Orga nome ta 1lics 1991, IO, 1671-1676
At 24 "C, in toluene as solvent, about 140 mol of CGHllC1 was produced per mole of platinum in 120 h. Under the same conditions, in the absence of the platinum complex, cyclohexene and HCl gave no significant reaction. Similar results were obtained by using Pt&14(CO)2 or cis-PtC12GO), as catalyst precursors. In order to ascertain the stereochemistry of the reaction, cyclohexene-1,3,3-d3was hydrochlorinated in the presence of cis-PtClz(CO)z. This reaction was run with a stoichiometric amount of the platinum complex in order to increase the rate and thus minimize deuterium scrambling over long times. At room temperature, all the olefin had substantially reacted; the solution contained the products shown in eq 4. It is worth noting that these results again differ considerably from those obtained in glacial acetic acid as solvent20bic in the hydrochlorination of the same deuterated substrate, the main difference being that no anti product 3 was observed in the platinum-catalyzed reaction. The prevailing for-
/-& 3
mation of the syn adduct suggests that addition of the HC1 components occurs on the same side of the carbon-carbon double bond coordinated to platinum. Platinum-catalyzed hydrochlorination was also verified with l-decene, cis-2decene, trans-Bdecene, trans-5-decene, styrene, and norbornene. In all cases, an increase of the reaction rate was observed with platinum(I1): the increase was high (cy-
1671
clohexene, l-decene) or moderate (propylene, cis-Bdecene, trans-Zdecene, styrene, norbornene). For example, styrene and norbornene (Tables V and VI) undergo HCl addition without PtCl,(CO),, but the reaction is promoted by the metal complex. In the case of nonsymmetrical olefins, such as propylene, l-decene, and styrene, the product of hydrochlorination arising from the chlorine addition to the less-substituted carbon atom (Markovnikov rule) was found, namely, 2-chloropropane, 2-chlorodecane and 1(chlorophenyl)ethane,respectively, as if protonation of the unsaturated carbon atom, leading to the more stable carbocation, were the primary attack. In conclusion, this paper has shown that soluble platinum(I1) carbonyl derivatives are able to promote the hydrochlorination of several olefins. The reaction is regioselective in the case of terminal olefins giving the Markovnikov product. While the addition of HBr or HI to olefins are well known to occur at room temperature, HC1 usually requires higher temperatures% or the presence of a catalyst, generally a Lewis acid, such as AlC13 or FeC13.36*37
Acknowledgment. The authors wish to thank the NATO Collaborative Research Grants Programme for an award (Grant No. 0052/89), the Consiglio Nazionale delle Richerche (C.N,R.,Roma), Progetto Finalizzato di Chimica Fine 11and the Natural Sciences and Engineering Research Council of Canada for support of this research. (35) March, J. Advanced Organic Chemistry: Reactions, Mechanism and Structure, 3rd ed.; J. Wiley: New York, 1985. (36) Brouwer, L. G.; Wibaut, J. P. Rec. Trav. Chim. 1934,53, 1001. (37) Henne, A. L.; Kaye, S. J. Am. Chem. SOC.1950, 72, 3369.
Synthesis and Reactivity of (q5-C5H5)Os( N)(CH,SiMe,),, the First Cyclopentadienyl-Nitrido Transition-Metal Complex Robert W. Marshman, Jeanine M. Shusta, Scott R. Wilson, and Patricia A. Shapley' School of Chemical Sclences, University of Illinois, Urbana, Illinois 6 180 1 Received September 17, 1990
The first cyclopentadienyl-nitido complexes of a transition metal were prepared by the reactions between and either NaC5H5or LiC5MeS. The complexes (r15-CsH5)Os(N)(CHzSiMe~)z [ M u " ] [OS(N)C~~(CH#~M~B)~] and (qb-C5Me5)Os(N)(CHzSiMe3)2 were characterized by spectroscopictechniques and elemental analysis. They are soluble in organic solvents, volatile, and stable to air and water. The nitrogen atom in (q5C5H5)Os(N)(CH2SiMe3)2 is a "soft" Lewis base. It binds reversibly to BF, in solution, forming a 1:l adduct. With silver(1) salts, a 2:l adduct is formed. The silver-bridged complex ([(?5-C5H5)Os(CH,SiMe3)212(rNAgN))(BF4) was isolated in good yield from the reaction between (q5-C5H5)0s(N)(CH2SiMe3) and AgBF, and was structurally characterized. Crystal data for Os2AgSi4F4N2CzsBHare a = 15.348 (3) 1,b = 18.272 (3) 1\, c = 14.114 (2) A, 0 = 91.76 (l)', V = 3956 (2) if3,p = 1.817 g/cmy, I.L = 70.56 cm-*,space group = R 1 / c (C5,), and 2 = 4. Final agreement factors are R = 0.065 and R, = 0.078. The nitrido complex is displaced from silver by PPh3 but not by Me2NCH2CH2NMe2.Alkylation of the nitrogen atom in (q5C5H5)Os(N)(CH2SiMe3)2 and CH30S02CF3produced an alkylimido complex, [(v5-C5H5)Os(NMe)(CH2SiMe3)2] [OS02CF31.
