Browsing by Author "Chandrakantha, B."

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1-Cyclohexyl-5-(4-methoxyphenyl)-1H-pyrazole-4-carboxy-lic acid
(2011) Fun, H.-K.; Ching Kheng, C.K.; Chandrakantha, B.; Isloor, A.M.; Shetty, P.
In the title compound, C17H20N2O 3, the meth-oxy-phenyl unit is disordered over two sets of sites in a 0.715 (4):0.285 (4) ratio. The pyrazole ring forms dihedral angles of 55.88 (16) and 72.6 (4)°with the benzene rings of its major and minor components, respectively. The cyclohexane ring adopts a chair conformation and its C-N bond is in an equatorial orientation. In the crystal, molecules are linked into inversion dimers by pairs of O-H?O hydrogen bonds, generating R 2 2(8) loops..
1-Dibromomethyl-4-methoxy-2-nitrobenzene
(2009) Fun, H.-K.; Goh, J.H.; Chandrakantha, B.; Isloor, A.M.
The asymmetric unit of the title compound, C8H 7Br2NO3, comprises two crystallographically independent molecules (A and B). The nitro groups are twisted from the attached benzene rings, making dihedral angles of 39.26 (9) and 35.90 (9)° in molecules A and B, respectively. In each mol-ecule, the dibromo-methyl group is orientated in such a way that the two Br atoms are tilted away from the benzene ring. An inter-esting features of the crystal structure is the two short Br?Br inter-actions which, together with inter-molecular C - H?O hydrogen bonds, link the molecules into an extended three-dimensional network. The crystal structure is further stabilized by weak C - H?? inter-actions. © Fun et al. 2009.
2,6-Dichloro-3-nitro-pyridine
(2011) Fun, H.-K.; Arshad, S.; Chandrakantha, B.; Isloor, A.M.; Shetty, P.
The asymmetric unit of the title compound, C 5H 2C l2N 2O 2, consists of two crystallographically independent mol-ecules. The pyridine ring in each mol-ecule is essentially planar, with maximum deviations of 0.004 (4) and 0.007 (4) Å. Short Cl?O [3.09 (3) and 3.13 (4) Å] and Cl?Cl [3.38 (12) Å] contacts were observed. No significant inter-molecular inter-actions were observed in the crystal packing. © Fun et al. 2011.
2-Chloro-4-nitro-1H-imidazole
(2010) Fun, H.-K.; Goh, J.H.; Chandrakantha, B.; Isloor, A.M.; Shetty, P.
The molecule of the title compound, C3H2ClN 3O2, is almost planar; the dihedral angle between the imidazole ring and the nitro group is 1.7 (2)°. In the crystal structure, pairs of inter-molecular C-H?O hydrogen bonds link inversion-related molecules into dimers, generating R22(10) ring motifs. The dimers are inter-connected into two-dimensional networks parallel to (102) via inter-molecular N-H?N hydrogen bonds. Further stabilization is provided by short inter-molecular Cl?O inter-actions [3.142 (2) and 3.1475 (19) Å].
2-Methyl-5-[(3-methyl-4-nitrobenzyl)-sulfanyl]-1,3,4-thiadiazole
(2011) Fun, H.-K.; Chantrapromma, S.; Chandrakantha, B.; Isloor, A.M.; Shetty, P.
The molecule of the title thiadiazole derivative, C11H 11N3O2S2, has a butterfly-like structure and the whole molecule is disordered with a site-occupancy ratio of 0.629 (4):0.371 (4). The molecule is disordered in such a way that the 3-methyl-4-nitrophenyl units of the major and minor components are approximately related by 180° rotation around the C - N bond axis. The dihedral angle between the 1,3,4-thiadiazole and benzene rings is 70.8 (4) ° in the major component and 74.9 (6) ° in the minor component. In the crystal, molecules are arranged into screw chains along the c axis. These chains are stacked along the b axis. Weak intermolecular C - H?O and C - H?? interactions and a short C?O contact [3.005 (7) Å] are present.
4-(1,2,4-triazol-1-yl)aniline
(2011) Fun, H.-K.; Ching Kheng, C.K.; Chandrakantha, B.; Isloor, A.M.; Shetty, P.
In the title compound, C8H8N4, the dihedral angle between the triazole ring [maximum deviation = 0.003 (1) Å] and the benzene ring is 34.57 (7)°. In the crystal, molecules are linked into sheets lying parallel to the ac plane via intermolecular N - H?N and C - H?N hydrogen bonds. Aromatic ?- ? [centroid-centroid distance = 3.6750 (8) Å] stacking and N - H? ? interactions are also observed.
