摘要:
J. CHEM. SOC. DALTON TRANS. 1986 213New Diazenido-complexes of Molybdenum(lv), Tungsten(iv), and Rhenium(ii1)Hapipah Mohd. Ali and G. Jeffery LeighA. F. R. C. Unit of Nitrogen Fixation and School of Molecular Sciences, University of Sussex, BrightonBNI 9RQThe reaction of [ MCI,( Ph,PCH,CH,PPh,)] with phenylhydrazine produces the complexes[MCI,(N,Ph) (Ph,PCH,CH,PPh,)] ( M = Mo or W). Similar derivatives containing Et,PCH,CH,PEt,and PMe,Ph have also been isolated. The structures have been assigned by n.m.r. spectroscopy. Animproved synthesis of [ReCI,( N,Ph) (NH,)( PMe,Ph),] is reported. The diazenido-ligand can bequaternised with methyl iodide.It has been known for some time that diazenido-complexesof transition elements can be synthesised by reaction ofan appropriate transition-metal compound with a hydrazinederivative.Examples include the formation of [Mo(N,Ph),-(S,CNEt ,),I from [MOO,( S,CNEt ,),I and phenyl hydrazine, 'and of [ ReCl ,( N ,Ph)( PMe, Ph),] and [ ReCI,(N, Ph)( NH 3)-(PMe,Ph),] from [ReCI,(PMe,Ph),] and phenylhydrazine.2The detailed mechanisms, including in particular the fate of the'excess' of hydrogen atoms, is not known, although it is clearthat in the former reaction both [Mo(N,Ph)(NHNHPh)-(S,CNEt,),] and aerial dioxygen are involved.' We herepresent some additional information regarding such complexesand their mode of formation.Results and DiscussionThe complexes [MCI,(N,Ph)(dppe)] [M = Mo or W, dppe =I ,2-bis(diphenylphosphino)ethane] were obtained from thereaction of [MCl,(dppe)] with (Me,Si)NHNHPh (ca.1 : 1) inbenzene at room temperature. The reaction of [MCl,(depe)][depe = 1,2-bis(diethylphosphino)ethane, M = Mo or W] isanalogous. The reaction of [MoCl,(dppe)] with a six-foldexcess of phenylhydrazine in ethanol yields [MoCI,(N,Ph),-(dppe)] as a purple solid, and the analogous reaction of[MoCI,(PMe,Ph),] generates [MoCI,(N,P~),(PM~,P~)~].Reaction of the latter with Na(S,CNEt2)-3H2O gives theknown compound [Mo(N,Ph),(S,CNEt,),].'These diazenido-complexes have a band in the i.r. spectra inthe range 1 48&-1 530 cm-' characteristic of v(N=N). The P-{ 'H) n.m.r. spectra of all the diphosphine complexes display adoublet of doublets (AB pattern) consistent with non-equivalent phosphorus nuclei, the only feasible structures beingthose of (I) and (11).The complex [MoCI,(N,Ph),(PMe,Ph),] shows a singlet inthe 31P-{ 'H) n.m.r.spectrum. In the 'H n.m.r. spectrum, themethyl groups give rise to one triplet (due to virtual coupling),and this also indicates a plane of symmetry containing the linearP-Mo-P ~ y s t e m . ~ The structure is shown by (111). Thealternative arrangement with trans phosphorus should give riseto two triplets.None of these complexes possesses an N,Ph group basicenough to react with HBr in tetrahydrofuran (thf), neither dothey react with Me1 in benzene, even under reflux. They allwould be expected to possess a singly bent NNPh structure, butthe nitrogen lone pairs are presumably not easily available,either because they are involved in N-N-Ph K bonding orbecause of the influence of the high-oxidation-state metals.The fate of the excess of hydrogens in these preparativereactions is not clear.It is likely that initial reaction of the metalhalogeno-complexes with the hydrazine derivatives forms areactive hydrazide( 1 - ) complex. Other workers have shownthat [WCI,( PMe,Ph),] reacts with (Me,Si)NHNHPh to formP h 7 4 7 - PMe2PhPhMc2PCI1111)[WCI,H(N,HPh)(PMe,Ph),] which loses the hydride hydro-gen during slow crystallisation from CH,CI,, but it is not clearhow. In addition, [WCl,(py),] (py = pyridine) reacts with(Me,Si)NHNHPh to form [WC1,(N2Ph),(py),], but thereaction route has not been clarified., In the same reaction,[WCI,(NHNHPh)(py),] may also be formed, but it has notbeen adequately characterised.The compound [ReCI,(N,Ph)(NH,)(PMe,Ph),] is obtainedin high yield (> 70%) by reaction of [ReCI,(PMe,Ph),] withPhNHNH, in ethanol.This reaction does not produce any[ReCI,(N,Ph)(PMe,Ph),], which always accompanies theformation of the ammine from [ReC1,(PMe,Ph),].2 It istempting to ascribe the formation of the ammine to a seriesof intramolecular hydrogen shifts between hydrazide( 1 -)ligands in an intermediate species containing the groupingRe(NHNHPh),. The mechanisms of such shifts are unknown,but aniline was isolated from the reaction mixture and identifiedby both thin-layer chromatography and gas chromatography.Clearly such hydrogen shifts, whether they are inter- or intra-molecular, are common features of the chemistry of hydrazido-complexes.It has already been reported that [ReCI,(N,Ph)(NH,)-(PMe,Ph),] reacts with proton acids to generate [ReCI,-(N,H Ph)( NH,)( PMe, Ph),] + , whereas [ ReCI,( N , Ph)( PMe,-Ph),] does not react with protons., We have now found that thelatter diazenido-complex does not react with MeI, whereas theformer reacts with Me1 in thf at reflux. The product is[ReC1,(N,MePh)(NH,)(PMe2Ph)2]I.Its P-{ 'H} n.m.r. spec-trum shows a single phosphorus resonance, and the methylgroups appear in the H n.m.r. spectrum as a pair of triplets.This is consistent with equivalent trans phosphorus nuclei, butno plane of symmetry containing the P-Re-P axis.3 Thestructure is that shown by (IV), similar to that of th214 J.CHEM. SOC. DALTON TRANS. 1986NMe Ph/N\(I V)phenylhydrazido(2 - )-complex which was determined by X-raystructure analysis.,Alkylation of the phenyldiazenido-complex presumably is anSN2 reaction at the carbon of methyl iodide.' In the amminecomplex, the ex0 nitrogen of the phenyldiazenido-group seemsbasic (it also reacts with acids), presumably due to the presenceof the donor ammonia rather than PMe,Ph. The difference inbasicity between the N,Phgroups in [ReCl,(N,Ph)(PMe,Ph),]and [ReCl,(N,Ph)(NH,)(PMe,Ph),] is unlikely to be correl-ated with the presence of straight or singly bent N,Ph groups,since the formal electron counts are the same. Consequently,one might expect the NNC(pheny1) angle in both compounds tobe between 120 and 150".The factors affecting basicity andreactivity are probably more subtle than gross geometricalchanges.ExperimentalAll reactions were carried out under dry dinitrogen. 1.r. spectrawere recorded in KBr discs using a Perkin-Elmer 577spectrometer. N.m.r. spectra were recorded using a JEOL FX-WQ spectrometer, with tetramethylsilane and trimethyl phos-phite as external standards for 'H and ,lP n.m.r. spectra,respectively. Conductivities were obtained using a PortlandElectronics conductivity bridge. Melting points were obtainedin sealed tubes in uacuo and using an Electrochemical meltingpoint apparatus. Analyses were carried out by Mrs. G. Olney(University of Sussex) and Mr. C. Macdonald (A.F.R.C., Unit ofNitrogen Fixation).The complexes [MCl,(dppe)] (M = Mo or W),6 CReC1,-(PMe,Ph,)],' [MOCI,(PM~,P~),],~ [WC14(MeCN)2],9 and(Me,Si)NHNHPh," were obtained by literature methods.