Organometallics 1986,5, 398-400
398
W(CBut)(dme)C13
Figure 1. An ORTEP drawing of 1. Ellipsoid option and hydrogen atoms have been omitted for clarity. Table I. Selected Bond Lengths (A) and Angles (deg) for 1 Bond Lengths (A) W-C(11) W-C(12) W-C(13) W-N(l) W-N(2) W-0(1)
2.345 (4) 2.330 (5) 2.360 (5) 1.667 (11) 2.005 (13) 2.237 (11)
C(1)-0(1) C(l)-N(2) CWC(2) C(2)-C(7) C(7)-0(2) N(l)-C(lO) N(2)-C(20)
o(l)-w-c(ll)
88.2 (2) 86.0 (2) 167.6 (2) 102.4 (4) 96.7 (4) 95.3 (4) 104.9 (5) 166.9 (5) 90.6 (3)
N(2)-W-0(1) N(B)-W-C(ll) W-N(l)-C(lO) W-O(l)-C(l) W-N(Z)-C(l) W-N(2)-C(20) N(2)-C(l)-O(l) N(2)-C(l)-C(2) C(2)-C(7)-0(2) C(l)-C(Z)-C(7)
CY
62.0 (5) 152.4 (4) 177.6 (11) 88.7 (9) 95.6 (9) 139.6 (10) 113.7 (13) 127.2 (13) 175.7 (19) 123.0 (15)
cy
"
John H. Freudenberger and Richard R. Schrock'
CY
-B
-
MeOH
C~NH!CH(BU~)!OCH~
ketenyl bond to give the bidentate acylamido ligand. This type of insertion of isocyanates into metal-carbon bonds has been documented in reactions involving MMexC1, (M = Nb, Ta; x = 1, 21°) and TiCp,(alkyl)ll species. The reaction shown in eq 2 is likely to be one of a general class of reactions between high oxidation state alkylidyne complexes and heteroatomic double bonds. For example, preliminary results suggest that carbodiimideslZreact with W(C-t-Bu)(dme)Cl, in a manner analogous to that described here for cyclohexyl isocyanate. The results reported here should be compared with those involving reactions between W(V1) alkylidyne or tungstenacyclobutadiene complexes and the carbonyl f~nctionality.~ Registry No. 1,99605-36-4; W(C-t-Bu)(dMe)Cl,,83416-70-0; CyNHC(O)CH(t-Bu)C(o)OCHS, 99605-37-5; CyNCO, 3173-53-3.
Wlttig-Like Reactlons of Tungsten Alkylidyne Complexes'
Treatment of 1 with methanol at room temperature yields the malonic ester shown in eq 1,according to NMR, IR, and mass spectral characteri~ation.~ C13(CyNlW:N'c-d!!u, 0"
--
(10)Wilkins, J. D.J. Organomet. Chem. 1974,67,269. (11)Klei, E.; Telgen, J. H.; Teuben, J. H. J. Organomet. Chem. 1981, 209, 297. (12)Weiss, K.;unpublished results.
stituted acylamido ligand. The C(1), 0(1), N(2), C(2), C(3), and C(7) atoms of the acylamido ligand lie in a plane, but the tungsten atom lies 0.373 (6) A out of this plane. The W-N(l) distance (Table I) is comparable to that in other imido complexes.8 The W-O( 1)bond is distinctly longer than the W-N(2) bond, and the C(1)-00) bond significantly shorter than the C(l)-N(2) bond, suggesting that mesomeric form A is a better description than B.
A -
CyNCO
Supplementary Material Available: Listings of the final atomic parameters, observed and calculated structure factors, and anisotropic thermal parameters (17 pages). Ordering information is given on any current masthead page.
