Nandiraju Rao

Assam University, Chemistry, Faculty Member

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Jayjit Majumdar

University of Kalyani

PROF. OM PRAKASH SINHA

Amity University

Sandip Chakrabarti

Amity University

Hugh Geaney

University College Cork

Sujit Sen

National Institute of Technology Rourkela

Rafael Abargues

Universitat de València

Anis Nurashikin Nordin

International Islamic University Malaysia

Sergey Moiseev

Ulyanovsk State University

Dr.Yousery Sherif

Mansoura University

Irina Kolesnik

Moscow State University

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Papers by Nandiraju Rao

Cybotactic nematic phase of achiral unsymmetrical bent-core liquid crystals – Quelling of polar ordering and the influence of terminal substituent moiety

by Nandiraju Rao and sourav patranabish

Journal of Molecular Liquids, 2018

Abstract Nematic phase of bent-core liquid crystals (LCs) exhibiting cybotactic clusters (NCyb) h... more Abstract Nematic phase of bent-core liquid crystals (LCs) exhibiting cybotactic clusters (NCyb) have gained significant importance owing to its promising ability to demonstrate macroscopic biaxiality and the ferronematic phase. In this context, three achiral unsymmetrical four-ring bent-core LC compounds, bearing a long alkyloxy chain and differing only in the terminal substituent moiety (methyl, chloro, nitro), are designed and synthesized followed by their optical, dielectric, electro-optic and structural investigations. The presence of NCyb in the methyl and chloro substituted compounds was confirmed via dielectric spectroscopy and X-ray diffraction observations. The absence of ferroelectric behaviour in any of these compounds, even in the cybotactic nematic phase and in presence of polar substituent moieties (chloro and nitro), is attributed to the increased alkyloxy chain length and antiparallel molecular arrangement. The density functional theory (DFT) optimized molecular structure along with the experimental observations further substantiates these findings. The study establishes that cybotactic clusters and polar end moiety, although being a prerequisite for ferroelectric-like nature, do not necessarily result in a ferronematic phase.

Organization of the polarization splay modulated smectic liquid crystal phase by topographic confinement

Proceedings of the National Academy of Sciences, 2010

Recently, the topographic patterning of surfaces by lithography and nanoimprinting has emerged as... more Recently, the topographic patterning of surfaces by lithography and nanoimprinting has emerged as a new and powerful tool for producing single structural domains of liquid crystals and other soft materials. Here the use of surface topography is extended to the organization of liquid crystals of bent-core molecules, soft materials that, on the one hand, exhibit a rich, exciting, and intensely studied array of novel phases, but that, on the other hand, have proved very difficult to align. Among the most notorious in this regard are the polarization splay modulated (B7) phases, in which the symmetry-required preference for ferroelectric polarization to be locally bouquet-like or “splayed” is expressed. Filling space with splay of a single sign requires defects and in the B7 splay is accommodated in the form of periodic splay stripes spaced by defects and coupled to smectic layer undulations. Upon cooling from the isotropic phase this structure grows via a first order transition in the ...

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Development of nematic and orthogonal smectic phases in short-core fluorinated hockey-stick shaped liquid crystal compounds

Journal of Molecular Liquids

Phase Transition and Structural Studies of 70.8 and TBAA12 Liquid Crystals By Several Experimental Techniques

Molecular Crystals and Liquid Crystals

This article may be used for research, teaching, and private study purposes. Any substantial or s... more This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. E. FANELLI et al. Whereas its behaviour is similar to that of the compounds with n = Y and II = 10 for the ordered phases, the behaviour in the smectic Cphase in TBAA12 is quite different. as compared to the other homologous, perhaps owing to the absence of S , phase. In spite of this different behaviour, the jump observed in the layer thickness at the SrSc phase transition of TBAA12 is coherent with the values previously obtained for homologous with lower n.

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Cybotactic nematic phase of achiral unsymmetrical bent-core liquid crystals – Quelling of polar ordering and the influence of terminal substituent moiety

Journal of Molecular Liquids

Synthesis and Liquid Crystalline Properties of Unsymmetrically Substituted Naphthalenediimides with a Polar Headgroup: Effect of Amide Hydrogen Bonding and Alkyl Chain Length

ChemistryOpen, 2018

A series of new unsymmetrically substituted naphthalenediimide (NDI) moieties to were synthesized... more A series of new unsymmetrically substituted naphthalenediimide (NDI) moieties to were synthesized. The structures of these compounds were confirmed by means of FT-IR, H NMR, C NMR, ESI-mass and HRMS spectroscopic measurements. UV/Vis and fluorescence spectroscopy were employed to investigate the photophysical properties of the prepared compounds in solution and in the solid state. Using the onset of UV/Vis absorption, the optical band gaps were calculated. Cyclic voltammetry measurements were performed to study the electrochemical behavior and to calculate the LUMO energy levels. The thermal properties of NDI derivatives were studied by differential scanning calorimetry. The mesomorphic birefringent behavior of the NDI derivatives was investigated with polarizing optical microscopy. Among all of the studied NDI derivatives, only , , and showed liquid crystalline texture, owing to the presence of an amide linkage for H-bonding along with aromatic moieties for π-π-stacking.

