7079
Communications t o the Editor relative configuration is assigned on the basis of the argument advanced in the text. The C-2-C-3erythro configuration is assigned by analogy to the known stereochemical outcome of a related reaction of this aldehyde. (15) C. T. Buse and C. H. Heathcock, J. Am. Chem. SOC.,99,8109 (1977). (16) The stereostructureof 17 was determined by single-crystal X-ray analysis: J. A. Bertrand and D. VanDerveer. That 15 and 17 have the same relative stereochemistry at the pertinent centers was shown by converting them into the same P-hydroxy aldehyde. The sequence of reactions for this conversion is reduction with lithium aluminum hydride in ether; removal of the trimethylsilyl group: cleavage of the resulting vicinal diol with Na104 in aqueous ethanol. Full details fo the X-ray determination on 17 and on the correlation of 15 with 17 will be reported in a full paper.
Table 1. Analyticala and Crystal Datab for TCVDMA Complexes TCVDMA-TNF calcd obsd
’
C H N a, A
107.02 ( 1 ) 102.49 ( 1 ) 91.38 ( 1 ) 1 198.9 1229.6 2 1.487 1.49 ( 1 )
Berkeley, California 94720 Received M a y 29, 1979
of p-Tricyanovinyldimethylaniline Sir: While, in principle, any molecular species may behave as a “donor” or “acceptor” i n complex formation, the behavior of a given species will depend not only on its own ionization potential (IP,) and electron affinity (EA,) but also on those of its complexing partner, as well as the specific experimental conditions under which the molecules interact. In this communication, we demonstrate for the first time that an organic molecule, p-tricyanovinyldimethylaniline’(TCVDMA, l ) , ( CN)2C = CI
e
CN
R
57.78 3.04 18.00
14.405 ( I )
Clayton H. Heathcock,* Michael C. Pirrung Charles T. Buse, James P. Hagen, Steven D. Young John E. Sohn Department of Chemistry, University of California
The Intermolecular ?r-Amphoteric Character
58.1 I 2.8 1 18.24 7.467 ( 1 ) 11.992 ( I )
DMA.4TCVDMA calcd obsdc 71.43 4.96 23.61 3.992 (6) 16.315 ( I O ) 20.562 ( 1 I) 90 90.27 (9) 90 I339 141 1
71.41 5.29 22.80
1
1.214 1.23 ( 1 )
Elemental analyses were performed by Schwarzkopf Microanalytical Laboratory, Woodside, N.Y. Lattice constants were determined by Molecular Structure Corporation, College Station, Texas, using Cu KLYradiation. Complexes of TCVDMA with volatile components such as DMA cannot be washed with solvents or vacuum dried without loss of the volatile component. Reference 3. e Molecular volume of TCVDMA from Chetkina. L. A,, Popova, E. G.; Kotov, B. V.; Ginzburg, S. L.; Smelyanska, E. M. J . Struct. Chem. 1976, 17, 902, Molecular volume of T N F from Dorset D. L.; Hybl, A,; Ammon, H. L. Acta Crystallogr., Sect. B 1972, 28, 3122. Molecular volume of DMA calculated from room temperature denSltY.
