scholarly journals Study of the Effect of Chalconyl Central Bridge on Mesomorphism

2015 ◽  
Vol 61 ◽  
pp. 19-27 ◽  
Author(s):  
P.K. Rakhasia ◽  
G.N. Bhola ◽  
Umed C. Bhoya
Keyword(s):  
Liquid Crystals ◽  
Homologous Series ◽  
Molecular Structures ◽  
Series Data ◽  
Molecular Formula ◽  
Group Efficiency ◽  
Similar Series ◽  
Molecular Rigidity ◽  
Derivatives Of ◽  
Optical Polarizing Microscopy

A novel homologous series of chalconyl ester derivatives of thermotropic type of liquid crystals (LC) variety have been synthesized with its general molecular formula RO-C6H4-CH=CH-COO-C6H4-CO-CH=CH-C6H4-N(CH3)2 (Para). Present investigation is planned with a view to understand and establish the relation between molecular structure and the mesomorphic behaviorur of the constituent homologue derivatives as well as to avail novel mesomorphic (LC) substances to the researcher working on multidisciplinary thermotropic LC material with different aims, objects and views at different angles. Novel homologous series consists of twelve homologues C1 to C5 homologues are nonliquid crystals (NLC) and the rest of the C6 to C16 are monotropically nematogenic liquid crystals. Transition temperatures and texture of the LC and NLC were determined by an optical polarizing microscopy equipped with heating stage (POM). Textures of nematic phase are threaded or schlieren. Analytical and spectral data confirms the molecular structures of homologues. Thermal stability for monotropy is very low of the magnitudes of few second and of negligible degree of temperature difference. Thermal properties of present novel series are compared with of structurally similar series, data interpreted in terms of molecular rigidity and flexibility to derive group efficiency order.

scholarly journals Molecular Rigidity/Flexibility Dependence of Mesomorphism

2015 ◽  
Vol 60 ◽  
pp. 120-128 ◽  
Author(s):  
N.R. Muniya ◽  
V.R. Patel
Keyword(s):  
Molecular Structure ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Molecular Structures ◽  
Transition Curve ◽  
Polarizing Microscopy ◽  
Group Efficiency ◽  
Normal Manner ◽  
Molecular Rigidity ◽  
Optical Polarizing Microscopy

A novel chalconyl homologous series of liquid crystalline derivatives; RO - C6H4- CH : CH - COO - C6H4-CO - CH : CH - C6H4 - OC8H17 (n) (para) have been synthesized and studied with a view to correlate the thermotropic liquid crystal (LC) behavioural properties and the molecular structure of a substance. Present novel series consisted of eleven homologue members (C1 to C16) whose, only nematogenic mesomorphism commences from C3 homologue and continued upto C16 homologue in enantiotropic manner with absence of smectogenic character. Transition temperatures and textures of nematic phase were determined using an optical polarizing microscopy equipped with a heating stage (POM). Transition curve Cr-N/I behaved in normal manner. N-I transition curve exhibited odd-even effect and deviated from its normal descending tendency from and beyond C8 homologue and adopted serpantile shape from C8 to C16 homologue in deviating manner. Textures of the nematic phase are threaded or schlieren. Analytical and spectral data supported molecular structures of homologues. Thermal stability for nematic is 112.66 and the degree of mesomorphism vary from 5.00C to 44.00C at the C12 andC4 homologue respectively. It is a middle ordered melting type series, whose relative group efficiency order for nematic derived.

scholarly journals Study of Thermotropic Mesomorphismin Nonlinear and Linear Isomeric and Nonisomeric Series

2015 ◽  
Vol 60 ◽  
pp. 1-10
Author(s):  
B.B. Jain ◽  
R.B. Patel
Keyword(s):  
Homologous Series ◽  
Liquid Crystalline ◽  
Molecular Structures ◽  
Transition Curve ◽  
The Novel ◽  
Transition Temperatures ◽  
Group Efficiency ◽  
Normal Manner ◽  
Optical Polarizing Microscopy ◽  
Transition Curves

Chalconyl homologous series: RO-C6H4-COO-C6H4(m)-CO-CH=CH-OC14H29(n) para has been synthesized and studied with a view to establish the relation between the molecular structure and thermotropic Liquid crystalline (LC) properties. Novel nonlinear series consists of thirteen members (C1 to C18) of a series. C6 to C18 members are enantiotropically nematogenic and the rest of the homologues ( C1 to C5 ) are nonliquid crystals (NLC). Smectogenic character is totally absent. Transition temperatures and the textures of the novel homologues were determined by an optical polarizing microscopy (POM) equipped with a heating stage. Textures of a nematic phase are threaded or schlieren. Transition curves Cr-N/I and N-I behaved in normal manner. N-I transition curve exhibited odd-even effect. Analytical and spectral data confirmed the molecular structures of homologues. Thermal stability is 107.0 and mesomorphic nematogenic degree of mesomorphism vary minimum to maximum are 17.0°C to 35.0°C at the C14 and C8 homologues respectively. Some mesogenic properties of presently investigated homologous series are compared with structurally similar isomeric and nonisomeric homologous series, and their group efficiency order derived. Thus, present novel series is nematogenic with absence of smectogenic character whose nematogenic transition temperatures vary from 74.0°C to 117.0°C.

