摘要:
J. CHEM. SOC. DALTON TRANS. 1995 155Bis(q-cyclopentadienyl)imidomolybdenum Compounds tMalcolm L. H. Green," Peter C. Konidaris, Despo M. Michaelidou and Philip MountfordInorganic Chemistry Laboratory, South Parks Road, Oxford OX 1 3QR, UKThe mono(q-cyclopentadieny1)imide compounds [Mo(q-C,H,R)( NR')CI,] ( R , R' = H, R"; Me, Pr';Me, R"; or Pr', R"; R" = C,H,Me,-2,6) and the new bis(q-cyclopentadieny1)imide compounds[Mo(q-C,H,R),(NR')] (R, R' = Me, But; H, Bur; H, Pri; H, Ph; H, R"; Me, Pr'; Me, Ph; Me, R"; Pr', Bur; orPr', R"), [Mo(q-C,H,)(q-C,H,Pri)(NBur)], [Mo(q3-C,H,)(q-C,H,Pri)(NBut)] and [Mo(q- C,H,Me),-Me(NBur)]X (X = I or BF,) have been prepared. The salt [Mo(q-C,H,Me)(PMe3),(NBut)] [C,H,Me] hasalso been prepared. The crystal structures of the latter and of [Mo(q-C,H,),(NBut)] have been determined.We and others have been exploring the chemistry ofq-cyclopentadienylimide derivatives of molybdenum andtungsten.'-,, Here we describe the first examples of bis-(q-cyclopentadieny1)imide derivatives of molybdenum.Apreliminary report of part of this work has been published.'Results and DiscussionThe most convenient route to the compounds [Mo(q-C,H,R),(NR')] is by treatment of [Mo(q-C,H,R)(NR')Cl,]with the corresponding sodium cyclopentadienide saltNa[C,H,R]. The ten precursor compounds in the class [Mo(q-C,H,R)(NR')Cl,] 1-10 used in this study are specified inScheme 1; 1-3,5,7 and 10 have been described previously. Thenew compounds 4, 6, 8 and 9 have been prepared by thepreviously described general reaction (1) 7,1 and characterisingdata are given in Table 1.[MO(~-C,H,R)CI~] + 3NR'HZ *[Mo(q-C,H,R)(NR')Cl,] + 2NR'HSCl (1)The precursor compounds 1-10 when treated with 2equivalents of the appropriate sodium cyclopentadienidereagent Na[C,H,R] give the corresponding bis(q-cyclo-pentadieny1)imidomolybdenum compounds [Mo(q-C,H,R),-(NR')] 11-20, respectively, as shown in Scheme 1.The datacharacterising the new compounds are given in Table 1 and onlyselected data are discussed below.In a typical synthesis, treatment of [Mo(q-C,H,)(NBu')Cl,]1 with 2 equivalents of sodium cyclopentadienide gave redcrystals of [Mo(q-C,H,),(NBu')] 11 in 46% yield. Similarly,treatment of [Mo(q-CSH,Me)(NBu')C12] 5 with 2 equivalentsof Na[C,H,Me] gave low-melting red-purple crystals of[Mo(q-C,H,Me),(NBu')] 15.The compounds 11 and 15 wereprepared in gram quantities and have been studied in greatestdetail.Compound 15 can also be prepared from the previouslydescribed 7*16 [Mo(q-C5H4Me)(q-C2H,)(NBut)Cl] 21 by treat-ment with sodium methylcyclopentadienide in thf, followed byphotolysis of the mixture using a medium-pressure mercurylamp. Although the yield from this route was 47%, the precursor21 is not so readily available as 5. The compound [Mo(q-C,H,),(NBu')] 11 can also be prepared in low yield (6%) bytreatment of the compound [Mo(q-C,H,Pr')(q-C2H,)(NBu')-Cl] 22 with sodium cyclopentadienide in thf, followed byt Supplementary dara available: see Instructions for Authors, J. Chem.SOC., Dulton Trans., 1995, Issue 1, pp.xxv-xxx.Non-SI unit employed: mmHg z 133 Pa.photolysis. This reaction involves exchange of a co-ordinatedq-C5H,Pri group by a q-CSH, ligand.The crystal structure of compound 11 has been determinedand is shown in Fig. 1. Comparison of the 'H NMR spectra of11 with those of the homologous compounds 12-20 clearlyindicates that these latter compounds are isostructural with 11.Further details of the structure of 11, including a discussion ofthe interesting features of the Mo(q-C,H,), moiety [namelyunusually long molybdenum-q-cyclopentadienyl ring centroid(Cp) distances and a low CpMo-Cp angle], have been givenelsewhere. Related metal-ligand multiply bonded Group 6bis(q-cyclopentadienyl) complexes of the type [M(q-C5R5),E][M = Mo or W; E = 0, S or P(c6H2But3-2,4,6)] have beendescribed previously.23-27The structure of the compound 11 appears to challenge the18-electron rule. The near linearity of the imide ligand impliesformal sp hybridisation at the nitrogen atom, and, in principle,the donation of four electrons to the Mo. This would result in aformally 20-electron compound. Related compounds with aformal electron count greater than 18 include [Mo(q-C,H,),-R(NO)] (R = alkyl)28-30 and p(q-C, Me,)(NC6H3Me,-2,6)] 31 and both show substantially distorted metal-q-cyclopentadienyl ring interactions. The molecular-orbitalcalculations which have been used to investigate the bondingin these systems 31*32 suggest that the 'surplus' electrons arelocated in orbitals that are essentially ligand based, thusavoiding violation of the eighteen-electron rule.Similar results have been obtained from calculations on themodel compound [Mo(q-C,H,),(NH)], and are supported byphotoelectron spectra of the methyl-substituted compound[Mo(q-C,H,Me),(NBu')] 15.7,33 Thus the complexes [Mo(q-C5H4R),(NRr)] possess a ligand-based lone pair which islocalised more or less equally on the q-C,H,R ligand ringcarbons and on the imide nitrogen atom. Thus neither theq-CSH4R ligands nor the NR' imide group in the complexes[Mo(q-C,H,R),(NR')] act as formal five- or four-electrondonor groups respectively and the bis(q-cyclopentadienyl)complexes are thus 18-electron species.In addition to the vanadium complex, ~(q-C,Me,),-(NC,H,Me,-2,6)], other complexes have also been shown topossess imide groups that donate fewer electrons to the metalcentre than would be expected from a consideration of formalhybridisation at nitrogen.Examples include [Os(NC,H,Pr',-2,6),] (three 3.33-electron donor imide groups) 34*35 and[Mo,(q-CsH,Me),(~Ph),(p-NPh),] (four three-electrondonor imide groups).The implied weakening of the metal-ring binding in thecomplexes [Mo(q-C,H,R),(NR')] by competition for metalacceptor orbitals by the imide ligand has importantconsequences for the reactivity of these bis(q-cyclopentadienyl156 J. CHEM. SOC. DALTON TRANS. 