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101.
Murugan Indrani Ramasamy Ramasubramanian Sudalaiandi Kumaresan Sung Kwon Kang Min Chen Miao Du 《Polyhedron》2008,27(18):3593-3600
Two new coordination complexes, viz. [Co(tmb)2(4,4′-bpy)2(H2O)2](Htmb)2 (1) and {[Ni(tmb)2(μ-4,4′-bpy)2(H2O)2](4,4′-bpy)}n (2), have been hydrothermally synthesized by reaction of the corresponding metal acetate with 2,4,6-trimethylbenzoic acid (Htmb) and 4,4′-bipyridyl (4,4′-bpy). X-ray single-crystal diffraction suggests that complex 1 represents a discrete mononuclear species in which the central metal ion is coordinated by the terminal carboxylate moiety and the 4,4′-bipyridyl ligand. The crystal structure of complex 2 reveals a 1D chain coordination polymer in which the Ni(II) ions are connected by the bridging 4,4′-bipyridyl ligands. In both cases, the coordination arrays are further extended via hydrogen bonding interactions to generate 3D supramolecular networks. Complexes 1 and 2 have also been characterized by spectroscopic (IR and UV/Vis), thermal (TGA) and magnetic susceptibility measurements. In addition, both complexes exhibit antimicrobial activity. 相似文献
102.
Highly regio- and stereoselective synthesis of tricyclic frameworks using Baylis-Hillman derivatives
Manickam Bakthadoss Nagappan Sivakumar Govindan Sivakumar Gandhi Murugan 《Tetrahedron letters》2008,49(5):820-823
A simple and convenient synthetic route for the synthesis of tricyclic chromeno[4,3-b]pyrrolidine frameworks using Baylis-Hillman bromides involving in situ formation of an imine, decarboxylation and a [3+2] cycloaddition sequence is described. 相似文献
103.
Sreedevi Mannam 《Tetrahedron letters》2008,49(15):2457-2460
Direct oxidation of primary alcohols to the corresponding carboxylic acids is performed highly efficiently at room temperature with anhydrous tert-butyl hydroperoxide in the presence of a catalytic amount of easily available CuCl under ligand free conditions in acetonitrile. Benzylic alcohols are more reactive than aliphatic alcohols, and these benzylic alcohols are selectively oxidized to the corresponding acids in the presence of aliphatic alcohols such as 1-octanol and 1-decanol. 相似文献
104.
Sreedevi Mannam 《Tetrahedron letters》2008,49(6):1083-1086
Oxidation of aldehydes to the corresponding carboxylic acids can be performed highly efficiently at room temperature with 70% tert-butyl hydroperoxide (in water) in the presence of a catalytic amount of easily available ligand free CuCl in acetonitrile as solvent under very mild conditions. This oxidation protocol works well for various aldehydes including aliphatic aldehydes and aliphatic dialdehydes. 相似文献
105.
Kong R Goh LP Liew CW Ho QS Murugan E Li B Tang K Liang ZX 《Journal of the American Chemical Society》2008,130(26):8142-8143
We have characterized a linear carbonyl-conjugated polyene generated by the iterative polyketide synthase (CalE8) involved in the biosynthesis of the 10-membered enediyne core of calicheamicin. The results provide insight into the mysterious biosynthetic mechanism of the unique enediyne. The carbonyl-conjugated polyene differs from the precursor for 9-membered enediyne, suggesting that the divergence of enediyne biosynthesis starts at the PKS stage. 相似文献
106.
