Organic compounds -- part of the class 532-570 series – Organic compounds – Nitrogen attached directly or indirectly to the purine ring...
Patent
1996-06-06
1998-07-14
Dees, Jose G.
Organic compounds -- part of the class 532-570 series
Organic compounds
Nitrogen attached directly or indirectly to the purine ring...
544298, 544301, 544302, 544322, 544335, 549429, 549464, 549465, 549467, 549473, 549480, 549491, 549496, 549498, 549499, 549502, 25229901, 25229961, 25229962, 25229965, C07D23926, C07D23936, C07D40704, C07D49304
Patent
active
057806292
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/EP94/04055 filed Dec. 6, 1994.
It is known that molecules which are anisotropic in shape can form liquid-crystalline phases, known as mesophases, on warming. The individual phases differ through the spatial arrangement of the major parts of the molecules on the one hand and through the molecular arrangement with respect to the long axes on the other hand (G. W. Gray, P. A. Winsor, Liquid Crystals and Plastic Crystals, Ellis Horwood Limited, Chichester, 1974). The nematic liquid-crystalline phase is distinguished by the fact that there is only one alignment long-distance ordering due to the long molecular axes lining up in parallel. Under the prerequisite that the molecules making up the nematic phase are chiral, a cholesteric phase forms, in which the long axes of the molecules form a helical superstructure perpendicular thereto (H. Baessler, Festkorperprobleme XI, 1971). The chiral moiety may be present in the liquid-crystalline molecule itself or added to the nematic phase as a dope. Phases produced by doping are known as induced cholesteric phases. This phenomenon was first studied on cholesterol derivatives (H. Baessler, M. M. Labes, J. Chem. Phys. 52 (1970) 631; H. Baessler, T. M. Laronge, M. M. Labes. J. Chem. Phys. 51 (1969) 3213; H. Finkelmann, H. Stegemeyer, Z. Naturforschg. 28a (1973) 799). The induction of cholesteric phases later also became possible through addition of other chiral substances which themselves are not liquid-crystalline (H. Stegemeyer, K. J. Mainusch, Naturwiss. 58 (1971) 599; H. Finkelmann, H. Stegemeyer, Ber. Bunsenges. Phys. Chem. 78 (1974) 869).
The cholesteric phase has remarkable optical properties: large optical rotation and pronounced circular dichroism caused by selective reflection of circular-polarized light within the cholesteric layer. The different colors to be observed depending on the viewing angle depend on the pitch of the helical superstructure, which is itself dependent on the twisting power of the chiral component. The pitch and thus the wavelength range of the selectively reflected light of a cholesteric layer can be varied, in particular, by changing the concentration of a chiral dope (J. E. Adams, W. E. L. Haas, Mol. Cryst. Liq. Cryst. 16 (1972) 33). Such cholesteric systems offer interesting opportunities for practical use. Thus, incorporation of chiral moieties into mesogenic acrylic esters after alignment in the cholesteric phase and photocrosslinking can give a stable, colored network, but the concentration of the chiral component therein cannot be changed (G. Galli, M. Laus, A. Angeloni, Makromol. Chem. 187 (1986) 289). Furthermore, admixing of non-crosslinkable, chiral compounds with nematic acrylic esters after photocrosslinking can give a colored polymer (I. Heynderickx, D. J. Broer, Mol. Cryst. Liq. Cryst. 203 (1991) 113), but this still contains volatile constituents which prevent use.
It is an object of the present invention to provide novel chiral compounds which firstly have a high twisting power and secondly can be incorporated in a stable manner into the cholesteric phase in any desired concentration without diffusing out of the phase or crystallizing.
We have found that this object is achieved by polymerizable, chiral compounds.
The present invention accordingly provides polymerizable, chiral compounds containing at least one divalent or polyvalent chiral group, at least one polymerizable group, at least one spacer and at least one mesogenic group, and to their use as polymerizable, chiral dopes for the preparation of cholesteric networks.
The polymerizable groups here are, in particular, vinyl radicals, which are present, for example, in acrylic compounds, vinyl ethers or styrene derivatives. Epoxides are also suitable.
Chiral groups which are suitable for the novel compounds are derived, in particular, from sugars, bifunctional or polyfunctional compounds from the biphenyl or binaphthyl series, optically active glycols, dialcohols or amino acids.
The spacers and mesogenic groups are the radicals conventi
REFERENCES:
patent: 5011623 (1991-04-01), Yoshinaga et al.
Liquid Crystals and Plastics Crystals, vol. 1, pp. 18-62, 1994, A. Saupe, "Classification and Organization of Mesomorphous Phases Formed by Non-Amphiphilic and Amphiphilic Compounds".
Festkoerper Probleme XI, pp. 99-133, 1971, H. Baessler, "Liquid Crystals".
The Journal of Chemical Physics, vol. 52, pp. 631-637, Jan. 1-Jun. 15, 1970, H. Baessler, et al., "Helical Twisting Power of Steroidal Solutes in Cholesteric Mesophases".
The Journal of Chemcial Physics, vol. 51, No. 8, pp. 3213-3218, Oct. 15, 1969, H. Baessler, et al., "Electric Field Effects on the Optical Rotatory Power of a Compensated Cholesteric Liquid Crystal".
Zeitschrift Fuer Naturforschung, vol. 28, pp. 799-800, 1973, H. Finkelmann, et al., "AB-Initio Study of Hydrogen Bonded Radical"--Abstract only.
Die Naturwissenschaften, vol. 58, pp. 599-602, 1971, H. Stegemeyer, et al., "Induzierung Von Optischer Aktivaet Und Zirkulardichroismus in Nematischen Phasen Durch Chirale Molekuele"--Abstract only.
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Macromolecular Chemistry and Physics, vol. 187, pp. 289-296, 1986, G. Galli, "Synthesis and Thermotropic Properties of New Mesogenic Diacrylate Monomers".
Organic Chemistry, A Short Course, 9.sup.th Ed., Hart, Hart and Crane; Houghton Mifflin Co., Boston, MA. (1995) pp. 34-38.
"Ferroelectric Liquid Crystal Mixtures with Carbohydrate Derivatives as Dopants," Vill, V. et al.; Z. Naturforsch, A.: Phys. Sci. (1989), 44(7), pp. 675-679.
"Helical Twisting Power of Carbohydrate Derivatives," V. Vill et al.; Z. Naturforsch, A.: Phys. Sci. (1988), 43(12), pp. 1119-1125.
Delavier Paul
Etzbach Karl-Heinz
Laupichler Lothar
Siemensmeyer Karl
Vill Volkmar
BASF - Aktiengesellschaft
Dees Jos,e G.
Osweckl Jane C.
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