1995CI21 R=Me22 R = PJ3 H Ph4 H NR"5 Me But7 Me Ph8 Me NK'9 Pr' NR"6 Me P+ .,2=x-10 pr' NBU'R K R W X11 H But 25 Me But I26 Me Bu' BF4 12 H P i2 7 H P S I16 Me Ps17 Me Ph23MeMe 30 29Scheme 1 R" = C',H,Me,-2,6. (i) Typically, Na[C,H,R] in tetrahydrofuran (thf) at room temperature (r.t.) for 12 h; yields 30-50%; (ii) for R =Pr', lithium indenide in thf for 1 h, then photolysis for 30 min, 33%; (iii) for R' = Pr', Na[C,H,] in thf at r.t.for 14 h, then photolysis for 1.5 h, 6% 11;for R = Me, Na[C,H,Me] in thf treated as before, 47% 15; (iu) typically, Me1 in thf for 10 min-5 h, yields 60-80%; ( u ) for R = Pr', R' = NBu',Na[C,H,] in thf for 2 d, then photolysis for 4 h, 45%; (ui) for R = Me, R' = But, HCI gas for 2 min in thf at -80 OC, 50%; (uii) for R = Me,R' = But, LiAIH, in thf at r.t. for 14 h, 71%; (uiii) for R = Me, R' = But, PMe, in thf at r.t.for 5 d, 50%; (ix) for R = Me, R' = But, ally1 iodide inthf at r.t. for 2 d, 21%been demonstrated for the isolated compound 15. Thusphotolysis with 2 equivalents of sodium cyclopentadienide,removal of solvent and extraction of the products with lightpetroleum yields a mixture of products. The 'H NMR spectrumof the mixture shows resonances assignable to the startingmaterial 15 and to the doubly ring-exchanged compound 11.The cyclic voltammogram of compound 11 displays twoirreversible one-electron oxidation waves at - 0.49 and - 0.19V relative to the ferrocene-ferrocenium couple. Theseoxidations are at low potential, and may be tentativelycorrelated with the low-ionisation-potential bands (assigned toionisation from the metal d2 orbital and to the ligand-basedlone pair) observed in the gas-phase photoelectron spectrumFig.1 Crystal structure of [Mo(q-C,H,),(NBu')] 11. Hydrogen of 15.7Treatment of the compound [Mo(q-C5H4Pr')(q-CTH4)- atoms omitted for clarity. Further details given elsewhere *(NBu')Cl] 22 with 0.9 equivalent of sodium cyclopentadienide incompounds. The formation of the ring-exchanged product 11 thf, followed by photolysis of the mixture, afforded the mixed-is indicative of the inherent substitution lability of the ring compound [Mo(q-C,H,)(q-C,H,Pr')(NBu')] 23 as a red,17-cyclopentadienyl rings in this system. Ring exchange has also extremely air-sensitive oil in 45% yield. This suggests that thJ. CHEM. soc. DALTON TRANS. 1995 157Table 1 Analytical and spectroscopic dataCompound and analysis a4 [Mo(q-CsHs)(NC6H,Me,-2,6)C12]C, 45.0 (44.5); H, 4.0 (4.0); N, 3.9 (4.0)m/z 354 (100%), M +6 [Mo(q-CsH4Me)(NRri)Clz]C, 35.5 (35.7); H, 4.6 (4.7); N, 4.55 (4.6)m/z 305 (75%), M +8 [Mo(q-C,H4Me)(NC6H,Me,-2,6)Clz]C, 46.3 (46.05); H, 4.55 (4.4); N, 3.7 (3.8)m/z 368 (loo%), M +9 [Mo(q-CsH,Pr')(NC6H,Me,-2,6)Cl~]C, 49.2 (48.9); H, 5.15 (5.1); N, 3.55 (3.6)m/z 397 (373, M +11 ~MO(~-CsHs),(NB~')1C, 56.5 (56.6); H, 6.4 (6.4); N, 4.6 (4.7)m/z 299 (373, M +12 [ Mo( q-C H s)2( NPr ')IC, 53.1 (55.1); H, 5.8 (6.05); N, 4.2 (4.95)m/z 283 (43%), M +13 CMo(rl-CsH,),(NPh)lC, 60.35 (60.6); H, 4.8 (4.8); N, 4.0 (4.4)m/z 319 (100%), M +l4 CMo(q-C5H5)2(NC6H3Me2-2,6)]C, 62.6 (62.6); H, 5.4 (5.55); N, 4.2 (4.1)mlz 347 (9773, M +15 [Mo(q-C,H,Me),(NBu')]C, 58.3 (59.1); H, 6.9 (7.1); N, 4.1 (4.3)16 [Mo(q-C,H,Me),(NPr')]m/z 327, M + ; 312, M + - Me; 256,M + - NBu'17 [Mo(q-C,H,Me),(NPh)]C,61.6(62.6);H,5.8(5.55);N,3.6(4.1)m/z 346 (24%), M +18 [Mo(q-C,H4Me),(NC6H,Me,-2,6)]C, 62.4 (64.3); H, 6.1 (6.2); N, 3.8 (3.75)m/z 375 (82%), M +19 [Mo( q-C5 H,Pr'),(NC,H,Me,-2,6)]C, 66.4 (67.1); H, 7.2 (7.3); N, 3.25 (3.3)m/z 432 (5373, M +20 [Mo( q-C5 H,Pr'),(NBu')]23 [ Mo( q-CSH s)( q-CSH4Pri)(NBu')]C, 59.9 (60.0); H, 7.5 (7.7); N, 4.0 (4.1)ml= 341, M + ; 326, M + - Me; 270,24 [Mo(q3-C9H7)(q-C,H4Pri)(NBu')]C, 64.6 (64.8); H, 6.9 (7.0); N, 3.5 (3.6)mi: 391, M+, 376, M + - Me; 320,25.26 [Mo(q-C,H,Me),Me(NBu')]Iand BF, -25C, 42.8 (43.7); H, 5.3 (5.6); I, 25.7(27.1); N, 3.0(3.0)M+ - NBu'M + - NBu'NMR and other dataESR:g = 1.9714IR (CsI, cm-'): 1586w, 1406w, 1320w, 1032m, 854s, 829m, 779sNMR data given elsewhere'H: 5.1 1 (s, 10 H, 2CSHs), 3.46 [spt, 1 H, J(H-H), 6.4, CH(CH,),], 0.99 [d, 6 H, J(H-H) 6.4,CH(CH,)zI13C-{1H):c 95.0 (s, CSHS), 66.8 [s, CH(CH,),],24.1 [s, CH(CH,),]'H:7.10[t,2H,J(H-H),7.8,m-H,Ph],6.72[t, 1 H,J(H-H)7.3,p-H,NPh],6.64[d,2H,J(H-H)7.6, O-H, NPh], 5.06 (s, 10 H, 2CsH5)13C-{1H):c 160.9 (s, C, NPh), 128.4 (s, CH, NPh), 120.0 (s, CH, NPh), 116.6 (s, CH, NPh), 95.0'H: 7.03 [d, 2 H, J(H-H) 7.3, NC&,(CH,),], 6.73 [t, I H, J(H-H) 7.5, NC6H,(CH3),], 4.94 (s,10 H, 2CsHs), 2.37 [s, 6 H, NC,H,(CH,),]157.3 [S, C, NC6H,(C&,),], 122.5 [S, C, NC6H,(CH,),], 120.5 [d, CH, J(' ,C-H) 158, 1 3 ~ : cNC6H,(CH,)J, 96.1 [d, CH, J(',C-H) 176, CSHS], 19.1 [q, CH3, J(I3C-H) 126,6, C,HJNC6H,(CH,),], one NC6H,(CH,),(CH) signal obscured by C6D6'H (CD3C6Ds): 5.17,4.77 [2 x 2 H, 2 x vt (J = 2.3), C,H,Me], 1.90 (6 H, s, CsH4Me), 1.08(9 H, s, But)'H: 5.13 [vt, 4 H, J(H-H) 2.3, 2MeC,H,], 4.96 [vt, 4 H, J(H-H) 2.3, 2MeCsH4], 3.70 [spt, 1 H,J(H-H) 6.4, CH(CH,),], 1.77 (s, 6 H, 2CH,CsH4), 1.08 [d, 6 H, J(H-H) 6.4, CH(CH,),]13C:c 112.4(~, C, CH,CsH4),94.7[d, CH,J(',C-H) 172,CH3CsH,], 94.0[d,CH,J(13C-H) 173,CH,CsHJ, 66.3 [d, CH, J(',C-H) 133, NCH(CH,),], 24.7 [q, CH3, J("C-H) 128,NCH(CH,),], 16.2 [q, CH3, J(',C-H) 127, CH3C5HJJ(H-H) 7.4, O-H, NPh], 5.34 [vt, 4 H, J(H-H) 2.1, 2CH,CsH4], 4.67 [vt, 4 H, J(H-H) 2.3,13C-{'H}:c 160.2 (s, C, NPh), 128.6 [s, CH, NPh], 119.0 (s, CH, NPh), 115.6 (s, CH, NPh), 115.3(s, C, CH,CSH,), 94.2 (s, CH, CH,CsH,), 93.7 (s, CH, CH,CsH,), 5.7 (s, CH,CsH4)'H: 7.05 [d, 2 H, J(H-H) 7.4, NC&,(CH,),], 6.73 [t, 1 H, J(H-H) 7.4, NC6H,(CH,),], 5.18 [vt,4 H, 2CH,CsH4],4.60 (vt, 4H, CH,CsH4), 2.38 [s, 6 H, NC6H,(CH,),], 1.55 (s, 6 H, 2CH3C5H4)156.7 [S, C, NC6H,(CH,),], 120.5 [s, C, NC6H,(CH,),], 119.6 [d, CH, J("C-H) 157, 1 3 ~ : cNC6H,(CH,),], 114.3 [s, C, CHjCsH4], 95.4 [d, CH, J(13C-H) 175, CH,CSHJ, 94.6 [d, CH,J(',C-H) 175, CHjC5H4], 15.2 [q, CH,,J(',C-H) 125, NC,H,(CH,),], 9.3 [q, CH,, J(l3C-H)'HI 7.04 [d, 2 H,J(H-H) 7.4, N(C6H,(CH,),], 6.71 [t, 1 H, J(H-H) 7.4, NC6H,(CH,),], 