Organometallics 1983,2, 565-566
stereoselective carbozincation of simple alkynes, e.g., 1octyne, with alkylzinc derivatives appears to be unprecedented. Delineation of itS scope and limitations is currently underway.
Acknowledgment. We thank the National Science Foundation and the donors of the Petroleum Research Fund, administered by the American Chemical Society, for support of this research. We also thank Larry D. Boardman of our laboratories for providing us with some 'H NMR spectral information. Registry No. 3, 51655-64-2; 4, 19150-21-1;5, 77161-69-4; 6, 84695-55-6; IzZrCp2,1298-41-5;BrzZrCpz, 1294-67-3;ClzZrCpz, 1291-32-3; EtaZn, 557-20-0; n-BuzZn,1119-90-0; MezZn, 544-97-8; I(Me)ZrCpz,63643-49-2;u-octyne, 629-05-0; ethylzinc chloride, 2633-75-2; 2-methyl-l-octene, 4588-18-5; 2-nonene, 2216-38-8; 5-decyne, 1942-46-7; 5-iodo-6-ethyl-5-decene, 84695-56-7; 2ethyl-1-octene, 51655-64-2; 1-octynylzinc chloride, 68113-72-4; l,l-dideuterio-2-methyl-l-octene, 84695-57-8; l-phenyl-2deuterioethyne, 3240-11-7; phenylethyne, 536-74-3.
Cyclooctatetraenyllanthanlde Complexes. 1. Alkyland Arylmonocyclooctatetraenyllutetlum Derivatives Andrea L. Wayda Bell Laboratories Murray Hill, New Jersey 07974 Received October 15, 1982
Summary: The class of monocyclooctatetrenyllanthanide complexes (CaH,)LnCI(THF), , previously known only for the early lanthanides (Ln = Ce, Pr, Nd, Sm), has been extended to include lanthanum and the late lanthanides erbium and lutetium. This synthetic extension provides an opportunity to systematically investigate the metathetical derivative chemistry of an inclusive homologous organolanthanide series. Such a study, aimed at the alkyl derivatization of (CaH,)LnCI(THF), has resulted in the isolation and characterization of (CaHa)Lu [CH,Si(CH,),] (THF), (1) and (CaHa)Lu [o-C6H,CH,N(CH,),] (THF) (2). Attempted derivatization of the analogous lanthanum and samarium complexes has failed to yield characterizable alkyl complexes.
Concomitant with the recent renewed interest in organolanthanide chemistry,' concerted effort has recently been directed toward the development of the synthesis and reaction chemistry of cyclopentadienyl derivatives of the lanthanide elements.2 In sharp contrast, little or no interest has been shown in the development of the chemistry of the monocyclooctatetraenyl complexes of the same ele m e n t ~ . ~This ~ ~ is surprising since these derivatives, (1) (a) Evans, W. J. "The Chemistry of the Metal-Carbon Bond"; Hartley, F. R., Patai, S., Eds.; Wiley-Interscience: New York, 1982; Chapter 12. (b) Marks, T. J. Prog. Znorg. Chem. 1978,24, 51. (2) (a) Wayda, A. L.; Evans, W. J. Inorg. Chem. 1980,19,2190. Tilley, T. D.;Andersen, R. A. Ibid. 1981,20, 3267. Watson, P. L.; Whitney, J. F.; Harlow, R. L. Zbid. 1981,20,3271. (b)John, J. N.; Tsutsui, M. Ibid. 1981,20,1602. Tsutsui, M.; Chen, Li-Ban; Bergbreiter, D. E.; Miyamoto, T. K. J. Am. Chem. SOC.1982,104,855. (c) Lappert, M. F.; Singh, A.; Atwood, J. L.; Hunter, W. E. J. Chem. SOC.,Chem. Commun. 1981,1190. (3) Mares, F.; Hodgson, K. 0.;Streitwieser, A., Jr. J. Organomet. Mares, F.; Starks, D. F.; StreitChem. 1971,223, C24. Hodgson, K.0.; wieser, A., Jr. J. Am. Chem. SOC.1973, 95, 8650. (4) Only one derivative of these complexes, (C&18)Ln(C6H6)(THF) has been reported. See: Jamerson, J. D.; Masino, A. P.; Takats, J. J.Organomet. Chem. 1974, 65, C33.
