Author: Gudneppanavar Rajsekhar

0000000001302630

AUTHOR

Gudneppanavar Rajsekhar

Complexation behaviour of hexadentate ligands possessing N2O4and N2O2S2cores: differential reactivity towards Co(ii), Ni(ii) and Zn(ii) salts and structures of the products

Reactions of divalent metal salts of Co, Ni and Zn with 1,2-di(salicylaldimino-o-phenylthio) ethane (H2L1) and 1,2-di(naphthaldimino-o-phenylthio) ethane (H2L2), having N2O2S2 cores, and 1,2-di(O-salicylaldimino-o-hydroxyphenyl) ethane (H2L3), having a N2O4 core, have been explored. Out of the three ligands and the nine products obtained from the corresponding reactions, two ligands and seven products were crystallographically characterized. However, all the ligands and the products were characterized by analytical and spectral methods. Reaction of H2L1 and H2L2 with Co(II) salts results in oxidative cleavage of the C-S bond to produce a Co(III) product bound to two dissimilar tridentate li…

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Synthesis and characterization of 4,6-O-butylidene-N-(2-hydroxybenzylidene)-beta-D-glucopyranosylamine: crystal structures of 4,6-O-butylidene-alpha-D-glucopyranose, 4,6-O-butylidene-beta-D-glucopyranosylamine and 4,6-O-butylidene-N-(2-hydroxybenzylidene)-beta-D-glucopyranosylamine

4,6-O-Butylidene-N-(2-hydroxybenzylidene)-β-D-glucopyranosylamine was synthesized and characterized using analytical, spectral and single-crystal X-ray diffraction methods. 1H and 13C NMR studies showed the presence of the β-anomer, which has also been confirmed by the crystal structure. The molecular structure of this compound showed the presence of the tridentate ONO ligation-core. Both precursors, 4,6-O-butylidene-α-D-glucopyranose and 4,6-O-butylidene-β-D-glucopyranosylamine were characterized using single crystal X-ray diffraction. The α-anomeric nature of the former and β-anomeric nature of the latter were proposed based on 1H NMR studies and were confirmed by determining the crystal …

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Unusual interaction extended between the pyranose ring oxygen and Zn(II) center in the complexes derived from 4,6-O-butylidene/ethylidene-N-(α-hydroxynaphthylidene/o-hydroxybenzylidene)-β-d-glucopyranosylamine: Evidence for a pseudo-bicapped tetrahedral complex of Zn(II) based on the crystal structure

The Zn(II) complexes of 4,6-O-butylidene/ethylidene-N-(α-hydroxynaphthylidene/o-hydroxybenzylidene)-β-Image -glucopyranosylamine have been synthesized and characterized using spectral and analytical methods and structure for one of the products was established. The geometry of the complexes vary from unusual distorted trigonal bipyramidal to pseudo-bicapped tetrahedron depending upon the extent of binding of pyranose ring oxygens to the Zn(II) ion, as evidenced from crystal structures. Such interaction is also reflected on the optical rotation and CD spectral properties of these complexes in solution.

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Glycosylamines of 4,6-O-butylidene-α-d-glucopyranose: synthesis and characterization of glycosylamines, and the crystal structure of 4,6-O-butylidene-N-(o-chlorophenyl)-β-d-glucopyranosylamine

A total of nine glycosylamines of 4,6-O-butylidene-α-D-glucopyranose were synthesized using primary amines having various groups in their ortho- or para-positions. Among these, six are monoglycosylamines, including one primary glycosylamine, and three are bis-glycosylamines. All these compounds were characterized by 1H, 1H–1H COSY, 1H–13C COSY and 13C NMR spectroscopy and FTIR spectra. The FAB mass spectra provided the molecular weights of the products by exhibiting the corresponding molecular ion peaks. The crystal structure of 4,6-O-butylidene-N-(o-chlorophenyl)-β-D-glucopyranosylamine revealed the C-1 glycosylation, the β-anomeric nature, and the 4C1 chair conformation of the saccharide …

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C–S bond cleavage by cobalt: synthesis, characterization and crystal structure determination of 1,2-di-(o-salicylaldiminophenylthio)ethane and its Co(III) product with C–S bond cleaved fragments

1,2-Di-(o-salicylaldiminophenylthio)ethane reacts with Co(II) salts to form a complex with oxidative cleavage of the C–S bond, to result in the formation of a Co(III) complex of the cleaved ligands.

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