Organometallics 1986,5, 397-398
sharp even at -88 OC. Thus, the addition of a triply bridging carbonyl ligand to 10 greatly reduces the barrier to alkyne rotation on the face of the trinuclear core. When a m-xylene solution of 10 is heated under nitrogen for 36 h, followed by evaporation of the volatiles and chromatography of the residue, a pink, air-stable, crystalline solid 6 is isolated in 69% yield.9cJs The 'H NMR (acetone-de) spectrum has singlets at 6 4.56 (15 H, C5H5) and 0.82 [18 H, Si(CH,),], and the 13C(lHJNMR (THF-$, -60 "C) spectrum has a resonance at 6 363 assigned to the carbyne carbon1 Similarly, when 11 is heated in m-xylene at reflux for 36 h and the volatiles are evaporated, a 'H NMR (benzene-d,) spectrum of the residue indicates a 2:l ratio of 3 to 6 (35% isolated yield of 6). The reactions of 10 and 11 to give 6 are particularly interesting in light of a recent report that (q5-C5H5),M3(CO)(C2Ph2) [M = Rh, Ir] are converted to (q5C5H5)3M3(CPh)2with no evidence for an unsaturated Cp3M3(C2Ph2)specie^.^ On the basis of the experimental data and a theoretical analysis for the corresponding reaction of ( v ~ - C ~ H ~ ) ~ M ~ ( C ~an H ~unsaturated ) ( C O ) , alkyne intermediate, (q5-C5H5),M3(C2R2), was discounted. The proposed mechanism invoked an edge-bonded alkyne which underwent a carbonyl shift (k3 to terminal) concerted with alkyne cleavage. In order to rule out the intervention of an arene complex in facilitating the conversion of 10 to 6, the same reaction was carried out in methylcyclohexane, providing the product at the same rate. To provide proof for the intramolecularity of this transformation and to rule out reversible dissociation of q5-C5H5Cofrom 10, formation (V~-C~H,),CO~(PL-CR)~ and reassociation to furnish 6 (as suggested by a reviewer) a crossover experiment was performed. Thus, heating 10 in the presence of (q5CH3C5H4)2C02(btmsa)gcJg gave 6 and the unchanged labeled dinuclear cluster without any sign of crossover. In conclusion, we now have evidence for the sequential conversion of a mononuclear cobalt precursor 7 to mononuclear 8, dinuclear 9, and trinuclear alkyne 10 complexes, with ultimate formation of a trinuclear bis(carbyne), 6. The entire process represents the first well-characterized case of alkyne-mediated assembly of a trinuclear bis(carbyne). In addition, we have demonstrated that the presence of an additional ligand in trinuclear cyclopentadienylcobalt is not a requirement for alkyne scission.
Acknowledgment. The crystal structure analysis was carried out by Dr. F. J. Hollander, staff crystallographer at the U.C. Berkeley, Department of Chemistry X-ray facility (CHEXRAY). This work was supported by NSFCHE 8504987. K. Peter C. Vollhardt is a Miller Professor in Residence (1985-1986).
Supplementary Material Available: A listing of positional and thermal parameters and tables of bond lengths, bond angles, a n d structure factors of 9 (22 pages). Ordering information is given on a n y current masthead page.
(19)Made in a manner analogous to 9 via (qS-CH3C&4)Co(C2H4)2 ['H NMR (benzene-d,) 6 4.56 (dd, J = 1.9,1.8Hz, 2 H), 4.11 (dd, J = 1.8,1.6 Hz, 2 H), 2.42,0.79 (AA'BB', 8 H), 1.26 ( 8 , 3 H); I3C NMR (benzene-d ) 6 96.40,86.13,84.56,39.21,11.881 by treatment with btmsa to give (qgCH3C5H1)2C02(btmsa) ['H NMR (THF-ds) 6 4.58 (dd, J = 1.9,1.8 Hz, 4 H), 3.89 (dd, J = 1.8,1.7 Hz, 4 H), 1.84 (s, 6 H), 0.27 ( 8 , 18 H)].
