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151.
Karunakaran C Thomas KR Shunmugasundaram A Murugesan R 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2001,57(3):441-449
Single crystal EPR of Cu(II)-doped low symmetry pentagonal bipyramidal Werner-type clathrate inclusion complexes of Cd(stpy)3(NO3)2 x 1/2stpy(1) and Zn(stpy)3(NO3)2 x 1/2stpy(2) (stpy = trans-4-styrylpyridine) is reported. The spin Hamiltonian parameters are found to be orthorhombic with g33 = 2.298, g22 = 2.108, g11 = 2.066, A33 = 107.3, A22 = 54.4 and A11 = 23.1 x 10(-4) cm(-1) for 1 and g33 = 2.292, g22 = 2.111, g11 = 2.067, A33 = 107.5, A22 = 54.7 and A11 = 22.9 x 10(-4) cm(-1) for 2. Angular variation studies for both 1 and 2 suggest that the Cu(II) ions are substitutionally incorporated in the host lattices. The magnitude of Cu(II) hyperfine coupling constant (A33) in both 1 and 2 are found to be low, in comparison to those of the pure Cu(II) complex, indicative of low symmetry for the substitutional sites in accordance with the crystal data. Such large reductions in Cu(II) hyperfine coupling are explicable in terms of a mixed d(x2 - y2)/dz2 ground state and delocalization of unpaired spin density onto the ligands. 相似文献
152.
C.?RameshEmail author G.?Velayutham N.?Murugesan V.?Ganesan K.?S.?Dhathathreyan G.?Periaswami 《Journal of Solid State Electrochemistry》2003,7(8):511-516
An improved polymer electrolyte membrane (PEM) fuel cell-based amperometric hydrogen sensor that operates at room temperature
has been developed. The electrolyte used in the sensor is a PVA/H3PO4 blend, which is a proton-conducting solid polymer electrolyte. A thin film of palladium is used as the anode and platinum
supported on carbon as the cathode. The sensor functions as a fuel cell, H2/Pd//PVA-H3PO4//Pt/O2, and the short-circuit current is found to be linearly related to the hydrogen concentration. The basic principle, details
of assembly, response behaviour of the sensor and its application are discussed. 相似文献
153.
Mothilal KK Karunakaran C Sambasiva Rao P Murugesan R 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2003,59(14):3337-3345
EPR of Cu(II) doped, low symmetry Co(II)-thiabendazole complex [Co(tbz)2(NO3)(H2O)](NO3) is investigated at 300 K. The spin Hamiltonian parameters are found to be orthorhombic with g33=2.305, g22=2.1351, g11=2.0626 and A33=147.0 x 10(-4), A22=33.5 x 10(-4) and A11=23.1 x 10(-4) cm(-1). Computer simulation of isofrequency plots reveal that the Cu(II) ions is substitutionally incorporated in the host lattice. Angular variation of the spectra shows the presence of two magnetic sites in the lattice. The low magnitude of A33 of the complex is rationalized in terms of admixture of d(x2-y2)/d(z2) ground state and delocalization of unpaired spin density onto the ligands. 相似文献
154.
V. Sivamurugan R. Suresh Kumar M. Palanichamy V. Murugesan 《Journal of heterocyclic chemistry》2005,42(5):969-974
The present short communication describes a Lewis acid (Zn[(L)proline]2) catalysed one pot synthesis of Hantzsch 1,4‐dihydropyridine (DHP) derivatives under solvent‐free condition by conventional heating and microwave irradiation. The Lewis acid catalyst Zn[(L)proline]2 used in this reaction afford moderate to good yield. The catalyst is reusable upto five cycles without appreciable loss of its catalytic activity. 相似文献
155.
P. Govindan A. Palamalai K. S. Vijayan S. Subbuthai S. Murugesan S. V. Mohan R. V. Subba Rao 《Journal of Radioanalytical and Nuclear Chemistry》2002,254(1):65-70
Ammonium uranyl carbonate (AUC) precipitation is developed for the conversion of uranyl nitrate to oxide in the uranium reconversion step of reprocessing of irradiated fuel by the addition of ammonium carbonate salt. Different precipitation conditions of AUC are studied. The solubility of AUC as a function of uranium concentration in the feed at different temperatures using ammonium carbonate salt as precipitant is studied. This study indicates that 95-99.8% of uranium is recovered as AUC by precipitating 5-125 g/l of uranium with loss of uranium (250-10 ppm) in the filtrate by adding ammonium carbonate salt. It is also observed that the solubility of AUC increased as the concentration of uranium decreased. Thermal decomposition is carried out by thermogravimetry/differential thermal analysis (TG/DTA) and evolved gas analysis-mass spectrometry (EGA-MS) to find out AUC decomposition and gases evolved during decomposition. Studies are also carried out to characterize AUC by using X-ray diffraction (XRD). The data show that AUC obtained by the above conditions is very much consistent with published information. 相似文献
156.
Murugesan Ramachandran Sami Ponnusamy Jeyabalan Thavasikani Shunmugasundaram Arunachalam 《Transition Metal Chemistry》1998,23(5):583-588
The Ti-substituted heteropolytungstates K7[TiIVW11–BO40] and K6[VVTiIVW10PO40] have been synthesized and characterized by elemental analyses and spectroscopic techniques. Their redox properties have been studied by cyclic voltammetry, and the compounds were found to be more difficult to reduce than the unsubstituted heteropolyanion. The one- and two-electron reduced heteropoly blues of [VVTiIVW10PO40]6–, namely [VIVTiIVW10PO40]7– and [VIVTiIIIW10PO40]8–, have also been prepared by chemical methods. Their optical spectra show low-energy intervalence charge-transfer bands as well as the expected d–d transitions. The optical and e.s.r. investigations indicate that VIV and TiIII are not vicinal in [VIVTiIIIW10PO40]8–. 相似文献
157.
