Molecular structure and smectic properties: the substituent effect on the smectic A phase in biphenyl ester systems

Takeda, Hitoshi; Sakurai, Yasuhisa; Takenaka, Shigeori; Miyake, Hajime; Doi, Takashi; Kusabayashi, Shigekazu; Takagi, Tatsuya

doi:10.1039/ft9908603429

Cited by 41 publications

(11 citation statements)

References 10 publications

(2 reference statements)

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“…The C(15B) 0.6907 (6) 1.0980(2) 0.7699 (7) 0.064 (2) distances are, however (6) The crystal of 4-octyloxypheny l 4¾ -(1-methylheptyloxy) -C(9A) 1.2472 (7) 0.3189 (1) 0.6348 (9) 0.080 (2) biphenyl-4-carboxylat e (8*O-O8 ) [2] belongs to this C(10A) 1.2964 (7) 0.3421 (1) 0.5423 (9) 0.073 (1) mode with corresponding distances of 3.39-3.58 A Ã for C(11A) 1.3793 (7) 0.3410 (1) 0.3512 (9) 0.076(2) C(12A) 1.4139 (7) 0.3167 (1) (7) 1.1899 (6) 0.081 (1) biphenyl-4-carboxylat e (10-COO8*) [14]. The reported behaviour [1,7] was con rmed for 8O-O8, Table 9. Atomic coordinates and equivalent isotropic dis- Table 8.…”

Section: Resultsmentioning

confidence: 89%

“…NonAll the compounds were synthesized by conventional hydrogen atoms were re ned anisotropically. Hydrogen methods [7]. Single crystals were obtained by slow atoms calculated geometrically were included in the calcuevaporation from the solutions described in Table 4.…”

Section: Introductionmentioning

confidence: 99%

“…The v scan mode 4¾ -methoxybiphenyl-4-carboxylat e (1O-8), and 4-octylwas applied. Three standard re ections were measured phenyl 4¾ -methylbiphenyl-4-carboxylat e (1)(2)(3)(4)(5)(6)(7)(8).…”

Section: Introductionmentioning

confidence: 99%

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Packing modes in crystals of mesogenic biphenyl esters with normal alkyl and/or alkoxy chains

Seo

Hori

2001

Liquid Crystals

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Crystal structures determined for eight compounds R-C 6 H 4 -C 6 H 4 -COO-C 6 H 4 -R¾ , where R and R¾ are achiral, four with octyloxy and/or octyl chains and four with a methyl or methoxy group at one end, are classi ed into three modes. First is a smectic-like layer composed of parallel molecules with closely arranged ester linkages; second is a layer comprising two crystallographically independent molecules, among which the ester linkages are close. Compounds with an octyloxy chain take these modes. Thirdly, for molecules with alkyl chains, the ester linkages are far apart among the parallel molecules. Melting and clearing points suggest stronger intermolecular interactions in the former two modes than in the last mode.

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Section: Resultsmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

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Packing modes in crystals of mesogenic biphenyl esters with normal alkyl and/or alkoxy chains

Seo

Hori

2001

Liquid Crystals

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“…PC-Containing compounds containing the ester moiety R 3 exhibit a broad interval of SmA phase (ferrocene analogues also exhibited a tendency to form smectic phases; however, these were detected only over a narrow temperature interval [16]). Benzene derivatives containing substituents of type R 2 and R 3 revealed the same mesogenic tendencies with respect to the mesophase type [17] [18] as those observed for the investigated cyclophane-containing compounds: as suggested in [18] both structural (unfavourable −bent× shape of fragment R 2 ) and electronic factors can explain the different mesogenic tendency of the derivatives with fragments R 2 and R 3 . c) Disubstituted para-PC Derivatives IIIa ± d. To study the influence of the substituent position on the mesophase behaviour of paracyclophane derivatives, compounds containing the same type of substituents (R 1 , R 2 or R 3 ) in para-position of the cyclophane moiety were synthesized, and the mesomorphic behaviour was compared with that of pseudo-para-PC analogues, as well as with the structurally related ferrocenomesogenes [19] [20].…”

