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1.
Cover Picture: Coordination Chemistry of N‐Heterocyclic Nitrenium‐Based Ligands (Chem. Eur. J. 19/2015) 下载免费PDF全文
2.
[reaction: see text] A facile and highly selective indium-mediated allylation of hydrazones utilizing BINOL ligands is described. Chiral (R)-3,3'-bistrifluoromethylBINOL afforded homoallylic amines in up to 97% ee with stoichiometric ligand. Employing only 10 mol % ligand afforded selectivity of up to 92% ee. 相似文献
3.
Subhasis Chakrabarti Ashim K. Maity T. N. Misra 《Journal of polymer science. Part A, Polymer chemistry》1992,30(8):1625-1631
Raman spectroscopy has been used to study solid-state photopolymerization reactions in dimethyl ester of α,α′-dicyano-p-phenylenediacrylic acid (p-CPAMe) and diethyl ester of p-phenylenediacrylic acid (p-PDAEt). The reactants and products were characterized by infrared and Raman spectroscopy. Excitation and emission spectra suggest that in p-CPAMe exciton–phonon coupling is strong, but in the other monomer it is very weak. Raman phonon spectroscopic study reveal that in both the samples the reaction mechanism is homogeneous in the initial stages. However, in the later stages the reaction becomes heterogeneous in p-PDAEt. In p-CPAMe the lattice becomes disordered with the progress of polymerization and finally becomes amorphous whereas in p-PDAEt the lattice remains highly ordered. © 1992 John Wiley & Sons, Inc. 相似文献
4.
2,8-Dimethyltricyclo[6.2.2.01,6]dodeca-2,5-diene-4,9-dione (
), 2,9-dimethyltricyclo [6.3.1.01,6]dodeca-2,5-diene-4,10-dione (
) and 2-methyltricyclo[6.3.1.01,6]dodeca-2,5-diene-4,10-dione (
) have been synthesised for entry into the ring systems of a few tetracyclic diterpenes. 相似文献
5.
Moorthy JN Venkatakrishnan P Mal P Venugopalan P 《The Journal of organic chemistry》2003,68(2):327-330
The supramolecular nonbonded C-H...X interactions between formyl hydrogens and ortho-halogen atoms (Br/Cl) have been exploited to achieve conformational control in the solid state of dimethyl-substituted iso- and terephthaladehydes (1-3) for unprecedented diphotocyclization. It is shown that the dihalogen substitution also contributes to the stability of the benzocyclobutenols relative to their precursor photoenols, so that the solid-state photolysis of dialdehydes 2b, 2c, and 3b leads to diphotocyclization to afford respectable yields of bis-benzocyclobutenols. 相似文献
6.
7.
Zinc ion (Zn2+) is an important and a most useful biological trace nutrient responsible for the activity of several enzymes. Zn2+ concentrations in the environment as well as in the human body increase beyond permissible limits as a consequence of its mining and widespread industrial applications. Such excess Zn2+ concentrations are toxic to humans and many aquatic organisms. The magnetic inertness and spin paired electronic configuration of Zn2+ makes it hard to detect by common analytical techniques. Therefore, fluorometric detection using chemosensor is the most effective tool for the environmental and biological detection of Zn2+. We have developed a novel pyridine-constrained bis(triazole-linked hydroxyquinoline) ligand as a reversible fluorescent chemosensor for Zn2+. The symmetrical ligand is highly selective for Zn2+ and fluoresces brightly upon complexation compared with other metal ions based on chelation-enhanced fluorescence mechanism. Interestingly, free ligand can be regenerated by treating the ligand–Zn2+ complex with aqueous ammonia. 相似文献
8.
9.
An efficient, straightforward and environmentally benign process has been developed for the synthesis of fluorenone and 1-tetralone derivatives using cyclic 1,3-dione, malononitrile and dialkylacetylenedicarboxylate as starting materials in aqueous medium. The reaction is favoured in presence of resorcin[4]arene which is effective as a reusable organocatalyst. The catalyst has been easily synthesized and characterized by 1H, 13C NMR, IR, XRD and HRMS analyses. Resorcin[4]arene afforded the resulted products in a shorter time and in good yields. The recyclability of the catalyst was established up to 6th cycle by FT-IR and SEM images. 相似文献
10.
An analytical study on nonlinear evolution of Langmuir waves in warm electron-positron-dusty plasmas is presented. The massive dust grains of either positively or negatively charged are assumed to form a fixed charge neutralizing background. A perturbative analysis of the fluid-Maxwell's equations confirms that the excited Langmuir waves phase-mix and eventually break, even at arbitrarily low amplitudes. It is shown that the nature of the dust-charge as well as the amount of dust grains can significantly influence the Langmuir wave phase-mixing process. The phase-mixing time is also found to increase with the temperature. 相似文献