Organometallics 1996,14, 162-169
162
Unexpected Synthesis of Ortho-Substituted Diselenophenylenezirconocenes from the Para-SubstitutedDiphenylzirconocenes. Chemical and Structural Evidence of the Participation of a Cyclometalated Intermediate That Behaves as a Benzyne Zirconocene Equivalent Corinne Legrand,? Philippe Meunier,**tJeffrey L. Petersen,*’$Pascale Tavares,? Jacques Bodiguel,? Bernard Gautheron,? and Gabriel Dousses Laboratoire de Synthlse et ZElectrosynthbse Organomktalliques (URA CNRS 1685), Universitk de Bourgogne, 6 boulevard Gabriel, BP 138,21004 Dcon Cedex, France, Department of Chemistry, West Virginia University, Morgantown, West Virginia, 26506-6045, and Laboratoire de Chimie des Organominkraux (URACNRS 477), Universitk Paul Sabatier, 118, route de Narbonne, 31062 Toulouse Cedex, France Received July 12, 1994@ Heating grey selenium with [v5-C5H4(t-Bu)lzZr(CsHq@-OCH3))2in boiling octane affords the diselenophenylenezirconocene complex containing a methoxy group in the ortho position. A similar reaction, although less selective, occurs when starting from [v5-C5H4(t-Bu)12Zr(Cd&(p-CH3))2. The structures of the diselenophenylenezirconocenesobtained were confirmed by NMR spectroscopy and definitively proved by comparison with the authentic orthosubstituted derivatives prepared from the corresponding methyl-o-anisyl- and methyl-otolylzirconocene. The mechanism proposed to explain this transformation involves the activation of a tert-butyl C-H bond by a transient benzynezirconocene species. The cyclometalation product, which is obtained by heating the diphenylzirconocene, reacts toward selenium and unsaturated organic compounds like the benzynezirconocene but the reaction takes place at room temperature. The cyclometalation pathway allows a more sterically hindered selenium-containing derivative [q5-C5H4(t-Bu)l2ZrSe2C6H3(o,o’-(CH&) to be prepared. The new diselenophenylenezirconocenesdescribed are good precursors to generate benzodiselenagermoles and related spiro compounds by a zirconium-germanium transmetalation reaction. All the new products synthesized, zirconocene complexes and cyclometalated derivatives, benzodiselenagermoles, and spirobisbenzodiselenagermoles,were identified by the multinuclear NMR methods and mass spectrometry. The structure of the cyclometalated product [q5-C5H4(t-Bu)IZr[(2,5-(CH3)2CgH3)(1;1l: v5-CH2C(CH3)2C5H4)Iwas determined by X-ray diffraction analysis. This compound crystallizes in the monoclinic space group P21/c with two molecules per asymmetric unit with cell dimensions a = 8.278(3).$,b = 20.113(9) c = 27.661(9) .$, and /3 = 93.13(2)’ at 295 K. Least-squares refinement led to a value for the final R index of 0.0642 for 2701 reflections with I =- 2 4 1 ) .
A,
Introduction We have previously shown that chalcogens readily insert in the zirconium-carbon bonds of arynezirconocene c~mplexes.l-~ In this way, dichalcogenatozirconacyclic complexes are obtained in good yield by refluxing various diphenylzirconoceneswith chalcogens in heptane (Scheme 1). In the case of para-substituted diphenylzirconocenes, complexes 2 (in which the substituent is positioned meta and para relative to the two carbon atoms bonded to the chalcogens) are selectively obtained.
Scheme 1
X = S, Se
114 X,
I
R = H, CH,, OCH,, NMe,, Br (?.BuCp)lZr RJJ< X 2
Universit6 de Bourgogne. West Virginia University. Universit6 Paul Sabatier. Abstract published in Advance ACS Abstracts, November 1,1994. (1)Gautheron, B.;Tainturier, G.; Pouly, S.; ThBobald, F.; Vivier, H.; Laarif, A. Organometallics 1984 , 3, 1495. (2) Meunier, P.; Gautheron, B.; Mazouz, A. J. Organomet. Chem. 1987.320. C39. -. (3) Bodiguel, J.;Meunier, P.; Gautheron, B. Appl. Organomet. Chem. 1991, 5, 479. +
8 8
@
~~
Such compounds represent very useful reagents for the generation of various organic or organometallic specie^.^-^ For example, they are used as a source of the o-diselenophenyl moiety through reactions with
, - - - I
0276-733319512314-0162$09.0010
(4) Meunier, P.; Gautheron, B.; Mazouz, A. J . Chem. SOC.,Chem. Comm. 1986,424.
0 1995 American Chemical Society
Ortho-Substituted DiselenophenylenezirconoceneSynthesis monofunctional (acid and benzyl halides), bi- and tetrafunctional (metal halides) electrophiles, affording o-diselenium-containing benzenic compound~,~ bicyclic5 and spiro6g7 derivatives. Some selenium-containing crown ethers have also been prepared by this way.g When the reaction of elemental selenium with parasubstituted diphenylzirconocenesis performed in boiling octane, the reaction proceeds with the formation of the ortho-substituted diselenophenylenezirconocene in some cases. The mechanism of the thermal isomerization involves a cyclometalated derivative resulting from the C-H bond activation of a tert-butyl group. We have isolated one representative of such intermediates for which the X-ray structure has been established. From the reactivity point of view, these cyclometalated complexes behave as arynezirconocene species, as evidenced by their analogous insertion chemistry with nitriles, alkynes, and ketones.