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(C$Is)LnCl(THF),, previously described only for the early lanthanides (Ln = Ce, Pr, Nd, Sm),3should readily lend themselves to facile metathetical derivatization. Furthermore, the extension of this homologous series to include the late lanthanides would provide only the second complete series of precursor organolanthanide c~mplexes.~ The existence of such homologous series is critically important to a systematic study of the derivative chemistry of organolanthanidecomplexes. In particular, only through such studies can important observations relating the reactivity of organolanthanide complexes (and their derivatives) to their position in the lanthanide series be made. "Reactivity tailoring" or "fine tuning" of the relevant chemistry of these complexes should directly accrue from such fundamental studies. Therefore, we have investigated the extension of the known (C8H8)LnC1(THF),derivatives to include lanthanum and the later lanthanides erbium and lutetium. As noted, the completion of this homologous series provides an opportunity to systematically investigate the metathetical derivative chemistry of an organolanthanide compound class. In this regard, as an initial and obvious synthetic goal, we have addressed the synthesis and characterization of cyclooctatetraenyllanthanide alkyl complexes. The synthesis of such derivatives should allow a rich reaction chemistry to be explored. (cf. the use of bis(cyclopentadieny1)lanthanide alkyls as precursors to heteroleptic alkynides,6 hydrides,I carbon monoxide insertion products: and Ziegler-Natta polymerization cata l y s t ~ ~ )We . therefore also report at this time the synthesis and characterization of the first cyclooctatetraenyllanthanide alkyl and aryl derivatives (C8H&U[CH2Si(CH,),](THF), (1) and (C8H8)Lu[o-CGH,CH2N(CHJ,I(THF) (2). The new (C8H8)LnC1(THF),complexes are synthesized by using the methodology of Streitwieser et al. with minor m~dification.~ Slow ambient-temperature addition of a freshly prepared THF solution of K2(C8H8)to an equimolar amount of LnC1, suspended in THF yields, after a reaction time of 24 h, characteristically colored slurries (pink for erbium, off-white for lutetium, and pale yellow for lanthanum). The crude products are isolated and initially purified by removal of solvent in vacuo followed by THF extraction to remove soluble by-products (such as K[Ln(C8H8)2]).3Final purification is achieved by Soxhlet extraction of the residue with THF for 24 h. Vacuum filtration of the Soxhlet receiver solution allows the isolation of pure, microcrystalline (C8H8)LnC1(THF),in 50% (Er, Lu) to 80% yield (La). These extremely air- and moisture-sensitive materials are only marginally soluble in THF. They are characterized by X-ray fluorescence (Ln and C1 present in 1:l ratios; no K), infrared [bands are observed that are assignable to coordinated THF (1020 cm-l)loand C8HC2(890, 700 cm")"], and 'H NMR [THF-d8,La, 6 6.18 (s), Lu, 6 6.33 (s)] spectroscopy and complexometric metal and N
(5) The first well-characterizedinclusive homologous precursor series was recently reported by Lappert and co-workers. See ref 2c. (6) Evans, W. J.; Wayda, A. L. J. Organomet. Chem. 1980, 202, C6. Atwood, J. L.; Hunter, W. E.; Wayda, A. L.; Evans, W. J. Inorg. Chem. 1981,20, 4115. (7) Evans, W. J.; Meadows, J. H.; Wayda, A. L.; Hunter, W. E.; Atwood, J. L. J. Am. Chem. SOC.1982, 104, 2008, 2015. Schumann, H.; Genthe, W. J. Organomet. Chem. 1981,213, C7. (8) Evans, W. J.; Wayda, A. L.; Hunter, W. E.; Atwood, J. L. J. Chem. SOC.,Chem. Commun. 1981, 706. (9) Watson, P.L. J. A m . Chem. SOC.1982, 104, 337. (10) Clark, R.J. H.; Lewis, J.; Machin, D. J.; Nyholm, R. S. J. Chem. SOC.1963, 379. (11) Fritz, H. P.; Keller, H. 2.Naturforsch., B: Anorg. Chem., Org. Chem., Biochem., Biophys. 1961,16B, 231.
