, 1943s,1968s, 1965s1984% 1950s1965s, 1950s1983s, 1975s1987m, 1969m2004sh, 1981s, 1972s1987w, 1977m, 1965m19201nRu 2 (co) 6 (pph2) 2Ru2(C0)6{P(C6H4) (C6H5) 212a Measured in cyclohexane.the presence of ortho-metallated phosphine ligands, andsix carbonyl groups attached to two metal atoms.Twostructures, (IIIa) or (IIIb), may be considered, and atpresent no distinction is possible between them.The v(C0) spectrum of a complex formally related to(IIIb), namely [Ru(azb) (CO),], (azb = phenylazophenyl-2C,N’), differs appreciably from that observed forcomplex (III).14 The osmium analogue of complex(111), however, exhibits a v(C0) pattern which is similarto that of the ruthenium comp1ex.lThe mass spectrum of the white air-stable complexhibited a parent ion corresponding to the indicatedcomposition, together with ions formed by the con-secutive loss of the six carbonyl groups.The lH n.m.r.spectrum showed two singlets in the methyl region,together with a multiplet for the phenyl protons. Therelative intensities, 3 : 3 : 8 respectively, indicate thatmetallation of the ring has not occurred, and in agree-ment with this, the 1600-600 cm-l region of the i.r.spectrum is identical with that of the precursor,Ru3( cO),[P (WZ-M~C,H,),]~. Only terminal v(C0) bandsare found, and we suggest that this complex contains twoRu(CO), groups bridged by two diarylphosphido-groups.The diamagnetism requires also the presence of a metal-metal bond, and the stereochemistry results in thepresence of two chemically inequivalent aryl groups.Asimilar complex, RU,(CO),(PMe,),, has been reported l5from the reaction between Ru3(CO),, and P,Me,, and thelH n.m.r. spectrum exhibits two apparent triplets atRU,(CO),[P(m-MeC6H,)J, (IV; Ar = m-MeC6H4) ex-l3 E. W. Ainscough, S. D. Robinson, and J. J. Levison,14 M. I. Bruce, M. 2. Iqbal, and F. G. A. Stone, J . Organo-J . Chern. SOC. ( A ) , 1971, 3413.metallic Chem., 1971, 31, 275.z 8-08 and 8-40, consistent with the presence of non-equivalent methyl groups.From the pyrolysis of Ru,(CO),(PMePh,), we haveisolated a white crystalline solid, with the compositionRu,(CO),[PMePh(C,H,)](PMePh) (V; R = Me). Thei.r. spectrum showed only terminal v(C0) bands, and thelH n.m.r.spectrum contained three resonances fromaromatic protons (total intensity 14), and two doublets(total intensity 6) at z 7-86 and 8-70, indicating twonon-equivalent methyl groups. The ratio of phenyl tomethyl protons is consistent with the above formulationand the wide range of chemical shifts observed for thearomatic protons, suggests the presence of an ortho-metallated phenyl ring. Comparison of the i.r. spectraof (V) and of the precursor in the fingerprint regionshowed new absorptions in the former, a t 1548, 1445,1124, and 871 cm-l. We suggest that this complexalso contains two Ru(CO), groups, but bridged by aphosphido-group (PMePh), and an ortho-met allatedphosphine ligand [PMePh(C,H,)] ; again its diamag-netism requires a ruthenium-ruthenium bond.Thelower field methyl doublet is probably due to the methylgroup attached to the phosphido-group.The complexes Ru,(CO),(PPh,), and Ru(CO),-[PPh,(C6H,)] (PPh,) were isolated in trace amounts fromthe pyrolysis of Ru,(CO),(PPh,),, and comparison oftheir i.r. spectra with those of complexes (IV) and (V)discussed above, suggests that these complexes havesimilar structures. The mass spectrum of Ru,(CO),-(PPh,), exhibits a parent ion and clusters correspondingto stepwise loss of six carbonyl