Table 11. Molecular Energy Levels and Redox Potentials molecule
IP,, eV
DMA TCVDMA T NF
7.45h
EA,, eV I .24
+1.6
El pred a 750 nm not due to either component of the complex and assigned to the tail of a charge-transfer absorption band. A further attempt to observe a charge-transfer maximum in T C V D M A - T N F was made. In 0.5-mm-path-length cells, a IO-' M solution of TCVDMA in ethanol or chloroform gave a level base line. Portionwise solution of T N F in the sample cell gave new absorbance in both cases between 500 and 530 nm, with maxima a t 517 nm in ethanol and 502.5 and 527.5 nm in chloroform attributed to charge-transfer absorption.I4 Charge-transfer absorption between D M A and T C V D M A was observed as follows. In chloroform solution, IO-' M in TCVDMA, a "window" in the absorption spectrum is apparent between 350 and 400 nm. Portionwise addition of D M A up to a concentration of lo-* M in this solution reveals new absorption with absorbance increasing from 0.04 a t 390 nm to 0.44 a t 350 nm; however, no maximum was observed in this region. The new absorption, which we assign to charge-transfer absorption in both DMA. 4TCVDMA and TCVDMAaTNF, is a t energies expected15 for molecular species with the energy levels and redox potentials listed in Table 11. In summary, we have demonstrated the 7r-amphoteric character of T C V D M A by its formation of solid complexes with T N F where it functions as a donor and with D M A where it functions as the acceptor in a solid complex of rare 1 :4 stoichiometry. New absorption attributed to complex formation has been observed for each of the new complexes. A potential outgrowth of this work might be the use of 7r-amphoteric molecules to form new classes of complexes with three interacting component^.^ Our attempts to use T C V D M A to form three-component complexes with D M A and T N F have led only to the isolation of mixtures of the two-component complexes of these compounds to date. Acknowledgments. The authors thank G . T. Fekete for X-ray powder diffraction patterns of the materials discussed herein and K. Fuller and K. Graham for typing the manuscript.
References and Notes McKusick, 8.C.; Heckert, R. E.; Cairns, T. L.; Coffman, D. D.; Mower, H. R. J. Am. Chem. SOC.1958,80, 2806. Solid molecular complexes in which aromatic hydrocarbons such as pyrene, anthracene, and perylene behave as donors have been structurally chara ~ t e r i z e dHowever, .~ the behavior of these hydrocarbons as acceptors with tetrakis(dimethy1amino)ethylenehas been detected spectroscopically only in solution ~ t u d i e s . ~ Herbstein. F. H. "Perspectives in Structural Chemistry", Dunitz. J. D., Ibers, J. A,. Eds.; Wiley: New York, 1971;Vol. 4,p 166 ff. Hammond, P. R.: Knipe. R. H. J. Am. Chem. SOC.1967,89,6063. The solid polymeric Ziegler-Natta polyacetylene film behaves as a donor toward oxidants such as 12 or AsF5 and as an acceptor toward sodium naphthalide: Chiang, C. K.; Druy, M. A.; Gau, S. C.; Heeger, A. J.; Louis, E. J.; MacDiarmid, A. G.; Park, Y. W.; Shirakawa, H. J. Am. Chem. SOC. 1978, 100, 1013. The tendency of alkali metal atoms to lose an electron is far better known than their ability to form monoanions. For a discussion of the latter situation, see Dye, J. L. J. Chem. Educ. 1977, 54,332. Sasaki, A,; Aihara, J.; Matsunaga, Y. Bull Chem. SOC.Jpn. 1974, 47,
2926. Sandman, D. J., "Abstracts of Papers," 178th National Meeting of the American Chemical Society, Washington, D.C., Sept 9-14,1979;American Chemical Society: Washington, D.C., 1979: ORGN 60.Sandman, D. J.; Grammatica, S. J.; Holmes, T. J.; Richter, A. F. Mol. Cryst. Liq. Cryst., accepted for publication. (9)Williams, J. K. J. Am. Chem. SOC.1982,84, 3478. (10)Sandman. D. J : Richter. A. F.: Fekete. G. T.: Warner.. D. E.., Mol. Crvst Lio. Cryst., accepted for publication. A 1:4stoichiometry in molecular donor-acceptor complexes and ion-radical salts is unusual but not ~ n p r e c e d e n t e d . ~ , ' ~ Two structures of 4:1 salts of 7,7,8,8-tetracyanoquinodimethan and dications have been reported: Ashwell, G. J., et al. Acta Crystailogr., Sect. B 1976,32, 2948;1975,31, 1174. Shibaeva, R. P.; Atovmyan, L. 0. J. Struct. Chem. 1972, 13, 515.Kistenrnacher, T. J. Ann. N. Y. Acad. Sci. 1978,313, 333. The absorption spectrum of TCVDMA is sensitive to the solvent' or solvent mixture.'O Addition of lo-' M TNF causes no detectable shifl in the position
