1498
Organometallics 1987, 6, 1498-1502
previously and have been ascribed to steric crowding in the M2Czcore.2b The C5-C6-C7 angle 135.4 (4)’ is consistent with a change in the hybridization of the alkyne carbons from sp toward sp2 as a result of bonding to the metal atoms. It is interesting to note that this angle is close to the central C-C-C angle (139’) in cation 2. The lowfrequency IR band at 1820 cm-l observed for 11 shows that the semibridging carbonyl (C3-03) is maintained in solution. ‘Hand 13CNMR of 11 demonstrate that complex 11 is fluxional as are all the p-alkyne adducts of 1 investigated to date.2 At room temperature, all four Cp’ environments are identical, and the eight carbonyls give rise to only two
I3C NMR resonances. Similar behavior has been noted previously for M2(p-RC=CR’) adducts (R # R’).2 Further investigationsof carbon-rich hydrocarbyl ligands are in progress.
Acknowledgment. This work was supported by donors of the Petroleum Research Fund, administered by the American Chemical Society, and by the National Science Foundation (Grant CHE-8305235). Supplementary Material Available: Tables of thermal parameters and complete bond distances and angles (8 pages); lists of F,,vs. F, for 2.BF4 and 11 (21 pages). Ordering information is given on any current masthead page.
.’
Organometallic Compounds. 41 [2]Metacyclo[ 2]( 1,l’)ferrocenophane Masao Hisatome, Masamichi Yoshihashi, Kenji Masuzoe, and Koji Yamakawa Faculty of Pharmaceutical Sciences, Science University of Tokyo, Ichigaya-Funagawara, Shinjuku-ku, Tokyo 162, Japan
Yoichi Iitaka Faculty of Pharmaceutical Sciences, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan Received September 10, 1986
[2]Metacydo[2](1,1’)ferrocenophane (l),a standard organometallic system, was synthesized, and its crystal structure was determined by X-ray diffraction. Compound 1 crystallizesin the monoclinic system, space group P2,/a, with unit-cell parameters a = 17.547 (9) A, b = 5.914 (3) A, c = 14.499 (7) A, ,8 = 92.3 (5)O, and 2 = 4. The bond lengths and angles of the aromatic rings and methylene chains are normal. However, the two cyclopentadienyl (Cp) rings are tilted (dihedral angle 9.0°), and the bridge-carbon atoms linked directly to the Cp rings deviate considerably from the planes of the Cp rings (0.288 (9), 0.151 (9) A) in the direction opposite to the iron atom. The benzene ring is situated to the side of the ferrocene nucleus, and the 9-hydrogen atom of the benzene ring is close to the iron atom of the ferrocene. The 9-proton signal in the ‘H NMR spectrum appears unusually downfield (6 8.80) due to an anisotropiceffect of the ferrocene nucleus. The electronic spectrum exhibits a large bathochromic shift of the d-d absorption band of the iron atom (Ama = 470 nm). Attempted synthesis of [2]paracyclo[2](l,l’)ferrocenophane, which is more strained than 1, was unsuccessful.