4.89 [vt,2.29 [spt, 2 H, J(H-H) 6.9,2CH(CH,)J, 1.10 [d, 12 H, J(H-H) 6.8,2CH(CH,),]'H: 7.1 1 [t, 2 H, J(H-H) 7.7, m-H, NPh], 6.70 [t, 1 H, J(H-H) 7.3, p-H, NPh], 6.64 [d, 2 H,2CH3C5H4], 1.64 (s, 6 H, 2CH3C5H,)127, CH,CsH4], one NC6H3(CH,),(CH) signal obscured by C,D64 H, J(H-H) 2.4, 2Pr'CsH4], 4.73 [vt, 4 H, J(H-H) 2.3, 2Pr'C5H4], 2.36 [s, 6 H, NC,H,CH,],l3c:' 157.7 [s, c , NC6H,(CH,),], 122.0 [s, c , NC6H3(CH,),], 120.8 (s, C, Pr'C,H,), 119.6 [d,CH, J(13C-H) 158, NC6H,(CH,),], 96.4 [d, CH, J(',C-H) 165, PriCsH4], 94.1 [d, CH,J(',C-H) 178, PriCsH4], 28.8 [d, CH, J(',C-H) 128, CH(CH,),], 23.9 [q, CH,, J(13C-H) 126,NC6H3(CH3)ZI, 122.2 [S, c , NC6H3(CH3),], 120.6(s, c , PriCsH,), 96.6 (d, CH, J 174, Pr'CsH4),93.9 (d, CH, J 176, Pr'CsH4), 28.7 [d, CH, J 129, CH(CH,),], 23.7 [q, CH,, J 126, CH(CH,),],'H: 5.29 [vt, 4 H, J(H-H) 2.5, 2PriCsH,], 4.30 [vt, 4 H, J(H-H) 2.5, 2Pr'C,H4], 2.72 [spt, 2 H,13C-{'H):c 116.8 (s, C, PriCsH,), 101.1 (s, CH, PriCsH4), 91.5 (s, CH, PriCsH4), 69.5 [s,'H:5.30[2H,vt(J = 2.3),CsH4Pr'],5.14(5H,s,CsHs),4.23[2H,vt(J = 2.3),CsH4Pri],2.65[l H, spt (J = 6.8), CHMe,], 1.31 [6 H, d (J = 6.8), CHMe,], 1.05 (9 H, s, Bu')13C-{ 'H} DEPT:' 101.5 (CH of CsH4Pri), 95.1 (CsH,), 91.5 (CH of CsH4Pri), 30.4 (CMe,), 29.0(CHMe2),25.4(CHMe,)NMR data given elsewhereCH(CH,),] 19.2 [q, CH3, J(',C-H) 125, N(CH,),C,jH,]13C-{1H):e 157.4[s,C,NC,H,(CH,),], 118.6[d,CH,J158,NC6H,(CH,),], 127.1 [d,CH,J 155,18.7 [q, CH,, J 127, NC6H3CH3),]J(H-H) 6.8,2CH(CH,)J, 1.33 [d, 12 H, J(H-H) 6.8,2CH(CH,),], 1.10 [s, 9 H, C(CH,),]c(cH,),], 30.6 [s, C(CH,)J, 29.2 [s, CH(CH,),], 5.4 [s, CH(CH3)Z-J25,'H:'6.78,6.41,5.67,5.59[4 x 2H,4 x vq(J= 2.3),C,H4Me],2.20(6H,s,CsH,Me),1.68(3 H, s, MoMe), 1.20 (9 H, s, But)13C-{1H) DEPT (CD,Cl,): 115.8, 110.0, 108.3, 107.6 (4 x CH of CsH4Me), 28.5 (CMe,), 14.5(CsH,Me), 10.4 (MoMe158 J.CHEM. SOC. DALTON TRANS. 1995Table 1 (contd.)Compound and analysis"26C, 45.95 (47.8); H, 5.95 (6.1); N, 3.2 (3.3)27 [Mo(q-CSHS),Me(NPri)]IC, 39.2 (39.55); H, 4.9 (4.7); N, 3.1 (3.3)28 [Mo(q-C,Hs),Me(NC6H,Me,-2,6)]IC, 47.8 (46.8); H, 4.6 (4.55); N, 2.9 (2.9)29 [Mo(q-C,H,Me)(NBu')I,]C, 24.2 (24.0); H, 3.4 (3.2); N, 2.7 (2.8)m/z 502, M'; 445, M + - But; 318,Mf - But - I; 303, M + - But - I - Me30 [Mo(q-C,H,Me)(PMe,),(NBu')]-[C,H,MeJjC, 55.1 (55.3); H, 8.5 (8.65); N, 2.8 (2.9)NMR and other data26, 'H:"6.61,6.35,5.60,5.44[4 x 2H,4 x vq(J = 2.3),C,H4Me],2.18(6H,s,C,H,Me), 1.67(3 H, s, MoMe), 1.19 (9 H, s, But)'H: " 6.35 (s, 10 H, 2C,H,), 4.40 [spt, I H, J(H-H) 6.5, NCH(CH,),], 1.92 (s, 3 H, MoMe), 1.1413C-{'H}: 112.2(s,2C,H5),74.6 [s,NCH(CH,),],21.5 [s,NCH(CH3),],2.6(s,MoMe)10 H, 2C,H,), 2.27 [s,6 H,NC6H,(CH,),],2.22 (s, 3 H, MoMe)[d, 6 H, J(H-H) 6.4, NCH(CH3)J'H: 6.99 [d, 2 H, J(H-H) 7.6, NC,H3(CH3)2], 6.61 [t, 1 H, J(H-H) 7.6, NC,&,(CH,),], 6.48 (s,'H:"6.41,6.34[2 x 2H,2 x v t ( J = 2.4),2C,H4Me],5.03,4.57(2 x 2H,2 x brs,2C,H4Me),3.09 (3 H, s, C,H,Me), 1.72 (3 H, s, C,H,Me), 1.29 [ l S H, d (J = 9.1), PMe,], 0.80 (9 H, s, But)31P-{1H} (C6D6): " 10.36 (PMe,)" Given as found (calculated) in %.Given as chemical shift (6) [relative intensity, multiplicity (J in Hz), assignment]. Where required, assignmentswere confirmed by 'H-'H and 'H-I3C shift correlation experiments. At 300 MHz, in C6D6 unless otherwise indicated. vt = virtual triplet. At 75.5MHz, in C6D6. Satisfactory analysis could not be obtained. IR: v(M=N) 1353 cm-'. In CD,Cl,. IR: v(M=N) 1358 cm-'. Cyclic voltammogramshowed two irreversible one-electron oxidations: Eoxl = -0.61 and EOx2 = -0.37 V (both recorded in 0.1 mol dm-, NBu,PF6 solution inacetonitrile, relative to ferrocene-ferrocenium. IR: v(M=N) 1366 cm-'. Satisfactory analysis could not be obtained despite repeated efforts, possiblydue to trace contamination with sodium tetrafluoroborate. Cyclic voltammogram (recorded in 0.1 mol dm-, NBu,PF6 in thf) gave E,, = + 0.18and Ered = - 1.31 V relative to ferrocene-ferrocenium.j Synthesised by visiting student Mr. Frank Arnold of the Technical University of Munich.IR: v(M=N) 1359 cm-'.ring-exchange reaction implicit in the formation of 11 from 22proceeds uia 23. Treatment of the compound 22 with 1.1equivalents of lithium indenide in thf, followed by photolysis ofthe mixture, afforded the product [Mo(q3-CgH7)(q-C,H,Pr')(NBu')] 24 in 33% yield. This compound, a deepviolet-purple extremely air-sensitive solid, was isolated bycrystallisation from light petroleum at - 20 "C.The 'H and 13C-{ 'H} NMR spectra of compound 24 showresonances consistent with the proposed structure with anq3-indenyl ring. Thus the chemical shifts of the indenylquaternary carbons (6 135.8) are comparable with thoseobserved for other indenyl complexes in which the q-C,H7ligand adopts a q3 g e ~ m e t r y .~ ~ ~ ~ ~ The indenyl ligand is knownto adopt readily a trihapto co-ordination mode; by doing sohere it relieves the electronic congestion at the molybdenumcentre and gives a formal eighteen-electron configuration.Compound 24 can thus be considered to be formally analogousto the q -ally1 compounds [M o( q -C , H,R)(q -C H ,)(NBu')](R = Me or Pri).17 The isoelectronic, related mixed q5-cyclo-pentadienyl-q 3-indenyl ring cationic molybdenum complex[Mo(q 3-C,H,)(q-C,H,Pr')(C0)2] + has recently been struc-turally characterised. 