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131.
K. Kaviyarasu D. Sajan M.S. Selvakumar S. Augustine Thomas D. Prem Anand 《Journal of Physics and Chemistry of Solids》2012,73(11):1396-1400
We report the synthesis of PbI2 nanorods by reacting lead acetate with elemental iodine at room temperature by virtue of a wet chemical method at mild reactions. The diameters of the obtained PbI2 nanorods are about 54 nm. The present technique may open a new doorway to one-dimensional nanosized rods from the same kind of materials with irregular shape or large size. X-ray powder diffraction (XRD), Fourier transform infrared analysis (FTIR), ultraviolet–visible–near infrared analysis (UV–vis–NIR), photoluminescence measurements (PL) and scanning electron microscopy (SEM) were used to characterize PbI2 nanorods. The as obtained products were analyzed by X-ray powder diffraction, which confirms the formation of solid PbI2 nanorods. From the UV–vis–NIR studies the band gap of PbI2 nanorod was estimated. The various functional groups present in the PbI2 nanorods were identified by FTIR analysis. Intense photoluminescence was also observed with some spectral tuning possibly giving a range of emission photon energies approximately spanning from 2.1 to 3.5 eV. 相似文献
132.
Kadarkaraisamy Mariappan Gerald Caple Prem N. Basa Andrew G. Sykes 《Journal of Physical Organic Chemistry》2012,25(8):686-692
Reaction of mineral acids with a cyclic macromolecule containing a secondary alcohol produces ammonium, phosphonium, thiophene, and amide adducts via a carbocation intermediate. X‐ray crystallography confirms the structures of the products, including those when two competing nucleophiles are present. A reactivity series that mirrors the nucleophilicity index, where reactivity decreases in the order thiophene > pyridine > primary amides > alkyl nitriles >> aromatic nitriles (unreactive), results. Addition of metal ions to ammonium adducts dissolved in acetonitrile produces secondary amides via the Ritter amide synthesis. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
133.
Hari C. Bajaj Surendra Prasad Radhey M. Naik Prem C. Nigam 《Transition Metal Chemistry》1991,16(5):511-517
Summary The kinetics and mechanism of ligand substitution reactions of tetraethylenepentamine nickel(II), Ni (Teren), and triethylenetetraamine nickel(II), Ni(Trien), with 4-(2-pyridylazo)resorcinol (parH2) have been studied spectrophotometrically at I=0.1 M (NaClO4) at 25°C. In both systems two distinct reaction steps are observed. The rapid first step follows the rate law d[Ni(Polyamine)(ParH2)]/dt=k1 [Ni(Polyamine)] [ParH2]. The formation of ternary complexes of Ni (Polyamine) with ParH2 has been investigated under second order equal concentration conditions. The values of second order rate constants for the Trien and Teren reactions are (2.1±0.2)×104 M–1s–1 and (7.8±0.6)×103 M–1s–1 respectively at pH=9.0, I=0.1 M and 25°C.The rate law for the second step may be written as d[Ni(Par)2]/dt=k2[Ni(Polyamine)(ParH2)]. Values of k2 for the Trien and Teren systems are (2.5±0.1)×10–4 s–1 and (4.76±0.3)×10–5 s–1 respectively. 相似文献
134.
Summary The kinetics of oxidation of malonic acid by both [MnO4]– and MnO2 have been studied in an HClO4 medium. The oxidation product of the organic acid was found to be glyoxylic acid. A reaction mechanism assuming complexation between MnO2 and malonic acid is suggested. The rate is independent of [H+]. 相似文献
135.
136.
Madhu Madhasu Sai Reddy Doda Prem Kumar Begari Krishna Rao Dasari Gangadhar Thalari Sudhakar Kadari Jhillu Singh Yadav 《Journal of heterocyclic chemistry》2021,58(9):1861-1866
A concise, scalable, and an efficient total synthesis for dronedarone ( 2 ) was described using conjugate addition followed by intramolecular Heck cyclization. The other key reaction includes selective reduction of nitro functionality and addition of lithiated terminal alkyne to the aldehyde. The overall yield of this approach is 44% in six steps. 相似文献
137.
138.
Dielectric studies on copper doped derivatives of polycrystalline layered mixed alkali trititanate Na1.8K0.2Ti3O7 ceramics indicate that the losses are of mixed type and decrease on copper doping. However, the temperature dependent permittivity plots are characteristic of the diffuse nature of a possible ferroelectric phase transition and hence give indication of relaxor ferroelectric behaviour. From the EPR spectra, recorded at room temperature, it can be seen that the substitution of copper occurs at Ti4+ as preferred site with a divalent oxidation state (Cu2+) for all compositions. Also, copper doping enhances the transition temperature, which is indicative of the stabilization of the existing ferroelectric phase up higher temperatures. Besides bolstering electron hopping conduction, acceptor doping restrains the interlayer ionic conduction. Moreover, electron hopping (polaron) conduction is dominant over the lower temperature region, while interlayer ionic conduction prevails in the higher temperature region. 相似文献
139.
140.
A simple carbohydrate based convergent approach towards the total synthesis of (−)-synrotolide diacetate is described employing a Sharpless asymmetric epoxidation, a Grignard assisted lactol opening with a terminal alkyne and a Wittig reaction using the Horner-Emmons reagent as the key steps. 相似文献