Introduction A large number of monobridged (1,l’)ferro~enophanes~~~ have been studiedP6 since the discovery of ferrocene. Most of these are [m](1,l’)ferro~enophanes~~ which are intramolecularly linked with a carbon chain and [m.n](l,l’)ferrocen~hanes*-’~ which are intermolecularly bridged (1)Part 40 Hisatome, M.; Watanabe, J.; Yamakawa, K.; Kozawa, K.; Uchida. T. N ~ D DKapaku O ~ Kaishi 1985.572. (2)The nomenclature of ferrocenophkes in this paper is according to that presented by Vogtle and Neumanm3 (3)Vogtle, F.; Neumann, P. Tetrahedron 1970,26,5847. (4)Watts, W. E. Organomet. Chem. Reu. 1967,2, 231. ( 5 ) Kasahara, A. Kagaku 1983,38,859. (6)Mueller-Westerhoff, U. T. Angew. Chem., Int. Ed. Engl. 1986,25, 7n3 . _-. (7)Katz, T. J.; Slusarek, W. J . Am. Chem. SOC.1980,102, 1058. Lentzner, H. L.; Watts, W. E. Tetrahedron 1969,25, (8)Barr, T. H.; 6001. (9)(a) Rosenblum, M.; Brawn, N. M.; Clappenelli, D.; Tancrede, J. J. Organomet. Chem. 1970,24,469.(b) Kasahara, A.;Izumi, T. Chem. Lett. 1978,21. (c) Kasahara, A.; Izumi, T.; Shimizu, I. Ibid. 1979,1317. (10)(a) Biernat, J. F.; Wilczewski, T. Tetrahedron 1980,36,2521.(b) Sato, M.; Kubo, M.; Ebine, S.; Akabori, S. Tetrahedron Lett. 1982,23, 185. (c) Czech, B.; Ratajczak, A.; Nagraba, K. Monatsch. Chem. 1982, 113,965. (d) Izumi, T.; Tezuka, T.; Yusa, S.; Kasahara, A. Bull. Chem. SOC.Jpn. 1984,57,2435.
between two ferrocene nuclei. Recently, several ( 1,l’)ferrocenophanes containing aromatic rings in the bridge were synthesized,11J2 but there has been no report on [2]meta- and [2]paracyc1o[2](l7l’)ferrocenophanes(1 and 2). By inspection of a Dreiding molecular model, the benzene ring of 1 is situated to the side of the ferrocene nucleus and the 9-hydrogen of the ring is unusually close to the iron atom of the ferrocene (ca. 2.4 A). A space-filling (CPK) molecular model reveals that the 9-hydrogen and the ferrocene nucleus repel each other. This situation should cause a high strain and/or some distortion in the molecule. The ‘HNMR spectrum and the d-d absorption band in the electronic spectrum of 1 should reflect such an unusual molecular structure and show characteristic shifts. The magnetic anisotropy of ferrocene nucleus was (11) (a) Tanner, D.; Wennerstrom, 0. Acta Chem. Scand. 1980,B34, 529. (b) Kauffmann, K.; Ennen, J.; Lhotak, H.; Rensing, A.; Steinseifer, F.; Woltermann, A. Angew. Chem., Int. Ed. Engl. 1980,19, 328. (c) Shimizu, I.; Umezawa, H.; Kanno, T.; Izumi, T.; Kasahara,A. Bull. Chem. SOC.Jpn. 1983,56,2023. (12)(a) Tanaka, S.;Sato, M.; Ebine, S.; Morinaga, K.; Akabori, S. 16th Sympos~umon Structural Organic Chemistry, Urawa, Japan, 1983;The Symposium Papers, p 289. (b) Sato, M.; Tanaka, T.; Ebine, S.; Morinaga, K.; Akabori, S. J. Organomet. Chem. 1985,289,91.
0276-733318712306-1498$01.50/00 1987 American Chemical Society
[2]Metacyclo[2] (1,1’)ferrocenophane
Organometallics, Vol. 6, No. 7, 1987 1499 Table I. Bond Lengths (A) of 1 with Estimated Standard Deviations in Parentheses Fe-C(l) 2.131 (10) C(2’)-C(3’) 1.399 (15)
Figure 1. ORTEP drawing (30% probability thermal ellipsoids) of compound 1.
discussed by Turbit and Watts.13 The actual sign and magnitude of the effect in the region close to the iron atom can be evaluated from the chemical shift of the 9-proton in the IH NMR spectrum of 1. Paracyclophane 2 is even more highly strained than 1. The molecule cannot be constructed with molecular models. It should also have an unusual structure and spectroscopic behavior.