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Organometallics 1983,2, 566-569
complete elemental analysis.12 As analyzed the lanthanum derivative contains two molecules of THF while the erbium and lutetium derivatives contain one molecule of THF. The complexes are not sufficiently soluble in THF for 13C NMR spectroscopy or isopiestic molecular weight measurement. Attempted alkyl derivatization of the (C&-Ia)LnC1(THF), series has been initially confined to Ln = La, Sm, and Lu due to the ease of characterization of these complexes and their reaction products by 'H and 13CNMR spectroscopy. Accordingly, we have synthesized the first cyclooctatetraenyllanthanide alkyl and aryl complexes (CaHa)Lu[CH,Si(CH,),] (THF)2 (1) and (CaHa)Lu[o-CeH4CH2N(CH,),](THF) (2) by reaction of (CaH&LUCl(THF)and the appropriate lithium reagent.', The reactions are conducted in THF at -78 "C, and the reaction mixture is then allowed to slowly warm to ambient temperature with stirring. Solvent is removed in vacuo, and the resulting oils are triturated with pentane or hexane to yield offwhitelbeige powders. After the mixture was washed with additional alkane solvent, the powders are extracted with toluene, and the solvent is removed in vacuo to yield spectroscopically pure 1 and 2 in 5 0 4 5 % yield (eq 1). (C8H8)LuCl(THF)+ LiR
-78
"c
y
-+ workup
(C8Ha)LuR(THF), LiCl (1) R = CH2Si(CH3),,x = 2; R = o-C,H,CH,N(CH,),, x = 1 1 is marginally stable in toluene at ambient temperature
and cannot be readily crystallized. However, it can be satisfactorily characterized by infrared (bands characteristic of CH2Si(CH3),14at 1240, 1230, 1225, and 855 cm-', coordinated THF at 1015 cm-', and CaH8'- at 890 and 705 cm-' are observed) and 'H NMR spectro~copy'~ [benzene-de, 6 6.69 (s, cH8), 3.31 (m, a-THF), 1.18 (m, P-THF), 0.45 (s, CH,Si(CH,),), -1.72 (s, CH,Si(CH,),)], complexometric metal analysis [ % Lu(ca1cd) 32.10; % Lu (found) 33.161, and X-ray fluorescence (Lu and Si; no Cl). The marginal stability of 1 precludes complete elemental analysis. Compound 2 is more stable than 1 presumably due to the stability conferred by chelation of the integral Lewis base, -N(CHJ2. Unlike 1, it can be purified further by crystallization from a mixture of toluene and hexane maintained at -30 "C. Unfortunately, X-ray quality crystals have not yet been obtained. However, satisfactory characterization of the complex is provided by infrared [bands characteristic of C6H4CH2N(CH3)2'4 (1420, 1380, 1360,1305,1235,1170,1095,1040,1010,990,940,855,750 cm-'), and C8H2- (890, 700 cm-') are observed] and 'H NMR spectro~copy'~[benzene-d,, 6 8.15, 7.01 (m, C&4CH2N(CH,)2), 6.71 (s, c$is), 3.01, 1.00 (m, a- and 1.82 (s, P-THF, respectively), 2.79 (s, C6H4CH2N(CH3),),
C6H4CH2N(CH3)2], X-ray fluorescence (Lu; no Cl), and complete elemental analysis. (Anal. Calcd for LuC21HmNO: Lu, 36.04; C, 51.96; H, 5.81; N, 2.88; 0,3.29. Found: Lu, 36.45; C, 51.62; H, 5.68; N, 2.78; 0, 3.47 (by difference)). Unfortunately, analogous alkyl and aryl derivatives cannot be isolated for La and Sm. When R = CH2Si(CH,),, no characterizable product can be obtained for Sm. For La, only the THF-soluble [(C8Ha),La][Li(THF),] can be isolated (identified by infrared and 'H NMR spectroscopy and complexometric metal analysis),'6 suggesting that the desired alkyl or alkyl intermediate has formed but is unstable with respect to ligand redistribution. In this context, it should be noted that [ ( C B H ~ ) ~[Li(THF),]17 LU] is an isolated byproduct in the synthesis of 1, indicating that, even at the end of the lanthanide series, ligand redistribution is a concern when R = CH2Si(CH3),. When R = CeH4CH2N(CH3),,no characterizable product is obtained for either La or Sm. Despite these synthetic difficulties, this work clearly demonstrates that (1) an easily prepared homologous monocyclooctatetraenyl-based organolanthanide series exists and is available for systematic study and derivatization and (2) alkyl- and arylmonocyclooctatetraenyllutetium derivatives can be synthesized and characterized. Studies aimed at broadening the scope and number of these derivative complexes along with an investigation of their reaction chemistry are currently being conducted.