1.25 (2) 1.37 (2) 1.45 (2) 1.32 (2) 1.15 (2) 1.50 (2) 1.45 (2)
Bond Angles C(ll)-W-C(12) C(ll)-W-C(13) C(l2)-W-C(13) N(1)-W-C(l1) N(l)-W-C(12) N(l)-W-C(13) N( 1)-W-N(2) N(l)-W-O(l)
+
(I)
We propose that the first step in the reaction between W(C-t-Bu)(dme)Cl, and cyclohexyl isocyanate is that shown in eq 2. Metallacycles similar to the proposed tungsten azetin intermediate are formed in the reactions of SOz2and COz3noted earlier. A second equivalent of cyclohexyl isocyanate then inserts into the tungsten(8) (a) Weiher, U.; Dehnicke, K.; Fenske, D. 2.Anorg. Allg. Chem. 1979,457,105. (b) Nielson, A. J.; Waters, J. M. Polyhedron 1982,1,561. (9) Partial 13C NMR (CDCl,): 6 173.1 and 169.8 (NC=O, OC=O), 63.2 (NCH), 507 (OCHJ. IR (cm-I): 3290 ( 8 , NH), 1745 (vs, OC=O), 1640 and 1545 (vs, HNC=O). Mass spectrum: m / e 255.
0276-7333/86/2305-0398$01.50/0
Department of Chemistry, Room 6-33 1 Massachusetts Institute of Technology Cambridge, Massachusetts 02 139 Received September 6, 1985
Summary: W(C-t-Bu)(DIPP), (DIPP = 2,6-diisopropylphenoxide) reacts rapidly with acetonitrile to give [W(NMDIPP),]. and t-BuCzCMe. I t reacts with acetone, benzaldehyde, paraformaldehyde, ethyl formate, and N J-dimethylformamide to give oxo vinyl complexes of the type W(0)(t-BuC=CR,R2)(DIPP),. The tungstenacyclobutadiene complex W(C3Et3)(DIPP), reacts similarly with acetone, benzaldehyde, ethyl formate and N,Ndimethylformamide to give complexes of the type W(0)(EtC-CR,R,)(DIPP),. The oxo vinyl complexes can be hydrolyzed by base to yield the expected olefinic product in good to excellent yield. The olefin product is mainly the cis isomer in most cases.
Tantalum and niobium neopentylidene complexes2and an incipient titanium methylene complex3are known to react with the carbonyl function in a Wittig-like manner, not only with aldehydes and ketones but also with esters and amides. Recently, similar reactions with various zir(1)Multiple Metal-Carbon Bonds. 41. For part 40 see: Strutz, H.; Dewan, J. C.; Schrock, R. R. J. Am. Chem. SOC.1985,107, 5999. (2)Schrock, R. R. J. Am. Chem. SOC.1976,98, 5399. (3) (a) Tebbe, F. N.; Parshail, G. W.; Reddy, G. S. J. Am. Chem. SOC. 1977,100,3611.(b) Pine, S.H.; Zahler, R.; Evans, D. A.; Grubbs, R. H. Ibid. 1980,102, 3270.
0 1986 American Chemical Society
Communications
Organometallics, Vol. 5, No. 2, 1986 399
Table I. Preparation and Hydrolysis of Oxo Vinyl Complexes W(0)(vinyl)(O-2,6-C,H3-i-Prz)J yield, % R in W(CR)(DIPP), carbonyl is01 yield," % isomersb hydrolysis productsc t-Bu t-Bu t-Bu t-Bu t-Bu
Me2C0
81
CHZO
17
PhCHO EtOCHO MezNCHO MezCO PhCHO
Et Et Et Et
-
EtOCHO Me2NCH0
3:l (rot) none 1:4 (cktrans) none 3:2f 2:l (-45O; rot) none none none
82 78 78 80 40 17
Me,C=CH-t-Bu (i) H,C=CH-t-Bu (i) PhHC=CH-t-Bu (c) (L4; cis:trans) cis-(EtO)HC=CH-t-Bu (i or c) Me,NHC=CH-t-Bu (i or c) Me2C=CHEt (i) cis-PhHC=CHEt (i or c) cis-(EtO)HC=CHEt (i) Me,NHC=CH-t-Bu (i or c)
-
99d 85d 95d 60'9 60e* 97d 82d 30e~ 15e3h
" C and H analyses for the eight isolated products are satisfactory. bRatio of rotomers (rot) or geometric (cis, trans) isomers at 25 "C, unless otherwise noted. "None" implies that there are no geometric isomers and that any rotomers interconvert rapidly on NMR time scale at 25 "C. cHydrolysis of isolated (i) or crude (c) samples was effected by shaking samples dissolved in ether, toluene, or C6D6with -1 N aqueous KOH until the sample was essentially colorless (5-15 min). Stereochemistries were assigned according to 'H NMR spectra. d B y GLC vs. internal standard. e B y lH NMR integration vs. DIPPH (assuming 3.0 equiv). fIt is unknown at present whether these are rotational or geometric isomers. #Hydrolysis of crude product in CeD6yields 67% (EtO)HC=CH-t-Bu as a 1 4 1 mixture of cis and trans isomers along with a 19% yield of t-BuCH,CHO, presumably the result of hydrolysis of (EtO)HC=CH-t-Bu during workup. Yields using isolated, crystalline product are 60% pure cis-(EtO)HC==CH-t-Bu and 33% t-BuCH,CHO. Stereochemistry could not be assigned due to formation of the iminium ion in the presence of DIPPH. 'The products consist of 30% pure cis-(EtO)HC=CHEt and 41% PrCHO.
