C O M M U N I C A T I O N S
tetradentate aryloxy ligand environment. Differentiation of the
ligand binding sites, additional variation in peripheral substitution
pattern, and applications to polymetallic coordination chemistry and
catalysis are in progress.
Acknowledgment. Financial support from NOVA Chemicals
Corporation and the Natural Sciences and Engineering Research
Council of Canada is gratefully acknowledged.
Supporting Information Available: Experimental procedures and
complete characterization of all new compounds (PDF); details of the
crystallography for compounds 1a, 7, and 8 (CIF). This material is
Figure 1. ORTEP diagram of compound 1a.
References
(1) Leininger, S.; Olenyuk, B.; Stang, P. J. Chem. ReV. 2000, 100, 853.
Swiegers, G. F.; Malefetse, T. J. Chem. ReV. 2000, 100, 3483. Holliday,
B. J.; Mirkin, C. A. Angew. Chem., Int. Ed. 2001, 40, 2022. Fujita, M.;
Umemoto, K.; Yoshizawa, M.; Fujita, N.; Kusukawa, T.; Biradha, K.
Chem. Commun. 2001, 509. Eddaoudi, M.; Moler, D.; Li, H.; Chen., B.;
Reineke, T.; O’Keefe, M.; Yaghi, O. M. Acc. Chem. Res. 2001, 34, 319.
(2) Gutsche, C. D. Calixarenes ReVisited; Royal Society of Chemistry:
Cambridge, England, 1998, and references therein.
(3) (a) Wieser, C.; Dielman, C. B.; Matt, D. Coord. Chem. ReV. 1997, 165,
93. Roundhill, D. M. Prog. Inorg. Chem. 1995, 43, 533. (b) Oude Wolbers,
M. P.; van Veggel, F. C.; Peters, F. G. A.; van Beelen, E. S. E.; Hofstraat,
J. W.; Geurts, F. A. J.; Reinhoudt, D. N. Chem. Eur. J. 1998, 4, 772.
Figure 2. ORTEP diagram of molybdenum complex 7.
(4) See: Floriani C. Chem. Eur. J. 1999, 5, 19 and references therein. Giannini,
L.; Guillemot, G.; Solari, E.; Floriani, C.; Re, N.; Chiesi-Villa, A.; Rizzoli,
C. J. Am. Chem. Soc. 1999, 121, 2797.
(5) Bridge-substituted calixarenes have been reported, but such substituents
do not sterically isolate the oxygen residues. See: Middel, O.; Greff, Z.;
Taylor, N. J.; Verboom, W.; Reinhoudt, D. N.; Sneickus, V. J. Org. Chem.
2000, 65, 667 and references therein.
(6) Mislow, K. Acc. Chem. Res. 1976, 9, 23 and references therein.
(7) Me, Cl, Ph: Zimmerman, H. E.; Paskovich, D. H. J. Am. Chem. Soc. 1964,
86, 2149. Willem, R.; Pepermans, H.; Hallenga, K.; Gielen, M.; Dams,
R.; Giese, H. J. J. Org. Chem. 1983, 48, 1890. Tomioka, H.; Katsuyuki,
H.; Nakayama, T. J. Am. Chem. Soc. 1993, 115, 1285. Rappoport, Z.;
Biali, S. E. Acc. Chem. Res. 1997, 30, 307. Chen, J.; Li, J.; Y, M.-H.;
Chen, W.-X.; Fu, H.-L. Org. Prep. Proc. Int. 1997, 5, 569.
(8) One tetrakis(2-alkoxyphenyl)ethene derivative has been reported, a double
crown ether isolated in 7% yield by oxidation of a 2,2′-crown ether-linked
benzophenone hydrazone, presumably via formation of an intermediate
carbene: von Itter, F. A.; Voegtle, F. Chem. Ber. 1985, 118, 2300.
Figure 3. ORTEP diagram of tetrakis(diethylaluminum) complex 8.
(9) Complete experimental details are provided as Supporting Information.
(10) Roberts, J. D.; Watanabe, W. J. Am. Chem. Soc. 1950, 72, 4869. Bethell,
D.; Callister, J. D. J. Chem. Soc. 1963, 3801, 3808.