scholarly journals Dependence of Mesomorphism on Molecular Rigidity

2015 ◽  
Vol 47 ◽  
pp. 67-76 ◽  
Author(s):  
R.R. Rola ◽  
G.N. Bhola ◽  
Umed C. Bhoya
Keyword(s):  
Homologous Series ◽  
Molecular Structures ◽  
Polarizing Microscopy ◽  
Normal Manner ◽  
Crystal Properties ◽  
Thermal Data ◽  
Molecular Rigidity ◽  
Optical Polarizing Microscopy ◽  
Transition Curves ◽  
Phase Length

A novel smectogenic homologous series of twelve homologues synthesized and studied with a view to understand and establish the effect of molecular structure on liquid crystal properties (LC) and LC behaviors of thermotropic homologues. First (C1) to last (C16) member of a series exhibited only enantiotropically smectogenic property without showing nematic property which is absent even in the monotropic condition. Transition and melting temperature including textures of homologues were determined by an optical polarizing microscopy equipped with a heating stage, texture of a smectic phase are of the type A or C. Smectogenic phase length ranger between 5.1°C to 22.6°C. Smectic-Isotropic (Sm-I) thermal stability is 153.55°C. Analytical, spectral and thermal data supported molecular structures of homologues. LC behaviors of present novel series are compared with the structurally similar homologous series. Transition curves viz. Cr-Sm and Sm-I transition curves of a phase diagram behaved in normal manner.

scholarly journals Mesomorphism Dependence on Cis-Trans Configuration and Varying Terminal/Lateral Group

2016 ◽  
Vol 65 ◽  
pp. 71-79
Author(s):  
G.N. Bhola ◽  
Umed C. Bhoya
Keyword(s):  
Thermal Stability ◽  
Homologous Series ◽  
Vinyl Ester ◽  
Molecular Structures ◽  
Transition Curve ◽  
Group Efficiency ◽  
Lateral Group ◽  
Normal Manner ◽  
Thermotropic Liquid Crystals ◽  
Transition Curves

A chalconyl trans vinyl ester homologous series of thermotropic liquid crystals RO-C6H4-CH=CH-COO-C6H4-CH=CH-CO-C6H3(OCH3)2meta-para is synthesized and studied with a view to understand and establish the relation between molecular structure and mesomorphism or mesomorphic behaviors. Novel homologous series consists of thirteen homologues (C1to C18). First five (C1to C5) homologues are nonmesogenic. Rest of the homologues (C6to C18) homologues is mesogenic. Monotropically smectogenic character appears from C6to C10homologue and C12to C18homologues are enantiotropically smectogenic. Nematogenic property is totally absent throughout a series. Textures of smectic phase are of the type smectic A or C. Transition curves of a phase diagram behaved in normal manner. Analytical, spectral and thermal data supports the molecular structures of homologues. Odd-even effect is observed for Sm-I/I-Sm transition curve. Thermal stability for smectic is 93.7 °C and the mesomorphic phase lengths from enantiotropic homologues for smectic from minimum to maximum is 6.0 °C to 28.0 °C at the C12and C18homologue respectively. Series is smectogenic without exhibition of nematic property. The group efficiency order on the basis of thermal stability is derived; from comparative study of present series and analogous series.

scholarly journals Study of Mesomorphism in Isomeric and Nonisomeric Linear and Nonlinear Chalconyl Series

2015 ◽  
Vol 60 ◽  
pp. 182-191 ◽  
Author(s):  
Vinay S. Sharma ◽  
R.B. Patel
Keyword(s):  
Molecular Structure ◽  
Homologous Series ◽  
Nematic Phase ◽  
Molecular Structures ◽  
Transition Curve ◽  
Geometrically Nonlinear ◽  
Group Efficiency ◽  
Normal Manner ◽  
Linear And Nonlinear ◽  
Transition Curves