Results and Discussion The products obtained by heating para-substituted diphenylzirconocenes 1 with grey selenium powder in refluxing octane are dependent on the substituents of the phenyl ring. When the substituent is a bromine atom or a dimethylamino group, decomposition is observed. When R is methyl, the reaction results in the formation of a mixture of complexes 2 and 3 (60/40).In the case where R is methoxy, complex 3 is the only observed product and the reaction proceeds with a satisfactory yield (60-65%).
2
R = CH, bl R = OCH,
a/
3
R = CH, bl R = OCH,
a/
As already observed for the meta-substituted derivatives,1,2 the mass spectra of compounds 3 show the molecular isotopic pattern in perfect accordance with theoretical prediction. The fragmentation initially involves the breaking of the zirconium-carbon bonds and is followed by loss of the metal atom and the subsequent fragmentation of the selenium-containing ring. The ortho- and meta-substituted complexes, 3 and 2, can be differentiated by lH and NMR.1° As expected, the position of the R group on the phenyl ring does not influence the chemical shifts of the cyclopentadienyl protons. The methyl protons of the R group in the ortho isomer, being closer to a selenium atom, are more deshielded than those of the corresponding meta isomer. The increment is about 0.13 ppm for the methoxy series and lies close to 0.60ppm for the methyl one. The phenyl protons are more sensitive to the sub( 5 ) Meunier, P.; Gautheron, B.; Mazouz, A. Phosphorus Sulfur Relat. Elem. 1987,33, 33. (6)Tavares, P Meunier, P.; Gautheron, B.; Dousse, G.; Lavayssiere, H.Phosphorus, Sulfur Silicon Relat. Elem. 1991,55, 249. (7) Tavares, P.; Meunier, P.; Kubicki, M. M.; Gautheron, B.; Dousse, G.; Lavayssiere, H.; SatgB, J. Heteroatom Chem. 1993,4 , 383. (8)Fagan, P. J.;Nugent, W. A.; Calabrese, J. C. J.Am. Chem. SOC. 1994,116,1880. (9) Mazouz, A.; Bodiguel, J.;Meunier, P.; Gautheron, B. Phosphorus, Sulfur Silicon Relat. Elem. 1991,61,247. (10)Granger, P.; Gautheron, B.; Tainturier, G.; Pouly, S. Org.Magn. Reson. 1984,22,701.
Organometallics, Vol. 14, No. 1, 1995 163 Scheme 2
bR Li
(t-BuCp),Zr /" +
a'
-->
dR=CH, b/ R = OCH,
(I-BuCp),Zr /"
0observed in (q5-C5Me5)Zr(q6-CgMe4CHz)(C&).17 Finally, within the bridging ethano group of 12 the C(ring)-C-C and C-C-Zr bond angles of 102.7(8) and 100.1(11)"deviate significantly from that normally expected for a sp3 carbon. The cyclometalation product 12 represents a useful precursor for the synthesis of crowded complexes containing two selenium atoms for which the corresponding diarylzirconocenes are not accessible for steric reasons (Scheme 9). The reaction of 12 with selenium proceeds in a good yield (83%), but the corresponding reaction for complex 11 affords a complex mixture. Moreover, the chemical intermediacy of 12 avoids the need to stabilize a benzynezirconocene with PMe3.l4 Spectroscopic data for 13 are in agreement with its high symmetry. The IH NMR displays the signal of the two homotopic phenyl protons near 7 ppm. In C6D6, the cyclopentadienyl protons appear as a singlet but this fortuitous equivalence is not observed in CDCls. As expected the tert-butyl and methyl groups resonate as two singlets a t 1.11 and 2.73 ppm, respectively. The 13C NMR spectrum of 13 is very comparable to that of 2 and fits well with the proposed structure. In addition, only one signal is viewed in NMR, the chemical shift of which (559.3 ppm) is close to that of the
molysis of (175-C5Me5)2Zr(CsH5)2. In this case the bifunctional (q6-C5Me4CH2)ligand is linked by a single C atom to the metal rather than by a two-carbon-atom bridge as observed in 12. As one might expect, the length of the hydrocarbon chain significantly affects the extent to which the methylene group of the metalated cyclopentadienyl ring is displaced from the mean plane defined by the internal carbons of the ring and the degree of canting of the cyclopentadienyl rings. The methylene group of (175-C5Me5)Zr(y6-C5Me4CH2)(CsH5) (21)Hunter, W. E.; Hmcir, D. C.; Vann Bynum, R.; Penttila, R. A.; is displaced by 0.89 A whereas the substituted methAtwood, J. L. Organometallics 1983,2,750. ylene group of 12 is displaced by only 0.48 A from the (22) Atwood, J. L.; Barker, G. IC;Holton, J.; Hunter, W. E.; Lappert, corresponding ring plane toward the Zr. The Cp(c)M. F.; Pearce, R. J.Am. Chem. SOC.1977, 99,6645.
Ortho-Substituted DiselenophenylenezirconoceneSynthesis unsubstituted congener 2c (562.9 ppm)l and those related to 3a (583.6and 546.0 ppm).
