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Original Articles

Molecular dynamics and X-ray scattering simulations of cyclic siloxane-based liquid crystal mesogens

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Pages 811-827 | Received 28 May 1992, Accepted 22 Dec 1992, Published online: 24 Sep 2006

References

  • Gray , G. W. 1989 . Side Chain Liquid Crystal Polymer , Edited by: McArdle , C. B. Blackie .
  • Janini , G. M. , Laub , R. J. , Purnell , J. H. and Tyagi , G. S. 1989 . Side Chain Liquid Crystal Polymers , Edited by: McArdle , C. B. Blackie .
  • Apfel , M. A. , Finkelamann , H. , Janini , G. M. , Laub , R. J. , Luhmann , B. H. , Price , A. , Roberts , W. L. , Shaw , T. J. and Smith , C. A. 1985 . Analyt. Chem. , 57 : 651
  • Coles , H. and Simon , R. 1985 . Polymer , 26 : 1801
  • Eich , M. , Wendorff , J. H. , Reck , B. and Ringsdorf , H. 1987 . Makromolek. Chem. rap. Commun. , 8 : 59
  • Cabrera , I. , Krongauz , V. and Ringsdorf , H. 1987 . Angew. Chem. Int. Ed. Engl. , 26 : 1178
  • Keller , P. 1990 . Chem. Mater. , 2 : 3
  • Cabrera , I. , Krongauz , V. and Ringsdorf , H. 1988 . Molec. Crystals liq. Crystals , 155 : 221
  • Creed , D. , Griffin , A. , Gross , J. , Hoyle , C. and Venkararam , K. 1988 . Molec. Crystals liq. Crystals , 3 : 34
  • Hahn , B. and Percec , P. 1987 . Macromolecules , 20 : 2961
  • Dumon , M. , Nguyen , M. T. , Mauzac , M. , Destrade , C. , Achard , M. F. and Gasparoux , H. 1990 . Macromolecules , 23 : 355
  • Lebarny , P. and Dubois , J. C. 1989 . Side Chain Liquid Crystal Polymers , Edited by: McArdle , C. B. Blackie .
  • Carr , N. , Goodwin , M. , McRoberts , A. , Gray , G. , Marsden , R. and Scrowston , R. 1987 . Makromolek. Chem. rap. Commun. , 8 : 487
  • Diele , S. , Oelsner , S. , Kushel , F. , Hisgen , B. and Ringsdorf , H. 1988 . Molec. Crystals liq. Crystals , 155 : 399
  • Diele , S. , Oelsner , S. , Kushel , F. , Hisgen , B. , Ringsdorf , H. and Zentel , R. 1987 . Makromolek. Chem. , 188 : 1993
  • Percec , V. , Hahn , B. , Ebert , M. and Wendorff , J. H. 1990 . Macromolecules , 23 : 2095
  • Davidson , P. , Levelut , A. M. , Achard , M. F. and Hardouin , F. 1989 . Liq. Crystals , 14 : 561
  • Percec , V. and Hahn , B. 1989 . Macromolecules , 22 : 1588
  • Richards , R. D. C. , Hawthorne , W. D. , Hill , J. S. , White , M. S. , Lacey , D. , Semlyen , J. A. , Gray , G. W. and Kendrick , T. C. 1990 . J. chem. Soc. chem. Commun. , : 95
  • Kreuzer , F. H. , Andrejewski , D. , Haas , W. , Haberle , N. , Riepl , G. and Spes , P. 1991 . Molec. Crystals liq. Crystals , 199 : 345
  • Bunning , T. J. 1991 . Technical Report WL-TR-91–4012
  • Provided by F. H. Kreuzer of the Consortium für Electrochemische Industrie of Germany
  • Bunning , T. J. , Klei , H. E. , Samulski , E. T. , Crane , R. L. and Linville , R. J. 1991 . Liq. Crystals , 10 : 445
  • Pinsl , J. , Brauchle , Chr. and Kreuzer , F. H. 1987 . J. molec. Electron. , 3 : 9
  • Ortler , R. , Brauchle , C. , Miller , A. and Riepl , G. 1989 . Makromolek. Chem. rap. Commun. , 10 : 189
  • Tsai , M. L. , Chen , S. H. and Jacobs , S. D. 1989 . Appl. Phys. Lett. , 54 : 2395
  • Everitt , D. R. R. , Care , C. M. and Wood , R. M. 1987 . Molec. Crystals liq. Crystals , 135 : 55