conium complexes have been suc~essful.~For some time we have been looking for Wittig-like reactions of do alkylidyne complexes, since the metal-carbon triple bond in such species is also thought to be polarized M+C-.5 We report several such reactions here for tungsten complexes containing the 2,6-diisopropylphenoxide(DIPP) ligand. W(C-t-Bu)(DIPP): in ether or toluene reacts immediately with acetonitrile to give t - B u C 4 M e quantitatively and a red, insoluble, air-stable complex that analyzes as W(N)(DIPP),. We propose that it is a polymer with linear W=N+W chains analogous to [W(N)(O-t-Bu),],.' By analogy with tungstenacyclobutadiene intermediates in acetylene metathesis: we believe the intermediate in the reaction to be an azatungstenacyclobutadiene complex (eq 1). The reaction between W(C-t-Bu)(DIPP), and tN=C
I
w=c
/Me
I
- w-cFi NII
/Me
-
W E N
+
t-BuCfCMe
\t-Bu
\f-Bu
(1)
BuCH,CN produces a monoadduct that can be crystallied from pentane at -40 "C and that decomposes over a period of several hours at 25 "C to give large, well-formed crystals of W(N)(DIPP),I,. W(C-t-Bu)(DIPP), in ether reacts immediately with acetone to give an orange-red crystalline product in high yield. IR, lH NMR, and 13CNMR data are all consistent with the product being an oxo vinyl species, i.e., W(O)(tBuC=CM~,)(DIPP),.~ Two isomers are observed at 25 (4) (a) Clift, S. M.; Schwartz, J. J. Am. Chem. SOC.1984, 106, 8300. (b) Hartner, F. W., Jr.; Schwartz, J.; Clift, S. M. Ibid. 1983, 105, 640. (5) Listemann, M. L.; Schrock, R. R. Organometallics 1985, 4, 74. (6) Churchill, M. R.; Ziller, J. W.; Freudenberger, J. H.; Schrock, R. R. Organometallics 1984, 3, 1554. (7) Chisholm, M. H.; Hoffman, D. M.; Huffman, J. C. Inorg. Chem. 1983, 22, 2903. (8) (a) vWo (I! 975 cm-' (Nujol). Two, presumably C,, vinylic carbon atom signals in the two isomers are found at 208.2 and 207.2 ppm in a ratio of -1:3. (b) AU oxo vinyl compounds exhibit a ~0 band at 975945 cm-' and C, resonances in the range of -180-220 ppm. C, resonances were found only for vinyl complexes containing an H in the range 114-129 ppm (JCH= 169-153 Hz) for those containing alfcyl groups and ( I ! 160-178 Hz) for 0- or N-substituted derivatives. 140-170 ppm (JCH The 'H and 13C NMR spectra of W(O)(C-t-Bu=CH,)(DIPP), will illustrate: 'H NMR (C De) 6 7.02 (d, 6, ,J = 7.5 Hz, Hm),6.84 (t, 3, 3J = 7.5 Hz, HJ, 6.65 (d, 1, = 3.1 Hz, C-t-Bu=CHAHB), 6.14 (d, 1, 'J 3.1 Hz, C-t-Bu=CHAH,), 3.73 (m, 6, CHMeZ), 1.20 (8, 9, C-t-Bu=CH&), 1.22, 1.17, andJ.12 (all d, 12, = 6.8 Hz, CHMe2); NMR (C6D6)6 213.4 (s, C&, 158.4 (Ciw), 158.1(8, Ciw), 140.3 (s, CJ, 137.9 (s, CJ, 124.9, 123.9, 123.5 (all d, JCH156-160 Hz, C, and Cp), 114.0 (dd, JCH = 153 and 159 Hz, C , 41.0 (8, m e 3 ) , 30.8 (q, JCH = 126 Hz, CMe,), 27.4, 27.2 (both d, JCH $)128 Hz, CHMe'), 24.5, 24.2, and 23.5 (all q, JCH = 124-126 Hz, CHMe2).