A novel nonlinear chalconyl homologous series of ester: RO-C6H4-COO-C6H4 (m)-CO-CH:CH-C6H4-OC16H33(n) (para) have been synthesized and studied with a view to understand and establish the relation between thermotropic liquid Crystal (LC) properties and geometrically nonlinear shaped molecular structure. Homologous series consists of thirteen members ( C1 to C18) whose enantiotropic nematogenic mesomorphism commences from C6 homologue without exhibition of smectic property. C1 to C5 homologues are nonmesomorphic. Transition temperatures and textures of homologues were determined by an optical polarising microscopy equipped with a heating stage (POM). Transition curves of a phase diagrams (Cr-N/I and N-I) behaved in normal manner. N-I transition curve exhibited odd-even effect. Textures of a nematic phase are threaded or schlieren. Analytical and spectral data supported molecular structures of homologues. Thermal stability for nematic is 104.5°C whose degree of mesomorphism vary minimum of 13.0°C to maximum of 37.0°C. Group efficiency order for nematic is derived by comparing present novel series with structurally analogous other homologous series. Thus, homologous series of present investigation is nematogenic with absence of smectic property and of middle ordered melting type with considerable degree of mesomorphism.

scholarly journals Study of the Effects of Lateral Substitution (Bromo) on Mesomorphic Behaviours of Chalconyl Ester Derivatives

2016 ◽  
Vol 64 ◽  
pp. 135-143
Author(s):  
Ravindra Solanki ◽  
R.B. Patel
Keyword(s):  
Homologous Series ◽  
Present Series ◽  
Transition Curve ◽  
Melting Points ◽  
Polarizing Microscopy ◽  
Group Efficiency ◽  
Normal Manner ◽  
Crystal Properties ◽  
Optical Polarizing Microscopy ◽  
Mesomorphic Properties

Novel homologous series: RO-C6H4-COO-C6H3-Br-CO-CH=CH-C6H4-OC18H3(n) (ortho bromo to –COO-) is synthesized and studied with a view to understand and establish the relation between mesomorphic properties and the molecular structure with reference to lateral substitution of bromine (-Br) at middle phenyl ring. Chalconyl homologous series consists of thirteen between (C1to C18) homologues. Nematogenic mesomorphism commences from C5homologue and continue up to C18homologue in enantiotropic manner. Transition and melting points were determined by an optical polarizing microscopy (POM) equipped with a heating stage. Textures of nematic phase are threaded or schlieren. Transition curve Cr-N/I behaved in normal manner. N-I transition curve exhibited odd-even effect up to C8homologue. It (N-I) rises and fall with negligible deviations from its normal descending tendency which appears in case of homologues C10to C18. Thermal stability for nematic is 142.89 °C and the mesophase lengths vary minimum 8.0 °C to maximum 26.0 °C at the C7and C8homologue respectively. Liquid Crystal properties of present series are evaluated and compared with structurally analogous series and relative group efficiency order derived. Thus ,present series is predominantly nematogenic with absence of Smectic property. Analytical and spectral data supported moleculars of homologues.

scholarly journals Molecular Flexibility Operated Mesomorphism

2015 ◽  
Vol 52 ◽  
pp. 163-171 ◽  
Author(s):  
Rajesh B. Marathe ◽  
N.N. Vyas ◽  
A.V. Doshi
Keyword(s):  
Molecular Structure ◽  
Nematic Phase ◽  
Molecular Structures ◽  
Transition Curve ◽  
Transition Temperatures ◽  
Polarizing Microscopy ◽  
Normal Manner ◽  
Similar Series ◽  
Optical Polarizing Microscopy ◽  
Phase Length

Novel homologous series: RO-C6H4-CH=CH-COO-CH2-C6H4-Br (p) synthesized and studied with a view to understand and establish the effects of molecular structure on liquid crystal (LC) behavior of a series. Series consists of eleven homologues. C1 to C7 members of a novel series are non-liquid crystals. Mesomorphism commences from Octyloxy (C8) homologue and continued upto hexadecyloxy homologue (C16) as enantiotropic nematic without exhibition of smectic property. The textures of a nematic phase are threaded or Schlieren. Transition temperatures (table-2) and textures are determined by an optical polarizing microscopy equipped with a heating stage. Cr-N/I and N-I transition curve behaved in normal manner in phase diagram, showing their phase behavior (figure-1). Odd-even effect is absent for N-I transition curve. Analytical and spectral data confirmed the molecular structures of a series. The LC properties are compared with the structurally similar series. The transition temperatures are relatively lower than the corresponding n-alkoxy benzoic acid. Thus, present novel series is partly nematogenic with absence of smectic property whose mesogenic phase length is low and of low ordered melting type. Thermal stability for nematic is 93.0°C and the mesophaselength ranges from 8 to 21°C.

scholarly journals Mesomorphism Molecular Rigidity and Flexibility

2015 ◽  
Vol 51 ◽  
pp. 61-68 ◽  
Author(s):  
Y.B. Dudhagara ◽  
G.N. Bhola ◽  
Umed C. Bhoya
Keyword(s):  
Liquid Crystalline ◽  
Molecular Structures ◽  
Transition Curve ◽  
Thermal Stabilities ◽  
Smectic Phases ◽  
Normal Manner ◽  
Molecular Rigidity ◽  
Nematic Phases ◽  
Optical Polarizing Microscopy ◽  
Transition Curves

