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81.
Antony Sekar Kulandai Raj Rai‐Shung Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(32):11096-11100
This work reports gold‐catalyzed bicyclic annulations of 2‐alkynyl‐1‐carbonylbenzenes with vinyldiazo ketones that serve as five‐atom building units. The importance of these reactions is to access 4,5‐dihydro‐benzo[g]indazoles, which form the structural cores of various bioactive molecules. According to our mechanistic analysis, we postulate initial [5+4]‐cycloadditions between benzopyrilium intermediates and vinyldiazo ketones, followed by 6‐π‐electrocyclizations to achieve the excellent stereoselectivity. 相似文献
82.
Organic‐inorganic hybrids based on phenanthrene‐functionalized gold nanoparticles for OLEDs
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Jayabharathi Jayaraman Abirama Sundari Ganapathy Venugopal Thanikachalam Jeeva Palanivel Panimozhi Sekar 《Journal of Physical Organic Chemistry》2018,31(5)
The electroluminescence intensity of the phenanthrene‐functionalized gold nanoparticles, PMPT‐Au nanoparticles/CPB: Ir(PIA)2 (acac) film, was increased by 4.9 times compared with control device, CPB: Ir(PIA)2 (acac) due to coupling between the excitons of emissive layer and localized surface plasmonic resonance of PMPT‐Au NPs. The maximum luminous efficiencies of devices II to IV with PMPT‐Au NPs were 39.2 cd A?1 (11.8 V), 40.1 cd A?1 (10.5 V), and 43.1 cd A?1 (9.0 V), respectively. The increment of current efficiency with PMPT‐Au NP coated devices was strongly related to the energy transfer between the radiated light generated from CBP: Ir(PIA)2 (acac) emissive layer and localized surface plasmonic resonance excited by PMPT‐Au NP layer. 相似文献
83.
S. S. Liji Sobhana J. Sundaraseelan S. Sekar T. P. Sastry A. B. Mandal 《Journal of nanoparticle research》2009,11(2):333-340
Growth of hydroxyapatite (HA) on gelatin–chitosan composite capped gold nanoparticles is presented for the first time by employing
wet precipitation methods and we obtained good yields of HA. Fourier transform infrared spectroscopy (FTIR) spectrum has shown
the characteristic bands of phosphate groups in the HA. Scanning electron microscopy (SEM) pictures have shown spherical nanoparticles
with the size in the range of 70–250 nm, whereas ≥2–50 nm sized particles were visualized in high resolution transmission
electron microscopy (HR-TEM). X-ray diffraction (XRD) spectrum has shown Bragg reflections which are comparable with the HA.
Energy dispersive X-ray (EDX) studies have confirmed calcium/phosphate stoichiometric ratio of HA. The thermogravimetric analysis
(TGA) has shown about 74% of inorganic crystals in the nanocomposite formed. These results have revealed that gelatin–chitosan
capped gold nanoparticles, acted as a matrix for the growth of HA. 相似文献
84.
Archana A. Bhagwat Kiran C. Avhad Dinesh S. Patil Nagaiyan Sekar 《Photochemistry and photobiology》2019,95(3):740-754
A set of linear and asymmetric coumarin–imidazole hybrid compounds having a N,N‐diethylamine at 7‐position and imidazole at 3‐position on the coumarin were synthesized. Insertion of thiophene π‐spacer between coumarin and imidazole moieties (5b, 5d) leads to redshifted absorption and emission compared to 5a and 5c. All the compounds show a noticeable response to trifluoroacetic acid with a redshifted absorption and an increase in emission intensity by twofold. The ratio of ground and excited state acidity constant was calculated using Förster energy cycle, and the ratios were found to be 0.25, 0.96, 0.52 and 1.87, respectively, for 5a‐5d. Due to the thiophene π‐spacer, elongation of π‐conjugation in 5b and 5d leads to high values of polarizability (α), first‐order hyperpolarizability (β) and second‐order hyperpolarizability (γ). Compound 5b exhibits a high value (895 GM) of two‐photon absorption cross section (σ2PA), measured using two‐level model. 相似文献
85.
The influence of Zn-doping on the crystal structure and magnetic properties of the spin ladder compounds La2Cu2O5 (4-leg) and La8Cu7O19 (5-leg) have been investigated. The La2(Cu1−xZnx)2O5 and La8(Cu1−xZnx)7O19 solid solutions were obtained as single phases with x=0-0.1 via the solid-state reaction method in the temperature range between 1005-1010 °C and 1015-1030 °C in oxygen and air atmospheres, respectively. The lattice parameters a and c of the monoclinic crystal structures as well as the unit cell volume V increase with increasing x, while b and β decrease for both series. The magnetic susceptibilities χ of both series show a very similar behavior on temperature as well as on Zn-doping, which is supposed to be due to the similar Cu-O coordination in both La2Cu2O5 and La8Cu7O19. For low Zn-doping (x?0.04), a spin-chain like behavior is found. This quasi-one-dimensional behavior is strongly suppressed in both series for x?0.04. Here, the maximum (characteristic for spin chains) in χ(T) disappears and χ(T) decreases monotonically with increasing temperature. 相似文献
86.
This work describes the development of a capillary electrophoresis(CE)method for the simultaneous separation of acetophenone(AP),2-hydroxyacetophenone(2-HAP),3-hydroxyacetophenone(3-HAP)and 4-hydroxyacetophenone(4-HAP)in synthetic mixtures using 10 mmol/L of sodium tetraborate buffer(pH 9.5).The aim of this work is to demonstrate the effectiveness of CE to separate AP and its monohydroxy isomers and to defne how the separations are affected by buffers,buffer pH,sample matrices and separation voltage.This method was successfully used for the trace level separation and determination of 2-HAP,3-HAP and 4-HAP in synthetic mixture and 4-HAP in spiked plasma samples. 相似文献
87.
88.
Highly important trans-3,4-dihydro-2H-1,4-benzoxazine moieties were easily synthesized by domino aziridine ring opening with o-bromophenols and o-chlorophenols followed by the palladium catalyzed coupling-cyclization (intramolecular C(aryl)–N(amide) bond formation) with good to excellent yields. 相似文献
89.
90.