Molecular Modeling-Studien schwefelhaltiger Wirt/Gast-Systeme

Rambusch, Torsten; Hollmann-Gloe, Kerstin; Gloe, Karsten

doi:10.1002/(sici)1521-3897(199904)341:3<202::aid-prac202>3.0.co;2-a

Cited by 19 publications

(6 citation statements)

References 16 publications

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“…This functional has previously been shown to give satisfactory geometries for several other silver-macrocycle complexes, 22 as well as for model amine and hydroxy complexes. 23 The present calculations were performed using the additional approximation that the coulomb integrals are approximated by a sum of atom centred s, p, d .…”

Section: Dft Calculationsmentioning

confidence: 95%

Macrocyclic ligand design. X-Ray, DFT and solution studies of the effect of N-methylation and N-benzylation of 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane on its affinity for selected transition and post-transition metal ions

Hambley

Lindoy

Reimers

et al. 2001

J. Chem. Soc., Dalton Trans.

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Potentiometric titration in 95% methanol (I = 0.1 mol dm Ϫ3 , Et 4 NClO 4 ) has been employed to investigate the effect of N-methylation and N-benzylation of 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane 1 on the binding of all three rings to cobalt(), nickel(), copper(), zinc(), cadmium(), silver() and lead(). The results show that enhanced selectivity for silver() is exhibited by the di-N-benzylated derivative 3 while the analogous dimethylated derivative 2 discriminates for both silver() and lead(). The crystal structures of [Ag(1)]PF 6 , [Ag(2)]PF 6 , [Ag (3)]PF 6 and [Pb(1)(NO 3 ) 2 ] have been determined. In the silver complexes the NH hydrogens of 1 and the N-methyl and N-benzyl substituents of the dialkylated derivatives 2 and 3 were found to lie on the same side of the mean donor planes of the co-ordinated macrocycles ('cis' arrangements). Density functional theory has been employed to model the silver complexes in both their energy-minimised 'cis' and 'trans' configurations. In accordance with the X-ray evidence, the calculations predict that the 'cis' arrangement is the more stable in each case. The crystal structure of the lead complex of 1 shows a 'trans' arrangement of its NH groups.

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Section: Dft Calculationsmentioning

confidence: 95%

Macrocyclic ligand design. X-Ray, DFT and solution studies of the effect of N-methylation and N-benzylation of 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane on its affinity for selected transition and post-transition metal ions

Hambley

Lindoy

Reimers

et al. 2001

J. Chem. Soc., Dalton Trans.

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“…Nonlocal functionals such as BP86 and B3LYP have been found to be superior to Hartree−Fock (HF) and Møller−Plesset second-order perturbation theory (MP2) methods for calculating thermodynamic properties of a variety of metal−ligand complexes, , and have found increasing use in coordination chemistry . They are also feasible to apply to metal complexes of smaller macrocyclic ligands, − including studies by us of macrocyclic ligand complexes of silver(I) …”

Section: Introductionmentioning

confidence: 99%

The Effect of Alkylation of N- and O-Donor Atoms on Their Strength of Coordination to Silver(I)

2001

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The observation that alkylation of amine ligands can lead to enhanced coordination to silver(I) is investigated through the determination of structures and incremental binding enthalpies for Ag + (L) n ionic clusters (with L ) NH 3 , NH 2 Me, NHMe 2 , NMe 3 , H 2 O, MeOH, and Me 2 O for n ) 1-2), using density-functional and CCSD(T) electronic structure methods. For the nonalkylated complexes Ag + (H 2 O), Ag + (NH 3 ), Ag + (H 2 O) 2 , and Ag + (NH 3 ) 2 , the calculated binding enthalpies agreed well with experimental values for all but Ag + -(NH 3 ) 2 , while good agreement between the binding entropies was achieved for all but Ag + (H 2 O). As a function of the degree of alkylation, the calculated binding enthalpies initially increase but then decrease. The results are interpreted in terms of the bonding models of Meyerstein and of Deng et al. as arising from increased ligand σ-donating ability and reduced ion-ligand electrostatic interactions. It is clear that gas-phase effects are insufficient to explain the sometimes observed increased binding energies of tertiary macrocyclic amines compared to secondary ones.

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“…The initial structures were obtained by conformation analysis by using molecular dynamics. The DFT method is applicable to the full range of molecular systems, including hydrogen‐bonded aggregates22 and transition metal complexes,23, 24 and gives results of quality comparable to ab initio level 23. Figure 3 shows the calculated “local minima” structures of 2 and 1 from the BP86 functional of the ADF software package 25.…”

Section: Resultsmentioning

confidence: 99%

A New Cryptophane Receptor Featuring Three endo‐Carboxylic Acid Groups: Synthesis, Host Behavior and Structural Study

Roesky

Weber

Rambusch

et al. 2003

Chemistry A European J

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Examples of a new type of cryptophane molecule incorporating aromatic groups in the bridges (1-4) and, for the first time, being also supplied with three endo-positional ionizable carboxylic acid functions (1) have been synthesized and characterized. The cryptophane triester 2 yielded a solvate (channel inclusion compound) with trichloromethane and water, the X-ray crystal structure of which is reported. The complexation of 1 with low-molecular-weight alcohols in solution was studied, and the liquid-liquid extraction of different metal ions including alkali (Na(+), Cs(+)), alkaline earth (Mg(2+), Ca(2+), Sr(2+), Ba(2+)), and the lanthanide metal ions Eu(3+) and Yb(3+) in an extraction system containing metal nitrate buffer/H(2)O/1/CHCl(3) was examined. Molecular modeling calculations of the cryptophanes 1 and 2, and of the Eu(3+) complex of 1 were carried out contributing to the discussion.

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Molecular Modeling-Studien schwefelhaltiger Wirt/Gast-Systeme

Cited by 19 publications

References 16 publications

Macrocyclic ligand design. X-Ray, DFT and solution studies of the effect of N-methylation and N-benzylation of 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane on its affinity for selected transition and post-transition metal ions

Macrocyclic ligand design. X-Ray, DFT and solution studies of the effect of N-methylation and N-benzylation of 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane on its affinity for selected transition and post-transition metal ions

The Effect of Alkylation of N- and O-Donor Atoms on Their Strength of Coordination to Silver(I)

A New Cryptophane Receptor Featuring Three endo‐Carboxylic Acid Groups: Synthesis, Host Behavior and Structural Study

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