  • Everitt , D. R. R. , Care , C. M. and Wood , R. M. 1991 . Molec. Crystals liq. Crystals , 201 : 41
  • Pachter , R. , Bunning , T. J. and Adams , W. W. 1991 . J. Comput. Polymer. Sci. , 1 : 179
  • Pachter , R. , Socci , E. P. , Farmer , B. L. R. , Bunning , T. J. , Crane , R. L. and Adams , W. W. 1992 . Die Makromolekulare Chemie, Theory and Simulations in press
  • This calculation was carried out in the Molecular Graphics Lab at the Department of Computer Science in the University of North Carolina-Chapel Hill. A collaboration with Dr William Wright in the Department using the force feedback ARM was set up in April 1991. The force feedback ARM uses a parallel MasPar computer (MP-1) operating with 4096 processors in order to calculate the intermolecular energy (using a combination of electrostatic and Lennard-Jones potentials, the parameters used were those of the CHARMm force field) between a rigid structure and a movable docking model. The resulting force information is used interactively to feed the ARM, so that the best position for the docked structure can be found by manipulating the movable structure on the screen. The structural model can be further improved by an energy minimization. The following experiments were performed: Rigid structure Moveable structure† 1 2 C† 2C† 2 2C 3B 3 3B 2C 4 3B 3B 5 2C + 2C (translation in y direction 17 Å) 3B 6 2C + 2C (translation in y direction 12 Å) 3B 7 2C + 2C (translation in y direction 12 Å) 2C 8 3B + 3B (translation in y direction 12 Å) 3B 9 3B + 3B (translation in y direction 12 Å) 2C 10 3B + 3B (translation in y direction 12 Å) 3B + 3B 11 2C + 2C (translation in y direction 12 Å) 3B + 3B †2C = two cholesteryl-4′-allyloxybenzoate side chains at an axial position; 3B = three biphenyl-4′-allyloxybenzoate mesogens at an equatorial position. In each case a few starting positions were attempted. The results of these experiments indicate that the interdigitation of the B mesogens is qualitatively more favourable in all cases. On the other hand, attempts to dock the C system were not successful
  • Natarajan , L. , Bunning , T. J. , Crane , R. L. and Adams , W. W. 1991 . Macromolecules , 24 : 6554
  • Pachter , R. , Cooper , T. M. , Natarajan , L. V. , Obermeier , K. , Crane , R. L. and Adams , W. W. 1992 . Biopolymers , 32 : 1129
  • Roe , R. J. 1991 . Computer Simulation of Polymers , Prentice-Hall .
  • Sorensen , R. A. , Liau , W. B. and Boyd , R. H. 1988 . Macromolecules , 21 : 194
  • Rutledge , G. C. and Suter , U. W. 1991 . Macromolecules , 24 : 1921
  • Dunmur , D. A. and Wilson , M. R. 1989 . Molec. Simul. , 4 : 37
  • Brooks , B. R. , Bruccoleri , R. E. , Olafson , B. D. , States , D. J. , Swaminathan , S. and Karplus , M. 1983 . J. comput. Chem. , 4 : 187
  • ‘Quanta/CHARMm’ (Chemistry at HARvard Macromolecular mechanics)
  • 1990 . Quanta Parameters: Release 3.0, Polygon Corporation
  • Grigoras , S. and Lane , T. H. 1988 . J. comput. Chem. , 9 : 25
  • Mulliken , R. S. 1955 . J. chem. Phy. , 23 : 1833 used in this study. A common technique applied in the derivation of atomic charges from wave functions rooted in the LCAO (Linear Combination of Atomic Orbitals) approximation is the Mulliken population analysis