(11) McMurry reaction of benzophenone 3a or related 3,3′-disubstituted
derivatives principally provides the over-reduced tetraarylethane, as
previously described;8 dehydrogenation of the tetraarylethanes failed.
(12) Lucas, P.; Mehdi, N. E.; Ho, H. A.; Belanger, D.; Breau, L. Synthesis
2000, 1253.
(13) Nakagawa, K.; Onoue, H.; Minami, K. Chem. Commun. 1966, 730.
structure, confirmed by X-ray crystallography (Figure 2), is closely
analogous to those of other Mo(V) tetraalkoxide complexes.16,17
The Mo-O bonds are nearly equidistant, and the ligand assumes
a slightly distorted propeller conformation, with the aryl rings canted
4-14° from perpendicular with respect to the ethene plane.
A stronger demonstration of the organizational potential of this
ligand template is provided by the polymetallic complex obtained
upon treatment of 1a with excess triethylaluminum in pentane.
Tetrakis(2-diethylaluminoxyphenyl)ethene (8) precipitates from
solution and was isolated in 65% yield; complex 8 is the only
product observed spectroscopically in solution.9 The 1H NMR
spectrum, invariant from -80 to 100 °C, shows four inequivalent
sets of ethyl groups, integrating to eight ethyl groups per ligand.
This suggests a robust C2-symmetric aluminum/oxygen structure
in solution; X-ray crystallography9 confirms this (AlO)4 structure
in the solid state (Figure 3).18
Neither the calix[4]arenes nor other conformationally less
constrained tetradentate aryloxy binding templates provide structur-
ally similar higher order polymetallic complexes.19,20 The confor-
mationally constrained tridentate ligand, tris(3,5-di-tert-butyl-2-
phenyloxy)methane, however, organizes a lower order but similarly
robust tris(aluminum/oxygen) crown complex analogous to complex
8.21
(14) Direct introduction of both o- and p-tert-butyl substituents by Friedel-
Craft alkylations led to inseparable product mixtures.
(15) Murray, R. C.; Blum, L.; Liu, A. H.; Schrock, R. R. Organometallics
1985, 4, 953.
(16) Walborsky, E. C.; Wigley, D. E.; Roland, E.; Dewan, J. C.; Schrock, R.
R. Inorg. Chem. 1987, 26, 1615.
(17) (a) Non-Cp Mo(calix[4]arene) complexes, see: Attner, J.; Radius, U.
Chem. Eur. J. 2001, 7, 783 and references therein. Gibson, V. C.; Redshaw,
C.; Clegg, W.; Elsegood, M. R. J. Chem. Commun. 1998, 1969. (b) Cp*Ta-
(calix[4]arene): Acho, J. A.; Doerrer, L. H.; Lippard, S. J. Inorg. Chem.
1995, 34, 2542.
(18) Eight-membered Al/O and Al/S rings have been characterized crystallo-
graphically, although there is no evidence that such higher oligomers are
maintained in solution. (a) (Me2AlSAr)4: Taghiof, M.; Heeg, M. J.; Bailey,
M.; Dick, D. G.; Kumar, R.; Hendershot, D. G.; Rahbarnoohi, H.; Oliver,
J. P. Organometallics 1995, 14, 2903. (b) (Me2AlOLi)4: Storre, J.;
Schnitter, C.; Roesky, H. W.; Schmidt, H. G.; Noltemeyer, M.; Fleischer,
R.; Stalke, D. J. Am. Chem. Soc. 1997, 119, 7505. (c) (MesAlO)4:
Wehmschulte, R. J.; Power, P. P. J. Am. Chem. Soc. 1997, 119, 8387.
(19) Atwood, J. L.; Gardiner, M. G.; Jones, C.; Raston, C. L.; Skelton, B. W.;
White, A. H. Chem. Commun. 1996, 2487.
(20) Cottone, A., III; Scott, M. J. Organometallics 2000, 19, 5254.
(21) Cottone, A., III; Morales, D.; Lecuivre, J. L.; Scott, M. J. Organometallics
2002, 21, 418.
Tetrakis(2-hydroxyphenyl)ethene and derivatives thus provides
a versatile, topologically unique, and conformationally constrained
JA027436U
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