b
"C in a ratio of -3:l. We propose that the structure of W(O)(t-BuC=CMe,)(DIPP), is either a trigonal bipyramid with the oxo and vinyl ligands in the equatorial plane or a related square pyramid with the oxo ligand in the apical position. (The structure of W(C3Et3)(DIPP),is actually somewhere between TBP and SP.6) The vinyl ligand probably lies in the same plane as the W = O bond, perhaps primarily for steric rather than electronic reasons (see below), and the isomers therefore arise due to restricted rotation about the W-C bond (eq 2). W(O)(t-BuC= CMe2)(DIPP)3can be hydrolyzed with aqueous 1N KOH in 15 min to give t-BuHC=CMe2 in high yield along with free DIPPH (Table I).
W(C-t-Bu)(DIPP), reacts' with benzaldehyde, paraformaldehyde,ethyl formate, and N,iV-dimethylformamide to give analogous oxo vinyl species in high yield.8b The slowest reaction is with DMF. In fact, an adduct is first observedg which upon being heated in toluene to 50 "C overnight yields dark red prisms of the oxo vinyl product. Geometric isomers of the oxo vinyl product of the reaction with benzaldehyde are observed; hydrolysis yields a mixture consisting largely of the trans olefin product. The tungstenacyclobutadienecomplex W(C,Et&(DIPP), also reacts with acetone, benzaldehyde, ethyl formate, and DMF to give complexes of the type W(0)(vinyl)(DIPP)3. The rate of the reaction is limited in this case by the apparently required loss of 3-hexyne from the tungstenacyclobutadiene rings to give intermediate W(CEt)(DIPP), (k E 4 X lo4 s-l; tl,z E 30 min). For example, the reaction with 1 equiv of acetone requires -3 h to go to completion at 25 "C. The reaction between W(C,Et,)(DIPP), and paraformaldehyde fails at 25 "C, probably because the concentration of formaldehyde is too low to compete with 3-hexyne for incipient W(CEt)(DIPP),. Ten equivalents of ethyl formate are required for the reaction to be com(9) W(CCMe,)(DIPP),(DMF): 'H NMR (C&) 6 7.60 (s, 1, Me,NCHO), 7.16 (d, 6, Hm), 6.92 (t, 3, Hp), 4.09 (hept, 6, J = 6.8 Hz, CHMez), 1.55 (s, 3, MeAMeBNCHO), 1.43 (8, 3, MeAMeBNCHO), 1.36 (d, 36, J = 6.8 Hz, CHMe2), 1.00 (8, 9, CMe,); l3cNMR (CeD,) 6 292.4 (e, CJ, 168.7 (d, JCH 198 Hz, MezNCHO), 160 (br, 8, Cipao),138.2 (8, CJ, 123.0 (d, J c H = 155 Hz, Cm),121.3 (d, JCH = 160 Hz, C 1, 51.0 (s, CMe,), 36.6 (q, JCH = 140 Hz, MeMe'NCHO), 34.1 (q, CMe,), 31.5 (4, JCH = 140 Hz, MeMe'NCHO), 26.8 (d,JcH= 129 Hz, CHMeJ, 24.0 (eCHMe,); IR (Nujol) vc0 1650 cm-'.
