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91.
Based on an analysis of previously reported structures and a potential geometry fit with substrates, a new family of chiral dioxocyclam derivatives have been designed. The synthesis of those ligands was accomplished starting from l-proline and α-d-amino acids (converted to β-amino acids) with a key step of macrocyclization reaction of amino esters. All ligands were converted into neutral copper(II) complexes (amide groups underwent deprotonation of upon treatment of ligands with copper(II) acetate). The complexes exhibit the desired shape of their active surfaces, as proved by X-ray analysis. 相似文献
92.
Helmut Bahrmann Klaus Bergrath Han -Jerg Kleiner Peter Lappe Christoph Naumann Dieter Peters Dieter Regnat 《Journal of organometallic chemistry》1996,520(1-2):97-100
BINAS is a new, very efficient ligand for propylene hydroformylation. BINAS is made by the sulfonation of NAPHOS. Different synthetic routes to NAPHOS are discussed. A new two step synthesis starting from 2,2′-bis(bromomethyl)-1,1′-binaphthyl is described. 相似文献
93.
Yu. G. Budnikova A. G. Kafiyatullina Yu. M. Kargin O. G. Sinyashin 《Russian Chemical Bulletin》2003,52(7):1504-1511
Electrochemical reduction of cobalt(ii) complexes containing -acceptor ligands (L = bpy, Ph2Ppy) proceeds through three consecutive reversible steps: one-electron transfer to form a more stable CoIL complex, transfer of two electrons at more negative potentials to form an anionic [NiL]– complex, and reduction of the ligand to the radical anion. The stability of the cobalt complexes with different ligands decreases in the series Ph2Ppy > Ph3P > bpy. 相似文献
94.
Summary A potentially heptadentated ligand (apytren) was obtained by condensation of 2-acetylpyridine andtris-(2-aminoethyl)-amine in the presence of lanthanoid(III) cations. Complexes of the formulaLn(apytren)(NO3)3·H2O (Ln=La, Eu, Gd, and Tb) have been isolated and characterized, both in the solid state and in solution, by means of vibrational and electronic spectroscopy and of conductometric measurements. Their photophysical properties, including emission quantum yields and lifetimes, were studied and are discussed.
Synthese und Lumineszenzuntersuchungen an Lanthanoid(III)-Komplexen mit einer aus 2-Acetylpyridin undtris-(2-Aminoethyl)-amin hergeleitetenSchiffschen Base
Zusammenfassung Durch Kondensation von 2-Acetylpyridin undtris-(2-Aminoethyl)-amin in der Gegenwart von Lanthanoid(III)-Kationen wurde ein potentiell siebenzähniger Ligand (apytren) erhalten. Komplexe der ZusammensetzungLn(apytren)(NO3)3·H2O (Ln=La, Eu, Gd und Tb) wurden isoliert und sowohl im festen Zustand als auch in Lösung mittels IR-und UV-Vis-Spektroskopie und Leitfähigkeitsmessungen charakterisiert. Ihre photophysikalischen Eigenschaften, einschließlich Emissionsquantenausbeute und Lebensdauer, wurden untersucht und werden diskutiert.相似文献
95.
Hubert Schmidbaur 《Angewandte Chemie (International ed. in English)》1985,24(11):893-904
Arene complexes of main-group metals were, until recently, rare species—in contrast to the now classical, analogous complexes of transition metals. In systematic investigations, it has been possible to prepare and structurally characterize arene complexes of the univalent elements gallium, indium, and thallium, which directly follow the d-block elements in the periodic table. This new type of compound is characterized by centric (η6) coordination of the metal to the arene; both mono- and bis(arene) complexes are known. The interaction can be explained by the perfect agreement between the HOMO/LUMO symmetry of the arene and of the low-valent metal. The electronic states of the nd10(n + 1)s2 configuration, which are partially modified by relativistic effects, play a particularly important role. The relationship to the few known complexes of the neighboring elements (SnII, PbII) becomes plausible via the isoelectronic principle. The arene/GaI, InI, TlI systems are of potential significance as homogeneous reducing agents and as agents for the activation of aromatic compounds, the purification of metals, and the separation of metals from nonaqueous media. 相似文献
96.
Norma A. Cortez 《Tetrahedron letters》2007,48(25):4335-4338
Monosulfonamide ligands with heteroatom/heterocyclic systems were derived from trans-(1R,2R)-cyclohexane-1,2-diamine and complexed with [Ru(benzene)Cl2]2, [Cp∗RhCl2]2 in situ and used in the ATH of aromatic ketones with aqueous sodium formate as the hydrogen source. The chiral secondary alcohols were obtained with >93% enantioselectivity and >89% yield. Reduction in water was faster than in isopropanol/KOH. Addition of surfactants showed little or no effects. 相似文献
97.
98.