Introduction Cyclopentadienylmetal compounds are known for all of the transition metals. The ligand is versatile and can coordinate through one carbon atom to form a simple u bond to the metal, through three carbon atoms to form an allyl-type metal complex (q3coordination), or with all five and atoms (" coordination)' The ceptor abilities of the ligand stabilize transition-metal complexes in low oxidation states. Complexes containing
=-"-
both carbonyl and cyclopentadienyl ligands have been studied for many years.' The cyclopentadienyl ligand is also compatible with metals in higher oxidation states. Many cyclopentadienyl (1) Collman, J. P.; Hegedus, L. S.; Norton, J. R.; Finke, R. G.B i n ciples and Applications of Orgumtransitionmetal Chemistry; University CA, 1987;Chapter 3.7 (see alsoreferencee Science Books: Mill
therein).
0276-7333/91/2310-l671$02.50/00 1991 American Chemical Society
Marshman et al.
1672 Organometallics, Vol. 10, No. 6, 1991 Scheme I f
N
Scheme I1 1
1
compounds containing oxo2+ and imido5ps ligands have recently been prepared. However, no examples of cyclopentadienyl compounds containing nitrido ligands have previously been reported. The terminal nitrido ligand and imido (NR2-)lig(N*) is isoelectronic with oxo (02-) ands. It is similar to oxo and imido groups in ita bonding to transition metals,' but differences have been observed in the reactivity of a series of oxo, imido, and nitrido complexes.* We present here the synthesis, characterization, and reaction chemistry of complexes of osmium(VI) that have both cyclopentadienyl and terminal nitrido ligands.
initially, a u cyclopentadienyl complex, [NBu",] [Os(N)Cl(t11-C5H5)R21 The reaction between sodium cyclopentadienide and [NBu",] [ O S ( N ) C ~ ~ ( C H ~ Sin ~M diglyme ~ ~ ) ~ ]is slow, requiring 5 h at 80 "C. Both chloride ligands are displaced and a s5-cyclopentadienylcomplex of osmium, (t5-CsH5)The osmium cycloO S ( N ) ( C H ~ S ~ (l), M ~is~ produced. )~ pentadienyl complex can be isolated as a yellow crystalline solid in 34% yield after purification by chromatography Results and Discussion on silica gel. It can also be readily purified by sublimation. Synthesis of ( T ~ ~ - C ~ H ~ ) O ~ ( N )and ( C (v5H ~ S ~ MComplex ~ ~ ) ~1 is very soluble in hydrocarbon solvents and has C5Me5)Os(N)(CH2SiMe3)2. We have previously shown a low melting point, 48-49 "C. The reaction between that the chloride ligands in the osmium complexes [NBu",] [ O S ( N ) C ~ ~ ( C H ~ S and ~ M ~lithium ~ ) ~ ] penta[NBun4][Os(N)C12&](R = Me, CHaiMed can be replaced methylcyclopentadienide in tetrahydrofuran produces the by a variety of other monodentate and bidentate ligand^.