Phase Transition Studies in N(p-n-Heptyloxy Benzylidene)p-Toluidine, 70.1, Across I-N, N-SA and SA-SB Phases

Molecular Crystals and Liquid Crystals

This article may be used for research, teaching, and private study purposes. Any substantial or s... more This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

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$Research paper thumbnail of Phase Transitions in N(p-n-Bu toxybenzylidene) p-n-Alkyl Anilines: Density and Refractive Index Studies$

Phase Transitions in N(p-n-Bu toxybenzylidene) p-n-Alkyl Anilines: Density and Refractive Index Studies

Molecular Crystals and Liquid Crystals

The density and refractive index variation with temperature in N(p-n-butoxybenzylidene)p-n-alkyla... more The density and refractive index variation with temperature in N(p-n-butoxybenzylidene)p-n-alkylanilines viz., 40.m compounds for m = 4 to 12 are presented. The density, thermal expansion coefficient and the refractive index results infer first order character for IN, AB and CB transitions and a second order character for NA and AC transitions. Pretransitional effects are discussed at IN and AB transitions. The odd-even effect is observed at both the IN and NA phase transitions. The variation of refractive index anisotropy as a function of temperature, in the nematic phase of the compounds in a homologous series has shown an interesting phenomena. The temperature dependence of nematic refractive index anisotropy yields mean field exponent v = 1 in the vicinity of NA transition. The influence of molecular chemical constitution, the nematic thermal range and the McMillan parameter values on the order of NA transition is discussed in detail.

Density Studies in N-(p-n-Butoxybenzylidene)-p-n-Butylaniline

Berichte der Bunsengesellschaft für physikalische Chemie

ABSTRACT The density ρ of N-(p-n-butoxybenzylidene) p-n-butylaniline (BBBA) has been measured as ... more ABSTRACT The density ρ of N-(p-n-butoxybenzylidene) p-n-butylaniline (BBBA) has been measured as a function of temperature from SH to isotropic liquid phase. The compound exhibits three smectic and two nematic phases. The phases assigned are SH ↔ SB ↔ SA ↔ NC ↔ NO ↔ I. The change of ρ across the transition SH-SB is more predominant than the other transitions. The SH-SB, SA-NC, and NC-NO transitions have been observed for the first time from density studies. The variation of ρ with temperature and the calculated thermal expansion coefficients in liquid crystalline region suggest that all the transitions are of first order. It is suggested that the transition of NC-NO at 59.4°C is cybotactic nematic to ordinary nematic phase.Die Dichte ρ von N-(p-n-butoxybenzyliden) p-n-butylanilin (BBBA) wurde als Funktion der Temperatur von SH bis zur isotropen flüssigen Phase gemessen. Die Verbindung zeigt drei smektische und zwei nematische Phasen. Die Zuordnung der Phasen ist die folgende: SH ↔ SB ↔ SA ↔ NC ↔ NO ↔ I. Die Änderung von ρ ist bei dem Übergang SH-SB stärker ausgeprägt als bei den anderen Übergängen. Die Übergänge SH-SB, SA-NC und NC-NO wurden zum ersten Mal durch Dichtemessungen beobachtet. Die Temperaturabhängigkeit von ρ und die berechneten thermischen Ausdehnungskoeffizienten für das Gebiet der flüssigkristallinen Phasen deuten darauf hin, daß alle Übergänge von erster Ordnung sind. Es wird vorgeschlagen, daß der Übergang NC-NO bei 59,4°C von einer cybotaktischen zu einer normalen nematischen Phase verläuft.