38 Compound 24 can be electrochemicallyoxidised; cyclic voltammetry shows two irreversible one-electron oxidation waves at -0.61 and -0.37 V.Treatment of compound 15 with an excess of iodomethane inthf afforded orange, air-stable crystals of [Mo(q-C,H,Me),Me-(NBu')]I 25 which were soluble in water.The structure of thecationic part of 25 is shown in Fig. 2. Further details of thestructure determination have been given elsewhere.8 The crystalstructure confirms that overall methylation occurs at the metal,rather than at the nitrogen lone pair. The spectroscopic data for25 are also consistent with the solid-state structure observed.The 'H and I3C-{ 'H} distortionless enhancements ofpolarisation transfer (DEPT) NMR spectra reveal resonancesassignable to tert-butylimide, diastereotopic methylcyclo-pentadienyl and metal-methyl ligands.Treatment of an aqueous solution of compound 25 with 1equivalent of sodium tetrafluoroborate in water afforded theBF,- salt 26 in 66% yield.The 'H NMR spectrum is closelysimilar to that of 25. The compounds [Mo(q-C,H,),Me(NPr')]I27 and [Mo(q-C,H,),Me(NC6H3Mez-2,6)]I 28 have beenprepared by treatment of 12 and 14 respectively with iodo-methane and the spectroscopic data suggest they are analoguesof 25. The complexes [Mo(q-C,H,R),Me(NR')] + are closelyc(21)\ C(26)Fig. 2 Crystal structure of the [Mo(q-C,H,Me),Me(NBu')l+ cationin compound 25. Hydrogen atoms omitted for clarity. Further detailsgiven elsewhere *related to the Group 5 and 6 bis(q-cyclopentadienyl) complexes w( q-C, Me5)2 Me(O)] + {prepared from [ W(q-C5 Me,),O]and MeI}, [Ta(q-C,Me,),H(NR)] (R = H, Bu' or Ph),mb(q-C,H,),X(NBu')] (X = Me, C1, Br, c,H,-~Cor CH,Ph)and [M(q-C,H,)(q-C,Me,)(NBu')Cl] (M = Nb or Ta).3944In an attempt to co-ordinate an allyl moiety to the metalcentre, and possibly induce coupling of the allyl and imideligands, compound 15 was treated with 1.2 equivalents of allyliodide in thf.However, only the air-sensitive, paramagnetic(NMR), 17-electron compound [Mo(q-C,H,Me)(NBu')I,] 29could be isolated. It is presumably analogous to the structurallycharacterised compounds of the type [M(q-C,R,)(NR')Cl,](M = V, Nb, Ta, Mo or Re).'6*45-47Treatment of compound 15 with trimethylphosphine in asealed ampoule for 5 d afforded the ionic [Mo(q-C,H,Me)-(PMe3),(NBu')][C,H,Me] 30, in ca.70% yield as red,extremely air-sensitive crystals. The crystal structure has beendetermined and is shown in Fig. 3. Selected bond lengths andangles are given in Table 2 and fractional atomic coordinatesfor the non-hydrogen atoms in Table 3. We have preparedC1- and BF4- salts of the cation [Mo(y-C,H,Me)(PMe,),-(NBu')] 'recently by an alternative route. ' The cation[Mo(q-C,H,Me)(PMe,),(NBu')] + is isolobal with theoxomolybdenum cations [Mo(q-C5H5)(PMe3),0] + and [Mo-(q-C, H ,)(dmpe)O] -+ (dmpe = Me,PCH,CH,PMe,, struc-turally characteri~ed).~~.~' The formation of 30 from 15 anJ. CHEM. soc. DALTON TRANS. 1995 159Fig. 3 Crystal structure of [Mo(q-C,H,Me)(PMe,),(NBu')][C,H,-Me] 30. Hydrogen atoms omitted for clarity.Atoms labelled 'B' arerelated to their counterparts by a crystallographic mirror plane at y = 4.Atom C(101C) is related to C(101) by a crystallographic inversioncentre at (b iy 4)PMe, under such mild conditions also supports the view thatthe metal-q-cyclopentadienyl ring bonding in the bis(q-cyclopentadienyl) complexes 11-20 is weakened by the imideligand.Removal of the imide ligand may be effected by treatment of,for example, compound 15 in thf at -80 "C with hydrogenchloride gas giving [Mo(q-CSH,Me),C12] 24950 in 50% .yield.Treatment of compound 15 with an excess of lithium aluminiumhydride in diethyl ether again led to cleavage of the metal-nitrogen bond and formation of the dihydride [Mo(q-C,H,Me)2H,],So in 71% yield.Table 2 Selected bond lengths (A) and angles (") for the [Mo(q-C,H,Me)(PMe,),(NBu')]+ cation in compound 30 (Cp refers to thecomputed q-C,H,Me ring carbon centroid)Mo-N(l) 1.716(9) Mo-N-C(l) 154.9(5)Mo-P(1) 2.442(2) P( 1)-Mo-P( 1 B) 92.8( 1)N-C( 1) 1.48( 1) P(l,lB)-Mo-N 95.7(2)M d p 2.03 N-Mo-Cp 131.1P(l)-Mo-Cp 114.9Table 3 Fractional atomic coordinates for [Mo(q-C,H,Me)-(PMe,),(NBu')lCC, H 4 W 30X0.264 87(9)0.309 6(2)0.469( 1)0.627(2)0.1 OO(2)0.054( 1)0.058(2)0.280(2)0.5241 1)0.178( 1)0.577(2)0.695(2)0.544 8(5)0.41 8( 1)0.250 0(9)0.273 2(5)0.733 3(9).0.032 l(8)Y0.250 00.151 6(1)0.254 6( 1)0.276 O(5)0.250 00.311 3(3)0.289 7(5)0.389 4(5)0.058 4(3)0.150 6(9)0.148 O(5)0.273 8(8)0.353 6(7)0.473 3( 1)0.442 4(3)0.477 O(5)0.529 3(4)0.451 2(6)z0.945 76(8)0.781 2(2)1 .OW( 1)1.223( 1)1.094( 1)1.008( 1)0.850( 1)1.07 l(2)0.837( 1)0.778(2)0.575 2(6)1.369( 1)1.200(2)0.468 l(4)0.322 7(5)0.296 4(7)0.426( 1)0.543( 1)ConclusionWe have demonstrated the facile synthesis of the first bis(q-cyclopentadieny1)molybdenum imide complexes, [Mo(q-C,H,R),(NR')], and their mixed-ring analogues.Preliminarystudies have shown that the metal-q-cyclopentadienyl ringbonding in these complexes is weakened by strong n donationfrom the imide nitrogen atom. These complexes promise todemonstrate an interesting reaction chemistry and furtherstudies are in progress.ExperimentalWhere necessary, reactions were performed under an inertatmosphere of dinitrogen using a dual nitrogen/vacuum line.Reactions were performed in Schlenk vessels, sealed at the B24cone by rubber Suba-Seals, or glass caps.Liquids weretransferred through stainless-steel cannulae (diameter 0.5-2mm) by an excess of dinitrogen pressure. Filtration wasachieved either by using such cannulae modified to take a paperor glass filter at one end, or by use of a glass frit covered with abed of oven-dried Celite (Koch-Light) or Kieselguhr.Toluene was distilled from over sodium, tetrahydrofuranfrom over potassium, and diethyl ether and light petroleum (b.p.40-60 "C) from over sodium-potassium alloy. Distillationwas conducted under dinitrogen. Dried solvents were storedover activated molecular sieves (4 A) in flame-dried Young'sampoules. Solvents were degassed prior to use by repeatedpumping and admission of dinitrogen.Deuteriated solventswere stored over molecular sieves (4 A) for 1 week priorto use. Microanalyses were either obtained from themicroanalytical department of this department, or fromAnalytische Laboratorien, Engelskirchen, Germany.Infrared spectra were recorded on either Mattson 'Polaris'Fourier-transform, Perkin-Elmer 17 10 Fourier-transform orPerkin-Elmer 457 grating spectrometers. Samples wereprepared as pressed CsI discs unless otherwise stated. The NMRspectra were recorded on a Bruker AM 300 instrument, 'H at300, "P at 121.6 and 13C at 75.5 MHz. They were referencedinternally by using the residual protio solvent resonance,solvent resonance (I3C) or by using the standard Briikersoftware SR command (for 'P, relative to trimethyl phosphatein D20).Mass spectra were either measured on an AEI MS 302spectrometer or obtained by Dr. Ballantine at the SERC facilityat the University of Swansea (for FAB) ESR spectra on a VarianE 109 instrument. Cyclic voltammograms were measured usingan Oxford Instruments potentiostat connected to a RikadenkiXY recorder.The compounds [Mo(q-C,H,R)Cl,] (R = H, Me or Pri),"[Mo(q-C,H,R)(NR')C12] (R, R' = H, But; H, Bu'; H, Ph; Me,But; Me, Ph; or Pri, But),16 and [Mo(q-C5H,R)(q-C2H4)-(NBu')Cl] (R = Me or Pri)16 were prepared as descnbedpreviously.Preparations.