^ analogous osmium pentamethylcyclopentadienyl complex Although the complexes [NBu",] [Os(N)X2R2]are coor(.r15-C5Me5)0s(N)(CH2SiMe3)2 (2) in 8% yield after 10 h dinatively unsaturated, they do not bind donor molecules at 80 "C. strongly in the sixth coordination position due to steric Both cyclopentadienyl complexes can be prepared in strain and the strong trans labilizing effect of the nitrido higher yield starting from O S ( N ) C I ( C H ~ S ~ MThe ~ ~ )re~. group. The anionic cyclopentadienyl group should also action between AgBF, and [NBu",] [ O S ( N ) C ~ ~ ( C H & ~ ~ M ~ ~ ) ~ ] substitute for a chloride at the osmium center to form, in diethyl ether cleanly produces OS(N)CI(CH,S~M~~)~ and AgC1. This neutral, four-coordinate complex of osmium(2) (a) Bottomley, F.; Darkwa, J.; Sutin, L.; White, P. S. Organo(VI) can be isolated as a yellow crystalline compound from metallics 1986,5,2165-2171. (b) van h l t , A.; Trimmer, M. S.;Henling, concentrated hexane solution, but it is very sensitive toL. M.; Bercaw,J. E. J. Am. Chem. SOC. 1988,110,8254-8265. (c) Alt, H. ward air and water. Solutions of O S ( N ) C ~ ( C H ~ S in ~M~~)~ G.; Hayen, H. I. J. Organomet. Chem. 1986,316,105-119. (d) Green, M. L. H.; Lynch, A. H.; Swan, M. G.J.Chem. Soc.,Dalton Trans. 1972,1445. diethyl ether, prepared in situ, react with sodium cyclo(e) Parkin, G.; Bercaw, J. E. J. Am. Chem. SOC.1989,111, 319-393. (0 pentadienide at room temperature to give 1 in 80% isoLegzdine, P.; Phillips, E. C.; Sbchez, L. Organometallics 1989, 8, lated yield. The pentamethylcyclopentadienylcomplex, 940-949. (g) Bokiy, N. G.; Gatilov, Yu. V.; Struchov, Yu. T.;Ustynyuk, N. A. J. Organomet. Chem. 1973, 54, 213-219. (h) Burkhardt, E. R.; 2, is produced in 35% isolated yield by reaction of OsDoney, J. J.; Bergman, R. G.;Heathcock, C. H. J . Am. Chem. SOC.1987, (N)C1(CH2SiMe3)2and LiC5Me5in tetrahydrofuran. 109,2022-2039. (i) Herrmann, W. A.; Herdtweck, E.; Flbl, M.; Kulpe, The cyclopentadienyl complexes are coordinatively J.; Klisthnrdt, U.; Okuda, J. Polyhedron 1987,6,1165-1182. (j) DeBoer, E. J. M.; DeWith, J.; Orpen, A. G. J. Am. Chem. SOC.1987, 109, saturated, 18-electron complexes. Complex 1 does not 68964898. react with carbon monoxide, ethylene, trimethylphosphine, (3) Legzdine, P.; Rettig, S. J.; Sbchez, L. Organometallics 1985, 4 , or triphenylphosphine. Both complexes 1 and 2 are 1470-1471. thermally stable and stable to air and water. (4) Hen", W. A.; Felixberger, J. K.; Anwander, R.; Herdtweck, E.; Kiprof, P.; Riede, J. Organometallics 1990, 9, 1434-1443. The cyclopentadienyl complexes 1 and 2 were charac(5) (a) Waleh, P. J.; Hollander, F. J.; Bergmann, R. G. J. Am. Chem. terized by IR, 'H, and 13C NMR spectroscopy and by elSOC.1988,110,8729-8731. (b) Wiberg, N.; HILring, H. W.; Schubert, U. emental analysis. A single resonance was observed for the Z. Naturforsch. 1980, B E , 5 M 3 . (c) Gambarotta,S.; Chiesi-Villa,A.; Guaetini, C. J . Organomet. Chem. 1984,270, C49452. (d) Osborne, J. cyclopentadienyl group in the 'H and 13C NMR spectra H.; Rheingold, A. L.; Trogler, A. L. J . Am. Chem. SOC.1985, 107, of 1, and there was no broadening of the cyclopentadienyl 7945-7952. (e) Mayer, J. M.; Curtis, C. J.; Bercaw, J. E. J. Am. Chem. resonances down to -80 "C. The 'H NMR of 1 showed a Soc. 19SS,105,2651-2860. (f)Meijboon, N.; Schaverien, C. J.; Orpen, A. G. Organometallics 1990,9,774-782. (g) Preuee, F.; Becker, H.; Wieland, singlet at 6 5.63 for the equivalent cyclopentadienyl proT. Z . Naturforsch. 