Conclusion We have proposed a mechanism for the thermal isomerization of a y2-arynezirconocenespecies based on the formation of a cyclometalation product resulting from the activation of a C-H bond of a tert-butyl group by the transient benzynezirconocene precursor. A crystallized representative has been isolated for the first time starting from the methyl(2,5-dimethylphenyl)ditert-butylzirconocene, and its molecular structure has been determined by X-ray diffraction. Like I, this cyclometalated product is very reactive a t room temperature toward grey selenium powder. Some complementary results concerning this reactivity will be reported in due time.
Experimental Section General Procedures. Reactions were carried out under an atmosphere of argon by means of conventional Schlenk techniques. Solvents (except benzene) were dried and deoxygenated before distillation from sodium benzophenone ketyl. Benzene and hexadeuteriobenzene were distilled from Na/K alloy. Acetonitrile was dried over anhydrous CaClz and distilled from PzO5. Acetone was dried over anhydrous CaClz and distilled from KzCO3. Di-tert-butylzirconocenedichloride was prepared according to l i t e r a t ~ r eChloromethyldi-tert.~~ butylzirconocene was prepared with the method Wailes used for the chloromethylzirconocene.24 Flash chromatographyzs was performed using silica gel Merck 9385. Melting points were measured on a Kofler beam without any correction. Elemental analysis were performed by the Service Central #Analyses du CNRS. Mass spectra (electronic ionization 70 eV) were recorded on a Kratos concept IS. 'H and 13CNMR spectra were recorded on a Bruker AC 200 (lH, 200 MHz; 13C,50.3 MHz) or a Bruker WM 400 apparatus (W, 100.4 MHz). The spectra were referenced t o TMS (external), 13C spectra being recorded using the JMOD technique. 77SeNMR drawings were obtained on a Bruker WM 400 (76.31 MHz) or Bruker WR 300 (57.24 MHz) spectrometer and referenced t o dimethylselenide (external). The following abbreviations were used: Cp-, C,,, Ctee, and Cquatfor the primary, secondary, tertiary, and quaternary carbon atoms, respectively. Preparation of 3a. A mixture of di(pto1yl)zirconocenel (0.59 g, 1.14 mmol) and grey selenium powder (0.19 g, 2.40 mmol) was heated with reflux for 17 h in octane (14 mL). The resulting brown mixture was then hot filtered. When cooled, the solution gave 0.29 g of brown crystals containing a mixture of the two isomers 3a and 2a (60/40) from which 3a has never been obtained in a pure state. The lH NMR of the meta isomer 2a had been previously published' at 100 MHz. More precise values (at 200 MHz) and 13C NMR data are reported here. 'H NMR, C6Ds: 7.86 (d, H8, J = 7.81 Hz), 7.83 (s, H5), 6.81 (dd, H7, J = 7.81, 1.95 Hz), 5.85 (pt, 4H, Cp), 5.73 (m, 4H, Cp), 2.07 (s, 3H, CH3), 1.13 (s, 18H, t-Bu). 13C NMR, CDC13: 145.9 (Cquat), 142.6 (Cquat),141.3 (Cquat, 2C), 135.4 (CteAr C6H3), 134.5 (Ctert, C6H3), 126.9 (ctert, C&3), 111.2 (Ckd, 4c, cp), 108.1 (Cbd, 4c, cp), 33.2 (CqUat,t-Bu), 31.8 (Cp-, t-Bu), 21.0 (Cpfim,CH3). NMR, CDC13: 567.9 (Se-l), 561.6 (Se-3). Spectroscopic data for 3a. Anal. Calcd for CzeH3zSezZr: C, 51.62; H, 5.54. Found: C, 51.43; H, 5.49. 'H NMR, C6D6: 7.88 (d, H8, J = 7.81 Hz), 7.02 (d, H6, J = 7.81 Hz), 6.97 (t, H7, J (23)Howie, R.A,; McQuillan, G. P.; Thompson, D. W.; Lock, G. A. J . Organonet. Chen. 1986,303,213. (24) Wailes, P. C.; Weigold, H.; Bell, A. P. J . Organonet. Chen. 1972,34,155. (25) Still, W. C.; Kahn, M.; Mitra, A. J. Org. Chem. 1978,43, 2923.