-[Mo(q-C,H,)(NC6H3Me2-2,6)C12] 4. 2,6-Dimethylaniline (3.77 cm3, 31 mmol) in toluene (10 cm3) wasadded slowly to a stirred suspension of [Mo(q-C,H,)Cl,] (3.10g, 10 mmol) in toluene (1 50 an3). It was stirred for 90 min andthe resulting red-brown mixture filtered through a Kieselguhrfrit to give a clear brown solution and a brown solid whichremained on the frit.The volume of the solution was reduced to30 cm3 under partial vacuum. Cooling to 0°C overnightproduced [Mo(~-C,H,)(NC~H,M~,-~,~)C~~] as a dark brownpowder which was isolated and dried in uczcuo. Yield 0.33 g,8.3%.[Mo(q-C,H,Me)(NPr')C12] 6. A red suspension of [Mo(q-C5H,Me)CI,] (3.38 g, 10.7 mmol) in thf (150 an3) was cooled to-50 "C and isopropylamine (1.89 g, 2.72 cm3, 32.1 mmol)added giving a brown solution. The reaction mixture wasallowed to warm slowly to room temperature and stirredovernight. It was filtered through Kieselguhr and the volumereduced to 50 cm3.After cooling to - 80 "C for 3 h a solidseparated. Light petroleum (70 an3) was added while keepingthe reaction mixture at that temperature and the solution wasthen decanted, leaving a light brown solid which was washedonce with light petroleum (50 cm3). Recrystallisation fro160 J. CHEM. SOC. DALTON TRANS. 1995toluene at -25 "C gave [Mo(q-CSH,Me)(NPr')C12] as a lightbrown crystalline solid. Yield 1.80 g, 55%.[Mo(q-CSH,Me)(NC6H3Me,-2,6)Cl,] 8. 2,6-Dimethyl-aniline (2.33 cm3, 19.0 mmol) in toluene (6 cm3) was addedslowly to a stirred suspension of [Mo(q-C,H,Me)Cl,] (2.0 g,6.3 -01) in toluene (I 5 cm'). The resulting brown-red reactionmixture was stirred for 12 h and subsequently filtered through aKieselguhr frit to give a clear red-brown solution and a brownsolid which remained on the frit.The volume of the solution wasreduced to 30 cm3 under reduced pressure. Cooling to -20 "Covernight produced [Mo(q-CSH,Me)(NC6H3Me2-2,6)C12](220 mg) as a brown crystalline solid, which was isolated bydecantation and washed twice with cold toluene (10 cm3) andonce with light petroleum. A further 0.80 g was isolated from themother-liquor. Yield 1 .O g, 43%.[Mo(q-C,H,Pr')(NC6H3Me2-2,6)C12] 9. 2,6-Dimethyl-aniline (3.39 cm3, 27.6 mmol) was added slowly to a stirred redsuspension of [Mo(q-CSH4Pri)Cl4] (3.17 g, 9.2 mmol) intoluene (1 50 cm3). The resulting red-brown reaction mixturewas stirred for 12 h and subsequently filtered through aKieselguhr frit to give a clear red-brown solution and a brownsolid which remained on the frit.The solvent was removedunder reduced pressure to give a red oil. Light petroleum(200 cm3) was added at a temperature of - 80 "C, causing[Mo(q-CSH,Pr')(NC6H3Me2-2,6)C12] to separate from the redoil as a brown solid. This was isolated, washed with lightpetroleum and dried in uacuo. Yield 1.6 g, 44%.[Mo(q-C,H,),(NBu')] 11. Method (a). A brown solution of[Mo(q-C,H,)(NBu')Cl,] 1 (0.22 g, 0.73 mmol) in thf (50 cm3)was added at room temperature to a colourless solution ofsodium cyclopentadienide (0.14 mg, 1.55 mmol) in thf (50 cm3).The colour immediately became deep red.The reaction mixturewas allowed to stir overnight after which the solvent wasremoved under reduced pressure and the residue extracted intolight petroleum (100 cm3). The volume was reduced to 10 cm3and the solution cooled to -80 'C to give [Mo(q-C,H,),-(NBu')] which was isolated as a red solid and dried in uacuo.Yield 100 mg, 46%.Method (b). The compound [Mo(q-C,H,Pr')(q-C2H,)(N-Bu')Cl] 22 (1.93 g, 5.72 mmol) in thf (100 cm3) was treatedwith sodium cyclopentadienide (0.97 g, 11 mmol) in thf (100cm3) dropwise over 30 min with stirring. The mixture wasstirred for 14 h, then photolysed for 1.5 h. The initiallyorange-yellow solution became deep red-purple. Solvent wasremoved under reduced pressure and the residual red solidextracted with light petroleum (50 cm3).The extract wascooled to -80 "C yielding a red solid which was filtered offand recrystallised from light petroleum at -80 "C. Yield ca.0.10 g, 6%.[Mo(q-C,H,),(NPr')] 12. A green-brown solution of [Mo(q-C,H,)(NPr')CI2] (0.10 g, 0.35 mmol) in thf (50 cm3) was addedat room temperature to a colourless solution of Na[C,H,] (0.4g, 4.5 mmol) in thf (70 cm3). The mixture immediately becamedeep red. It was allowed to stir overnight after which the solventwas removed under reduced pressure and the residue extractedinto light petroleum (100 an3). The volume was reduced to 20cm3 and the solution allowed to cool overnight to -80 "C togive red crystals of [Mo(q-C,H,),(NPr')] which were isolatedand dried in uacuo. Yield 80 mg, 8 1 %.[Mo(q-C,H,),(NPh)] 13.A brown solution of [Mo(q-C,H,)(NPh)Cl,] 3 (0.5 g, 2 mmol) in thf (70 cm3) was added atroom temperature to a colourless solution of Na[C,H,] (0.7 g, 8mmol) in thf (70 cm3). The solution became deeper brown. Thereaction mixture was allowed to stir overnight after which thesolvent was removed under reduced pressure and the residueextracted into toluene (100 cm3). The volume was reduced to 10cm3 and light petroleum (30 an3) was added. The solutionwas allowed to cool to - 80 "C overnight to give [Mo(q-C,H,),(NPh)] as a brown crystalline solid which was isolatedin uacuo. Yield 0.24 g, 49%.