J. Shashidhara Prasad

Theory of Rotatory Dispersion of Cholesteric Liquid Crystals

A theory is developed of the circular dichroism and rotatory power of thin films of cholesteric liquid crystals. It is an extension of the treatment for infinitely thick specimens discussed in a previous paper. The therory predicts that the circular dichroism of a thin film plotted as a function of wave-length should exhibit a principal maximum accompanied by subsidiary maxima, and that the rotatory dispersin should be anomalous. Experimental circular dichroism and rotatory dispersion curves are presented for cholesteric cinnamate, cholesteryl-2-propyn-1-yl carbonate and spectratherm. The results are in qualitative agreement with the theory both inside and outside the region of reflexion. The rotatory dispersion curves are also in accord with the de Vries equation outside the region of reflexion.

Crystal structure of 4-n-nonylbenzoic acid

The title compound, 4-n-nonylbenzoic acid, CH3(CH2)8C6H4COOH (NBA), has been characterized thus: triclinic, P1, a = 13.514(4)Å, b = 23.4672(5)Å, c = 7.658(3)Å, alpha = 90.914(3)°, beta = 100.403(3)°, gamma = 77.781(2)°, V = 2334(2)Å3, Z = 2, and F.W = 745.06, Dm = 1.161 g cm-3, Dc = 1.061 g cm-3, F000 = 816.00, lambda = 0.71069Å, mu = 0.6 cm-1, goodness-of-fit is 1.029, final R1 = 0.063 and wR2 = 0.16.

Orientational order in the nematogenic homologous series trans‐4‐alkyl (4‐cyanophenyl)‐cyclohexane

The temperature variation of refractive indices (ne,no), birefringence (Δn), density (ρ), and order parameter of the homologous compounds trans‐4‐alkyl (4‐cyanophenyl)‐cyclohexane are reported in the nematic and isotropic phases. The principal molecular polarizabilities (αe,αo) and the order parameters S have been evaluated using the anisotropic internal field model (Neugebauer’s approach). The theoretical estimations of the mean and principal molecular polarizabilities made by two different approaches, viz., the additivity rule of bond polarizability and the modified Lippincott‐δ‐function potential model are in close agreement with the values evaluated from the experimental studies.

The first copper(I) complex of tris(hydroxymethyl)phosphine

The first copper(I) complex of tris(hydroxymethyl)phosphine (THP) has been synthesized from a reaction with [Cu(CH3CN)4]ClO4. The crystal structure and spectroscopic properties of this complex showing the tetrahedral coordination around copper and a deprotonated THP coordinated to Cu through P are presented.

Crystal structure of 4-n-nonyl-4'-cyanobiphenyl

4-n-Nonyl-4′-cyanobiphenyl, C22H27N, M r= 305.45, triclinic, P1, a=9.765(1)A, b= 11.460(2)A, c=17.860(2)A, α=85.460(2), β=80.870(1), γ=71.630(1), V=1871.9(3)A3, Z= 4, D m=1.079M g-3, D c= 1.084 M g -3, μ=0.463 mm -1, F(000)=664, lambda (CuKα)=1.5418A, final R and wR2 are 0.0523 and 0.1559, respectively.

Refractive Indices and Molecular order in 4,4′Bis (Pentyloxy)azoxy Benzene in the Nematic State

Abstract The refractive indices and densities of 4,4Bis(pentyloxy)azoxy benzene [CH3(CH2)4OC6H4N:N(:O)C6H4O(CH2)4CH3] have been measured in the crystalline, nematic and isotropic phases. The orientational order parameters and polarizabilities in the mesophase have been evaluated by Neugebauers approach for several temperatures and wavelengths. The order parameter at the same temperature for different wavelengths turns out to be same. The universal curve of the order parameter is given.

Hydrothermal synthesis, structure and characterization of new NASICON related potassium iron (III) pyrophosphate

A new potassium iron (III) pyrophosphate was synthesized by hydrothermal technique and characterized by X-ray studies. The compound crystallizes in a monoclinic space group,P21/c, with cell parameters,a = 7 365(2) Å,b = 10017(2) Å,c = 8.214(1) Å,β = 106.50(1)° andZ = 4. The structure has tunnel-type cavities and are congenial for ion transportation through them. The compound exhibits moderate thermal stability.

Orientational order parameters and conformation of nematic p-ethoxybenzylidene-p-n-butylaniline.

Orientational order parameters for nematic liquid crystalline compound p‐ethoxybenzylidene‐p‐n‐butylaniline (EBBA) have been estimated by studying the dipole–dipole splitings in the wide line NMR absorption spectra. An attempt has been made to determine the conformation of the same by the NMR studies of one specifically deuterated derivative of the compound.

Synthesis and characterization of a new polymorphic modification of AlPO4

Synthesis of a new polymorphic modification of aluminum orthophosphate has been carried out by the hydrothermal method. Crystals were characterized by various methods such as X-ray diffraction, chemical analysis, morphology, DTA, IR spectroscopy and the study of some of its physical properties. This new modification of AlPO4 crystallizes in the monoclinic system, a = 8.63 A, b = 4.89 A, c = 5.03 A, β = 113.3° and V = 194.96 A3. Sodium was introduced into the composition of this new modification of AlPO4 in order to obtain a Na fast ionic conductor.

Synthesis and crystal structure of 1-(4-fluorophenyl)-3-(3,4,5-trimethoxyphenyl)-2-propen-1-one

The title compound C18 H17FO4 was synthesized and recrystallized from an organic solution. The crystal structure of 1-(4-fluorophenyl)-3-(3,4,5-trimethoxyphenyl)-2-propen-1-one was determined by X-ray diffraction analysis. The title compound crystallizes in the monoclinic crystal class in the space group P21/c with cell parameters a = 7.6930(6) Å, b = 15.2320(11)Å, c = 14.1280(12) Å, β = 106.596(3)°, Z = 4, and V = 1586.6(2) Å3. The unsaturated keto group is not strictly planar and is in a s-cis conformation.