Organometallics, Vol. 14,No. 1, 1995 167 = 7.81 Hz), 5.79 (pt, 4H, Cp), 5.66 (m, 4H, Cp), 2.67 (s, 3H, CH3), 1.12 (8, 18H, t-Bu). 13CNMR, CDCl3: 148.4 (Cq,t), 147.4 (Cquat), 140.7 (Cquat, 2C), 132.5 (Ctert, C6H3), 126.1 (Ctert, C6H3), 125.7 (Chrt, C&), 111.3 (Ckrt, 4c, cp), 108.3 (Ccrt, 4C, Cp), 33.1 (Cquat,t-Bu), 31.9 (Cp-, t-Bu), 26.6 (Cp-, CH3). W e NMR, CDCls: 583.6 (Se-l), 546.0 (Se-3). Preparation of 3b. A mixture of di@-anisy1)zirconocene (0.75 g, 1.37 mmol) and grey selenium powder (0.22 g, 2.79 "01) in 16 mL of octane was heated with reflux for 17 h. The obtained dark-red solution was hot filtered and gave after cooling 0.42 g (0.70 mmol, 51% yield) of brown crystals. mp: 160 "C. Anal, Calcd for C~5H320SezZr: C, 50.24; H, 5.40. F o n d : C, 49.99; H, 5.24. 'H NMR, C6D6: 7.68 (d, H8, J = 7.81 Hz), 7.01 (t, H7, J = 7.81 Hz), 6.44 (d, H6, J = 7.81 Hz), 5.86 (pt, 4H, Cp), 5.76 (m, 4H, Cp), 3.41 (s, 3H, OCHs), 1.14 (9, 18H, t-Bu). 13C NMR, CDC13: 158.6 (Cquat, C6H3), 147.8 (Cquat, C6H3), 141.4 (Cquat, 2C, CP), 135.8 (Cquat, C6H3), 127.6 (Cw, CsH3), 126.6 (ctert, C6H3), 111.5 (ctert,2c, CP), 111.0 (Ctert, 2C, Cp), 108.2 (Ckfi, 2C, Cp), 107.9 (Ctert, 2C, Cp), 106.4 (Ctert, CsH3), 56.3 (Cpnm, OCH3), 33.1 (Cquat, t-BU), 31.8 (Cpnm, t-Bu). 77SeNMR, CsD6: 576.1 (Se-l), 574.6 (Se-3). Preparation of 4a. o-Tolyllithium was prepared by action of lithium metal on o-tolyl bromide in ether. The aryllithium (65 mL, 20 mmol) was added dropwise at 0 "C to a solution of 4.04 g (10 mmol) of di-tert-butylzirconocene dichloride in 100 mL of diethyl ether. The stirring was maintained for 1h at 0 "C and for 2 h more at room temperature. The solvent was then removed. The solid residue was extracted by 60 mL of hot octane, and the mixture was hot filtered. After cooling, 2.3 g of colorless crystals (5 mmol, 50% yield) were isolated. mp: 151 "C. Anal. Calcd for C25H33ClZr: C, 65.25; H, 7.23. Found: C, 65.01; H, 7.18. lH NMR, CsD6: 7.98 (m, lH, C6H4), 7.02 (m, 3H, C6H4), 6.31 (q,2H, Cp), 5.90 (q,2H, Cp), 5.76 (9, 2H, Cp), 5.44 (q,2H, Cp), 2.00 (8,3H, CH31, 1.19 (s, 18H, t-Bu). Preparation of 4b. 4b was prepared according to the same method used for 4a (77% yield). Anal. Calcd for C25H33ClOZr: C, 63.06; H, 6.98. Found: C, 62.84; H, 6.87. lH NMR, C6D6: 7.81 (m, 2H, C&), 7.00 (dd, lH, C&), 6.85 (dd, lH, CsH41, 6.40 (pq, 2H, CP), 5.94 (pt, 4% CP), 5.64 (pq, 2H, CP), 3.29 (s,3H, OCHs), 1.24 ( 6 , 18H, t-Bu). Preparation of Sa. To 3.53 g (7.68 mmol) of (t-BuCp)zZr(Cl)(o-C6H4CH3)in ether at 0 "C were added dropwise 3.3 mL (7.99 mmol) of an etheral solution of CH3Li. The stirring was maintained for 1 h at 0 "C and for 2 h more at room temperature. The solvent was then removed and the residual solid extracted by 60 mL of hot hexane. After filtration and cooling, 2.18 g (4.96 mmol, 64% yield) of white crystals was obtained. Anal. Calcd for C36H36Zr: c, 71.01; H, 8.25. Found: C, 71.21; H, 8.27. lH NMR, GDs: 7.02 (m, 4H, C6H4), 6.20 (pq, 2H, Cp), 5.84 (pq, 2H, Cp), 5.57 (pq, 2H, Cp), 5.35 (pq, 2H, Cp), 2.10 (5, 3H, CH3), 1.06 (9, 18H, t-Bu), 0.47 (s, 3H, CH3). Preparation of Sb. Sb was isolated as white crystals according to the same method used for Sa (62% yield). mp: 69-70 "C. Anal. Calcd for C26H360Zr: c, 68.52; H, 7.96. Found: C, 68.42; H, 7.90. 'H NMR, C6D6: 7.06 (m, 2H, C6H4), 6.91 (dd, l H , C6H4), 6.41 (dd, l H , CsH4), 6.27 (pq, 2H, Cp), 5.87 (pq, 2H, Cp), 5.75 (pq, 2H, CP), 5.52 (pq, 2H, Cp), 3.26 (s, 3H, OCH3), 1.12 (s, 18H, t-Bu). Preparation of 3a from Sa. A mixture of 0.68 g (1.55 "01) of ( ~ - B U C ~ ) Z Z ~ ( C H ~ ) ( O - and C ~ H0.25 ~ CgH(3.16 ~ ) mmol) of grey selenium in 40 mL of hexane was heated with reflux for 4 h. The hot filtered mixture led after cooling to 0.07 g (0.12 mmol, 8%yield) of red crystals identified to 3a by the usual spectroscopic methods. Preparation of 2 (R= H, X = Se) from I. A 0.27 g (0.66 mmol) sample of I was heated for 2 h with grey selenium powder (0.112 g, 1.42 mmol) in refluxing benzene (8 mL). The red reaction mixture was then filtered and the solvent was removed, leading t o a red-brown solid (quantitative yield) identified as 2 by the usual spectroscopic methods.2 Preparation of 6 from 3 (R= OCHs, R' = C&). A red solution of 0.44 g (0.74 mmol) of (t-BuCp)zZrSez(o-CsH3OCH3)