4-(3-Chlorophenyl)-3-[(2,6-difluorobenzyl)sulfanyl]-5-(3,4, 5-trimethoxyphenyl)-4H-1,2,4-triazole
(2011) Fun, H.-K.; Asik, S.I.J.; Chandrakantha, B.; Isloor, A.M.; Shetty, P.
In the title compound, C24H20ClF2N 3O3S, the essentially planar triazole ring (r.m.s. deviation = 0.001 Å) forms dihedral angles of 22.35 (10), 68.17 (10) and 42.01 (10)°with the mean planes of the trimethoxyphenyl, chlorophenyl and difluorophenyl rings, respectively. A weak intramolecular C-H?? interaction occurs. In the crystal, molecules are linked into sheets lying parallel to the bc plane by C-H?O and C-H?N hydrogen bonds. The crystal packing also features weak C-H?? interactions.
4-(4-Bromophenyl)-1-(2,6-difluorobenzyl)-3-(3,4,5-trimethoxyphenyl)-1H-1,2, 4-triazole-5(4H)-thione
(2012) Fun, H.-K.; Ooi, C.W.; Chandrakantha, B.; Isloor, A.M.; Shetty, P.
In the title compound, C 24H 20BrF 2N 3O 3S, the triazole ring (r.m.s. deviation = 0.0107 Å) makes dihedral angles of 28.18(14), 63.76(14) and 77.01(18)°, respectively, with the trimethoxy-, bromo-, and difluoro-substituted benzene rings. The C atoms of the meta methoxy groups are roughly coplanar with their ring [displacements =-0.289(4) and 0.083(7) Å], whereas the C atom of the para group is displaced [1.117(3) Å]. In the crystal, inversion dimers linked by two pairs of C-H··· O hydrogen bonds occur. The ring motif of the two hydrogen bonds to their symmetry-generated O-atom acceptors is R 2 2(8).
4-(o-Tolyl)piperazin-1-ium chloride
(2011) Fun, H.-K.; Asik, S.I.J.; Chandrakantha, B.; Isloor, A.M.; Shetty, P.
In the title mol-ecular salt, C11H17N2 +·Cl-, the piperazin-1-ium ring adopts a chair conformation with the aromatic ring in a pseudo-equatorial orientation. The dihedral angle between the benzene ring and the mean plane of the piperazin-1-ium ring is 51.22 (6)°. In the crystal, N - H?Cl hydrogen bonds link the molecules into chains propagating in [100]. Weak C - H?? interactions also ocur. © Fun et al. 2011.
5-[(4-methoxybenzyl)sulfanyl]-2-methyl-1,3,4-thiadiazole
(2011) Fun, H.-K.; Chantrapromma, S.; Chandrakantha, B.; Isloor, A.M.; Shetty, P.
The title molecule, C11H12N2OS 2, is twisted with a dihedral angle of 83.63 (12)° between the 1,3,4-thiadiazole and benzene rings. The methoxy group deviates slightly from the attached benzene ring, with a C - C - O - C torsion angle of 4.2 (4)°. In the crystal, molecules are linked by weak C - H?N interactions and stacked along the c axis.
5-Dimethyl-amino-N,N-dimethyl-2-nitro-benzamide
(2009) Fun, H.-K.; Jebas, S.R.; Chandrakantha, B.; Padmar, V.; Isloor, A.M.
In the title compound, C11H15N3O 3, one of the methyl groups attached to the benzamide unit is slightly twisted with a C - N - C - C torsion angle of 4.04 (13)°. The crystal packing is stabilized by weak intermolecular C - H?O hydrogen bonds together with a weak C - H?? inter-action.
Ethyl 1,5-diphenyl-1H-pyrazole-4-carboxylate
(2010) Fun, H.-K.; Ching Kheng, C.K.; Chandrakantha, B.; Isloor, A.M.; Shetty, P.
The asymmetric unit of the title compound, C18H 16N2O2, contains two independent molecules (A and B). In molecule A, the pyrazole ring is inclined at angles of 48.86 (6) and 60.80 (6)° with respect to the two phenyl rings; the corresponding angles for molecule B are 46.86 (6) and 58.63 (6)°. In the crystal, molecules of type A are linked into sheets parallel to (001) via weak C-H?O hydrogen bonds, whereas the molecules of type B are linked into chains along [010] via weak C-H?O hydrogen bonds.
Ethyl 1-cyclohexyl-5-(4-methoxyphenyl)-1H-pyrazole-4-carboxylate
(2011) Fun, H.-K.; Ching Kheng, C.K.; Chandrakantha, B.; Isloor, A.M.; Shetty, P.
In the title compound, C19H24N2O 3, the benzene ring forms a dihedral angle of 65.34 (7)°with the pyrazole ring. The cyclo-hexane ring adopts a chair conformation. In the crystal, molecules are linked into a22(22) ring motifs.