Organometallics 1986,5,400-402
400
plete in -5 h, and the oxo vinyl complex is isolated in only poor yield (-40%) from pentane at -40 "C. The oxo vinyl complexes of the type W(O)(EtC=CRR')(DIPP), differ from those of the type W(O)(t-BuC=CRR')(DIPP), in that no rotational isomers are observed at 25 OC. Note also that in this case only one geometric isomer of the oxo vinyl product of the reaction with benzaldehyde is observed, and only the cis hydrolysis product is observed. Reactions of W(CR)(DIPP), (R = t-Bu or Et) with the carbonyl function are believed to involved nucleophilic attack on the Lewis acid activated carbonyl carbon atom by the alkylidyne carbon atom to give an oxytungstenacyclobutene intermediate which then rearranges to the oxo vinyl product (eq 3). The ring opening becomes stereoselective when R is not tert-butyl as a result of the larger of R1 or R2 being forced away from the crowded coordination sphere of the metal.
It is interesting to note that analogous reactions involving W(CR)(O-t-Bu), either are considerably slower'O or do not yield analogous oxo vinyl species at all.'l We also know that acetyl chloride reacts with W(C-t-Bu)(DIPP), to give an -85% yield of t-BuC-Me and what appears to be a mixture of W(O)(DIPP),Cl and a small amount of W(O)(DIPP),. Further experiments will be required in order to establish the scope, generality, and selectivity of Wittig-like reactions involving complexes of the type W(CR)(OR'),.
Acknowledgment. R.R.S. thanks the National Science Foundation for support (Grant CHE 84-02892). Registry No. W(C-t-Bu)(DIPP),, 91229-76-4; t-BuCSMe, 999-78-0;W(N)(DIPP),, 99594-92-0;t-BuCHZCN, 3302-16-7; W(O)(t-BuC=CH,W (0)(t-BuC-CMez)(DIPP),, 99594-93-1; (DIPP),, 99594-94-2; W(O)(t-BuC=CHPh)(DIF'P)3,99594-95-3; W(0) (t-BuC=CHOEt) (DIPP),, 99594-96-4; W (0)(t-BuC=CH(NMe,))(DIPP),, 99594-97-5;W(C3Et3)(DIPP),, 91229-77-5; W(O)(EtC=CMe,)(DIPP),, 99594-98-6;W(O)(EtC=CHPh)(DIPP),, 99594-99-7; W(O)(EtC=CHOEt)(DIPP),, 99595-00-3; W(0)(EtC=CH(NMe,)) (DIPP),, 99595-01-4. (10)W(C-t-Bu)(O-t-Bu), does not react readily with acetonitrile at 25 "C, although W(CEt)(O-t-Bu), will react with excess acetonitrile over a period of several minutes. (11) The reaction between W(C-t-Bu)(O-t-Bu), and acetone is sluggish. The reaction is complete after 16 h at 60 OC, but several products are observed.
A Hlgh-Resolution Solld-State I3C NMR Study of Fe( C,H,)( CO),CH,/Alumina Surface Chemistry Paul J. Toscano and Tobin J. Marks" Department of Chemistry, Northwestern University Evanston, Illinois 6020 1 Received September 17, 1985
Summary: 13CCPMAS NMR spectroscopy has been employed to characterize surface reaction pathways involving the complexes CpFe(CO),CH,, CpFe('3CO),CH,,
C P F ~ ( C O ) ~ ( ' ~ C(Cp H ~= ) q5-C5H,), and dehydroxylated (DA) or partially dehydroxylated (PDA) y-alumina. A number of possible reaction modes can be ruled out, and surface-induced migratory CO insertion to yield a carbene-like acyl complex is identified as the predominant if not exclusive pathway.