3
2 44’
14
2’ 1
2.081 (11) 2.015 (13) 2.042 (12) 2.083 (10) 2.097 (10) 2.058 (11) 2.045 (11) 2.038 (11) 2.058 (11) 1.466 (17) 1.381 (16) 1.363 (18) 1.479 (18) 1.461 (15) 1.405 (18)
2
Y
(13) Turbitt, T. D.; Watts, W. E. Tetrahedron 1972, 28, 1227. (14) Hisatome, M.; Yoshihashi, M.; Yamakawa, K.; Iitaka, Y. 16th Symposium on Structural organic Chemistry, Urawa, Japan, 1983; The Symposium Papers, p 293. (15) (a) Mitchell, R. H.; Boekelheide, V. J. Am. Chem. SOC.1970,92, 3510. (b) Boekelheide, V.; Hollins, R. A. Zbid. 1970, 92, 3512. (c) Umemoto, T.; Otsubo, T.;Sakata, Y.; Misumi, S. Tetrahedron Lett. 1973,593. (d) Mitchell, R. H.; Boekelheide, V. J. Am. Chem. SOC.1974,96, 1547. (e) Mitchell, R H.; Vinod, T. K.; Bushnell, G. W. Ibid. 1985,107, 3340. (16) (a) Mitchell, R. H.; Otsubo, T.; Boekelheide, V. TetrahedronLett. 1975, 219. (b) Boekelheide, V.; Tsai, C.-H. Tetrahedron 1976, 32, 423. (17) (a) Boekelheide, V.; Reingold, I. D.; Tuttle, M. J . Chern. SOC., Chern. Commun. 1973,406. (b) Bruhin, J.; Jenny, W. Tetrahedron Lett. 1973, 1215. (c) Umemoto, T.; Otsubo, T.; Misumi, S. Zbid. 1974, 1573. (d) Fukazawa, Y.; Aoyagi, M.; Ito, S. Tetrahedron Lett. 1978, 1067. (18) (a) Otsubo, T.; Boekelheide, V. Tetrahedron Lett. 1975,3881. (b) Otsubo, T.; Boekelheide, V. J. Org. Chern. 1977,42,1085. (c) Otaubo, T.; Kitasawa, M.; Misusmi, S. Bull. Chem. SOC.Jpn. 1979,52, 1515.
1.408 (18) 1.475 ( i 7 j 1.445 (17) 1.484 (16) 1.526 (16) 1.524 (17) 1.505 (16) 1.468 (20) 1.568 (20) 1.431 (18) 1.443 (18) 1.349 (21) 1.383 (21) 1.418 (20) 1.360 (19)
ay 5 : X=Br 6: X=SH
3: X=OH 4 : X=SH
a : meta b: para
We attemted the synthesis of 1and 2 via rearrangement of the corresponding precursor disulfides 7a and 7b and succeeded in obtaining 1 but not 2. This paper describes the synthesis, X-ray crystal structure, and spectral characterization of 1. The 6,Edithia analogue of 1 was presented by Sat0 et a1.I2 simultaneously with a preliminary report of this work14at the same symposium, but the X-ray crystal structure of the disulfide has not been investigated.
Results and Discussion Synthesis. The method via cyclic sulfide, which is well-known as a convenient plane synthesis,15-1swas applied to the present study. The sodium thiolate of dithiol 4, prepared from diol 3, was allowed to react with dibromide 5a or 5b in ethanol under high dilution conditions to give cyclic sulfide 7a or 7b in good yields (7a, 58%;7b, 75 %) together with the intramolecularly bridged disulfide
C(3’)-C(4’)
8. On the other hand, we found the coupling reaction of 1,3-bis(hydroxymethyl)ferrocene and dithiols 6 with trifluoroacetic acid (TFA)to give the corresponding cyclized d i s ~ l f i d e s . ~Reaction ~ ~ ~ ~ of 3 with 6a under the same conditions gave 7a in a 40% yield, but coupling with 6b afforded only macrocyclic sulfide 9. The disadvantage in the acid-catalyzed reaction of 3 and 6b to prepare 7b is, possibly, due to the thermodynamical instability of 7b.