1990,45E, 191-198. (h) Glueck, D. S.;Hollander, F. tons, two doublets at 6 2.08 and 0.85 for the diastereotopic J.; Bergmann, R. G. 1989, 111, 2719-2721. methylene protons on the (trimethylsily1)methyl ligands, (6) Herr", W. A.; Weicheelbaumer,G.; Paciello, R. A.; Fischer, R. A.; Herdtweck, E.; Okuda, J.; Marz, D. W. Organometallics 1990, 9, and a singlet at 6 0.16 corresponding to the equivalent 489-496. trimethylsilyl groups of the alkyl ligands. The same (7) N ent, W. A.; Mayer, J. M. Metal-Ligand Multiple Bonds; John pattern was seen in the spectrum of 2, with the pentaWiley &3one: New York, 1988; Chapter 2. (8)Marshman, R. W.; Shapley, P. A. J . Am. Chem. SOC.,in press. methylcyclopentadienyl protons at 6 1.47, the methylene (9) (a) Zhang, N.; Mann, C.; Shapley, P. A. J.Am. Chem. SOC.1988, protons at 6 0.99 and 0.86, and the trimethylsilyl protons 110, 66914692. (b) Zhang, N.; Wileon, S.R.; Shapley, P. A. Organoat 6 0.47. The a-carbon atoms of the (trimethylsily1)methyl metallics 1988, 7,1126-1131. (c) Zhang, N.; Shapley, P. A. Inorg. Chem. 1988,27,976-977. ligands showed an unusual upfield shift in the I3C spectra 9
Organometallics, Vol. 10,NO.6,1991 1673
Table I. Bond Lengths (A) in 4 (Labels Shown in Figure 1)
Scheme I11
G
I
R)O*.R
mN
+
A9BF4
bond
-
1
jHg)
d
R
4
Os1
1.60 (1) 2.13 (2) 1.85 (2) 1.88 (2) 1.85 (2) 1.83 (3) 1.39 (4) 1.41 (4) 1.47 (4) 2.18 (3) 2.47 (2) 1.40 (3) 1.40 (4) 2.00 (3)
Os2 1.61 (2) 2-11 (2) 1.87 (2) 1-90 (3) 1.88 (3) 1.84 (3) 1.42 (3) 1.41 (3) 1.38 (3) 2.22 (3) 2.43 (2)
bond
Os1 2.15 (1) O&b 2.13 (2) Cb-Sib 1.88 (2) Sib-clb 1.89 (3) Sib-CZb 1.87 (3) Sib43b 1.85 (2) CZ-CB 1.41 (3) C446 1.38 (4) OS-C, 2.26 (3) Os43 2.28 (2) 2.45 (3) Os-C, 1.29 (3) B-Fp 1.35 (4) B-F4
Ag-N
Os2 2.12 (2) 2.16 (2) 1.86 (2) 1.86 (2) 1.89 (2) 1.84 (2) 1.41 (3) 1.42 (3) 2.30 (2) 2.25 (2) 2.45 (2)
2.01 (3)
Table 11. Selected Bond Angles (de& in 4 (Labelr Shown in Figure 1) angle os1 os2 angle os1 os2 N-Oe-C:, 98.4 (8) 97.4 (8) Nl-OS-Cb 97.9 (8) 102.6 (7) An-N-Os 166.7 (10) 163 (1) N-Ae-N 175.8 (6) .. C-OsXb 87 (ij 84.6 (7) 0s-C.-Si 117 (1) 120.6 (9) Os-Ch-Si 115 (1) 115.4 (9) 112 (2) c1-C&3 110 (3) 103 (2) Cz-C3&!4 108 (2) 110 (2) c44&1 110 (2) c3 2u(r). Crystal data for 3b: space group P42/n; a = 25.486 (61, c = 9.747 (4) A; Z = 8; final RF = 0.034, R, = 0.030 for 3724 reflections with I > 2o(O.
Introduction The C2hydrocarbons hold a key position in t h e development of organometallic chemistry.' Much research has 'To whom inquiries concerning the X-ray crystallographicwork should be addressed. 0276-7333/91/2310-1676$02.50/0
been focused on the synthesis of complexes containing the so-called C2 hydrocarbon ligands such as acetylene, ethylene, vinyl, vinylidene, or acetylide.2 T h e synthesis (1) Muettertiea, E. L.;Stein, J. Chem. Reo. 1979, 79, 479.
0 1991 American Chemical Society