Elastic and dielectric properties of ferroelectric nanoparticles/bent-core nematic liquid crystal blend

The European physical journal. E, Soft matter, 2017

Bent-core liquid crystals present the first evidence of forming polar superstructures from achira... more Bent-core liquid crystals present the first evidence of forming polar superstructures from achiral molecules. The nematic phase is the newest member of the bent-core family and turns out to be extremely interesting owing to its distinct features compared to its calamitic counterpart. Here the investigation of one achiral unsymmetrical 2-methyl-3-amino-benzoic acid (2,6-substituted toluene)-derived four-ring bent-core nematic (BCN) liquid crystals (11-2M-F) is presented after nanodispersion. Ferroelectric nanoparticles significantly affect the phase transition temperature, threshold voltage, dielectric permittivity, elastic constants and splay viscosity of the pristine BCN. In most bent-core nematic liquid crystals the bent elastic constant (K33) is usually lower than the splay elastic constant (K11) owing to the presence of short-range smectic-C-like correlations in the nematic phase. Thus the elastic anisotropy ([Formula: see text]) is usually negative in bent-core nematics unlike ...

Synthesis and thermal behavior of chiral oligomers derived from cholesterol

Tetrahedron, Jan 3, 2009

ABSTRACT a b s t r a c t Synthesis and thermal properties of a series of Schiff base oligomers de... more ABSTRACT a b s t r a c t Synthesis and thermal properties of a series of Schiff base oligomers derived from naturally occurring cholesterol are described. In particular, four of them show smectic A and/or chiral nematic phase/s or an unknown mesophase, while the other is non-mesomorphic. Molecular packing in the SmA phase has been determined by the HRXRD experiment.

1A13 アキラルW字屈曲型液晶分子が発現する光学活性な新規液晶相(物理・物性)

日本液晶学会討論会講演予稿集, Oct 14, 2003

Highly Polarized Fluorescent Illumination Using Liquid Crystal Phase

ACS Applied Materials & Interfaces, 2016

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Novel Nonlinear Optical Chromophores Exhibiting Mesomorphism

Molecular Crystals and Liquid Crystals Science and Technology Section a Molecular Crystals and Liquid Crystals, 2003

Page 1. NOVEL NONLINEAR OPTICAL CHROMOPHORES EXHIBITING MESOMORPHISM Nandiraju VS Rao and Manoj K... more

Phase Transition Studies in 70.8 and 80.8 Benzylidene Liquid Crystals

Acta Acustica united with Acustica

ABSTRACT

Phase transition studies in polymesomorphic compounds

Il Nuovo Cimento D, 1985

The interlayer and the in-plane intermolecular distances were obtained as a function of temperatu... more The interlayer and the in-plane intermolecular distances were obtained as a function of temperature through all the mesophases. Pretransitional effects were observed at the So-Ss phase transition, which corresponds to a progressive reduction to zero of the molecule inclination angle with respect to the normal to the smectic layers. The layer thickness in the Sa phase appeared smaller than that in the SB due to molecular axial fluctuations.

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Phase Transition Studies in Polymesomorphic Compounds II. Ultrasonic Velocity Studies in N(p-n-Heptyloxy Benzylidene)p-n-Butyl Aniline

Zeitschrift für Naturforschung A, 1982

The variation of ultrasonic velocity in N (p-n-heptyloxy benzylidene)p-n-butyl aniline, (HyBBA) w... more The variation of ultrasonic velocity in N (p-n-heptyloxy benzylidene)p-n-butyl aniline, (HyBBA) with temperature in isotropic, nematic, smectic-A, smectic-C and smectic-G phases is measured. All the phase transitions I-N, N-SA, SA-SC and SC-SG are found to be of first order. The adiabatic compressibility βad, molar sound velocity or Rao number Rn, and molar compressibility or Wada constant AW are computed. Rn and AW of HyBBA are compared with theoretical values and found to be in good agreement with the theory.

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Green Synthesis of Gold and Silver Nanoparticles Using Achyranthes Aspera L. Leaf Extract

The importance of leaf extract of Achyranthes aspera L. as reducing agent in the synthesis of gol... more The importance of leaf extract of Achyranthes aspera L. as reducing agent in the synthesis of gold, silver nanoparticles (NPs) in quantitative yield, by the reaction of aqueous chloroaurate ions and aqueous silver ions with a small quantity of leaf extract is demonstrated. Changes in concentration of leaf extract can modify the phase morphology and the size of the nanoparticles can be tuned. UV-Visible spectra of the solution evidenced the variation in the dimension of anisotropic nanostructures. The formation of spherical nanostructures and nanotriangles of noble metal gold and silver nanoparticles is confirmed by transmission electron microscopy (TEM) investigations. The gold nanoparticles are poly dispersed and the average size of spherical nanoparticles is found to be 183 ± 10 nm. The average edge length of the triangle is 272 ± 20 nm. Selected area diffraction pattern (SAED) confirmed the polycrystalline molecular structure. SAED diffraction patterns of biogenic silver nanotria...

