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排序方式: 共有859条查询结果,搜索用时 15 毫秒
1.
Tapasi Chand Laxmikanta Khamari Deepak Chopra Saptarshi Mukherjee Manmohan Kapur 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(43):e202200723
A one-step Rh-catalyzed site-selective ortho-C−H alkynylation of perylene as well as naphthalene mono- and diimides is reported. A single step regioselective access to ortho-C−H alkynylated derivatives of these ryleneimides not only increases the step economy of the ortho-functionalization on these dyes but also provides a quick access route towards highly functionalized dyes that have potential optoelectronic applications. Increased solubility of tetra(triisopropylsilyl)acetylenyl PDIs in organic solvents greatly enhances their utility for further derivatization. 相似文献
2.
From flash photolysis data of benzil and 2,2′-dichlorobenzil, the role of conformeric triplets in the formation of hydrogen
adduct radicals has been discussed. The planar relaxed triplet absorbing at 470 nm is less efficient in forming a hydrogen
adduct radical as compared to its puckered conformeric partner. Among the hydrogen donors, triethyl amine and isopropanol,
the former is more efficient in converting puckered triplets and less efficient in the case of planar conformers. Absorptions
of radicals and radical anions of 2,2′-dichlorobenzil appear at 355 nm and 460 nm respectively. These are blue-shifted as
compared to those of the parent compound benzil appearing at 370 nm and 540 nm, respectively. This blue-shift has been discussed
in terms of steric hindrance due to ortho-substitution. 相似文献
3.
Lukman O. Alimi Mram Z. Alyami Santanu Chand Walaa Baslyman Niveen M. Khashab 《Chemical science》2021,12(7):2329
Biologics, such as functional proteins and nucleic acids, have recently dominated the drug market and comprise seven out of the top 10 best-selling drugs. Biologics are usually polar, heat sensitive, membrane impermeable and subject to enzymatic degradation and thus require systemic routes of administration and delivery. Coordination-based delivery vehicles, which include nanosized extended metal–organic frameworks (nMOFs) and discrete coordination cages, have gained a lot of attention because of their remarkable biocompatibility, in vivo stability, on-demand biodegradability, high encapsulation efficiency, easy surface modification and moderate synthetic conditions. Consequently, these systems have been extensively utilized as carriers of biomacromolecules for biomedical applications. This review summarizes the recent applications of nMOFs and coordination cages for protein, CRISPR–Cas9, DNA and RNA delivery. We also highlight the progress and challenges of coordination-based platforms as a promising approach towards clinical biomacromolecule delivery and discuss integral future research directions and applications.SACs can be efficiently used to load biologics such as proteins, CRISPR–Cas9, DNA and RNA and release them on-demand. 相似文献
4.
A total synthesis of d-(+)-biotin is described starting from d-(+)-glucosamine using acyliminium chemistry. 相似文献
5.
Substituted 6-ethoxyanilino-5H-benzo[a]phenothiazin-5-ones (3a-f) were synthesized by the cyclocondensation of 2-chloro-3-ethoxyanilino-1,4-naphthoquinones with zinc mercaptides of 2-aminothiophenol in pyridine. The nmr, ir and mass spectral data are presented and discussed. 相似文献
6.
A simple and accurate method has been developed for the determination of organoisothiocyanates and organoisocyanates based on their quantitative reaction with n-butylamine in dimethylformamide medium to form substituted thioureas and ureas, respectively. The solution is mixed with 6 to 7 times its volume of acetonitrile and an excess of carbon disulphide, which converts the residual amine quantitatively into the corresponding n-butylammonium n-butyl dithiocarbamate. The determination is completed by titrating the resulting dithiocarbamate with iodine monobromide solution in acetonitrile. The end point is detected visually by the yellow color imparted to the solution by the first drop of oxidant solution in excess. The dithiocarbamates are quantitatively oxidized to the corresponding thiuram disulphides. 相似文献
7.
The molybdenum complexes of Schiff base ligands viz. [MoO2LH2O] where L1 = tris(hydroxymethyl)(salicylide-neamino)methane, L2 = tris(hydroxymethyl)(2,3-dihydroxybenzylideneamino)methane and L3 = tris(hydroxymethyl)(2,3,4-trihydroxybenzylideneamino)methane have been synthesized and characterized by spectroscopic and electrochemical techniques. The X-ray crystal structure of the complex [MoO2L1H2O] reveals a distorted octahedral geometry with one ligand and a water molecule coordinated to the MoO2 center. No previous complex of this type contains a coordinated water molecule. The complex undergoes an oxotransfer in the presence of Bu3P to form a -oxobridged molybdenum(V,V) dimer. This rules out Mo—S coordination as a prerequisite for oxotransfer in such molybdenum(VI) complexes. 相似文献
8.