groups.Also found as products from these reactions are thedark red air-stable crystalline trinuclear complexes ofcomposition Ru,(CO),(PAr,) (PAr,) (Ar = Ph, m-MeC,H,, p-MeC,H,) (VI) , confirmed by analysis and massspectra, which show parent ions, and ions formed bysuccessive loss of seven carbonyl ligands.The i.r.spectra show terminal v(C0) bands, and the 1600-650 cm-l region shows little change compared to thespectra of Ru,(CO),(PAr,),.The lH n.m.r. spectra of these complexes containseveral multiplets in the region T 2.30-3.80. In thetolyl derivatives, the methyl resonances are found asthree singlets, with relative intensities 2 : 2 : 1. Neitherin this, nor in any other spectra, were any resonancesfound in the region z 10-40, indicating the absence ofmetal-bonded protons. These results confirm a formu-lation with five aryl groups, four of which could beinvolved in bridging diarylphosphido-groups, as discussedabove.The nature of the fifth aryl group remains indoubt; an ortho-metallated ligand is suggested by the1H n.m.r. data, but not confirmed by the i.r. spectra.When this work had been completed, the results of aninvestigation of the products obtained from the reactionbetween Os,(CO),, and PPh, in refluxing xylene werecommunicated.16 One of these has a similar com-l5 J. P. Candlin, K. K. Joshi, and D. T. Thompson, Chenz.Ind., 1966, 1960.l6 C . W. Bradford, R. S. Nyholm, G. J. Gainsford, J. M. Guss,P. R. Ireland, and R. Mason, J.C.S. Chem. Comm., 1972, 871972 2099position to the trinuclear complex discussed above, andan X-ray determination of the structure revealed thatthe fifth aryl group is a benzyne group, stabilised byco-ordination to the Os, cluster.Other features of thestructure confirm the deductions we have made on thebasis of spectroscopic evidence.The present study is complementary to the work onthe osmium system, and several interesting differenceshave been found. In the first place, the preponderanceof binuclear complexes for ruthenium, compared withthe trinuclear osmium compounds, reflects the greaterstrength of the metal-metal bonds in the Os, cluster.Secondly, we have found no evidence for any rutheniumhydride species, in contrast to the three such complexesobserved for the osmium system; the dramatic increasein stability of H,Os(CO), l7 over H,Ru(CO), l8 is nowwell known. Finally, in the three trinuclear osmiumcomplexes whose structures have been determined, theortho-metallated phosphine ligand bridges two metalatoms, suggesting that for complex (111) the formulation(IIIa) should be preferred.EXPERIMENTALSpectra were obtained with Perkin-Elmer 257 (i.r.),Varian HA 100 (lH n.m.r.), or AEI MS 902 (mass) instru-ments. All reactions were carried out under nitrogen.Light petroleum had b.p.40-60". Chromatography wason Florisil columns, initially packed in light petroleum.Analytical and m.p. data for all complexes are given inTable 4.and Tertiary Phosphines OYArsines.-Carbonyl stretching frequencies and lH n.m .r.data for compounds described in this section are collectedin Tables 2 and 3, respectively.In general, the carbonyl was refluxed with the ligand inequimolar (i.e. Ru: P or As = 1 : 1) proportions, in hexanefor a short period (1-3 h).Filtration and chromato-graphy enabled the various products to be separated bycontinued elution from a long (ca. 50 cm) column with lightpetroleum or light petroleum-ether. The complexes werefinally purified by recrystallisation from light petroleum-ether