168 Organometallics, Vol. 14,No. 1, 1995 in 14 mL of THF was added dropwise at room temperature to a colorless solution of dichlorodiphenylgermane (0.22 g, 0.74 mmol) in THF (9 mL). After 15 h under stirring, the mixture had become yellow. The solvent was removed and the product extracted with a mixture of pentane and diethyl ether (l/l). After evaporation of the solvents, the residue was chromatographed on silica gel with pentadether (8/2). The solvents were then removed, and the product was obtained as a pale yellow crystalline solid (0.23 g, 0.47 mmol, 64% yield). mp: 148 "C. Anal. Calcd for C19H160SezGe: C, 46.49; H, 3.28. Found: C, 46.69; H,3.56. '€3 NMR, CsDs: 7.78 (m, 4H, CsHs), 7.44 (m, 6H, C.&), 7.16 (dd, H8, J = 7.86 and 1.22 Hz), 7.07 (t, H7, J = 7.86 Hz), 6.60 (dd, H6, J = 7.86, 1.22 Hz), 3.87 (s, 3H, OCH3). 77SeNMR, C&: 185.9 (Se-I), 140.4 (Se-3). Preparation of 7. To a solution of (t-BuCp)~ZrSe~(o-CsH3OCH3) (0.93 g, 1.56 mmol) in THF (43 mL) was added a solution of germanium tetrachloride (0.17 g, 0.78 mmol) in THF (17 mL). The mixture progressively discolored. After 3 h under stirring at room temperature, the solvent was removed under vacuum. The residual product was extracted by a mixture of pentane and diethyl ether (3/2). After evaporation of the solvents, the residue was chromatographed on silica gel with pentane/ether (3/2). The yellow fraction was collected, and the solvents were evaporated. The resulting solid was recrystallized from a mixture of methylene dichloridehexane (l/l). After cooling, 0.26 g (0.43 mmol, 56% yield) of yellow crystals was isolated. mp: 197 "C. Anal. Calcd for C14H12Ge02Sed: C, 27.99; H, 2.01. Found: C, 27.75; H, 1.89. 'H NMR, CDC13: 7.14 (dd, H8, J = 7.8, 1.3 Hz), 7.11 (t, H7, J = 7.8 Hz), 6.60 (dd, H6, J = 7.8, 1.3 Hz), 3.88 (s, 6H, OCH3). I3CNMR, CDC13: 157.9 (Cquat),156.2 (Cquat), 139.4 (Cquat), 126.9 (Ctert, C6H3), 121.0 (Ctert, C6H3), 107.4 (Ctert, C6H3), 56.5 (Cprim, OCH3). 77SeNMR, CsDs: 346.5 (Se-11, 296.6 (Se-3). Preparation of 8. (a) From I. To a yellow solution of 0.30 g (0.73 mmol) of I in benzene (12 mL) was added dropwise a solution of CH3CN (0.04 mL, 0.76 mmol) in benzene (4 mL). The stirring was maintained for 24 h at room temperature after what the solution had become orange. The solvent was then removed, leading t o an orange solid containing a little amount of nonreacted I1 (quantitative yield from I). (b) Direct Synthesis. Compound 8 can also be synthesized directly from the diphenyldi-tert-butylzirconocenel via the following way: a mixture of 0.60 g (1.23 mmol) of diphenylditert-butylzirconocene and 0.07 mL of CHsCN (1.33 mmol) in heptane (20 mL) was heated with reflux for 17 h. After this, the solution had turned from yellow to dark orange. The solvent was then removed, and the residue was recrystallized from heptane (15 mL), leading, after cooling, t o 0.42 g (0.93 mmol, 76% yield) of orange crystals. mp: 136-7 "C. Anal. Calcd for C26H33NZr: C, 69.27; H, 7.37. Found: C, 69.42; H, 7.37. 'H NMR, CsDs: 7.74 (dd, J = 6, 2.2 Hz, lH, CsH4), 7.40 (dd, J = 6.8, 1.7 Hz, lH, C&), 7.22 (m, 2H, C&), 5.93 (q, 2H, Cp), 5.62 (9, 2H, Cp), 5.55 (4, 2H, Cp), 5.41 (9, 2H, Cp), 1.61 (s,3H, CH3), 0.97 (s, 18H, t-Bu). l3C NMR, CsDs: 186.3 (Cquat), 172.4 (Cquat), 156.3 (CquaJ, 148.8 (Cquat), 140.8 (Ctertt, Cs&), 125.5 (ctert, C6H4), 123.9 (ctert,C6H4), 123.1 (Ctert, C6H4), 113.8 (Ctert, 2C, Cp), 109.8 (Ctert, 2C, Cp), 105.8 (Ctert, 2C, Cp), 101.1 (Ckrt, 2C, Cp), 32.7 (Cquat, t-Bu), 31.2 (Cprim, t-Bu), 24.1 (Cprim, CH3). Preparation of 9. (a) From I. To a yellow solution of 0.30 g (0.73 mmol) of I in benzene (12 mL) was added dropwise a solution of hex-3-yne (0.08 mL, 0.76 mmol) in benzene (4 mL). The stirring was maintained for 24 h at room temperature. The solution had then become orange. The solvent was removed and the residue was washed several times with pentane. The product was obtained as an orange solid (0.25 g, 0.51 mmol, 70% yield). (b)Direct Synthesis. A mixture of 0.35 g (0.72 mmol) of diphenyldi-tert-butylzirconoceneland 0.09 mL of hex-3-yne (0.79 mmol) in heptane (12 mL) was heated with reflux for 20 h. After this period, the solution had turned from yellow to dark orange. The solvent was then evaporated, leading to 0.36 g (0.72 mmol, 100%yield in crude product) of an orange solid.