Acknowledgment. X-ray fluorescence analyses were performed by S. M. Vincent. 200-MHz 'H NMR spectra were obtained by L. W. Jelinski and J. J. Dumais. We also acknowledge E. A. Chandross and F. Wudl for critical comments. Registry No. 1, 84582-80-9;2, 84582-81-0. (16)IR (Nujol mull, cm-'): 1045 (THF coordinated to lithium), 895, 695 (CeHl-). H NMR (THF-ds): 6.5.75(?). (17)IR (Nujol mull, cm-') identical with that of [Li(THF),][La(CeH&]. 'H NMR (THF-de) 6 5.62 ( 8 ) .
Surface and Catalytlc Chemlstry of Organoactinldes. Evldence for Surface-Stablllzed Alkylldenes Mlng-Yuan He, Robert L. Burwell, Jr.," and Tobln J. Marks" Department of Chemistry, Northwestern University Evanston, Illinois 6020 1 Received October 4. 1982
Summary: The reaction of M [$-(CH,),C,] 2(CH3)2 and M [v5-(CH3),C5] ,(CD3), compounds, M = Th and U, with partially dehydroxylated and nearly completely dehydroxylated alumina yields methane via protolysis by surface OH, ring H atom abstraction, and elimination within the M(CH,), groups. The latter pathway is proposed on the basis of chemical evidence to result in alumina-stabilized actinide alkylidenes.
(12)Anal. Calcd for LaC&,C102: La, 32.86;c, 45.46;H, 5.72;c1, 8.38;0,7.56. Found La, 33.20;C, 45.17;H, 5.48;C1, 7.80;0,8.35 (by difference). Anal. Calcd for ErCI2H&10: Er, 44.13;C, 38.03;H, 4.25; C1,9.35;0,4.22.Found Er, 44.40;C, 37.78;H, 4.13;C1,9.20; 0,4.49(by difference). Anal. Calcd for LuC12H1&10: Lu, 45.25. Found: Lu, 45.61 (complexometric);Lu:Cl ratio = 1.01. Complete elemental analyses and determination of Lu:Cl ratio were performed by Analytische Laboratorien, Engelskirchen, West Germany. (13)LiCH2Si(CH8),is prepared using the method described by Lewis We have previously shown that bis(pentamethylcycl01970,92,4664). and Brown (Lewis, H. L.; Brown, T. L. J. Am. Chem. SOC. pentadieny1)thorium and bis(pentamethylcycl0L ~ [ o - C ~ H ~ C H ~ N (isCprepared H ~ ) ~ ] by following the procedure described by Cope and Gourley (Cope, A. C.; Gourley, R. N. J . Organomet. Chem. pentadieny1)uranium dialkyls, when supported upon high 1967,8,527). surface area metal oxides such as y-alumina, are precursors (14)Band assignments are made by comparison with the infrared spectra of the lithium salta LiCH2Si(CH3)3and L ~ [ O - C ~ H & H ~ N ( C H ~ ) ~for ] . highly active olefin hydrogenation and polymerization catalysts.' In an effort better to delineate the nature of (15)Integrated ratios are as expected.
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0 1983 American Chemical Society
