Molecular Mechanics Calculations and the Metal Ion Selective Extraction of Lanthanoids

1998 ◽  
Vol 37 (13) ◽  
pp. 3310-3315 ◽  
Author(s):  
Peter Comba ◽  
Karsten Gloe ◽  
Katsutoshi Inoue ◽  
Torsten Krüger ◽  
Holger Stephan ◽  
...  
Keyword(s):  
Molecular Mechanics ◽  
Metal Ion ◽  
Selective Extraction ◽  
Molecular Mechanics Calculations

Metal ion complexes of 1,4,7-triazacyclononane and their aminoalkyl derivatives. Analysis of chelate rings fusion and molecular mechanics study

1994 ◽  
Vol 72 (5) ◽  
pp. 1404-1411 ◽  
Author(s):  
Igor V. Pletnev
Keyword(s):  
Quantitative Analysis ◽  
Molecular Mechanics ◽  
Metal Ion ◽  
Chelate Ring ◽  
Critical Role ◽  
Molecular Mechanics Calculations ◽  
Metal Ion Complexes ◽  
X Ray ◽  
Coordination Bonds ◽  
Chelate Rings

Stereochemistry of metal ion complexes of 1,4,7-triazacyclononane, their N,N′,N′′-tris(aminoethyl), tris(aminopropyl), and their N,N′-(4,7-diazadecylene) derivatives is described in terms of the fusion of chelate rings at metal–nitrogen coordination bonds. Molecular mechanics calculations and analysis of the X-ray data confirm that the semi-quantitative analysis is valid and that fusion plays a critical role in the structure of the complexes. Molecular mechanics study of puckering of the ethylenediamine chelate ring, an essential part in this study, is also presented.

Strong cooperative protonation of a small tris-urea cryptand

1988 ◽  
Vol 66 (11) ◽  
pp. 2914-2919 ◽  
Author(s):  
Pierre G. Potvin ◽  
Man Hung Wong
Keyword(s):  
Hydrogen Bonds ◽  
Molecular Mechanics ◽  
Metal Ion ◽  
Proton Exchange ◽  
Carbonyl Groups ◽  
Fast Proton ◽  
Molecular Mechanics Calculations ◽  
Complexation Studies ◽  
Coupling Procedure ◽  
Exchange Kinetics

A small bicyclic cryptand 3 bearing urea groups along the 7-atom bridges was synthesized in 22% yield by a novel tripod-tripod coupling procedure. Protonation and complexation studies are reported and compared with results with polyoxa-[2]-cryptands and [3]-cryptand 6. These show that 3 is a moderate base, a weak metal ion binder, but a two-proton binder exhibiting strong positive cooperativity (pKa2 > pKa1) and fast proton exchange kinetics. As demonstrated by molecular mechanics calculations, an inward rotation of the carbonyl groups to form hydrogen bonds to cryptated protons was invoked to explain the cooperativity.

The conformational properties of calix[4]arenes 1h NMR and molecular mechanics calculations

1989 ◽  
Vol 86 ◽  
pp. 945-954 ◽  
Author(s):  
F. Bayard ◽  
D. Decoret ◽  
D. Pattou ◽  
J. Royer ◽  
A. Satrallah ◽  
...  
Keyword(s):  
Molecular Mechanics ◽  
1H Nmr ◽  
Molecular Mechanics Calculations ◽  
Conformational Properties
Sign in / Sign up

Export Citation Format

Share Document