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41.
Four new supramolecular compounds of Cu(II)-Ni(II) have been synthesized and characterized: [Cu(Me(2)oxpn)Ni(mu-NCS)(H(2)O)(tmen)](2)(ClO(4))(2) (1), [Cu(Me(2)oxpn)Ni(mu-NCS)(H(2)O)(tmen)](2)(PF(6))(2) (2), [Cu(oxpn)Ni(mu-NCS)(NCS) (tmen)](n) (3), and [Cu(Me(2)oxpn)Ni(mu-NCS)(NCS)(tmen)](n) (4), where oxpn = N,N'-bis(3-aminopropyl)oxamidate, Me(2)oxpn = N,N'-bis(3-amino-2,2'-dimethylpropyl)oxamidate, and tmen = N,N,N',N'-tetramethylethylenediamine. Their crystal structures were solved. Complexes 1 and 2 have the same tetranuclear cationic part but a different counteranion. The cationic part consists of two [Cu(Me(2)oxpn)Ni] moieties linked by SCN(-) bridged ligands and intra-tetranuclear hydrogen bonds. In the case of complex 3, a two-dimensional system was built, the thiocyanate ligand linking the dinuclear units gives a chain, and the chains are linked together by hydrogen bonds; intrachain hydrogen bonds are also present. For complex 4, the thiocyanate ligands produce intermolecular linkages between the dinuclear entities, giving a one-dimensional system; intrachain hydrogen bonds are also present. The magnetic properties of the four complexes were studied by susceptibility measurements vs temperature. DFT calculations were made to study the contribution of the SCN(-) and hydrogen bond bridges in the magnetic coupling. 相似文献
42.
Figuerola A Ribas J Llunell M Casanova D Maestro M Alvarez S Diaz C 《Inorganic chemistry》2005,44(20):6939-6948
The reaction of Ln(NO3)3(aq) with K3[Fe(CN)6] or K3[Co(CN)6] and 2,2'-bipyridine in water/ethanol led to eight trinuclear complexes: trans-[M(CN)4(mu-CN)2{Ln(H2O)4(bpy)2}2][M(CN)6].8H2O (M = Fe3+ or Co3+, Ln = La3+, Ce3+, Pr3+, Nd3+, and Sm3+). The structures for the eight complexes [La2Fe] (1), [Ce2Fe] (2), [Pr2Fe] (3), [Nd2Fe] (4), [Ce2Co] (5), [Pr2Co] (6), [Nd2Co] (7), and [Sm2Co] (8) have been solved; they crystallize in the triclinic space group P and are isomorphous. They exhibit a supramolecular 3D architecture through hydrogen bonding and pi-pi stacking interactions. A stereochemical study of the nine-vertex polyhedra of the lanthanide ions, based on continuous shape measures, is presented. No significant magnetic interaction was found between the lanthanide(III) and the iron(III) ions. 相似文献
43.
A rapid and simple fractionation procedure using solid-phase extraction (SPE) cartridges was developed for an accurate determination of aliphatic and polycyclic aromatic hydrocarbons in petroleum residues and further application in chemical fingerprinting of oil spills by gas chromatography-mass spectrometry (GC-MS). Among the adsorbents evaluated, SiO2/C3-CN exhibited the best selectivity, providing, by elution with n-hexane (4 ml) and n-hexane-CH2Cl2 (1:1) (5 ml), two well-resolved aliphatic and aromatic hydrocarbon fractions, with recoveries of 97 +/- 7.2 and 99.7 +/- 13.9%, respectively. The SPE fractionation procedure was compared with the conventional silica-alumina adsorption chromatography showing similar results but practical advantages in terms of reproducibility, analysis time, solvent reduction and cost. Moreover, is particularly suitable for routine analysis with a high sample throughput. The developed methodology was tested in the characterization of fuel-oil samples collected along the Spanish north-west coast, after the Prestige oil spill accident. 相似文献
44.
Summary The new complex double saltscw-[Co(NH3)(en)2(H2O)]2 [M(CN)4]3 (en = ethylenediamine; M = Ni, Pd or Pt),cis-[Co(NH3(en)2(H2O)]2[FeNO(CN)5]3 andcis-[Co(NH3)(en)2(H2O)][Co(CN)6] have been synthesized and by anation in the solid state the corresponding new dinuclear complexes with a cyano bridgecis- ortrans-[(NH3)(en)2Co-NC-M(CN)3]2 [M(CN)4] (M = Ni, Pd or Pt);cis-, trans-[(NH3)(en)2Co-NC-FeNO(CN)4]2[FeNO(CN)5] andcis-[(NH3)(en)2Co-NC-Co(CN)5 have been prepared. The complexes have been characterized by chemical analysis, t.g. measurements, and by i.r. and electronic spectroscopy. With [Ni(CN)4][2– and [Co(CN)in]6
3– only thecis-isomer is produced; with [Pd(CN)4]2–, [Pt(CN)4]2– and [FeNO(CN)5]2– thetrans- isomer is the dominant species. The dinuclear complex derived from [Pt(CN)4]2– shows strong Pt-Pt interactions both in the solid state and in solution. 相似文献
45.
Taoufik Hmidi Joan Mateu Joan Verdera 《Archive for Rational Mechanics and Analysis》2013,209(1):171-208
We show that the boundary of a rotating vortex patch (or V-state, in the terminology of Deem and Zabusky) is C ∞, provided the patch is close to the bifurcation circle in the Lipschitz norm. The rotating patch is also convex if it is close to the bifurcation circle in the C 2 norm. Our proof is based on Burbea’s approach to V-states. 相似文献
46.
Abstract The influence of the composition of the initiator system used in the polymerization of PGE is studied. Structural studies of intermediate species by NMR and IR spectroscopies are made which allow confirmation of some characteristics on the previously proposed mechanism and clarification of the mechanism leading to the chlorinated insoluble polymer fraction. This can be explained by the formation of halogenated oligomers in the first stage of the reaction which interchange with different aluminum alkoxides to give another type of initiator system. 相似文献
47.
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49.
Julia Vallejo Alejandro Pascual‐Álvarez Dr. Joan Cano Dr. Isabel Castro Prof. Dr. Miguel Julve Prof. Dr. Francesc Lloret Dr. J. Krzystek Prof. Dr. Giovanni De Munno Dr. Donatella Armentano Prof. Dr. Wolfgang Wernsdorfer Dr. Rafael Ruiz‐García Dr. Emilio Pardo 《Angewandte Chemie (International ed. in English)》2013,52(52):14075-14079
50.
Dr. Celeste Are Dr. Maria Pérez Dr. Roberto Ballette Dr. Stefano Proto Dr. Federica Caso Nihan Yayik Prof. Joan Bosch Prof. Mercedes Amat 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(69):15929-15933
The synthesis of enantiopure ABCE and ABCD tetracyclic advanced intermediates en route to madangamine alkaloids and studies for the construction of the triunsaturated 15-membered D ring of madangamine B and the saturated 13-membered D ring of madangamine E are reported. 相似文献