[Mo(q-C5H,),(NC6H3Me,-2,6)] 14. A brown solution of[Mo(q-CSH,)(NC,H3Me,-2,6)C12] 4 (0.585 g, 1.67 mmol) inthf (70 cm3) was added at room temperature to a colourlesssolution of Na[C,H,] (0.350 g, 3.4 mmol) in thf (50 cm3).Thesolution became deeper brown. It was allowed to stir for 12 hafter which the solvent was removed under reduced pressureand the residue extracted into light petroleum (100 cm3). Thevolume was reduced to 20 cm3 and the solution allowed to coolto - 80 "C to afford [Mo(q-C,H,),(NC6H3Me2-2,6)] as abrown crystalline solid which was isolated and dried in uacuo.Yield 150 mg, 26%.[MO(~-C,H,M~)~(NBU')] 15. Method (a). This preparationwas performed in a similar fashion to that described above inmethod (a) for [Mo(q-C,H,),(NBu')]. The compound [Mo(q-C,H,Me),(NBu')] 15 was isolated as a red oil by cooling thepetroleum solution to - 80 "C overnight.Method (b).The compound [Mo(q-C,H,Me)(q-C,H,)-(NBu')Cl] 21 (4.07 g, 0.013 mol) in thf (100 cm3) was treatedwith Na[C,H,Me] (1.42 g, 0.014 mol) in thf (50 cm3). Then asfor method (b) of [Mo(q-C,H,),(MBu')] above. The extractwas cooled to - 80 "C and orange crystals separated which werefiltered off, washed with cold light petroleum (3 an3), and driedin uacuo. Yield 1 .O g. The combined washings were concentratedand cooled to -80 "C, producing a second crop (1.0 g). Totalyield 2.0 g, 47%.[Mo(q-C,H,Me),(NPr')] 16. A green-brown solution of[Mo(q-C,H,Me)(NPr')Cl,] 6 (0.3 g, 1.3 mmol) in thf (50 cm3)was added at room temperature to a colourless solution ofNa[C,H,Me]-thf (0.7 g, 4.02 mmol) in thf (50 cm3). Thesolution became red. It was allowed to stir overnight after whichthe solvent was removed under reduced pressure and the residueextracted into light petroleum (100 cm3).The volume wasreduced and the solution cooled to - 80 "C overnight. No solidcould be obtained uia crystallisation, therefore the solvent wasremoved under reduced pressure to afford a pure red oil fromwhich solvent was removed in uacuo.[Mo(q-C,H,Me),(NPh)] 17. A brown solution of [Mo(q-C5H,Me)(NPh)C1,] 7 (0.5 g, 1.5 mmol) in thf (70 cm3) wasadded at room temperature to a colourless solution ofNa[C,H,Me] (0.7 g, 6.8 mmol) in thf (70 an3). The solutionbecame red-brown. It was allowed to stir overnight, after whichthe solvent was removed under reduced pressure and the residueextracted into light petroleum (100 cm3) and filtered.Thesolvent was removed under reduced pressure and the remainingbrown solid sublimed in high vacuum at 80 "C to give [Mo(q-C,H,Me),(NPh)] as a brown solid. Yield 0.20 g, 39%.[Mo(q-CSH,Me),(NC6H3Me2-2,6)] 18. A brown solution of[Mo(q-C,H,Me)(NC6H3Me2-2,6)C12] 8 (0.590 g, 1.62 mmol)in thf (50 cm3) was added at room temperature to a colourlesssolution of Na[C,H,Me]*thf (0.750 g, 4.3 mmol) in thf (100cm3). The solution became deeper brown. It was allowed to stirfor 24 h after which the solvent was removed under reducedpressure and the residue extracted into light petroleum (200cm3). The volume was reduced to 30 cm3 and the solutionallowed to cool to -80 "C overnight to give brown crystallineneedles of [Mo(q -C ,H,Me),(NC,H Me,-2,6)] which wereisolated and washed with cold light petroleum and dried inuacuo.Yield 0.380 g, 62%.[Mo(q-C,H,Pri),(NC6H3Me2-2,6)] 19. A brown solution of[Mo(q-C5H4Pri)(NC6H3Me2-2,6)C12] 9 (0.583 g, 1.48 mmol)in thf (75 cm3) was added at room temperature to a colourlesssolution of Na[C,H,Pr']-thf (0.650 g, 3.2 mmol) in thf (50 cm3).The solution became deeper brown. It was allowed to stir for 48h after which the solvent was removed under reduced pressureand the residue extracted into light petroleum (100 cm3). Thevolume was reduced to 20 cm3 and the solution allowed to coolto -80 "C overnight to give dark brown needles of [Mo(q-C,H,Pr'),(NC6H3Me,-2,6)]. Yield 0.335 g, 50%.[Mo(q-C,H,Pr'),(NBu')] 20. Treatment of [Mo(q-C,H,-Pr')(NBu')Cl,] 10 (ca.0.2 g) with Na[C,H,Pr'] (ca. 0.6 g) in thf(50 cm3) gave a red solution. The solvent was removed underreduced pressure and the solid extracted into light petroleumJ. CHEM. SOC. DALTON TRANS. 1995 161A red sticky solid was isolated by crystallisation. Sublimation ofthis afforded an oil which was identified as [Mo(q-C,H,Pr'),-(NBu')] by 'H NMR spectroscopy only.[Mo(q -C , H ,)(q -C , H,Pri)(NBut)] 23. The compound[Mo(q-C5H4Pr')(q-C2H4)(NBut)Cl] 22 (1.1 g, 3.25 mmol) inthf (50 cm3) was treated with sodium cyclopentadienide (0.25 g,2.84 -01) in thf (50 an3). The mixture was stirred for 2 d, thenphotolysed for 4 h. The initially orange-yellow solution becamedeep red. Solvent was removed under reduced pressure yieldinga red solid. Extraction with light petroleum (50 an3) afforded adeep red-purple solution. Removal of solvent under reducedpressure yielded a red oil (m.p.ca. r.t.). Final purification waseffected by sublimation [lop2 mmHg (ca. 1.33 Pa), ca. 60 "C].Yield ca. 0.50 g, 45%.[Mo(q3-C9H,)(q-C,H,Pri)(NBut)] 24. The compound[Mo(q-C,H,Pr')(q-C,H,)(NBu')Cl] 22 (200 mg, 0.59 mmol) inthf (30 cm3) was treated with lithium indenide (80 mg, 0.66mmol) in thf (50 an3). The mixture was stirred for 1 h, thenphotolysed for 30 min. The initially orange-yellow solutionbecame deep violet-purple. Solvent was removed under reducedpressure and the deep purple residue extracted with lightpetroleum (30 cm3). The extract was concentrated and cooled to- 20 "C. Crystalsformedwhichwerefilteredoff, washedwithcoldlight petroleum (2 x 1 cm3) and dried in uacuo.Yield 75 mg,33%.[Mo(q-C,H,Me),Me(NBu')]I 25 and [Mo(q-C,H,Me),-Me(NBu')][BF,] 26. The compound [Mo(q-C,H,Me),-(NBu')] 15 (0.20 g, 0.61 mmol) in thf (50 cm3) was treated withiodomethane (0.1 cm3, 1.6 mmol) in thf (50 cm3) over 3 min.The initial deep red-purple solution rapidly became yellow-orange and yellow-orange air-stable crystals of 25 formed.These were filtered off, washed with thf (0.5 cm3) and dried inuacuo. Yield 0.175 g, 60%.A solution of the compound 25 (0.10 g, 0.21 mmol) in water(50 an3) was treated with sodium tetrafluoroborate (23 mg, 0.21mmol) in water (50 cm3). The solution was slowly concentratedunder reduced pressure, affording orange needle crystals of 26which were filtered off, washed with cold water (2 x 3 cm3),cold thf (1 cm3), and light petroleum (5 cm3), and dried in uacuo.Yield ca.60 mg, 66%.