Ethyl 1-tert-butyl-5-phenyl-1H-pyrazole-4-carboxylate
(2010) Fun, H.-K.; Ching Kheng, C.K.; Chandrakantha, B.; Isloor, A.M.; Shetty, P.
In the title compound, C16H20N2O 2, the pyrazole ring is essentially planar [maximum deviation = 0.008 (2) Å] and is inclined at an angle of 82.82 (10)° with respect to the phenyl ring. The crystal packing is consolidated by pairs of intermolecular C-H?O hydrogen bonds, which link the molecules into centrosymmetric dimers stacked along the a axis.
Investigation of the photoalignment effect of 1, 3, 4-oxadiazoles bearing 2-fluoro-4-methoxy phenyl moiety
(2010) Alla, R.A.; Hegde, G.; Isloor, A.M.; Chandrakantha, B.; Shetty, P.; Komitov, L.
A new series of 1,3,4-oxadiazole derivatives containing 2-fluoro-4-methoxy moiety were synthesized by refluxing mixture of acid hydrazide 3 with different aromatic carboxylic acid in phosphorous oxychloride. Photoalignment studies were performed on these materials indicating that the position of fluorine plays vital role in promoting planar alignment either parallel or perpendicular to the light polarization direction. � 2010 ITE and SID.
Investigation of the photoalignment effect of 1, 3, 4-oxadiazoles bearing 2-fluoro-4-methoxy phenyl moiety
(2010) Alla, R.A.; Hegde, G.; Isloor, A.M.; Chandrakantha, B.; Shetty, P.; Komitov, L.
A new series of 1,3,4-oxadiazole derivatives containing 2-fluoro-4-methoxy moiety were synthesized by refluxing mixture of acid hydrazide 3 with different aromatic carboxylic acid in phosphorous oxychloride. Photoalignment studies were performed on these materials indicating that the position of fluorine plays vital role in promoting planar alignment either parallel or perpendicular to the light polarization direction. Â© 2010 ITE and SID.
N,N-Bis(2,6-difluorobenzyl)-1,3,4-thia-diazol-2-amine
(2009) Fun, H.-K.; Liew, W.-C.; Chandrakantha, B.; Isloor, A.M.
In the title compound, C16H11F4N 3S, the dihedral angles between the thia-diazole ring and the difluorobenzyl rings are 81.95 (7) and 81.96 (7)°, whereas the dihedral angle between the difluorobenzyl rings is 11.41 (7)°. In the crystal structure, C - H?N and C - H?F inter-actions link the molecules into two-dimensional arrays parallel to the bc plane. © Fun et al. 2009.
Novel N-substituted-5-phenyl-1H-pyrazole-4-ethyl carboxylates as potential NLO materials
(2013) Chandrakantha, B.; Isloor, A.M.; Sridharan, K.; Philip, R.; Shetty, P.; Padaki, M.
In the present investigation we have synthesized a novel series of N-substituted-5-phenyl-1H-pyrazole-4-ethyl carboxylates, which are characterized by 1H NMR, UV-Vis and FT-IR spectroscopy methods. The optical nonlinearity of the compounds in chloroform solution has been studied at 532nm using 5ns laser pulses, employing the open-aperture z-scan technique. It is found that compound 3c having carboxylic acid group and ester substituent has maximum nonlinearity. From measurements we conclude that compounds 3c (4-[4-(ethoxycarbonyl)-5-phenyl-1H-pyrazol-1-yl]benzoic acid) and 3e (ethyl 1-(2-bromophenyl)-5-phenyl-1H-pyrazole-4-carboxylate) are potential candidates for optical limiting applications. © 2011.
Quinolin-3-amine
(2012) Islor, A.M.; Chandrakantha, B.; Shetty, P.; Gerber, T.; Hosten, E.; Betz, R.
In the crystal structur of the achiral title compound, C9H 8N2, N-H?N hydrogen bonds connect the molecules into zigzag chains in [100]. Weak intermolecular N-H?? interactions further consolidate the crystal packing.
Redetermination of the structure of 4-amino-benzonitrile, C 7H6N2
(2013) Islor, A.M.; Chandrakantha, B.; Gerber, T.; Hosten, E.; Betz, R.
C7H6N2, monoclinic, P21/c (no. 14), a = 7.2382(6) Å, b = 5.4770(4) Å, c = 16.040(2) Å, ? = 101.680(4)°, V = 622.7 Å3, Z = 4, Rgt(F) = 0.0500, wRref(F2) = 0.1377, T = 200 K. © by Oldenbourg Wissenschaftsverlag, München.