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11.
[VIVO(acac)2] reacts with the methanolic solutions of tridentate dibasic ONO donor hydrazone ligands derived from the condensation of
benzoyl hydrazine with either 2-hydroxyacetophenone (H2L1) or its para-substituted derivatives (H2L2–4) (general abbreviation H2L), in the presence of vanillin (Hvan) in equimolar ratio under aerobic conditions generating the mixed-ligand oxovanadium(V)
complexes of the type [VVO(L)(van)], (1)–(4) in good yield. All the complexes are diamagnetic and exhibit only ligand-to-metal charge transfer (l.m.c.t.) band near 510 nm
in addition to intra-ligand (π → π*) transition band near 330 nm in CH2Cl2 solution. 1H-n.m.r. spectra of the complexes in CDCl3 solution indicate the presence of two isomeric forms [(1A), (1B); (2A), (2B); (3A), (3B) and (4A), (4B)] in different ratios, which is explained by the interchange of the two binding sites of van− motif between its coordinated equatorial and axial positions. Complexes display two quasi-reversible one electron reduction
peaks near +0.10 V and near +0.30 V versus s.c.e. in CH2Cl2 solution which are attributed to the successive reduction of VV→ VIV and the VIV→ VIII motifs, respectively. λmax (for l.m.c.t. transition), and the two reduction potential values (E
1/2)I (average of the first step anodic and first step cathodic peak potentials) and (E
1/2)II (average of the second step anodic and second step cathodic peak potentials) of the complexes, are found to be linearly related
to the Hammett constants (σ) of the substituents in the aryloxy ring of the hydrazone ligands. λmax, (E
1/2)I and (E
1/2)II values show large dependence: dλmax/dσ = 37.29 nm, d(E
1/2)I/dσ = 0.21 V and d(E
1/2)II/dσ = 0.21 V, respectively, on σ. 相似文献
12.
Rati Ranjan Nayak 《European Polymer Journal》2007,43(12):4916-4923
Effective side wall functionalization of single-walled carbon nanotube (SWCNT) with 4-vinylaniline was carried out through solvent free functionalization. The functionalized SWCNT was characterized through FT-IR and NMR. Typical peaks to identify the functionalization were observed. Thermal analysis shows around 48% weight loss in functionalized SWCNT in comparison to the pure SWCNT. The ratio of disordered to order transition (ID/IG) in FT-Raman, indicated the generation of some surface defects due to functionalization. Near infrared spectrum of functionalized SWCNT also confirmed the functionalization of SWCNT. The polystyrene nanocomposite materials were prepared with functionalized SWCNT as fillers by solution casting from tetrahydrofuran. The functionalized SWCNT nanocomposite showed significant improvement in mechanical properties and electrical properties. The dispersibility of the carbon nanotube in the composite was investigated by using scanning electron microscopy. 相似文献
13.
Ratna Dasgupta Pranab R. Kanjilal Swapan K. Patra Manish Sarkar Usha Ranjan Ghatak 《Tetrahedron》1985,41(23):5619-5625
The efficacy of a new acid-catalyzed intramolecular C-alkylation has been demonstrated by the synthesis of 1-methyl-4--methoxyphenylbicyclo [2.2.2] octan-2-one () and 4--methoxyphenylbicyclo [2.2.2] octan-2-one () from easily accessible starting materials. The carbinol , derived from , undergoes facile rearrangement leading to 1--methoxyphenyl-4-methyl bicyclo [3.2.1] oct-3-ene (), which has been transformed to -1--methoxyphenyl-4-methylbicyclo [3.2.1] octan-3-one (). 相似文献
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Yashwantsinh S. Jadeja Khushal M. Kapadiya Hetal J. Jebaliya Anamik K. Shah Ranjan C. Khunt 《Magnetic resonance in chemistry : MRC》2017,55(6):589-594
Hesperidin is flavonoid molecule found in citrus fruits (Citrus reticulata), especially difficult to extract, classify and characterize. Present work is to study the unresolved relative configuration of Hesperidin through the dihedral angle, coupling constant and different NMR techniques. The Karplus equation and its modifications have been originated from the valence bond theory and associated with dihedral angle and coupling constant. The result data set of calculated dihedral angle can probe significant method to assign the virtual configuration of natural products and also resolved stereochemistry of Hesperidin at C‐2 position in. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Gakhyun Kim Dr. Ranjan Dutta Dr. Won-Young Cha Dr. Seong-Jin Hong Dr. Juwon Oh Dr. Dikhi Firmansyah Hongil Jo Prof. Dr. Kang Min Ok Prof. Dr. Chang-Hee Lee Prof. Dr. Dongho Kim 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(69):16434-16440
π–π Stacking is omnipresent not only in nature but in a wide variety of practical fields applied to our lives. Because of its importance in a performance of natural and artificial systems, such as light harvesting system and working layer in device, many researchers have put intensive effort into identifying its underlying nature. However, for the case of π–π stacked systems composed of antiaromatic units, the understanding of the fundamental mechanisms is still unclear. Herein, we synthesized a new type of planar β,β’-phenylene-bridged hexaphyrin (1.0.1.0.1.0), referred as naphthorosarin which possesses the 24π-electron conjugated pathway. Especially, the corresponding antiaromatic porphyrinoid shows the unique property to form dimeric species adopting the face-to-face geometry which is unprecedented in cases of known annulated naphthorosarins. In order to elucidate the intriguing properties derived from the stacked dimer, the current study focuses on the experimental support to rationalize the observed π–π interactions between the two subunits. 相似文献