Legrand et al. mp: 85-6 "C. lH NMR, CsD6: 7.28 (dd, lH, C6H4, J = 8,1.16 Hz), 7.15 (td, lH, CsH4, J = 7, 1.66 Hz), 6.96 (td, 1H, c6& J = 7, 1.16 Hz), 6.85 (dd, lH, C6H4, J = 7, 1.66 Hz), 6.39 (Pq, 1H, Cp), 6.11 (pq, lH, Cp), 5.87 (pq, 1H, Cp), 5.70 (pq, 1H, Cp), 2.46 (9, 2H, CH2, J = 7.5 Hz), 2.06 (9, 2H, CHz, J = 7.5 Hz), 1.23 (t, 3H, CH3, J = 7.5 Hz), 1.03 (8,18H, t-Bu), 1.02 (t, 3H, CH3, J = 7.4 Hz). NMR, CsDs: 196.5 (Cquat), 185.1 (Cquat), 146.6 (Cquat), 144.1 (Cquat), 141.3 (Cquat), 137.7 (Ctertt, CsH4), 126.3 (ctert,Cs&), 122.6 (ctert, CsH4), 121.8 (Ctert, CsH4), 111.5 (Ctert, 2C, Cp), 111.3 (Ctert, 2C, CP), 108.3 (Ctertt,4C, CP), 33.0 (Cquat, t-Bu), 31.5 (Cp-, t-Bu), 28.1 (Csec, CHd, 21.8 (Csec, CH2), 15.3 (Cprim, CH3), 13.9 (Cprim, CH3). Preparation of 10. (a) From I. To a yellow solution of 0.29 g (0.71 mmol) of I in benzene (15 mL) was added dropwise 0.08 mL (0.82 mmol) of CH3COCH3. After 5 h stirring at room temperature, the solution had discolored. The solvent was removed, and the residue was recrystallized from pentane. After cooling, 0.16 g (0.34 mmol, 48% yield) of pale yellow crystals was isolated (the yield was limited by the presence of diphenyldi-tert-butylzirconocenelwhich was not totally transformed into I). (b) Direct Synthesis. A mixture of 0.74 g (1.52 mmol) of diphenyldi-tert-butylzirconoceneand 0.12 mL of CH3COCH3 (1.63 mmol) in heptane (30 mL) was heated with reflux for 16 h. The solvent was then removed, and the residue was recrystallized from heptane. After cooling, 0.57 g (1.22 mmol, 80% yield) of pale yellow crystals was isolated. mp: 152-3 "C. Anal. Calcd for C27H3&rO: C, 69.32; H, 7.75. Found: C, 69.49; H, 7.70. Mass spectrum (main fragments): 451 (M+ - CH3,39), 409 (M+ - t-Bu, loo), 351 (M+- t-Bu-CH3COCH3, 20), 211 (t-BuCpZr+, 38). 'H NMR, C6D.5: 7.20 (m, 3H, C6H4), 6.85 (dd, lH, CsH4, J = 4.7, 2.2 Hz), 6.36 (pq, 2H, Cp), 6.08 (pq, 2H, Cp), 5.93 (pq, 2H, Cp), 5.35 (pq, 2H, CP), 1.55 (s, 6H, CH3), 1.17 (6, 18H, t-Bu). I3C NMR, C6Ds: 180.2 (Cquat), 170.3 (Cquat),142.7 (Cquat),139.2 (Ckrt, C6H4), 124.8 (Ctert, C6H4), 124.7 (Ce,rt,C a ) , 124.5 (Ctert, C a ) , 117.9 (Ctert, 2C, CP), 110.4 (Ctert, 2C, Cp), 110.0 (Ctert, 2'2, Cp), 103.8 (Ctert, 2C, CP), 87.5 (Cquat), 32.6 (Cquat, t-Bu), 32.1 (Cprim, CH3), 31.8 (Cprim, t-Bu). Preparation of 11. (a) (C&Xs)(C&)aLi.The aryllithium was prepared by action of 2-bromo-p-xylol(2.76g, 14.91 mmol) in ether (15 mL) on lithium metal (0.23 g, 32.81 mmol) in ether (30 mL). The stirring was maintained for a night and the mixture was then filtered leading to a yellow solution (which concentration was found t o be 0.255 mol-L-l, 77% yield). (b) (t-BuCp)zZr(CHs)[CsHs(CHs)zl.To a 0 "C cooled solution of chloromethyldi-tert-butylzirconocene(0.90 g, 2.35 "01) in ether (20 mL) was added dropwise 10 mL of the above aryllithium solution (2.55 mmol). The stirring was maintained for 2 h at 0 "C and for 30 min at room temperature. The solvent was then removed. The residue was extracted with 20 mL of hexane, and the mixture was filtered. After cooling, 0.30 g (0.66 mmol) of yellow crystals was isolated (28% yield). mp: 90 "C. 'H NMR, C&: 6.99 (d, lH, C6H3, J = 6.6 Hz), 6.86 (d, lH, CsH3, J = 6.6 Hz), 6.78 (s, lH, CsHs), 6.19 (pq, 2H, Cp), 5.88 (pq, 2H, Cp), 5.55 (pq, 2H, Cp), 5.34 (pq, 2H, Cp), 2.18 (s,3H, CH3), 2.12 (s, 3H, CH31, 1.05 (s,18H, t-Bu), 0.51 (8,3H, CH3). NMR, C6Ds: 142.3 (Cquat), 140.0 (Cquat), 133.0 (C,,t), 132.9 (cquat), 128.5 (ctert, CsH3), 127.0 (ctert, C6H3), 124.9 (Ctert, C&), 111.3 (ctert,2c, CP), 110.9 (Ctert, 2c, CP), 106.3 (Ctert, 2C, Cp), 103.2 (Ctert, 2C, Cp), 33.2 (Cquat, t-Bu), 31.3 (Cprim, t-Bu), 28.7 (Cprim, CH3), 25.2 (Cprim, CHd, 21.8 (Cprim, CH3). Preparation of 12. A solution of (t-BuCp)zZr(CH3)[CsH3(CH&] (1.58 g, 3.49 mmol) in benzene (25 mL) was heated with reflux for 2.5 h. ARer removal of the solvent, the residual solid was recrystallized from pentane, leading to pale yellow crystals suitable for X-ray analysis. mp: 94-5 "C. Anal. Calcd for c26H3&: C, 71.33; H, 7.83. Found C, 71.22; H, 7.89. 