1-(2-Chloro-phen-yl)-3-(2-ethyl-hexa-noyl)thio-urea.

In the title compound, C15H21ClN2OS, the central chromophore moiety (C2N2OS) is approximately planar, with a maximum deviation of -0.027 (1) Å, and is oriented at a dihedral angle of 86.7 (1)° with respect to the chloro-phenyl ring. An intra-molecular N-H⋯O hydrogen bond stabilizes the mol-ecular conformation. In the crystal, mol-ecules associate via N-H⋯S hydrogen bonds, forming inversion dimers with motif R 2 (2)(8). These dimers are further connected by N-H⋯O hydrogen bonds, forming R 2 (2)(12) dimers. As a result, hydrogen-bonded chains running along [110] are formed. C-H⋯S inter-actions also occur. The terminal two C atoms of the butyl chain are disordered over two positions with an occupancy ratio of 0.54:0.46.

Growth and combined experimental and quantum chemical study of glycyl-L-Valine crystal.

Glycyl-L-Valine (GLV) crystals were grown using distilled water as the solvent at room temperature by solution growth technique. Powder X-ray diffraction confirms the crystalline quality of GLV crystal. The molecular structure of GLV crystal was identified by 13C NMR spectral studies. The nonlinear optical (NLO) behavior of the crystal was found to be ∼4.3 times greater than that of potassium dihydrogen orthophosphate. FT-Raman and FT-IR spectra of the GLV were recorded and complete functional group assignment of the determined vibrational bands of GLV have been reported. Density functional theoretical method (DFT) was performed using B3LYP with the 6-311+G (d, p) basis set and the results were compared with the experimental values which confirm the intermolecular interactions responsible for the enhanced NLO activity of the molecule, as evident from NBO and Hirshfeld analyses. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. In addition, the molecular electrostatic potential (MEP) analysis, Mulliken atomic charges of the GLV molecule has been investigated using theoretical calculations.

Structural, thermal and optical characterization of an organic NLO material--benzaldehyde thiosemicarbazone monohydrate single crystals.

Single crystals of the organic NLO material, benzaldehyde thiosemicarbazone (BTSC) monohydrate, were grown by slow evaporation method. Solubility of BTSC monohydrate was determined in ethanol at different temperatures. The grown crystals were characterized by single crystal X-ray diffraction analysis to determine the cell parameters and by FT-IR technique to study the presence of the functional groups. Thermogravimetric and differential thermal analyses reveal the thermal stability of the crystal. UV-vis-NIR spectrum shows excellent transmission in the region of 200-1100 nm. Theoretical calculations were carried out to determine the linear optical constants such as extinction coefficient and refractive index. Further the optical nonlinearities of BTSC have been investigated by Z-scan technique with He-Ne laser radiation of wavelength 632.8 nm. Mechanical properties of the grown crystal were studied using Vickers microhardness tester. Second harmonic generation efficiency of the powdered BTSC monohydrate was tested using Nd:YAG laser and it is found to be ∼5.3 times that of potassium dihydrogen orthophosphate.

Growth and characterization of thiosemicarbazide hydrochloride: a semiorganic NLO material.

Thiosemicarbazide hydrochloride (TSCHCL) was synthesized by mixing thiosemicarbazide and hydrochloride in 1:1 molar ratio in double distilled water. Single crystals of TSCHCL were grown by slow evaporation at room temperature and were characterized by single crystal X-ray diffraction study to determine the molecular structure and by FT-IR, (1)H and (13)C NMR spectral analyses to confirm the synthesized compound. Thermogravimetric and differential thermal analyses reveal the thermal stability of the crystal. The transmission spectrum of TSCHCL showed that the crystal is transparent in the wavelength range 380-1100 nm. High resolution X-ray diffractometry (HRXRD) was employed to evaluate the perfection of the grown crystal. Mechanical properties of the grown crystal were studied using Vickers microhardness test. Second harmonic generation efficiency of the powdered TSCHCL was tested using Nd:YAG laser and is ∼1.5 times that of potassium dihydrogen orthophosphate.

Synthesis and spectral characterization of acetophenone thiosemicarbazone--a nonlinear optical material.

Acetophenone thiosemicarbazone (APTSC) was synthesized. Solubility of APTSC was determined in ethanol and methanol at different temperatures. Single crystals were grown from ethanol by slow evaporation at room temperature. The grown crystal was subjected to FTIR, Laser-Raman and (1)H NMR spectral analyses to confirm the synthesized compound. Thermal properties were investigated by thermogravimetric and differential thermal analyses. High-resolution X-ray diffractometry (HRXRD) was employed to evaluate the perfection of the grown crystal. The range and percentage of optical transmission was ascertained by recording UV-vis-NIR spectrum. The third order nonlinear optical parameters (nonlinear refractive index and nonlinear absorption coefficient) were derived by the Z-scan technique.