[ 1,2- Bis( diethy1phosphino)ethane) tetrachloromolyb-denum(Iv).-To a suspension of [MoCl,(thf),] (2.0 g, 0.53mmol) in tetrahydrofuran (thf) (120 cm3) was added depe (1.2 g,5.8 mmol).The suspension changed to brick red, in a green-brown solution. The mixture was reduced to 5 cm3, diethyl ether(30 cm3) added, and the red-brown solid filtered off and dried invacuo. Yield: ca. 65% (Found: C, 28.0; H, 5.3. C,oH2,Cl,MoP,requires C, 27.0; H, 5.4%).Since this complex and the related tungsten material (seebelow) were required only as intermediates, they were notfurther purified.[ 1,2 - Bis( diet h y lp h osph ino)e thane] te trachlo r o tungsten ( I v )-Acetonitrile (l/l).-A mixture of [WCl,(MeCN),] (0.60 g, 1.47mmol) and depe (0.5 g, 2.4 mmol) in toluene (20 cm3) was heatedunder reflux for 1.5 h, yielding a brown solution and suspension.The suspension was filtered off and the residue washed withdiethyl ether (30 cm3) and dried in vacuo. Yield: ca.75% (Found:Table. Analytical and physical data for the complexes[ReCI,(N,MePh)(NH,)-(PMe,Ph),]I'ColourBrownRed-purpleBrownRed-brownPurplePurplePinkAnalysis aYield I.r./cm-'M.p./"C (%) C H N (KBr)b162 50 48.7 3.1 4.3 1494s,(48.4) (3.70) (3.55) 1 310m169 50 55.6 4.6 4.4 1 530br,s(54.5) (4.75) (3.95)94 35 33.6 5.2 4.4 1480s,(33.7) (5.65) (4.00) 1310s79 35 40.9 6.3 4.8 1 520br,s(41.4) (5.65) (5.10)185 40 58.2 4.6 7.6 1 515br,s(58.9) (4.40) (7.20)185 60 51.3 5.2 8.9 1 515br,s,(51.5) (4.95) (8.60) 1470s197 40 34.6 4.2 5.3 1 332m(34.6) (4.5) (5.25)SolventC6D6C6D6C6D6C6D6C6D6C6D6CH,Cl,'H(6)' 31P-{ 'H}/p.p.m.d8 .M . 5 0 - 101.48, - 101.834.50-3.10 - 129.63, - 129.688.49-6.69 - 102.32, - 102.53(m, 25 H, Ph) (7.6)4.31-1.50 - 124.87, - 125.08(m, 4 H, CHJ (7.6)8.00-7.30 - 94.89, - 95.383.0-1.5(m, 25 H, Ph) (12.7)(m, 4 H, CH,) (1 2.7)(m, 5 H, Ph) (1 7.8)(br, m, 24 H, CH, + CH,) (17.8)(m, 5 H, Ph) (1 2.7)(br, m, 24 H, CH, + CH,) (13.0)(m, 25 H, Ph) (7.6)(m, 4 H, CHJ (7.6)- 1 10.44, - 1 10.937.40-6.60 - 95.73, - 96.082.8-0.4 - 115.20, - 1 1 5.558.39-6.74 - 95.12, - 95.33- 1 17.67, - 1 17.88 3.27-2.138.12-7.12- 144.34 (m, 15 H, Ph)2.40-2.30(t, 12 H, CH3)7.30-7.10(m, 15 H, Ph)5.24 (s, br, 3 H, NH,)3.58 (s, br, 3 H, NMe)(d oft, 12 H, Me)-171*922.03-1.75"Calculated values in parentheses.b~ = Strong, m = medium, br = broad; region of nitrogen-nitrogen stretching frequency. 'm = Multiplet,s = singlet, d = doublet, t = triplet, br = broad. All signals singlets, J in parentheses in Hz, shifts with respect to external P(OMe),. ' A, = 83ohm-' cm2 mol-' in solution in MeNO,J. CHEM. SOC. DALTON TRANS. 1986 215C, 26.4; H, 4.7; N, 2.7. C,,H,,Cl,NP,W requires C, 25.1; H, 4.7;N, 2.4%).[ 1,2- Bis(dipheny1phosphino)ethanel trichloro(pheny1-diazenido)molybdenum(Iv).-To [ MoCl,(dppe)] (0,64 g, 1mmol) in benzene (30 cm3) was added (Me,SiNHNHPh (0.2 g,1 . 1 mmol) and the solution stirred at 20 "C for 20 h.Theresultant red-purple solution was reduced in vacuo to 2 cm3 anddiethyl ether (20 cm3) added to precipitate the product as a red-purple solid. The analysis in the Table could not be improved bycrystallisation. Indeed, it seems likely that the mono(diazenid0)-complex disproportionates in some way in solution to yield thebis(diazenid0)-complex. This was not pursued.Similar procedures were used to prepare [ 1,2-bis(diphenylphos-p h in o)e t hane] t r ic hlo r o(phen y ldiazen ido) t ungs ten( 1 v ) . The samemethod was also used to prepare [ 1,2-bis(diethylphos-phino)ethane] trichloro(pheny1diazenido)-molybdenum( ~ v ) and-tungsten( I v).