[Mo(~-C,H,)~M~(NP~')]I 27. A red solution of [Mo(q-C,H,),(NPr')] 12 (0.1 g) in thf (25 cm3) was treated with anexcess of MeI. An orange precipitate formed immediately. Afterfurther stirring for 5 min, the solvent and excess of Me1 wereremoved under reduced pressure and the orange product waswashed three times with light petroleum and dried in vacuo.Yield ca. 80%.[Mo(q-C,H,),Me(NC6H3Me2-2,6)]I 28. The compound[Mo(q-C,H,),(NC,H3Me,-2,6)] 14 (0.1 g) was dissolved in thf(25 cm3) giving a brown solution and an excess of Me1 wasadded. The solution was stirred for 5 h during which time someprecipitate appeared.The solvent and excess of Me1 were thenremoved under reduced pressure to give [Mo(q- C,H,),Me-(NC6H3Me2-2,6)]I as a brown-orange powder which waswashed three times with light petroleum and dried in uacuo.Yield ca. 80%.[Mo(q-C,H,Me)(NBu')12] 29. The compound [Mo(q-C,H,Me),(NBu')] 15 (0.30 g, 0.92 mmol) in thf (50 cm3) wastreated with ally1 iodide (0.1 cm3, 1.10 mmol). The mixture wasstirred for 2 d. The initially deep red-purple solution becameburgundy red. Solvent was removed under reduced pressureyielding a red oily solid. This was extracted with light petroleum(75 cm3) and the solution cooled to -20 "C. Deep red, veryair-sensitive crystals formed which were filtered off, washed withcold light petroleum (1 cm3), and dried in uacuo. Yield ca.0.10 g,21 %. Final purification was effected by sublimation ( lo-,mmHg, ca. 50 "C).[Mo(q-C5H4Me)(PMe3),(NBu')][C,H4Me] 30. The com-pound [Mo(q-C5H4Me),(NBu')] 15 (0.10 g, 0.30 mmol) wastreated with trimethylphosphine (ca. 2 cm3) at r.t. in a sealedampoule for 5 d. Red crystals were obtained and dried byevaporation of solvent in an inert atmosphere. Yield ca. 75 mg,50%.Reactions of [Mo(q-C,H,Me),(NBu')] 15.- With lithiumaluminium hydride. Compound 15 (70 mg, 0.22 -01) in diethylether (50 an3) was treated with lithium aluminium hydride (0.20g, 5.2 mmol) in diethyl ether (40 cm'). The mixture was stirredfor 14 h. The initially purple suspension became grey. Solventwas removed under reduced pressure and the grey solidextracted with light petroleum (2 x 50 an3).Concentrationand cooling the yellow extracts to -20 "C yielded yellowcrystals of the previously reported [MO(~-C,H,M~),H,].~~Yield 40 mg, 71%.With hydrogen chloride. Compound 15 (0.20 g, 0.62 mmol) inthf (100 an3) was treated with hydrogen chloride gas by purgingfor 2 min at - 80 "C. The red-purple solution rapidly becamepale yellow-green, and a dark green solid precipitated. Thesolution was filtered and the precipitate recrystallised from hotacetone, yielding dark green crystals of the previously reported[MO(~-C,H,M~)~CI,].~~~~~ Yield ca. 0.10 g, 50%.Structure Determination of [Mo(q-C,H4Me)(PMe,),(NBut)]-[C,H,Me] 30.-C22H,3MoNP2, M = 479.46, crystal size= 0.20 x 0.30 x 0.30 mm, monoclinic, space group P2,/m,a = 8.328( l), b = 17.971(2), c = 9.176(2) A, p = 11 1.95( l)O,U = 1273.8 A3, Z = 2 (cation lies across mirror plane, anion liesoninversioncentre), D, = 1.24gcmP3, p = 6.32~-',I;yooo) =504, h(Mo-Ka) = 0.710 69 A, 2 < 20 < 48O, scan mode 0-20,total unique data 2074, observations [I > 3o(I)] 1580, variables166, observations/variables 9.5, Chebyshev parameters 16.3, -A red crystal of compound 30 was sealed in a Lindemannglass capillary under N, and transferred to the goniometer headof an Enraf-Nonius CAD4 diffractometer.Unit-cell parameterswere calculated from the setting angles of 25 reflections. Threereflections were chosen as intensity standards and measuredevery 3600 s of X-ray exposure time, and three orientationcontrols were measured every 250 reflections.The data were corrected for Lorentz and polarisation effectsand an empirical absorption correction 5 2 based on azimuthalscan data was applied.Equivalent reflections were merged andsystematically absent reflections rejected. The molybdenumatom position was determined from a Patterson synthesis.Subsequent Fourier-difference syntheses revealed the positionsof all other non-hydrogen atoms of the [Mo(q-C,H,Me)-(PMe,),(NBu')] + cation. The Mo atom lies on a mirror planeat y = $. Two sites were found for the NBu' group N and Catoms (i. e. none of these atoms lies at y = $) and were treated asbeing statistically disordered either side of the mirror plane (theatoms of the NBu' group were each assigned 0.5 chemicaloccupancy factors). The q-C,H,Me methyl group carbon, C(7),did not lie on y = and so was assigned a chemical occupancyfactor of 0.5 and was also treated as being disordered either sideof the mirror plane.The q-C,H,Me ring (metal-bound) carbonsshowed no evidence of disorder with C(4) at y = $. FurtherFourier-difference syntheses revealed electron density locatedabout (i, i, i) which was successfully modelled as a planarC,H,Me anion disordered across the crystallographic inversioncentre. Atoms C(102), C(103), C(104) and C(105) were assignedchemical occupancy factors of 0.5 and C(101) one of 1.0. Therefinement was found to be considerably more stable andproduced smaller estimated standard deviations (e.s.d.s) andmore chemically reasonable bond lengths and angles in thecentrosymmetric P2Jm as compared with the alternative choiceof space group P2, in which the disorder persisted.Non-hydrogen atoms were refined with anisotropic thermalparameters subject to slack restraints.Hydrogen atoms wereplaced in estimated positions (C-H 0.96 A) with fixed isotropicthermal parameters (1.3 x the equivalent isotropic thermalparameter of the carbon atom to which they were bonded) andrefined riding their supporting carbon atoms. A Chebyshev25.2, 14.0, -6.89, Rmerge = 0.027, R =0.054, R' = 0.049J. CHEM. SOC. DALTON TRANS. 