0276-7333/86/2305-0397$01.50/0
397
Metathesis-Like Reaction of a Tungsten Alkyildyne Complex with Cyclohexyl Isocyanate' Karin Weiss, Uirich Schubert,$and Rlchard R. Schrockg Laboratorium fur Anorganische Chemie der Universitat Bayreuth, Postfach 3008 8580 Bayreuth, West Germany, Institut fur Anorganische Chemie der Universitat Wiirzburg, Am Hubland 8700 Wurzburg, West Germany, and Department of Chemistty, Room 6-331 Massachusetts Institute of Technology Cambridge, Massachusetts 02 139 Received August 5, 1985
Summary: The reaction between W(C-t-Bu)( 1,2dimethoxyethane)Cl, and cyclohexyl isocyanate is proposed to yield an intermediate containing a cyclohexylimido and a ketenyl ligand. A second cyclohexyl isocyanate then inserts into the tungsten-carbon single bond of the ketenyl ligand to form an oxazetin tungstenacycle. Crystals of the final product are monoclinic with a = 9.311 (9) A, b = 16.60 (2) A, c = 14.91 (I) A, p = 100.26 (7)O, v = 2268.1 A3, space group P2,lc, Z = 4, and d(calcd) = 1.79 g/cm3.
Reactions between carbyne or alkylidyne complexes and organic compounds containing a double bond are rare. Two examples are addition reactions of heterocumulenes like S022to carbyne complexes prepared by Roper and addition of COZ3to Fischer-type carbyne complexes. We report here a metathesis-like reaction between cyclohexyl ibocyanate and W(C-t-Bu)(dme)Cl, (dme = 1,2-dimethoxyethane). This reaction is one example of what is likely to be a class of reactions whose crucial feature is a metathesis-like or Wittig-like4 reaction of the alkylidyne ligand. Addition of 2 equiv of cyclohexyl isocyanate in dichloromethane at 0 OC to 224 mg of W(C-t-B~)(dme)Cl,~ yields a deep red reaction mixture from which red crystals can be obtained (260 mg, 85% yield) upon addition of pentane., An X-ray structural study7shows the product to be the molecule W(NCy)[N(Cy)C(O)C(CO)(t-Bu)]Cl, (1; Figure 1)containing three meridional chloride ligands, a cyclohexylimido ligand, and a bidentate, ketenyl-subUniversitat Bayreuth.
* Universitat Wurzburg.
*(1)Massachusetts Institute of Technology. Investigations of Polymerizations and Metathesis Reactions.
6. For Part 5 see: Weiss, K.;Krauss, H. L. J. Catal. 1984,88, 424. (2)Wright, A. H. Ph.D. Thesis, University of Auckland, 1983. Filippou, A. C.; Alt, H. G.; Thewalt, U. Angew. (3)Fischer, E. 0.; Chem. 1985,97,215;Angew. Chem. Int. Ed. Engl. 1985,24,203. (4)See: Freudenberger, J. H.; Schrock, R. R.; following paper in this issue. (5)Schrock, R. R.; Clark, D. N.; Sancho, J.; Wengrovius, J. H.; Rocklage, s. M.; Pedersen, s. F. Organometallics 1982,I , 1645. (6)Partial 13CNMR 6 184.8 and 183.5 (C=C=O and NC=O), 73.3 (=NCH), 61.4(-N-CH),50.5 (C=C=O). IR (cm-I): 2110 (vs, C=C==O), 1605 (m, NCO), 1620 (m, NCO). Mass spectrum parent ion observed in the region m / e 610 with appropriate isotopic pattern. (7) Crystals were grown from CDCls A total of 2577 independent reflections (2O 5 28 5 48O,Mo Ka radiation, Syntex P21 diffractometer) were used to solve the structure by the Patterson method (Syntex XTL). Empirical absorption, Lorentz, and polarization corrections were applied. Hydrogen positions were found by difference Fourier methods or were calculated according to ideal geometry. Full-matrix least-squares refinement with anisotropic thermal parameters for all non-hydrogen atoms (hydrogen parameters were not refined) led to R = 0.083and R, = 0.087 (l/w= u2), all structure factors included.
0 1986 A m e r i c a n C h e m i c a l Society
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