or -dichloromethane.Some complexes were also obtained from reactionsbetween Ru,(CO) 12 and platinum-phosphine complexes ;details of these experiments can be found in the earlierpaper. In other cases (see below), pure products wereobtained by crystallisation of the reaction product;chromatography having showed only one complex waspresent.Tris (dimethylamino) phosphine (204mg; 1.25 mmol) was added to a suspension of Ru,(CO),,(200 mg; 0.31 mmol) in hexane (25 ml), and the mixturerefluxed for 2 h.The solid which precipitated on coolingl7 I?. L'Eplattenier and F. Calderazzo, Inorg. Chewz., 1967, 6,2092.Reactions between Ru,(CO)(a) Witla P (NMe,) ,.was washed with n-hexane (2 x 10 ml), and recrystallisedfrom light petroleum-dichloromethane to give dark redprisms of enneacarbonyltris[tris (dimethyZnvrzino)fihosphine]tri-ruthenium.Dimethyl phenylphosphonite (222mg; 1.31 mmol) was added to Ru,(CO),, (200 mg; 0-31mmol) in hexane (20 ml), and the mixture refluxed for 1 h.Crystallisation (light petroleum-dichloromethane) of thesolid which precipitated on cooling afforded pure octa-carbonyZtetrakis(dimethy1 phenyZphosphonite)trirzdlzeniunz.(c) With AsMe,Ph.14 similar reaction between dimethyl-phenylarsine (250 mg; 1.37 inmol) and Ru,(CO),, (250 mg;0.39 mmol) after 2 h afforded plates of enneacarbonyltris-(dimethylpheny larsine) trirutheniurn.Controlled Pyrolysis Reactions.-1.r. spectra [v(CO) bands],and 1H n.m.r. data for complexes described in this Sectionare given in Tables 5 and 6.A suspension of Ru,(CO),(PPh,),(1.12 g) in decalin (15 ml) was refluxed for 20 min, and theresulting solution was chromatographed on alumina.Elution with light petroleum removed the decalin, followedby trace amounts of two white solids, probably I<u,(CO),-(PPh,), and Ru,(CO),[PPh,(C,H,)] (PPh,). Further elutionafforded Ru,(CO),(PPh2),(C,H,), obtained as prisms fromlight petroleum-ether. Elution with light petroleum-ether(9 : 1) gave Ru,(CO) 6[PPh2C6H,)],, recrystallised from lightpetroleum-ether as prisms.The trinuclear product was isolated in 20% (30 min) and21% yield (60 min) on refluxing for longer periods, and in31% yield when the reaction was carried out in refluxingmesitylene for 30 min.(b) Ru,(CO),[P(m-MeC,H,),],. A suspension of Ru,-(CO),[P(m-MeC,H,),], (1.14 g) in decalin (15 ml) was re-fluxed for 20 min as above. Chromatography gave separ-ately Ru,(CO),[P(m-MeC,H,),],, which recrystallised fromlight petroleum-ether as prisms, and Ru,(CO) ,[P(m-MeC,H,)J,(MeC,H,), which afforded prisms from lightpetroleum (b.p. 30-40").(c) Ru,(C~),[P(~-M~C,H,)~],. The complex Ru,(CO),-[P(P-MeC,H,),], (0-92 g) was refluxed in decalin (15 ml)for 15 min. Chromatography afforded Ru,(CO),[P(p-M&,H,)&(MeC,H,), eluted with light petroleum-ether(9 : l), and recrystallised from light petroleum (b.p. 30-40")as prisms.A similar reaction using themethyldiphenylphosphine complex (1.2 g) gave Ru,(CO),-[PMePh(C,H,)] (PMePh) , which was recrystallised fromlight petroleum-ether as prisms. Further elution withlight petroleum gave a red fraction, but no pure complexcould be obtained.We are indebted to I.C.I. Ltd., for a Research Fellowship(G. S.) and the U.S.A.F. Office of Scientific Research for[2/6S2 Received, 22nd March, 19721(b) With PPh(0Me) ,.(a) Ru,(CO),(PPh,),.(d) RU,(CO)~(PM~P~,),.support.18 J . D. Cotton, 11. I. Bruce, and F. G. ,4. Stone, J . Chem. SOC.( A ) , 1968, 2162

ISSN:1477-9226    

DOI:10.1039/DT9720002094

出版商:RSC    

年代:1972

数据来源: RSC