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A donor-acceptor compound based on N,N,N',N'-tetramethyl-p-phenylene-diamine and 1,2,4,5-tetracyanobenzene (TMPD:TCNB) has been synthesized. The crystal structure of the black 1:1 complex formed between TMPD and TCNB has been determined by single crystal X-ray diffraction at room temperature. The compound crystallizes in the triclinic space group P-1 with cell dimensions: a = 7.4986(15) ?, b =7.6772(11) ?, c = 8.0764(15) ?, alpha = 78.822(12) degrees, beta = 83.3779(19) degrees, gamma = 86.289(17) degrees .TMPD and TCNB molecules are stacked alternately in infinite columns along the a-axis. The structure does not seem to show the usual pi-pi interaction between the two aromatic rings, but indicates an n-pi interaction localized between the nitrogen atoms of the donor and the cyano groups of the acceptor. 相似文献
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Prasanna S. Ghalsasi 《Polyhedron》2009,28(9-10):1856-1859
1,2,4,5-Tetracyanobenzene (TCNB), a moderate electron acceptor, reacts readily with N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD), a strong electron donor, to form black colored TMPD:TCNB complex when treated in 1:1 molar ratio. Single crystal X-ray diffraction studies on this complex showed that molecule of TMPD and TCNB are alternately stacked with an interplanar distance of 3.4 Å between them. The structure of the complex does not seem to show usual π–π interaction between the two aromatic rings, but indicates the presence of n–π interaction localized between the nitrogen atoms of TMPD and the cyano groups of TCNB. Along with this a prominent presence of CN···HAr hydrogen bonded ribbon network between nitrogen of cyanide moiety and hydrogen of neighboring aromatic carbon is observed with distance of 2.610 Å and angle of 147.19°. Magnetic measurements on the powdered compound using SQUID magnetometer (5–20 K) showed that the complex is weakly antiferromagnetic (θ = ?0.85 K). To my best knowledge CN···HAr interaction amongst electron acceptor molecules, to form a ribbon-like network, has not been observed before for a magnetic complex. 相似文献
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Tributylphosphine oxide (TBPO) is proposed as an extractant for the extraction of lead(II) and copper(II) from salicylate media. The optimum conditions were evaluated by varying the experimental parameters, such as the pH, sodium salicylate concentration, tributylphosphine oxide (TBPO) concentration, shaking period and various diluents. The probable extracted species, deduced from log-log plots were Pb(HSal)2.2TBPO and Cu(HSal)2.2TBPO. The extraction took place through a solvation mechanism. The method permits the binary separation of lead(II) and copper(II) from commonly associated elements as well as the mutual separation of lead(II) and copper(II). The method is applicable to the determination of lead(II) and copper(II) in various alloys as well as environmental and pharmaceutical samples. 相似文献
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Ashok K. VishwakarmaPrasanna S. Ghalsasi Arulsamy NavamoneyYanhua Lan A.K. Powell 《Polyhedron》2011,30(9):1565-1570
Compounds of the general formula A2CuCl4, (where A = 4-fluoroanilinium (1) and 4-chloroanilinium (2)) were prepared, structurally characterized and their thermal and magnetic properties studied. These compounds have a layered structure, distorted perovskite, where layers of CuCl42− are sandwiched between a 4-haloanilinium cation bilayer. A single crystal X-ray diffraction study on (4-fluoroanilinium)2CuCl4, (1), shows that it crystallizes in the monoclinic P21/c space group with cell dimensions a = 15.5113(5) Å, b = 7.3788(2) Å, c = 7.0929(2) Å, β = 99.004(2)°, volume 801.81(4) Å3 at 150 K. Compound 2, (4-chloroanilinium)2CuCl4, crystallizes isostructurally to 1 at RT, but at 150 K it adopts the Pccn space group. This structural transition for 2 is reversible, and has been observed using Differential Scanning Calorimetric (DSC) measurements. The dc-magnetic studies using a SQUID magnetometer suggest that both compounds are soft ferromagnets and show an onset of long range magnetic ordering below 9 K. The ac-susceptibility measurements confirm the presence of this ferromagnetic ordering in both the compounds. 相似文献
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Ashok K. Vishwakarma Prasanna S. Ghalsasi 《Journal of Thermal Analysis and Calorimetry》2012,107(1):155-158
The thermal decomposition paths of anilinium, 4-chloro anilinium tetrachlorocopper(II) complexes are compared to their benzilinium