From conductance and viscosities measurements on Pr4NCl, Et4NBr, and AgNO3 in acetonitrile and Et3NBr in nitrobenzene, the Walden products of the anion at infinite dilution were determined in presence of various concentrations of substituted benzoic acids. From these data it was possible to compute the values of the Walden products of the once complexed anions and to estimate the order of magnitude of the Walden products of twice complexed anions. Stokes' law is not obeyed, and the Walden products are not proportional to the third root of the molar volume of the complexed ions, as a consequence of their lack of sphericity. The assumption that the drag force which acts on the ions is proportional to the volume of the substituents results in a linear expression between the reciprocals of the Walden products and the molar volume of the ligands. The experimental results fit this expression within the limits of the experimental errors, and the slopes of the lines are nearly the same for all the anions and for the two solvents studied here, namely, 2.5×10–4 ohm-cm–5 mole-cP–1. 相似文献
99.
Summary. A series of novel tridentate ligands with nitrogen and oxygen donor sites was synthesized starting from enantiomerically
pure (S)- and (R)-1-(pyridin-2-yl)ethylamine, the preparation and resolution of which was developed. The new optically active ligands were
tested as in situ catalysts together with Ru(PPh3)3Cl2 in the enantioselective transfer hydrogenation of acetophenone with isopropanol. The secondary amine ligand (S)-2,4-di-tert-butyl-6-(1-(pyridin-2-yl)ethylamino)methylphenol gave the best results with almost quantitative conversion and 47%ee.
Received August 17, 2001. Accepted August 27, 2001 相似文献
100.
The reactions of the cationic, diiron-bridging carbyne complexes [Fe(2)(mu-CAr)(CO)(4)(eta(8)-C(8)H(8))]BF(4) (1, Ar=C(6)H(5); 2, Ar=p-CH(3)C(6)H(4); 3, Ar=p-CF(3)C(6)H(4)) with LiN(C(6)H(5))(2) in THF at low temperature gave novel N-nucleophilic-addition products, namely, the neutral, diiron-bridging carbyne complexes [Fe(2)(mu-CAr)(CO)(4)(eta(7)-C(8)H(8)N(C(6)H(5))(2))] (4, Ar=C(6)H(5); 5, Ar=p-CH(3)C(6)H(4); 6, Ar=p-CF(3)C(6)H(4))). Cationic bridging carbyne complexes 1-3 react with (C(2)H(5))(2)NH, (iC(3)H(7))(2)NH, and (C(6)H(11))(2)NH under the same conditions with ring cleavage of the COT ligand to produce the novel diiron-bridging carbene inner salts [Fe(2)[mu-C(Ar)C(8)H(8)NR(2)](CO)(4)] (7, Ar=C(6)H(5), R=C(2)H(5); 8, Ar=p-CH(3)C(6)H(4), R=C(2)H(5); 9, Ar=p-CF(3)C(6)H(4), R=C(2)H(5); 10, Ar=C(6)H(5), R=iC(3)H(7); 11, Ar=p-CH(3)C(6)H(4), R=iC(3)H(7); 12, Ar=p-CF(3)C(6)H(4), R=iC(3)H(7); 13, Ar=C(6)H(5), R=C(6)H(11); 14, Ar=p-CH(3)C(6)H(4), R=C(6)H(11), 15, Ar=p-CF(3)C(6)H(4), R=C(6)H(11)). Piperidine reacts similarly with cationic carbyne complex 3 to afford the corresponding bridging carbene inner salt [Fe(2)[mu-C(Ar)C(8)H(8)N(CH(2))(5)](CO)(4)] (16). Compound 9 was transformed into a new diiron-bridging carbene inner salt 17, the trans isomer of 9, by heating in benzene. Unexpectedly, the reaction of C(6)H(5)NH(2) with 2 gave a novel COT iron-carbene complex [Fe(2)[=C(C(6)H(4)CH(3)-p)NHC(6)H(5)](mu-CO)(CO)(3)(eta(8)-C(8)H(8))] (18). However, the analogous reactions of 2-naphthylamine with 2 and of p-CF(3)C(6)H(4)NH(2) with 3 produce novel chelated iron-carbene complexes [Fe(2)[=C(C(6)H(4)CH(3)-p)NC(10)H(7)](CO)(4)(eta(2):eta(3):eta(2)-C(8)H(9))] (19) and [Fe(2)[=C(C(6)H(4)CF(3)-p)NC(6)H(4)CF(3)-p](CO)(4)(eta(2):eta(3):eta(2)-C(8)H(9))] (20), respectively. Compound 18 can also be transformed into the analogous chelated iron-carbene complex [Fe(2)[=C(C(6)H(4)CH(3)-p)NC(6)H(5)](CO)(4)(eta(2):eta(3):eta(2)-C(8)H(9))] (21). The structures of complexes 6, 9, 15, 17, 18, and 21 have been established by X-ray diffraction studies. 相似文献