[ 1,2 - Bis( diphen y lp h osphino )e t hane] dichlor o bis(p hen yl-diazenid0)-molybdenum(Iv).-To [MoCl,(dppe)] (0.95 g, 1.5mmol) dissolved in ethanol (30cm3) was added phenylhydrazine(1.05 cm3, 10.7 mmol) and the mixture heated to 55 "C for 2 h.The red-purple precipitate was filtered off, and recrystallisedfrom benzene4iethyl ether as purple crystals.D ich lor o b is( dime t h y Iphen y lp h osph ine)bis(phen y ldiazen id0 )-molybdenum(lv).-To a solution of [MoCl,(PMe,Ph),] (0.80 g,1.3 mmol) in ethanol (60 cm3) was added phenylhydrazine (0.83cm3, 8.4 mmol) and the mixture heated to 75 "C for 0.75 h,during which time it changed from a yellow suspension to adeep red solution.The solvent was removed in vacuo yielding anoil.This was dissolved in methanol (30 cm3) and stirred toyield a purple solid which was recrystallised from benzenepentane as deep purple crystals.Bis( NN-diethy(dithiocarbamato)bis@henyldiazenido)molyb-denum(rv).'-To a solution of [MoC1,(N2Ph),(PMe,Ph),1(0.03 g, 0.04 mmol) in methanol (30 cm3) was addedNa(S2CNEt2)*3H20 (0.024 g, 0.11 mmol) and the mixturestirred at 20 "C for 3 d. Reduction in volume yielded blackcrystals (2073, m.p. 99 "C (lit.,' 103 "C) (Found: C, 43.8; H, 5.5;N, 13.3. C,,H,,MoN,S, requires C, 43.8; H, 5.00; N, 13.9%).Amminedichlorobis(dimethylphenylphosphine)(phenyldiuzen-ido)rhenium(nr).'-To a solution of [ReCl,(PMe,Ph),] (0.23 g,0.38 mmol) in ethanol (50 cm3) was added phenylhydrazine (0.24cm3, 2.3 mmol).The mixture was heated to 60 "C for 0.5 h, andthe brown solution reduced in uacuo to 10 cm3. Addition ofhexane (30 cm3) produced a yellow solid, which was filtered offand dried in uacuo, yield 70%, m.p. 160-164 "C (decomp.) [lit.,2164-171 "C (decomp.)] (Found: C, 34.6; H, 4.3; N, 5.3.C2,H3,Cl,N,P,Re requires C, 34.6; H, 4.15; N, 5.25%).Amminedichlorobis(dimethylphenylphosphine)[ N,N-methyl-phenylhydrazido(2 - )-N']rhenium(v) Iodide.-A mixture of[ReCI,(N,Ph)(NH,)(PMe,Ph),] (0.50 g, 0.63 mmol) andmethyl iodide (2 cm3, 32 mmol) in thf (100 cm3) was heatedunder reflux for 5 h. The volume was reduced to ca. 5 cm3 inuacuo, and pentane ( 5 cm3) added, giving a pink-brown solid,which was recrystallised from thf-pentane.AcknowledgementsWe acknowledge financial assistance from the University ofMalaysia (to H. M. A,).References1 M. W. Bishop, G. Butler, J. Chatt, J. R. Dilworth, and G. J. Leigh, J.2 P. G. Douglas, A. R. Galbraith, and B. L. Shaw, Transition Met.3 J. M. Jenkins and B. L. Shaw, J. Chem. SOC. A, 1966,770.4 J. Chatt, M. E. Fakley, P. B. Hitchcock, R. L. Richards, and N. Tiiyet5 J. Chatt, W. Hussain, G. J. Leigh, H. Neukomm, C. J. Pickett, and6 P. M. Boorman, N. N. Greenwood, and M. A. Hilden, J . Chem. SOC.7 J. Chatt, G. J. Leigh, D. M. P. Mingos, and R. J. Paske, J. Chem. SOC.8 M. W. Anker, J. Chatt, G. J. Leigh, and A. G . Wedd, J. Chem. SOC.,9 E. A. Allen, B. J. Brisdon, and G. W. A. Fowles, J . Chern. SOC., 1963,Chem. SOC., Dalton Trans., 1979,1843.Chem., 1975/76, 1, 17.Luong-Thi, J. Chem. SOC., Dalton Trans., 1982,345.D. A. Rankin, J. Chem. SOC., Chem. Commun., 1980,1024.A, 1968,2466; A. V. Butcher and J. Chatt, ibid., 1970,2652.A, 1968,2636.Dalton Trans., 1975,2639.4649.10 U. Wannagat and W. Liehr, Angew. Chem., 1957,69,783.Received 30th October 1984; Paper 41 185
ISSN:1477-9226
DOI:10.1039/DT9860000213
出版商:RSC
年代:1986
数据来源: RSC