10 l 1
15
3’
Fe-C(2) Fe-C(3) Fe-C(4) Fe-C(5) Fe-C(l‘) Fe-C(2‘) Fe-C(3‘) Fe-C (4’) Fe-C (5’) c(l)-c(2) C(2)-C(3) C(3)-C(4) c(4)-C(5) C(5)-C(1) C(lf)-C(2’)
la, b
0
Ih\
9
10
[B.B]Phanes can be generally prepared by Stevens rearrangemenP via S-methylation of the corresponding sulfide with Boach reagent.21 However, the methylation of 7a and 7b gave only complex mixtures but no sulfonium salt. Subsequently, Wittig rearrangement reported by Boekelheide et a1.I6 for preparation of cyclophanes was (19) Hisatome, M.; Yoshihashi, M.; Yamakawa, K.; Iitaka, Y. Tetrahedron Lett. 1983, 24, 5757. (20) Czech, B.; Ratajczak, A. Pol. J. Chem. 1980,54, 767. (21) Borch, R. F. J. Org. Chem. 1969, 34, 627.
Hisatome et al.
1500 Organometallics, Vol. 6, No. 7, 1987 Table 11. Bond Angles (deg) of 1 with Estimated Standard Deviations in Parentheses 116.8 (10) C(5)-C(l)-C(2) 106.4 (9) C(7)4(8)-C(9) 123.7 (10) 108.4 (10) C(7)-C(8)-C(13) C(l)-C(2)-C(3) 121.7 (11) 110.8 (11) C(5’)-C(l’)-C(l5) C(2)-C(3)-C(4) 130.4 (11) 109.3 (10) C(2’)-C(l’)-C(l5) C(3)-C(4)-C(5) 105.0 (9) C(1’)4(15)4(14) 117.4 (11) C(4)-C(5)-C(l) C(5’)4(1’)-C(2’) 107.7 (10) C(15)-C(14)-C(lO) 116.9 (12) C(l’)-C(2’)4(3’) 109.3 (10) C(14)4(1O)-C(9) 115.0 (11) C(2’)-C(3’)-C(4’) 109.9 (10) C(14)4(10)-C(ll) 126.8 (12) 119.5 (11) C(3’)-C(4’)-C(5’) 106.3 (10) C(l3)4(8)-C(9) 118.7 (11) C(4’)-C(5’)-C(l’) 106.7 (10) C(8)-C(9)-C(lO) 118.1 (12) 123.1 (10) C(8)-C(lO)-C(ll) C(5)-C(l)-C(6) 129.3 (10) C(lO)-C(ll)-C(l2) 123.9 (13) C(2)-C(l)-C(6) 120.0 (10) C(ll)-C(l2)-C(l3) 117.8 (13) C(l)-C(6)-C(7) 112.9 (10) C(12)-C(13)-C(8) 121.5 (12) C(6)-C(7)-C(S)
6 9.0“
1
2a(Io)] were obtained in the 6' 5 28 5 120" range, corresponding to about 56% of the theoretically possible reflections within the same angular range. Lorentz and polarization corrections were made, but no absorption correction was applied. The structure was solved by the heavy-atom method. Atomic coordinates of the Fe atom were deduced from the Patterson map, and all 20 carbon atoms were located in the Fourier map. The refinement was carried out by a block-diagonal-matrix leastsquares procedure, and the final R value was reduced to 0.090. The final atomic parameters are shown in Table IV.
Acknowledgment. We are indebted to Dr. M. Hillman for helpful discussions. Thanks are due to Dr. M. Sasho for preparation of compound 9. Supplementary Material Available: Tables of temperature factors and deviations of atoms from least-squares planes through the Cp rings (2 pages); a listing of structure factors (6 pages). Ordering information is given on any current masthead page.