Influence of Electric and Magnetic Fields on the Molecular Alignment in EBBA

Molecular Crystals and Liquid Crystals, 1976

The effects of external dc and af electric fields of strengths up to 25 kV/cm on the nematic liqu... more The effects of external dc and af electric fields of strengths up to 25 kV/cm on the nematic liquid crystal p-ethoxybenzylidene-p'-n-butyl aniline (EBBA) are investigated. The effectiveness of electric fields and of high magnetic fields in producing molecular alignment are compared. Changes in the molecular alignment are observed in terms ofchanges in the rf dielectric constant. These measurements are as fruitful as microwave measurements in studying the degree of ordering of molecules in bulk samples of liquid crystals. The threshold voltages for chevron formation in the dielectric regime are found to be considerably lower than the threshold voltages necessary to induce changes in dielectric constant in the same regime.

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Effective flow viscosities of four-ring bent-core material

Cybotactic nematic phase of achiral unsymmetrical bent-core liquid crystals – Quelling of polar ordering and the influence of terminal substituent moiety

by Nandiraju Rao and sourav patranabish

Journal of Molecular Liquids, 2018

Organization of the polarization splay modulated smectic liquid crystal phase by topographic confinement

Proceedings of the National Academy of Sciences, 2010

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Development of nematic and orthogonal smectic phases in short-core fluorinated hockey-stick shaped liquid crystal compounds

Journal of Molecular Liquids

Phase Transition and Structural Studies of 70.8 and TBAA12 Liquid Crystals By Several Experimental Techniques

Molecular Crystals and Liquid Crystals

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Cybotactic nematic phase of achiral unsymmetrical bent-core liquid crystals – Quelling of polar ordering and the influence of terminal substituent moiety

Journal of Molecular Liquids

Synthesis and Liquid Crystalline Properties of Unsymmetrically Substituted Naphthalenediimides with a Polar Headgroup: Effect of Amide Hydrogen Bonding and Alkyl Chain Length

ChemistryOpen, 2018

Phase Transition Studies in N(p-n-Heptyloxy Benzylidene)p-Toluidine, 70.1, Across I-N, N-SA and SA-SB Phases

Molecular Crystals and Liquid Crystals

This article may be used for research, teaching, and private study purposes. Any substantial or s... more This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

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$Research paper thumbnail of Phase Transitions in N(p-n-Bu toxybenzylidene) p-n-Alkyl Anilines: Density and Refractive Index Studies$

Phase Transitions in N(p-n-Bu toxybenzylidene) p-n-Alkyl Anilines: Density and Refractive Index Studies

Molecular Crystals and Liquid Crystals

Density Studies in N-(p-n-Butoxybenzylidene)-p-n-Butylaniline

Berichte der Bunsengesellschaft für physikalische Chemie

Elastic and dielectric properties of ferroelectric nanoparticles/bent-core nematic liquid crystal blend

The European physical journal. E, Soft matter, 2017

Synthesis and thermal behavior of chiral oligomers derived from cholesterol

Tetrahedron, Jan 3, 2009

1A13 アキラルW字屈曲型液晶分子が発現する光学活性な新規液晶相(物理・物性)

日本液晶学会討論会講演予稿集, Oct 14, 2003

Highly Polarized Fluorescent Illumination Using Liquid Crystal Phase

ACS Applied Materials & Interfaces, 2016

Download

Novel Nonlinear Optical Chromophores Exhibiting Mesomorphism

Molecular Crystals and Liquid Crystals Science and Technology Section a Molecular Crystals and Liquid Crystals, 2003

Page 1. NOVEL NONLINEAR OPTICAL CHROMOPHORES EXHIBITING MESOMORPHISM Nandiraju VS Rao and Manoj K... more

Phase Transition Studies in 70.8 and 80.8 Benzylidene Liquid Crystals

Acta Acustica united with Acustica

ABSTRACT

Phase transition studies in polymesomorphic compounds

Il Nuovo Cimento D, 1985

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Phase Transition Studies in Polymesomorphic Compounds II. Ultrasonic Velocity Studies in N(p-n-Heptyloxy Benzylidene)p-n-Butyl Aniline

Zeitschrift für Naturforschung A, 1982

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Green Synthesis of Gold and Silver Nanoparticles Using Achyranthes Aspera L. Leaf Extract

Influence of Electric and Magnetic Fields on the Molecular Alignment in EBBA

Molecular Crystals and Liquid Crystals, 1976

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Effective flow viscosities of four-ring bent-core material

Nandiraju Rao

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