3,5-Bis(2-hydroxyphenyl)-1H-1,2,4-triazole based ligands — protonation and metal complex formation

2008 ◽  
Vol 62 (4) ◽  
Author(s):  
Stefan Stucky ◽  
Nadine Koch ◽  
Uwe Heinz ◽  
Kaspar Hegetschweiler
Keyword(s):  
Crystal Structure ◽  
Cyclic Voltammetry ◽  
Nitrogen Atom ◽  
Complex Formation ◽  
1H Nmr ◽  
Temperature Dependent ◽  
Spectroscopic Measurements ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Spectrophotometric Titrations

Abstract3,5-Bis(2-hydroxyphenyl)-1H-1,2,4-triazole (H2La) and 4-[3,5-bis(2-hydroxyphenyl)-1H-1,2,4-triazol-1-yl]benzoic acid (H3Lb) have been prepared, and crystal structure of the intermediate 2-(2-hydroxyphenyl)-4H-1,3-benzoxazin-4-one has been determined. Temperature dependent 1H NMR spectroscopic measurements of H2La indicated dynamic behavior with the equilibrium between the two asymmetric tautomers. For H3Lb, pD-dependent 1H NMR spectroscopic measurements showed small but characteristic shifts in the range of 0 ≤ pD ≤ 1, indicative of a triazole nitrogen atom protonation; the corresponding pK a of 0.98 ± 0.04 was determined by spectrophotometric titrations. (H2O, 26°C, 1 M KCl/HCl). Formation of [FeIII(La)]+ (pH 2.5) and [FeIII(La)2]− (pH > 6) was verified by UV-Vis spectroscopy. Complex formation of H3Lb with Al3+ and VO2+ was investigated by 1H NMR spectroscopic titration and cyclic voltammetry, respectively. Single crystals of the phenoxo bridged [VVO(HLb)(EtO)]2·2EtOH were characterized by X-ray structural analysis.

Synthese und Kristallstruktur des Dichloroselenonitren-Komplexes (PPh4)2[WCl5(NSeCl2)] / Synthesis and Crystal Structure of the Dichloro-selenonitrene Complex (PPh4)2[WCl5(NSeCl2)]

1992 ◽  
Vol 47 (3) ◽  
pp. 301-304 ◽  
Author(s):  
Stefan Vogler ◽  
Kurt Dehnicke
Keyword(s):  
Crystal Structure ◽  
Nitrogen Atom ◽  
Structure Determination ◽  
Selenium Atom ◽  
Tungsten Atom ◽  
Chlorine Atoms ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Distorted Octahedral

The title compound has been prepared by the reaction o f [WCl4(NSeCl)]2 with PPh4Cl in CH2Cl2 solution. It forms red crystals, which were characterized by an X-ray structure determination. Space group P21/c, Z = 4, 3856 observed unique reflections, R = 0.073. Lattice dimensions at 25 °C: a = 2266.0(5), b = 1121.0(2), c = 2013.0(4) pm, β = 109.66(3)°. The structure consists o f PPh4+ ions and anions [WCl5(NSeCl2)]2-, in which the tungsten atom is surrounded in a distorted octahedral way by five chlorine atoms and by the nitrogen atom of the (NSeCl2)3- ligand. The W = N = SeCl2 group is characterized by WN and SeN double bonds; the selenium atom has a pseudo trigonal-bipyramidal coordination with the N atom and two lone pairs in equatorial and the chlorine atoms in axial positions.

Synthesis, x-ray crystal structure, and temperature-dependent NMR spectrum of tetraethylammonium (.alpha.-methoxybenzyl)pentacarbonyltungstate

1978 ◽  
Vol 17 (11) ◽  
pp. 3045-3049 ◽  
Author(s):  
Charles P. Casey ◽  
Stanley W. Polichnowski ◽  
Hendrik E. Tuinstra ◽  
Loren D. Albin ◽  
Joseph C. Calabrese
Keyword(s):  
Crystal Structure ◽  
Temperature Dependent ◽  
Nmr Spectrum ◽  
X Ray

Das 7,8-Benzo-5-chloro-1,4,4-trimethyl-1-aza-4-azonia-6,9-dioxa-5 λ5-phosphaspiro[4.4]nonanyl-Kation: Röntgenstrukturanalyse und temperaturabhängige 1H-NMR-Spektren: The 7, 8-Benzo-5-chloro-1,4,4-trimethyl-1-aza-4-azonia-6,9-dioxa-5 λ).5-phosphaspiro[4.4]nonanyl Cation: X-Ray Crystal Structure Determination and Variable 1H NMR Spectra

1992 ◽  
Vol 47 (6) ◽  
pp. 755-759 ◽  
Author(s):  
Thomas Kaukorat ◽  
Peter G. Jones ◽  
Reinhard Schmutzler
Keyword(s):  
Crystal Structure ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Crystal Structure Analysis ◽  
Acceptor Interaction ◽  
Nmr Spectrum ◽  
X Ray ◽  
H Nmr ◽  
Trigonal Bipyramidal ◽  
Donor Acceptor

The 1H NMR spectrum of the spirophosphorane 3 at room temperature indicates dynamic behaviour of the cation. The low-temperature 1H NMR spectra of 3 exhibit two sets of doublets for the protons of the diastereotopic N(CH3)2 groups. The free enthalpy of activation for the dynamic process was determined (58.6 KJ/mole). In the reaction of 3 with sodium tetraphenylborate the crystalline compound, 4, involving the non-coordinating anion, [B(C6H5)4]-, was obtained. The X-ray crystal structure analysis of 4 reveals the presence of a five-membered ring, formally as a result of intramolecular donor-acceptor interaction between the nitrogen atom of the N(CH3)2 group and phosphorus. The geometry at phosphorus deviates somewhat from ideal trigonal bipyramidal.

scholarly journals The structure of polyisoprenes. I. The crystal structure of geranylamine hydrochloride

1945 ◽  
Vol 183 (995) ◽  
pp. 388-404 ◽  
Keyword(s):  
Crystal Structure ◽  
Nitrogen Atom ◽  
Three Dimensional ◽  
Trans Configuration ◽  
Single Bond ◽  
Interatomic Distances ◽  
X Ray ◽  
Gutta Percha ◽  
Carbon Bonds ◽  
Molecular Dimensions

An X-ray analysis employing three-dimensional Fourier syntheses has established the crystal structure and molecular dimensions of the di-isoprene derivative, geranylamine hydrochloride. The molecules, which have a trans configuration and are therefore analogous to gutta- percha, lie parallel and end to end in pairs within an ionic framework where each nitrogen atom is equidistant from four chlorine neighbours. The two isoprene units are planar and have normal interatomic distances, but are linked by a C-C bond markedly shorter than a normal single bond. This unusual bond feature is accompanied by a coplanar arrangement with the adjacent carbon bonds.

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