1995weighting scheme 53 was applied and the data were corrected forthe effects of anomalous dispersion and isotropic extinction (viaan overall isotropic extinction parameter 54) in the final stagesof refinement. All crystallographic calculations were performedusing the CRYSTALS suite 5 5 on a MicroVAX 3800 computer inthe Chemical Crystallography Laboratory, Oxford.Neutralatom scattering factors were taken from the usual sources.56Additional material available from the Cambridge Crystallo-graphic Data Centre comprises H-atom coordinates, thermalparameters, and remaining bond lengths and angles.AcknowledgementsWe thank Mr. Frank Arnold of the Technical University ofMunich for experimental assistance, the SERC for a studentship(to P. C. K.) and Wolfson College, Oxford for a junior researchfellowship (to P. M.).References1 J. Sundermeyer, Chem. Ber., 1991,124, 1977.2 M. S. Rau, C.M. Kretz, G. L. Geoffroy and A. L. Rheingold,3 J. Sundermeyer, U. Radius and C. Burschka, Chem. Ber., 1992,125,4 U. Radius and J. Sundermeyer, Chem. Ber., 1992,125,2183.5 T. E. Glassman, M. G. Vale and R. R. Schrock, Organometallics,1991,10,4046.6 M. L. H. Green, G. Hogarth, P. C. Konidaris and P. Mountford,J. Chem. SOC., Dalton Trans,, 1990, 3781.7 M. L. H. Green, P. C. Konidaris, P. Mountford and S. J. Simpson,J. Chem. SOC., Chem. Commun., 1992,256.8 J. C. Green, M. L. H. Green, J. T. James, P. C. Konidaris,G. H. Maunder and P. Mountford, J. Chem. Soc., Chem. Commun.,1992,1361.9 J. Fletcher, G. Hogarth and D. A. Tocher, J. Organomet. Chem.,1991,403,345.10 G. Hogarth, P. C. Konidaris and G. S. Saunders, J. Organomet.Chem., 1991,406,153.11 M.G. Vale and R. R. Schrock, Inorg. Chem., 1993,32,2767.12 T. E. Glassman, M. G. Vale and R. R. Schrock, Organometallics,13 G. HogarthandP. C. Konidaris, J. Organornet. Chem., 1990,399,149.14 H. Brunner, W. Meier, J. Wachter, I. Bernal and E. Raabe,15 J. Fawcett, J. H. Holloway, E. G. Hope, D. R. Russell and16 M. L. H. Green, P. K. Konidaris and P. Mountford, J. Chem. SOC.,17 M. L. H. Green, P. K. Konidaris and P. Mountford, J. Chem. SOC.,18 E. B. Brouwer, P. Legzdins, S. Rettig and K. J. Ross,19 P. Legzdins, E. C. Phillips, S. J. Rettig, J. Trotter, J. E. Veltheer and20 P. Legzdins, S. J. Rettig, K. J. Ross and J. E. Veltheer, J. Am. Chem.21 S . R. Huber, T. C. Baldwin and D. E. Wigley, Organometallics, 1993,22 P. Legzdins and J.E. Veltheer, Ace. Chem. Res., 1993,2641.23 M. L. H. Green, A. H. Lynch and M. G. Swanwick, J. Chem. SOC.,Organometallics, 1993, 12, 3447.2379.1991,10,4046.J. Organomet. Ch,?m., 1989,362,95.M. J. Atherton, J. Organomet. Chem., 1994,464, C20.Dalton Trans., 1994,2851.Dalton Trans., 1994,2975.Organometallics, 1994, 13,2088.V. C. Yee, Organometallics, 1992,11,3104.SOC., 1991,113,4361.12,91.Dalton Trans., 1972, 1445.24 N. D. Silavwe, M. Y. Chiang and D. R. Tyler, Inorg. Chem., 1985,24,25 G. Parkin and J. E. Bercaw, J. Am. Chem. SOC., 1989,111,391.26 P. B. Hitchcock, M. F. Lappert and W.-P. hung, J. Chem. SOC.,27 R. S. Pilato, K. A. Eriksen and E. I. Stiefel, Znorg. Chem., 1993,32,28 F. A. Cotton and G. A. Rusholme, J. Am. Chem. SOC., 1972, 94,29 F.A. Cotton and P. Legzdins, J. Am. Chem. SOC., 1968,90,6232.30 J. L. Caulderon, F. A. Cotton and P. Legzdins, J. Am. Chem. SOC.,3 1 J. H. Osborne, A. L. Rheingold and W. C. Trogler, J. Am. Chem. SOC.,32 J. W. Lauher and R. Hoffmann, J. Am. Chem. Soc., 1976,948,1729.33 G. H. Maunder, Part I1 Thesis, University of Oxford, 1992.34 M. H. Schofield, T. P. Kee, J. T. Anhaus, R. R. Schrock,K. H. Johnson and W. M. Davis, Inorg. Chem., 1991,30,3595.35 J. T. Anhaus, T. P. Kee, M. H. Schofield and R. R. Schrock, J. Am.Chem. SOC., 1990,112,1642.36 F. H. Koher, Chem. Ber., 1974,107,570.37 M. C. Chisholm, M. J. Hampden-Smith, J. C. Huffman, J. D. Martinand K. A. Stahl, Polyhedron, 1988,7, 1991.38 J. R. Ascenso, C. G. de Azevendo, I. S. Goncalves, E. Herdtweck,D. S. Moreno, C. C. Romao and J. Zuhlke, Organometallics, 1994,13,429.4219.Chem. Commun., 1987,1282.3799.402.1969,91,2528.1985,107,7945.39 G. Parkin and J. E. Bercaw, Polyhedron, 1988,7,2053.40 D. M. Antonelli, W. P. Schaefer, G. Parkin and J. E. Bercaw,J. Organomet. Chem., 1993,462,213.41 G. Parkin, A. van Asselt, D. J. Leahy, L. Whinnery, N. G. Hua,R. W. Quan, L. M. Henling, W. P. Schaefer, B. D. Santarsiero andJ. E. Bercaw, Inorg. Chem., 1992,31,82.42 A. Chernega, M. L. H. Green and A. Suarez, J. Chem. SOC., DaltonTrans., 1993,3031.43 M. L. H. Green, D. M. Michaelidou, P. Mountford, A. G. Suarez andL.-L. Wong, J. Chem. SOC., Dalton Trans., 1993, 1593.44 S, Schmidt and J. Sundermeyer, J. Organomet. Chem., 1994,472,127.45 D. N. Williams, J. P. Mitchell, A. D. Poole, U. Siemeling, W. Clegg,D. C. R. Hockless, P. A. O’Neil and V. C. Gibson, J. Chern. SOC.,Dalton Trans., 1992,739.46 W. A. Herrmann, G. Weichselbaumer, R. A. Paciello, R. A. Fischer,E. Herdtweck, J. Okuda and D. Marz, Organometallics, 1990,9,489.47 F. Preuss, H. Becker and H.-J. Hausler, 2. Naturforsch., Teil B, 1987,42, 881.48 M. Brookhart, K. Cox, F. G. N. Cloke, J. C. Green, M. L. H. Green,P. M. Hare, J. Bashkin, A. E. Derome and P. D. Grebenik, J. Chem.SOC., Dalton Trans., 1985,423.49 G. S. B. Adams and M. L. H. Green, J. Chem. SOC., Dalton Trans.,1981,353.50 G. J. S. Adams, Part I1 Thesis, University of Oxford, 1976.51 M. L. H. Green, J. D. Hubert and P. Mountford, J. Chem. SOC.,52 A. C. T. North, D. C. Philips and F. S. Mathews, Acta Crystallogr.,53 J. S . Rollet, Computing Methods in Crystallography, Pergamon,54 A. C. Larson, Acta Crystallogr., Sect. A , 1967,23,664.55 J. R. Carruthers, D. J. Watkin and P. W. Betteridge, CRYSTALSUser Guide, Chemical Crystallography Laboratory, University ofOxford, 1985.56 International Tables for X-Ray Crystallography, Kynoch Press,Birmingham 1974, vol. 4, p. 99.Dalton Trans., 1990, 3793.Sect. A, 1968,24,351.Oxford, 1965.Received 3 1st August 1994; Paper 4/05301
ISSN:1477-9226
DOI:10.1039/DT9950000155
出版商:RSC
年代:1995
数据来源: RSC