Ga(ClO4)3-catalyzed synthesis of quinoxalines by cycloaddition of α-hydroxyketones and o-phenylenediamines
摘要:
A new approach for the synthesis of 2-substituted quinoxalines by Ga(ClO4)(3)-catalyzed cycloaddition of alpha-hydroxyketones and o-phenylenediamines is introduced. The reaction is catalyzed by 10 mol % of Ga(ClO4)(3) in EtOH at room temperature. It is performed under simple and mild conditions to afford the product in good yield. (C) 2012 Elsevier Ltd. All rights reserved.
Kinetics and equilibria of Ga(III)thiocyanate complex formation. Mechanism of ligand substitution reactions of Ga(III) in aqueous solution
作者:Anthony Campisi、Peter A. Tregloan
DOI:10.1016/s0020-1693(00)85294-9
日期:1985.6
The complexation equilibrium quotient [GaNCS2+]/([Ga3+][NCS−]) has been independently determined by spectrophotometric titration to be 20.8 ± 0.3 M−1 at 25 °C and ionic strength 0.5 M. These kinetic results lead to an interpretation of the data, and a reinterpretation of other data for aquo-Ga(III) complex formation kinetics from the literature which support the assignment of a dissociative interchange
Exploring the Lewis basicity of the metalloligand [Pt2(µ-Se)2(PPh3)4] on metal substrates by electrospray mass spectrometry. Synthesis, characterization and structural studies of new platinum selenido phosphine complexes containing the {Pt2Se2} core
作者:Jeremy S. L. Yeo、Jagadese J. Vittal、William Henderson、T. S. Andy Hor
DOI:10.1039/b104996h
日期:2002.1.23
basic metalloligand leads to the identification and isolation of the doubly-protonated species, [Pt2(μ-SeH)2(PPh3)4]2+, whose sulfide analogue cannot be isolated. A three-step strategy is employed in the use of ESMS as a probe: (i) preliminary screening of the metalloligand with an array of acidic main group and transition group metal compounds, (ii) identification of potentially stable and isolable
of the phosphopeptides, as in the case of dinuclear copper complexes. In contrast, dinuclear zinc complexes efficiently bind to phosphopeptides with an increase in the charge state, facilitating phosphopeptide sequencing by ETD-MS/MS. The fragmentation of the ligand and peptide backbone in the dinuclear zinc–phosphopeptide complex were competitively induced by ETD. These processes are influenced by
indium(III) with halide and thiocyanate ions has been studied by calorimetry in N,N-dimethylformamide (dmf). Four mononuclear halogeno complexes [InX(dmf)5]2+, [InX2(dmf)4]+, [InX3(dmf)3] and [InX4]–(X = Cl, Br, I) are found for lnIII, whereas only two complexes are found for GaIII: [GaX(dmf)5]2+ and [GaX4]–(X = Cl, Br). The absence of GaIII di- and tri-halogeno complexes in solution has been confirmed
equilibria between gallium(III) and the 5-nitrosalycylate ion, HA–, have been investigated by spectrophotometry in acid solution (pH 1–2.5). Two complexes are identified, their formation constants being K1=[GaA+][H+]/[Ga3+][HA–]= 49 ± 2 and K1′=[Ga(HA)2+]/[Ga3+][HA–]= 500 ± 55 dm3 mol–1 at 25 °C and I= 0.1 mol dm–3. The kinetics of the formation and decomposition of the complexes have been investigated