Chandran Karunakaran K. R. Justin Thomas Arunachalam Asurname Ramachandran Murugesan 《Journal of inclusion phenomena and macrocyclic chemistry》2000,38(1-4):233-249
New clathrate inclusion compounds with the general formula,MA3X2 1/2G (M = Co(II)(1),Cd(II)(2), and Zn(II)(3), X = NO3
- andA and G = trans-4-styrylpyridine), differing from the usualWerner clathrates, MA4X2 2G, have been prepared and characterized by elemental and thermal analyses,IR and electronic spectroscopy and X-ray crystallography. Tworepresentative compounds [Co(stpy)3(NO3)2] 1/2stpy (1) and [Cd(stpy)3(NO3)2] 1/2 stpy (2)are investigated by single crystal X-ray diffraction. Compound (1)crystallizes in the triclinic space group P¯1 with a = 10.966(2),b = 12.802(4), c = 16.063(5) Å = 83.38(3), = 71.30(2), = 76.88(3) °,Z = 2. The structure is made up of discretemolecules of [Co(stpy)3(NO3)2]. The central Co(II) issurrounded by three stpy nitrogen atoms and four oxygen atoms of twoasymmetrically coordinated bidentate nitrate ligands. One of the oxygensis semicoordinated leading to a distorted octahedral geometry for Co(II).Compound (2) crystallizes in the monoclinic space group P21/nwith a = 15.597(3), b = 18.313(5), c = 16.188(3) Å = 115.998(14)° and Z = 4. The structure consists of neutralmolecules of [Cd(stpy)3(NO3)2]. The geometry aroundCd(II) is best described as pentagonal bipyramid with four oxygen atomsfrom symmetrical bidentate nitrate groups and one stpy nitrogen atom inthe equatorial positions. Two other nitrogen atoms from stpy ligands occupythe axial positions. The guest stpy molecules are trapped in the centrosymmetricalcavities in lattices of both 1 and 2. Compound 3is found to beisomorphous with 2. A large splitting of the symmetric and asymmetricNO2 stretching vibrations reveals the presence of bidentate nitrate ligands.Thermogravimetric and DTA studies on the Cd(II) compound, show it to be athermally stable inclusion compound. 相似文献
158.
A functional on-chip pressure generator using solid chemical propellant for disposable lab-on-a-chip
This paper presents a functional on-chip pressure generator that utilizes chemical energy from a solid chemical propellant to perform fluidic delivery in applications of plastic-based disposable biochips or lab-on-a-chip systems. In this functional on-chip pressure generator, azobis-isobutyronitrile (AIBN) as the solid chemical propellant is deposited on a microheater using a screen-printing technique, which can heat the AIBN at 70 degrees C to produce nitrogen gas. The output pressure of nitrogen gas, generated from the solid chemical propellant, is adjustable to a desired pressure by controlling the input power of the heater. Using this chemical energy source, the generated pressure depends on the deposited amount of the solid chemical propellant and the temperature of the microheater. Experimental measurements show that this functional on-chip pressure generator can achieve around 3 000 Pa pressure when 189 mJ of energy is applied to heat the 100 microg of AIBN. This pressure can drive 50 nl of water through a microfluidic channel of 70 mm and cross-sectional area of 100 microm x 50 microm. Due to its compact size, ease of fabrication and integration, high reliability (no moving parts), biologically inert gas output along with functionality of gas generation, this pressure generator will be an excellent pressure source for handling the fluids of disposable lab-on-a-chip, biochemical analysis systems or drug delivery systems. 相似文献
159.
Murugesan Srinivasan 《Tetrahedron》2006,62(33):7726-7732
The five-component tandem reaction of ethyl acetoacetate with aromatic aldehydes in the presence of pyrrolidine affords t(3),t(5)-diaryl-t(4)-[(E)-3-aryl-2-propenonyl]-r(2)-ethoxycarbonylcyclohexanones stereoselectively in good yields presumably via a tandem Knoevenagel condensation-Michael addition-condensation via enamine-deethoxycarbonylation-Michael addition sequence. The same reactants in the presence of DBU led to the formation of t(3)-aryl-r(2),c(4)-bisethoxycarbonyl-c(5)-hydroxy-t(5)-methylcyclohexanones in excellent yields via a tandem Knoevenagel condensation-Michael addition-aldol reaction sequence. 相似文献
160.
Gábor Blaskó Natesan Murugesan Alan J. Freyer Daniella J. Gula Bilge Şener Maurice Shamma 《Tetrahedron letters》1981,22(33):3139-3142
Stereoselective rearrangement of indenobenzazepine cis ketols and with TPAA in pyridine produces spirobenzylisoquinolines and , respectively. The latter product is also obtained by rearrangement of trans ketol . The transformation of ketols and must, therefore, proceed through the intermediacy of aziridinium cation . A similar process obtains in the transformation of to . NaBH4 reduction of gives (±)-raddeanine (). Rearrangement of diol supplies directly. (±)-Yenhusomine () is obtained from the reamangement of either diol, or . In like fashion, diols and supply spirobenzylisoquinoline . 相似文献