HLA affinities of Iyers, a Brahmin population of Tamil Nadu, South India.

Seventy-four randomly sampled Iyers, a Brahmin population of Tamil Nadu and preachers and followers of the Advaita philosophy, living in Madurai, were studied for their HLA-A, HLA-B, HLA-C, HLA-DR, HLA-DQ, C4A, C4B, and BF polymorphisms and compared with other populations. HLA alleles A1, A11.1, A24, A33, B35, B44, B51, B52, B57, Cw4, Cw6, Cw7, DR4, DR7, DR8, DR10, DR11, DR15, and DQ1 and C4A*3, C4A*4, C4A*6, C4A*Q0, C4B*1, and BF*S were represented in 15% of the samples studied. HLA alleles A25, A69, Cw3, Cw8, B45, B14, B39, B18, B50, and B56 were not identified. Various populations of Tamil Nadu were compared, but the Iyers of Madurai formed a separate cluster with Sourashtrans of Madurai and major group 4 (various Brahmin populations of Tamil Nadu); hill tribes (Irulas, Malayalis, and Badagas) and caste groups in the plains (Kallars and Nadars) formed distinct clusters. Comparison of the Iyers with other Indian and world populations revealed that Iyers form a distinct branch of the Indo-European and Central Asian tree. The Bhargavas of Lucknow, another Brahmin caste group from Uttar Pradesh, did not cluster with the Iyers but clustered with Central Asian populations. The Punjabis of Delhi clustered with European and Middle Eastern populations. Studies on two-locus haplotypes of Iyers revealed unique haplotypes in them (A26-B8, A33-B44, A33-Cw7, A1-B57, B8-DR3, B44-DR7, DR7-DQ2, C4A*32-C4B*Q0, and C4A*6-C4B*2), most of which were not identified in the Bhargavas of Lucknow and the Punjabis of Delhi. Thus it is possible that various Brahmin populations of India differ in their origin, migration, and settlement, although all of them adopted Hinduism in ancient times. A comparison of haplotypes in Iyers with the world population reveals a sharing of haplotypes with Southeast Asian populations. This implies that the ancestors of the Iyers of Madurai, who originated in the Eurasian steppes or Central Asia, might have migrated to India through Southeast Asia, thus developing the prevalent haplotypes en route.

Sociobiology and HLA genetic polymorphism in hill tribes, the Irula of the Nilgiri hills and the Malayali of the Shevroy hills, south India.

Two endogamous tribes of Tamil Nadu, South India, the Irula of the Nilgiri hills and the Malayali of the Shevroy hills, were studied for their sociobiology and HLA polymorphism. For sociobiological studies 166 marriages in the Irula and 368 marriages in the Malayali were recorded. The number and spatial distribution of patrilineal clans and their marriageable range (number of clans from which the brides came) were studied. Eight clans in the Irula and 16 clans in the Malayali were identified. Of these the Kuppar of the Irula and the Malayan of Malayali were the largest clans, and both of them had the greatest marriageable range. The numerical strength and the resultant spatial distribution correlated well with the marriageable range. HLA-A, B, and DR polymorphism was studied on 191 Irula and 42 Malayali following standard procedures. HLA typing revealed high frequencies (> 10%) of alleles HLA-A2, A9, A11, B17, B35, B40, DR2, and DR7 in both tribes, but the Irula had elevated HLA-A10, B8, and DR8 frequencies and the Malayali had elevated HLA-A31, B7, DR4, and DR5 frequencies. Two-locus haplotypes A10-B8 and A2-B5 were identified in both tribes, but A11-B40 and A2-B53 were present only in the Irula and A33-B44 and B15-DR6 were present only in the Malayali. The sociobiology of the Irula was correlated to the HLA genetic profile. The Irula sample was stratified based on clan and HLA data; The Kuppar clan was closer to the Kalkatti, the second largest clan, than to the Pungar and the Sambar clans. Thus the numerical strength and spatial distribution of various exogamous clans, presumably a result of migration during different periods of history, is reflected in the marriageable range and thus in the genetic distance. In studying HLA or any other genetic polymorphism of an endogamous tribe or caste, one needs to consider the social structure, spatial distribution, and marriageable range.