Ghosh SK Hossain SU Bhattacharya S Bhattacharya SC 《Journal of photochemistry and photobiology. B, Biology》2005,81(2):121-128
The compound 2-(2-selenocyanic acid ethyl ester)-1H-benz[de] isoquinoline-1,3-(2H)-dione (SEBID), a ubiquitous, bioactive naphthalimide derivative is expected to possess an anticancer, anti-tumor and other important therapeutic activities of significant potency with low systematic toxicity. In this paper, the synthesis of the compound, photophysics of the newly prepared naphthalimide derivative and its interaction with model transport protein Bovine serum albumin (BSA) have been reported using the absorption and steady state fluorescence spectroscopic techniques exploiting the intrinsic fluorescence emission properties of BSA as a probe. Interaction of this organoselenium compound in different dioxane-water mixtures with increase in the polarity of the medium has been studied spectroscopically. Interaction of SEBID with BSA leads to a dramatic decrease in the fluorescence intensity of BSA, which suggests the binding of SEBID with the tryptophan residue of BSA. Furthermore, different thermodynamic parameters for SEBID-BSA interaction have been calculated. Rationalization of the data has been attempted, particularly in relation to prospective applications in the biomedical research. 相似文献
9.
Subhash C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2007,90(3):625-626
The fifth CBRATEC (V Congresso Brasileiro de Análise Térmica e Calorimetria) conference was held in April 02–05, 2006 in Poços de Caldas, MG. One third of the 370 participants was graduates and Ph.D. students well representing the continuous interest in thermal analysis among Brazilian researchers. The structure of conference was characteristic and refreshing, since every morning one of the leading Brazil thermoanalysts held an opened teaching course especially for the representatives of the young generation. After then plenary lecturers and keynote speakers (J. Rouquerol, Cs. Novák, D. Burlett, M. Suchyta and A. Riga) occupied the podium. The afternoon sessions consisted of mainly short lectures and poster exhibitions; both provided excellent possibility for the Ph.D. students to introduce their scientific work. The scope of conference covered practically all aspects of thermal analysis. Since 1998, when the first CBRATEC conference was held, the participation of young scientists and the organization of teaching courses played essential role for them. As an effort to increase international experiences, the universities pay continuous attention to foreign language education (first of all English), so the communication between the invited international researchers, the representatives of the instrument companies and the domestic conference attendants became much more efficient in recent years. During the conference the new Executive Committee was elected. Prof. Valter José Fernandes Junior was elected as President of ABRATEC supported by the members of the Executive (Jivaldo do Rosário Matos (Vice-President), Massao Ionashiro, Lázaro Moscardini D’Assunção, Clóvis Augusto Ribeiro, Elias Yuki Ionashiro, Carlos Isidoro Braga, Manoel Luiz Cunha Rodrigues, Rodrigo Maciel). In recognition of his continuous cooperation for the development of thermoanalytical researches in Brazil and its scientific divulgation in Thermal Analysis, the ‘Special Award’ of ABRATEC (Brazilian Association for Thermal Analysis and Calorimetry) was presented to Prof. Csaba Novák. For their outstanding achievements in developing the international relation of ABRATEC, Honourable Membership of the Thermoanalytical Sub-Branch of the Hungarian Chemical Society was presented to Prof. Jivaldo do Rosário Matos, Massao Ionashiro, Prof. Valter José Fernandes Junior and Prof. Éder Tadeu Gomes Cavalheiro at the opening ceremony. At last but not least, according to the decision of ICTAC Council during the 13th ICTAC (2004, Chia Laguna, Italy) Brazil was elected as the host of ICTAC 14 in 2008. The Brazilian thermoanalytical community feels extremely honored to be entrusted with the organization of the 14thICTAC Conference that will take place in São Pedro, SP, in September 14–19, 2008, where the scientists, researchers and students, who are acting in the field of thermal analysis and calorimetry are cordially invited. The link to the conference site is www.ictac14.com.br. 相似文献
10.
Kailash C. Malhotra Brij Bala Neeraj Sharma Subhash C. Chaudhry 《Transition Metal Chemistry》1995,20(4):388-390
Summary Complexes of composition [VOCl2(OC6H4Bu-t-4)] (1) and [VOCl(OC6H4Bu-t-4)2] (2) have been synthesized by the reaction of VOCl3 with equimolar and bimolar amounts, respectively, of 4-t-BuC6H4OSiMe3 in CCl4 and characterized by physio-chemical techniques. The complexes react with -hydroxyaldehydes and ketones such as 2-hydroxybenzaldehyde (salicylaldehyde, salH), and 2-hydroxy-2-phenylacetophenone (benzoin, benzH), 2-hydroxyacetophenone (hapH) and also with the potassium salt of p-chlorobenzohydroxamic acid (KBHACl) in 11 and 12 molar ratios, to yield five- and six-coordinate complexes. 相似文献