'H NMR, CsDs: 7.01 (d, lH, CsH3, J = 7.5 Hz), 6.85 (d, lH, CsH3, J 7.5 Hz), 6.42 (s,l H , C6H3), 6.29 (q,2H, Cp),6.16 (9, 1H, Cp), 5.64 (q, lH, Cp), 5.27 (9, 1H, Cp), 5.15 (4, 1H, Cp), 5.08 (9, lH, Cp), 5.03 (9, lH, Cp), 2.16 (8,3H, CHd, 2.14 (s, 3H, CH3), 1.49 (s, 3H, CHz), 1.23 (s, 3H, CH3), 0.99 (s, 9H,
Organometallics, Vol. 14, No. 1, 1995 169
Ortho-Substituted DiselenophenylenezirconoceneSynthesis Table 3. Structure Determination Summary empirical formula color, habit crystal size (mm) crystal system space group unit cell dimens volume Z
formula wt density (calc) absorption coeff F(0W diffractometer used radiation temp (K) monochromator 26' range scan type scan speed scan range (w) background measurement std reflcns index ranges reflcns collected independentreflcns observed reflcns absorptn correction min/max transmission
Crystal Data C26H3& pale yellow, rectangular 0.080 x 0.120 x 0.230 monoclinic P21lc a = 8.278(3) A, b = 20.113(9) A, c = 27.661(9) A, = 93.13 (2)" 4599(2) A3 8 437.8 1.264 g/cm3 4.85 cm-I 1840 Data Collection Siemens P4 Mo K a (1= 0.710 73 A) 295 highly oriented graphite crystal 3.0-45.0" w
fixed, 5.00"/min in w f0.55" stationary crystal and stationary counter at beginning and end of scan, each for 0.5% of total scan time 3 measured every 200 reflections 0 5 h 5 8 , 0 5 k 5 21, -29 5 I 2 9 6470 5989 (Rrm = 1.64%) 2701 ( F > 4.0a(F)) face-indexed numerical 0.9450/0.9673
Solution and Refinement Siemens SHELXTL PLUS (PC Version) system used solution direct methods refinement method full-matrix least squares quantity minimized M F 0 - Fd2 riding model, fixed isotropic U hydrogen atoms w-' = a2(F) 0.0008P weighting scheme no. of params refined 487 R = 6.42%, R , = 5.90% fmal R indices (obs data) R = 15.92%,R, = 8.12% R indices (all data) goodness of fit 1.10 0.002, O.Oo0 largest and mean A/a data-to-parameterratio 5.5: 1 largest difference peak 0.52 eA-3 largest difference hole -0.46 eA-3
+
t-Bu), 0.30 (d, lH, CH2, J = 11.3 Hz), -1.22 (d, lH, CHz, J = 11.3 Hz). I3C NMR, C6D6: 187.1 (Cquat, C6H3), 142.4 (Cquat), 140.0 (Cquat),132.9 (CqUt),a CqUtwas not observed, 127.1 (CW, 2c, C&), 121.0 (ctert, C&), 113.5 (Ctert, CP), 111.9 (ctert, CP), 111.1(Ctert, 2C, Cp), 104.0 (Csrt, Cp), 103.6 (Ctert, Cp), 100.9 (Ckrt, Cp), 99.3 (Ctert, Cp), 34.3 (Cquat or C d , 33.6 (CqU,t or C d , 32.9 (Cquator C,,,), 31.2 (Cpfim,t-Bu), 30.4 (Cpfim,CH3), 25.2 (Cp-, CH3), 21.6 (Cp-, CH3). Preparation of 13. A mixture of 12 (57.6 mg, 0.132 mmol) and grey selenium powder (21.1 mg, 0.264 mmol) in benzene (6 mL) was heated with reflux for 15 h. The mixture was then filtered, and the benzene was removed. The product extracted with pentane was obtained as a red product (65.5 mg, 83% yield). Anal. Calcd for C26H34Se~Zr: c , 52.42; H, 5.75. Found: C, 52.31; H, 5.78. Mass spectrum (main fragments): 596 ( M + , 23), 475 (M+ - t-Bu, 181,335 ([t-BuCp]zZr+,68), 264 ( C ~ H Z ( C H ~ ) 201, Z S ~170 ~ , (CsH3SeCH3, 43). 'H M R , C a b : 7.08 (s, 2H, CsHz), 5.81 (t, 8H, Cp), 2.73 (s,6H,CH3), 1.11(s, 18H, t-Bu). I3C NMR, C&: 150.3 (Cquat, C6HZ), 140.6 (Cquat, CsH2), 138.2 (Cquat, cp), 126.9 (&fit, CsHZ), 110.8 (ctert,CP), 108.3 (Ckd, Cp), 32.8 (Cq,at, t-Bu), 31.8 (Cpfim,t-Bu), 26.9 (Cpfim, CH3). 77SeNMR, CDC13: 559.5. Action of the Selenium Powder on the Benzynezirconocene TrimethylphosphineAdduct. A mixture of CpzZ ~ ( P M ~ ~ ) ( C O(0.10 H ~ ) 'g,~ 0.27 mmol) and grey selenium powder (0.05 g, 0.63 mmol) in benzene (20 mL) was heated