derivative. All these complexes crystallize in the layered structure, typical for a A2MX4 family, are studied in literature for their magnetic, semiconducting properties. TG analyses of (anilinium)2CuCl4 (A) and (4-chloro anilinium)2CuCl4 (B) loses one molecule of organic ammonium hydrochloride along with one molecule of amine, to form (H)CuCl3, which subsequently completely decomposes to Cu above 500 °C. On the other hand, (benzilinium)2CuCl4 (C) loses two molecules of hydrochloride along with chlorine molecule first then two molecules of benzyl amine with formation
of Cu above 300 °C. DSC studies on C have shown reversible endothermic phase transition at 130.95 °C (−1.98 J g−1) while heating and exothermic phase transition at 117.07 °C (0.93 J g−1) while cooling. Thus, the observed changes in the decomposition pathway can be correlated to the order–disorder phase transition
occurred in the compound C. 相似文献
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Jatinder Kaur Madhura Damle Hemant Mande Prasanna Ghalsasi Rajendra Kondedeshmukh 《Journal of Coordination Chemistry》2017,70(10):1667-1682
Four Ru(II) complexes with tridentate ligands viz. (4-hydroxy-N′-(pyridin-2-yl-ethylene) benzohydrazide [Ru(L1)(PPh3)2(Cl)] (1), N′-(pyridin-2-yl-methylene) nicotinohydrazide [Ru(L2)(PPh3)2(Cl)] (2), N′-(1H-imidazol-2-yl-methylene)-4-hydroxybenzohydrazide [Ru(L3)(PPh3)2(Cl)] (3), and N′-(1H-imidazol-2-yl-methylene) nicotinohydrazide [Ru(L4)(PPh3)2(Cl)] (4) have been synthesized and characterized. The methoxy-derivative of L3H (abbreviated as L3H*) exists in E configuration with torsional angle of 179.4° around C7-N8-N9-C10 linkage. Single crystal structures of acetonitrile coordinated ruthenium complexes of 1 and 3 having compositins as [Ru(L1)(PPh3)2(CH3CN)]Cl (1a) and [Ru(L3)(PPh3)2(CH3CN)]Cl (3a) revealed coordination of tridentate ligands with significantly distorted octahedral geometry constructed by imine nitrogen, heterocyclic nitrogen, and enolate amide oxygen, forming a cis-planar ring with trans-placement of two PPh3 groups and a coordinated acetonitrile. Ligands (L1H-L4H) and their ruthenium complexes (1–4) are characterized by 1H, 13C, 31P NMR, and IR spectral analysis. Ru(II) complexes have reversible to quasi-reversible redox behavior having Ru(II)/Ru(III) oxidation potentials in the range of 0.40–0.71 V. The DNA binding constants determined by absorption spectral titrations with Herring Sperm DNA (HS-DNA) reveal that L4H and 1 interact more strongly than other ligands and Ru(II) complexes. Complexes 1–3 exhibit DNA cleaving activity possibly due to strong electrostatic interactions while 4 displays intercalation. 相似文献
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Surajit Saha Pallavi Ghalsasi D. V. S. Muthu Surjeet Singh R. Suryanarayanan A. Revcolevschi A. K. Sood 《Journal of Raman spectroscopy : JRS》2012,43(8):1157-1165
We revisit the assignment of Raman phonons of rare‐earth titanates by performing Raman measurements on single crystals of O18 isotope‐rich spin ice and nonmagnetic pyrochlores and compare the results with their O16 counterparts. We show that the low‐wavenumber Raman modes below 250 cm−1 are not due to oxygen vibrations. A mode near 200 cm−1, commonly assigned as F2g phonon, which shows highly anomalous temperature dependence, is now assigned to a disorder‐induced Raman active mode involving Ti4+ vibrations. Moreover, we address here the origin of the ‘new’ Raman mode, observed below TC ~ 110 K in Dy2Ti2O7, through a simultaneous pressure‐dependent and temperature‐dependent Raman study. Our study confirms the ‘new’ mode to be a phonon mode. We find that dTC/dP = + 5.9 K/GPa. Temperature dependence of other phonons has also been studied at various pressures up to ~8 GPa. We find that pressure suppresses the anomalous temperature dependence. The role of the inherent vacant sites present in the pyrochlore structure in the anomalous temperature dependence is also discussed. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Mei Q Siewenie JE Benmore CJ Ghalsasi P Yarger JL 《The journal of physical chemistry. B》2006,110(20):9747-9750
Spallation neutron and high-energy X-ray diffraction experiments have been performed to investigate the local structure of the glacial and supercooled liquid states in triphenyl phosphite. The observed diffraction patterns have been interpreted using a Reverse Monte Carlo modeling technique. The results show that the glacial state forms unusually weak intermolecular hydrogen bonds between an oxygen atom connected to a phenyl ring and an adjacent phenyl ring aligned in an approximately antiparallel configuration. The structure is very different from the hexagonal crystal which is characterized by two weaker hydrogen bonds between linear arrays of molecules which are offset from each other and packed in a hexamer arrangement. 相似文献