A Study on the Antioxidant Activity of Pyridylselenium Compounds and their Slow Release from Poly(acrylamide) Hydrogels
摘要:
The antioxidant activity of pyridylselenium compounds has been evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and nitric oxide (NO) scavenging methods. Pyridylselenium compounds have shown far superior (100-1000 times) antioxidant property than ebselen. The control release of bis(2-pyridyl) diselenide from poly(acrylamide) hydrogels has been studied in order to evaluate its release mechanism and diffusion coefficient. The later study also demonstrates that the pyridylselenium loading into the polymer matrix increases the magnitude and the rate of the radical scavenging activity of the poly(acrylamide) hydrogels.
Synthesis, characterization and X-ray structure of 3,4-lutidinyl-, 3-/4-picolyl- and pyridylselenium compounds
摘要:
Bis(4,5-dimethyl-2-pyridyl)-, bis(5-methyl-2-pyridyl)- and bis(4-methyl-2-pyridyl) diselenide have been synthesized directly from 3,4-lutidine (1a), 3-picoline (1b) and 4-picoline (1c) respectively via BF3 aided lithiation reaction. The lithiation of 3,4-lutidinium-, 3- and 4-picolinium-BF3 adduct (2a/2b/2c) gives the corresponding carbanion (3a/3b/3c) which on subjecting to selenium insertion reaction followed by aerial oxidation affords the related diselenide in good yield. Reaction of BF3 complexed pyridylselenolate anion (4a/4b/4c) with diiodomethane gives the corresponding bis(2-pyridylseleno)methane. The dilithiation of 4-picolinium-/pyridinium-BF3 adduct (2c/2d) followed by reaction with 2.2 equiv. of selenium and iodomethane affords the related 2,6-bis(methylselenenyl)pyridine and 2-(methylselenenyl)pyridine in varying proportions. Preparation of tris(methylselenenyl) derivatives of 1a and 1c have been given in the present study. LiAlH4 has also been utilized to synthesize unsymmetrical monoselenides from the corresponding diselenides. Single crystal X-ray studies of bis(4,5-dimethyl-2-pyridyl) diselenide (5a), 3,4-dimethyl-2,6-bis(methylselenenyl)pyridine (9a), 4-methyl-2,6-bis(methylselenenyl)pyridine (9c), 2,6-bis(methylselenenyl)pyridine (9d) and 4-methyl-2,6-bis(methylselenenyl)-4-(methylselenenylmethyl)pyridine (12a) have also been carried out. The crystal data of these compounds reveals that the instances of Se center dot center dot center dot Se secondary interactions decreases with the increase in the number of methyl group attached to the pyridine ring. (C) 2012 Elsevier B. V. All rights reserved.
A novel and convenient synthesis towards 2-pyridylselenium compounds: X-ray crystal structure of 4,4′-dimethyl-2,2′-dipyridyl diselenide and tris(2-pyridylseleno)methane
作者:K.K Bhasin、Jaspreet Singh
DOI:10.1016/s0022-328x(02)01627-3
日期:2002.9
hydrazine hydrate in sodium hydroxide reacts in situ with 2-bromopyridines to afford the title compounds in good to excellent yields. Hydrazine hydrate readily cleaves the selenium-selenium bond in these diselenides to generate 2-pyridylselenolate anion, which reacts with halomethanes to afford 2-pyridylseleno methanes. X-ray crystalstructure of 4,4′-dimethyl-2,2′-dipyridyl diselenide (4) and tris(2-pyridylseleno)methane
A mechanistic study of the synthesis, single crystal X-ray data and anticarcinogenic potential of bis(2-pyridyl)selenides and -diselenides
作者:Jaspreet S. Dhau、Avtar Singh、Amritpal Singh、Neha Sharma、Paula Brandão、Vítor Félix、Baljinder Singh、Vishal Sharma
DOI:10.1039/c5ra15577k
日期:——
A mechanistic study on LiAlH4 assisted scission of C–Se bond in bis(2-pyridyl)diselenides leading to bis(2-pyridyl)selenides generation has been presented.
Preparation and Characterization of Methyl Substituted 2,2′-Dipyridyl Diselenides, 2,2′-Dipyridyl Ditellurides, and Their Derivatives
作者:K. K. Bhasin、V. K. Jain、H. Kumar、Shweta Sharma、S. K. Mehta、Jaspreet Singh
DOI:10.1081/scc-120016362
日期:2003.1.4
Abstract A number of methylsubstituted 2,2′-dipyridyl diselenides and -ditellurides have been prepared. Effect of the solvent and the substituents on the rate of these reactions have also been studied. The preparation of 2-methylseleno/telluro picolines by reductive cleavage of the diselenides and ditellurides and by one pot reaction using n-BuLi at −78°C in THF is reported.
Synthesis and characterization of novel pyridyl/naphthyl/(diphenyl)methylseleno substituted alkanoic acids: X-ray structure of 2-pyridylselenoethanoic acid, 2-naphthylselenoethanoic acid and 2-(diphenyl)methylselenoethanoic acid
作者:Aman Bhalla、Yogesh Nagpal、Rajeev Kumar、S.K. Mehta、K.K. Bhasin、S.S. Bari
DOI:10.1016/j.jorganchem.2008.10.020
日期:2009.1
sodium borohydride in ethanol. The ethyl pyridyl/naphthyl/(diphenyl)methylseleno substituted alkanoates (8–13) on basic hydrolysis and subsequent acidification afford pyridyl/naphthyl/(diphenyl) methylseleno substitutedalkanoicacids (20–25) in excellent yields. These selenoalkanoates (8–13) and selenoalkanoic acids (20–25) have been characterized by elemental analysis and various spectroscopic techniques
Facile one pot synthesis of highly photoresponsive coinage metal selenides (Cu<sub>1.8</sub>Se and Ag<sub>2</sub>Se) achieved through novel Cu and Ag pyridylselenolates as molecular precursors
作者:Gourab Karmakar、Adish Tyagi、Alpa Y. Shah、Sandeep Nigam、A. P. Wadawale、G. Kedarnath、Bal Govind Vats、N. Naveen Kumar、Vishal Singh
DOI:10.1039/d2dt01897g
日期:——
morphology, elemental composition and band gap of these nanocrystals were determined from pXRD, electron microscopy (SEM and TEM), EDS and DRS-UV, respectively. The band gap of these nanocrystals lies in the range suitable for solar cell applications. Finally, these nanocrystal-based prototype photo-electrochemical cells exhibit high photoresponsivity and stabilityunder alternating light and dark conditions
硒化铜 (Cu 1.8 Se) 和硒化银 (Ag 2 Se) 作为具有成本效益和可持续发展的太阳能电池的高效吸收材料,受到了前所未有的关注。非常需要在纳米范围内对这些奇异材料进行相纯制备。该帐户概述了使用新型配合物 [Cu2-SeC 5 H 2 ( Me-4,6) 2 N}] 4 ( 1 ), [ Ag 2 -Sec 5 H 2 (Me-4,6) 2 N}] 6 ( 2 ) 和 [Ag2-SeC 5 H3 (Me-5)N}] 6 ·2C 6 H 5 CH 3 ( 3 ·2C 6 H 5 CH 3 ) 作为单源分子前体 (SSP)。结构研究表明,Cu 和 Ag 配合物分别结晶成四聚体和六聚体形式。这种在配合物中观察到的结构多样性已通过DFT 计算合理化,并归因于金属-金属键背书的能量学。配合物1在油胺中相对较低的温度下热解得到立方白锆石 Cu 1.8 Se 和配合物2和3制备了斜方晶系瑙曼石Ag