  • Besler , B. H. , Merz , K. M. Jr. and Kollman , P. R. 1990 . J. comput. Chem. , 11 : 431 Note that alternatively, the charges may be extracted by fitting the molecular electrostatic potential, In Mulliken's scheme it is assumed that the overlap population associated with any atoms M and N due to AOs of type k and l, respectively, arising from an ith MO (molecular orbital), can be divided equally between the two atoms, and equals 2 V i C kMi C lNi S kMlN where c are the AO coefficients and S their overlap integral, and v i is the occupation number of the ith MO. Mulliken's population analysis yields the population on an atom from the appropriate sums over all doubly occupied MOs and over all types of basis functions
  • Momany , F. A. 1982 . J. phys. Chem. , 82 : 592 Although this scheme has been questioned
  • Williams , D. E. and Yan , J. M. 1988 . Adv. atom. molec. Phys. , 23 : 87
  • Rao , P. S. , McEachern , R. J. and Weil , J. A. 1991 . J. comput. Chem. , 12 : 254 it provides in this case atomic charges which are consistent with those derived by other methods
  • Abraham , R. J. , Grant , G. H. , Haworth , I. S. and Smith , P. E. 1991 . J. comput.-aided Molec. Design , 52 : 21 justified to be used
  • Dewar , M. J. S. and Thiel , W. 1977 . J. Am. chem. Soc. , 99 : 4899 4907, The MNDO
  • Stewart , J. J. P. 1988 . Quant. Chem. Prog. Exch. , 455 ‘MOPAC’ version 5.0, (modified neglect of differential overlap) semiempirical technique which invokes the NDO approximation was used, The semiempirical calculation gave a reasonable geometry with the optimized Si–O–Si and O–Si–O ring angles assuming values of 133° and 110°, respectively. A comparison of the MNDO derived partial atomic charges and standard values used by the molecular mechanics force field (in parentheses) for these isomers reveals some differences: O = 0.98 (− 0.44); Si = 1.70 (0.53; C = 0.4 to −0.5 (0.02); H(-Si) = 0.03 (−0.02); H(-C) = 0.02 to −0.02 (− 0.03). The q(MNDO) values thus derived are consistent with ab initio results, and were used for the geometry optimization of the ring system. Optimized structures by CHARMm using either q(MNDO) or q(standard) for the electrostatic contribution to the force field differ by 0.1–0.5 Å RMSD
  • Pachter , R. and Wessels , P. L. 1988 . J. molec. Struct. (Theochem.) , 164 : 189
  • Pachter , R. and Wessels , P. L. 1988 . J. molec. Struct. (Theochem.) , 178 : 323
  • McCammon , J. A. and Harvey , S. C. 1987 . Dynamics of Proteins and Nucleic Acids , Cambridge University Press .
  • Vainsthein , B. K. 1966 . Diffraction of X-Rays by Chain Molecules , Elsevier .
  • 1990 . Cambridge Molecular Design Corporation . ‘CERIUS’ program and manual: release 2.1
  • Almenningen , A. , Bastiansen , O. , Fernholt , L. , Cyvin , B. N. , Cyvin , S. and Samdal , S. 1985 . J. molec. Struct. , 128 : 59
  • Clebre , G. , de Luca , G. , Longeri , M. , Catalano , D. , Veracini , C. A. and Emsley , J. W. 1991 . J. chem. Soc. Faraday Trans. , 87 : 2623
  • Gray , G. W. 1987 . Thermotropic Liquid Crystals , Wiley .
  • Davidson , P. and Levelut , A. M. 1992 . Liq. Crystals , 11 : 469

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