A novel homologous series of liquid crystalline (LC) behaviors of Schieff’s bases: RO-C6H4-CH=CH-COO-C6H4-N=CH-C6H4-OC2H5 have been synthesized and studied with a view to understand and establish the effect of molecular structure on LC properties of a novel substances. The members of a novel series are enantiotropically nematogenic (C1 to C10) or the some of the homologues (C12 to C18) are smectogenic phase nematogenic. Transition temperatures, textures and melting behaviors observed or determined by an optical polarizing microscopy equipped with a heating stage. Thermometric temperatures are varied between 102 °C and 311 °C. Textures of the nematic phases are threaded or schlieren and that of the smectic phases are of the type A or C. Smectic and nematic thermal stabilities are 122.5 °C and 270.7 °C. Total mesophase lengths vary from 111.0 °C to 194.0 °C. Analytical and spectral data confirms the molecular structures of homologues. Some LC properties o present novel series are compared with the structurally similar known series. Transition curves viz. Cr-M, Sm-N and N-I behaved in normal manner. N-I transition curve exhibited odd-even effect. Thus present novel series is partly smectogenic and fully nematogenic with high mesophase length and higher observed melting type

scholarly journals Mesomorphism Dependence on Molecular Flexibility at Constant Rigidity

2015 ◽  
Vol 50 ◽  
pp. 1-8
Author(s):  
D.T. Pidwani ◽  
G.N. Bhola ◽  
Umed C. Bhoya
Keyword(s):  
Thermal Stability ◽  
Liquid Crystal ◽  
Homologous Series ◽  
Molecular Structures ◽  
Smectic A ◽  
Crystal Properties ◽  
Smectic Mesophase ◽  
High Transition ◽  
Nematic Phases ◽  
Optical Polarizing Microscopy

A Novel homologous series of high transition temperature RO-C6H4-CH=CH-COO-C6H4-N=CH-CH=CH-C6H5 has been synthesis and studied with a view to understand establish and evaluate the relation between liquid crystal properties and the molecular structure of a substance. A series consists of thirteen homologues. All the homologues are mesogenic. Smectic mesophase commences from C12 to C18 homologues. Nematic mesophase appears from C1 to C18 homologues. The textures of a nematic phases are of threaded or schlieren and that of the smectic phase are focal conic fan shaped of smectic-A or C type. Transition temperatures and textures were determined by an optical polarizing microscopy equipped with a heating stage. The analytical and spectral data confirms the molecular structures of homologues. Thermal stability for smectic and nematic are 118.5 0C and 224.77 °C, whose total mesophase length ranger from 73.0 °C to 111 °C. The liquid crystal properties from homologue to homologue varies in the same series. Some liquid crystal properties of present series are compared with the structurally similar known homologous series. Present novel homologous series is partly smectogenic and fully nematogenic and of higher ordered melting type and high thermal stability

scholarly journals Dependence of Liquid Crystalline Behaviors on Molecular Flexibility

2015 ◽  
Vol 47 ◽  
pp. 77-86 ◽  
Author(s):  
S.A. Maheta ◽  
G.N. Bhola ◽  
Umed C. Bhoya
Keyword(s):  
Liquid Crystal ◽  
Homologous Series ◽  
Liquid Crystalline ◽  
Molecular Structures ◽  
Melting Temperatures ◽  
Normal Manner ◽  
Optical Polarizing Microscopy ◽  
Transition Curves ◽  
Mesomorphic Properties ◽  
Phase Length

A novel homologous series of thermotropic liquid crystal (LC) has been synthesized with a view to understand and establish the effect of molecular structure on liquid crystal behaviors of a series. The present LC series consist of twelve homologues (C1 to C16); whose mesomorphic properties commence from octyloxy (C8) homologue of a series. C8, C10 and C12 members of a series are monotropic smectic and C14, C16 members are enantiotropically smectogenic. C1 to C7 homologues are nonmesomorphic. Nematogenic property is totally absent. Transition and melting temperatures are determined by an optical polarizing microscopy equipped with a heating stage. Textures of smectic mesophases are focal conic three or two dimensional networking of the type A or C. Cr-I/Sm and Sm-I or I-Sm transition curves behaved in normal manner. Analytical and spectral data confirms the molecular structures of homologues. Thermal stability of smectogenic mesophase is 100.6 oC and mesomorphic phase length is very short (12.9 °C to 15.3 oC). LC properties of a present novel series are compared with the structurally similar homologous series. Present series is partly smectogenic and partly non mesomorphic with poor degree of mesomorphism and middle ordered melting type without exhibition of nematogenic behavior.

Sign in / Sign up

Export Citation Format

Share Document