Elucidating the structure(s) of adsorbates arising from the chemisorption of organometallic molecules on high surface area metal oxides (e.g., y-alumina, si1ica)l is a challenging problem of considerable significance in catalysis.'v2 Proposed surface reaction pathways include protonolysis of hydrocarbyl ligands by surface OH groups,'J transfer of hydrocarbyl ligands to exposed Lewis acid sites,4 substitution of carbonyl or other ligands by surface oxide (02-) or OH g r ~ u p s , ~coordination ~,~,~ of carbonyl ligands by surface Lewis acid sites,lanucleophilic addition of surface 02-or OH groups to carbonyl ligands,'aC oxidative addition of OH groups to metal-metal bonds,'a,s and a host of others.' These reaction pathways and the structures of the resulting organometallic moleculesurface complexes have largely been inferred from the nature of products evolved during the chemisorption process and/or, with varying degrees of definition, from surface spectroscopies (principally vibrational, but also Mossbauer, XPS, EPR, etc.). In many cases, these structural assignments are qualitative in nature and could be greatly strengthened by additional information. In this communication, we illustrate the efficacy in such structural studies of high-resolution solid-state NMR spectroscopy, utilizing cross polarization (CP), high-power 'H decoupling, and magic-angle spinning by characterizing for the first time the reaction pathways of a transition-metal carbonyl alkyl complex (selected isotopomers of CpFe(C0)&H3, Cp = T ~ ~ - C with ~ H &y-alumina surfaces. This particular compound is of interest since it offers a multiplicity of potential surface transformations (vide supra), including surface-induced migratory CO insertion (A, inferred as a contributing pathway largely on (1) (a) Basset, J. M.; Chaplin, A. J. Mol. Catal. 1983, 21, 95 and references therein. (b) Yermakov, Yu. I. J.Mol. Catal. 1983,21,35 and references therein. (c) Iwamoto, M.; Kusano, H.; Kagawa, S. Inorg. Chem. 1983,22,3365and references therein. (d) Yermakov, Yu. I.; Kuznetsov, B. N.; Zakharov. V. A. "Catalysis by Supported Complexes"; Elsevier: Amsterdam, 1981. (e) Bailey, D. C.; Langer, S. H. Chem. Reu. 1981,81, 109. (0 Ballard, D. G. H. J . Polym. Sci., Polym. Chem. Ed. 1975, 13, 2191-2212. (2) (a) Firment, L. E. J . Catal. 1983, 82, 196-212 and references therein. (b) Gavens, P. D.; Bottrill, M.; Kelland, J. W.; McMeeking, J. In "Comprehensive Organometallic Chemistry"; Wilkinson, G., Stone, F. G. A,, Abel, E. W., Eds.; Pergamon Press: Oxford, 1982; Chapter 22.5. (c) Galli, P.; Luciani, L.; Checchini, G. Angew. Makromol. Chem. 1981, 94,63. (d) Karol, F. J.; Wu, C.; Reichle, W. T.; Maraschin, N. J. J. Catal. 1979, 60, 68. (3) He, M.-Y.; Xiong, G.; Toscano, P. J.; Burwell, R. L., Jr.; Marks, T. J. J . Am. Chem. SOC. 1985, 107,641-652. (4) Toscano, P. J.; Marks, T. J. J. Am. Chem. SOC. 1985,107,653-659. (5) (a) Bowman, R. G.; Burwell, R. L., Jr. J . Catal. 1980,63,463-475 and references therein. (b) Bowser, W. M.; Weinberg, W. H. J . Am. Chem. SOC.1981,103, 1453-1458. (6) Li, X.-J.; Gates, B. C.; KnBzinger, H.; Delgado, E. A. J. Catal. 1984, 88, 355-361 and references therein. (7) For authoritative reviews of the subject, see: (a) Fyfe, C. A. "Solid State NMR for Chemists"; CRC Press: Guelph, 1983. (b) Maciel, G . E. Science (Washington, D.C.) 1984, 26, 282-288. (c) Mehring, M. "Principles of High Resolution NMR in Solids"; Springer-Verlag: New York, 1983; Chapters 2 and 4. (d) Yannoni, C. S. Acc. Chem. Res. 1982, 15, 201-208. (8)For other recent applications of 13C CPMAS NMR to organometallic surface chemistry, see: (a) Hanson, B. E.; Wagner, G. W.; Davis, R. J.; Motell, E. Inorg. Chem. 1984,23,1635-1636 and references therein (Mo!CO)6/alumina). (b) Liu, D. K.; Wrighton, M. S.; McKay, D. R.; Maciel, G. E. Inorg. Chem. 1984,23,212-220 (silica "anchored" ruthenium carbonyls). (c) McKenna, W. P.; Eyring, E. M. J . Mol. Catal. 1985, 29, 363-369 (Mo,(C,H,),/silica and alumina). (d) Reference 4 (organoactinide alkyls on alumina).
0276-733318612305-0400$01.50/00 1986 American Chemical Society