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confidence: 89%

Thermotropic Liquid Crystals from Planar Chiral Compounds: [2.2]Paracyclophane as a Mesogen Core

Rozenberg

Popova

Hopf

2002

HCA

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New thermotropic mesomorphic compounds containing a [2.2]paracyclophane (PC) unit were synthesized and investigated (Scheme). Carboxylic acids were selected as the starting PC building blocks. The influence of structural features on the stability of the mesomorphic phases was studied (Figs. 1 and 2): for this purpose, the structures of the PC-carboxylate unit and the organic fragment of the aryl-ester moiety were varied systematically. Esters derived from PC-monocarboxylic acid did not exhibit liquid-crystalline (LC) properties, while diaryl PC-dicarboxylates favored mesomorphism. Dicarboxylate substituents arranged in the paraposition provided LC phases in a broad temperature range and considerably increased the mesomorphic interval in comparison with that of the structurally related pseudo-para PC derivatives.Introduction. ± Unique physical properties, providing wide application in electrooptic devices and particularly the recent discovery of new mesophases, such as antiferroelectric, ferrielectric, and twist-grain boundary phases, have put chiral liquidcrystalline (LC) materials in the centre of liquid-crystal research [1] [2]. Historically, up to now, most chiral LC compounds contain molecules incorporating a centre of chirality. More recently, compounds with planar and axial chirality are beginning to attract the growing interest of researchers dealing with LC materials. The unique geometry of this type of compounds provides a rigid interaction between the origin of the symmetry-breaking chirality and the mesogenic unit, thus resulting in a definite fixation of the source of chirality in a LC matrix.In principle, planar chirality could drastically change the physical properties of the resultant LC material: 1) In terms of molecular structure, a rigid steric coupling between the transverse dipole, chiral centre, and the mesogen rod should maximize the local ferroelectric polarization [3], allowing consideration of the above compounds as possible chiral dopants for ferroelectric compositions, which are able to confer a high value of spontaneous polarization (P s ) to the achiral host [4]. 2) Electro-optical effects exhibited by LC materials such as electroclinic effects or nonlinear optical (NLO) properties are expected to be larger for compounds with rigid interaction between the chiral and optical portions of the molecule [5].However, the bulkiness of the structural units necessary to realize an axis or a plane of chirality significantly disturbs the desired rigid rod-like shape of the molecule, thus creating a serious obstacle to achieving stable mesomorphic properties. So far, only a

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“…T hermal and general data mesomeric eOE ect of the nitro group [14] induces a Many attempts have been made to understand such positive charge on the nitrogen atom and increases the factors as the electronic and geometrical parameters of electronegativity of the group [15]. The mesomeric molecular substituents in uencing mesophase behavior interaction with the other part of the molecule is basically [1][2][3][4][27][28][29][30][31][32][33]. However, the prediction and rationalizatio n reduced simultaneously and only appears in the case of the mesomorphic properties of liquid crystals still of strong electron-donation which leads to throughremain di cult problems [2,3,5,27,.…”

Section: Introductionmentioning

confidence: 99%

Nitro substitution in achiral calamitic liquid crystals

Petrov¹,

Shimizu

2001

Liquid Crystals

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Molecular structure and smectic properties: the substituent effect on the smectic A phase in biphenyl ester systems

Cited by 41 publications

References 10 publications

Packing modes in crystals of mesogenic biphenyl esters with normal alkyl and/or alkoxy chains

Packing modes in crystals of mesogenic biphenyl esters with normal alkyl and/or alkoxy chains

Thermotropic Liquid Crystals from Planar Chiral Compounds: [2.2]Paracyclophane as a Mesogen Core

Nitro substitution in achiral calamitic liquid crystals

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