Electrochemical Activation of Graphite Nanosheets Decorated with Palladium Nanoparticles for High Performance Amperometric Hydrazine Sensor
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Chelladurai Karuppiah Murugan Velmurugan Shen‐Ming Chen Rajkumar Devasenathipathy Raj Karthik Sea‐Fue Wang 《Electroanalysis》2016,28(4):808-816
Herein, we have demonstrated a preparation of palladium nanoparticles on electroactivated graphite nanosheets modified screen printed carbon electrode (PdNPs‐EGNS/SPCE) by a simple electrochemical method. The well‐prepared electrocatalyst was potentially applied to the high performance electrocatalytic oxidation of hydrazine in neutral medium. The PdNPs‐EGNS novel composite was characterized by scanning electron microscope (SEM) and the average diameter and thickness of PdNPs and EGNS were found to be ~38 nm and 85 nm, respectively. The high performance electrocatalytic determination of hydrazine was performed by the amperometric i‐t method. The fabricated sensor displayed irreversible electrocatalytic oxidation of hydrazine with diffusion‐controlled electrode process. The oxidation of hydrazine at PdNPs‐EGNS/SPCE showed wider linear range 0.05–1415 µM and high sensitivity 4.382 µA µM?1 cm?2. The as‐prepared electrocatalyst achieved quick response towards hydrazine with a lower detection limit 4 nM. 相似文献
107.
We report a new electrophoretic set-up and method for rapid specificity screening of an immobilised enzyme against a range of substrates present in a mixture. The penicillinase-catalysed reaction is carried out on-the-fly, following separation of putative substrates and preceding separation of the reaction products. The new active pixel sensor detector gives an option of using multiple detection windows on a single flow line and enables efficient on-line monitoring of this heterogeneous biocatalytic process with multiple putative substrates injected simultaneously. 相似文献
108.
Baruah PK Sreedevi NK Gonnade R Ravindranathan S Damodaran K Hofmann HJ Sanjayan GJ 《The Journal of organic chemistry》2007,72(2):636-639
This note describes the design, synthesis, and conformational studies of a novel hybrid foldamer that adopts a definite compact, three-dimensional structure determined by a combined effect of the special conformational properties of the foldamer constituents. The striking feature of this de novo designed foldamer is its ability to display periodic gamma-turn conformations stabilized by intramolecular hydrogen bonds. Conformational investigations by single-crystal X-ray studies, solution-state NMR, and ab initio MO theory at the HF/6-31G* level strongly support the prevalence of gamma-turn motifs in both the di- and tetrapeptide foldamers, which are presumably stabilized by bifurcated hydrogen bonds in the solid and solution states. The strategy disclosed herein for the construction of hybrid foldamers with periodic gamma-turn motifs has the potential to significantly augment the conformational space available for foldamer design with diverse backbone structures and conformations. 相似文献
109.
Using first-principles calculations with ultrasoft pseudopotential formalism and the generalized gradient approximation for the exchange-correlation functional, we study the stability of MonSm (n =1-6 and m ranging from n to 3n) clusters and obtain the optimal stoichiometry for each n corresponding to the magic cluster. It is found that in this size range, the lowest-energy structures favor a core of metal atoms, which is covered by sulfur. In particular, we observe that for Mo6S14 isolated clusters, a 3D structure is significantly lower in energy as compared to platelet structures found recently on Au (111) surface. The composition ratio between S and Mo in the magic clusters is less than 2 for n=3 and greater than 2 for n<3. The structural stability of the magic clusters arises from the optimization of the Mo-Mo and Mo- S bonding as well as the symmetry of the cluster. Addition of a terminal sulfur in a magic cluster generally lowers its binding energy. The presence of partially occupied d-orbitals in Mo atoms contributes to Mo-Mo bonding and for higher S concentration it leads to sulfur-sulfur bond formation. The variation in energy due to a change in the sulfur composition suggests that sulfurization of the magic clusters is generally more favorable than desulfurization. 相似文献
110.
Theetharappan Murugan Neelakantan Mallanpillai Ananthakrishnan 《Journal of fluorescence》2021,31(5):1277-1290
Journal of Fluorescence - A water-soluble Schiff base, 2,3-bis((E)-(2-hydroxy-3-methoxybenzylidene)amino) propanoic acid (ODA) prepared by condensing o-vanillin and DL-2,3-diaminopropionic acid was... 相似文献