with reflux for 18 h. The red mixture was then filtered, the benzene was removed, and the residual solid was washed with pentane (20 mL). The product was obtained as a red solid (0.07 g, 55% yield) and identified by the usual spectroscopic method.2 X-ray Structural Analysis of 12. Suitable crystals of 12 were obtained by slow crystallization from a pentane solution. A single crystal of &H3& was sealed under nitrogen in a capillary tube and then optically aligned on the goniostat of a Siemens P4 automated X-ray difiactometer. The corresponding lattice parameters and orientation matrix for the sample were determined from a least-squares fit of the orientation angles for 25 reflections at 22 "C. The systematic absences are consistent with the centrosymmetric monoclinic space group, P21Ic. The refined lattice paramaters and other pertinent crystallographic information are provided in the structure determination summary. Intensity data were measured with graphite-monochromated Mo Ka radiation (, =I0.710 73 A) and variable w scans. Background counts were measured at the beginning and at the end of each scan with the crystal and counter kept stationary. The intensities of three standard reflections were measured periodically during data collection and decreased by ca. 21% during data collection. The data were corrected for Lorentz-polarization effects, crystal decomposition, and absorption; the symmetry-equivalent reflections were averaged. Approximate positions for the two independent Zr atoms were located by using direct methods (SHELXTL PLUS operating on a Professional Computing Systems 486 66 MHz computer), and all non-hydrogen atoms were revealed by successive difference Fourier syntheses. Following anisotropic refinement of the non-hydrogen atoms, idealized positions for the hydrogen atoms were included as fxed contributions by using a riding model. Full-matrix least-squares refinement, based upon the minimization of XwilF, - Fcl2, with w i - l = a2(F,) 0.00O8Fo2,converged to give final discrepancy indicesz6 of R(FJ = 0.0642, R,(F,) = 0.0590, and a1 = 1.10 for 2701 reflections with F, > 4.0dFO). The refined positional parameters are provided in Table 1, and selected interatomic distances and bond angles for the C26H3zr are given in Tables 2. A summary of crystallographic data for the structural analysis of 12 is provided in Table 3.
+
Acknowledgment. J.L.P. acknowledges the financial support provided by the Chemical Instrumentation Program of the National Science Foundation (Grant CHE-9120098)for the acquisition of a Siemens P4 X-ray diffractometer by Department of Chemistry at West Virginia University. Authors from the University of Bourgogne thank Mrs. S. Gourier for her technical assistance. SupplementaryMaterial Available: The positional parameters and equivalent isotropic displacement coefficients for CZ&,& are given in Table I. The whole of interatomic distances and angles for the two independent molecules of C&&r are given in Tables I1 and 111, respectively. The anisotropic thermal paramaters for the 54 non-hydrogen atoms and the idealized coordinates for the 68 hydrogen atoms are Y and V, respectively (6 pages). Ordering given in Tables J information is given on any current masthead page. OM9405495 (26) The discrepancy indices were calculated from the expressions R(Fo)= ZJF, - F J m 0and R,(F,) = Z(:(W~)~'~F~ - FcIE(~i)'/'F0, and the standard deviation of an observation of unit weight 81 is equal to [(ZwilF, - Fc12)/(n- p)Im, where n is the number of observations and p is the number of paramaters varied during the last refinement cycle.
