Solid-state chemistry of polycarboxylate crown ether cation complexes: cooperative binding of water and metal ions by flexible chorands

Dutton, Philip J.; Fyles, Thomas M.; Suresh, Valia Veettil; Fronczek, Frank R.; Gandour, Richard D.

doi:10.1139/v93-035

Cited by 10 publications

(7 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The case of the sodium complex of 2,3,11,12-tetracarboxyl-(18-crown-6), where only four of the six ether oxygens are coordinated to the metal, is rather different from ours, since in the former, the Na ‫ם‬ is considerably deviated [0.4371(4) Å ] from the ring best plane, and, given the flattened twist-boat arrangement that the macrocycle adopts, two of the cycle oxygens are left outside of the bonding distance to the metal [34]. In the present case, by contrast, the coordination behavior observed in the complex cation seems to arise primarily from the position of the water molecules, determined in turn by the hydrogen bonding scheme in which they are involved, probably given mainly as a packing strategy of the solid.…”

Section: Structure Of the Ionic Moietiescontrasting

confidence: 69%

Structural studies of tetrazoles. Crystal and molecular structure and ab initio calculations of 1-phenyl-1H-tetrazole-5-thiolate, as its [diaqua(18-crown-6)sodium] salt: An anionic tetrazole free of direct metal interactions

Jimnez-Sandoval¹,

Cea‐Olivares²,

Hernndez-Ortega³

et al. 1997

Heteroat. Chem.

View full text Add to dashboard Cite

Section: Structure Of the Ionic Moietiescontrasting

confidence: 69%

Structural studies of tetrazoles. Crystal and molecular structure and ab initio calculations of 1-phenyl-1H-tetrazole-5-thiolate, as its [diaqua(18-crown-6)sodium] salt: An anionic tetrazole free of direct metal interactions

Jimnez-Sandoval¹,

Cea‐Olivares²,

Hernndez-Ortega³

et al. 1997

Heteroat. Chem.

View full text Add to dashboard Cite

“…> 6. c From ref and , but Tl(III) shows a C.N. value as high as 10 in other complexes (see ref ). d Structures of alums in ref .…”

Section: Resultsmentioning

confidence: 90%

Density Functional Theory-Based Prediction of the Formation Constants of Complexes of Ammonia in Aqueous Solution: Indications of the Role of Relativistic Effects in the Solution Chemistry of Gold(I)

Hancock

Bartolotti

2005

Inorg. Chem.

View full text Add to dashboard Cite

A prediction of the formation constants (log K1) for complexes of metal ions with a single NH3 ligand in aqueous solution, using quantum mechanical calculations, is reported. DeltaG values at 298 K in the gas phase for eq 1 (DeltaG(DFT)) were calculated for 34 metal ions using density functional theory (DFT), with the expectation that these would correlate with the free energy of complex formation in aqueous solution (DeltaG(aq)). [M(H2O)6]n+(g) + NH(3)(g) = [M(H2O)5NH3]n+(g) + H2O(g) (eq 1). The DeltaG(aq) values include the effects of complex changes in solvation on complex formation, which are not included in eq 1. It was anticipated that such changes in solvation would be constant or vary systematically with changes in the log K(1) value for different metal ions; therefore, simple correlations between DeltaG(DFT) and DeltaG(aq) were sought. The bulk of the log K1(NH3) values used to calculate DeltaG(aq) were not experimental, but estimated previously (Hancock 1978, 1980) from a variety of empirical correlations. Separate linear correlations between DeltaG(DFT) and DeltaG(aq) for metal ions of different charges (M2+, M3+, and M4+) were found. In plots of DeltaG(DFT) versus DeltaG(aq), the slopes ranged from 2.201 for M2+ ions down to 1.076 for M4+ ions, with intercepts increasing from M2+ to M4+ ions. Two separate correlations occurred for the M3+ ions, which appeared to correspond to small metal ions with a coordination number (CN) of 6 and to large metal ions with a higher CN in the vicinity of 7-9. The good correlation coefficients (R) in the range of 0.97-0.99 for all these separate correlations suggest that the approach used here may be the basis for future predictions of aqueous phase chemistry that would otherwise be experimentally inaccessible. Thus, the log K1(NH3) value for the transuranic Lr3+, which has a half-life of 3.6 h in its most stable isotope, is predicted to be 1.46. These calculations should also lead to a greater insight into the factors governing complex formation in aqueous solution. All of the above DFT calculations involved corrections for scalar relativistic effects (RE). Au has been described (Koltsoyannis 1997) as a "relativistic element". The chief effect of RE for group 11 ions is to favor linear coordination geometry and greatly increase covalence in the M-L bond. The correlation for M+ ions (H+, Cu+, Ag+, Au+) involved the preferred linear coordination of the [M(H2O)2]+ complexes, so that the DFT calculations of DeltaG for the gas-phase reaction in eq 2 were carried out for M = H+, Cu+, Ag+, and Au+. [M(H2O)2]+(g) + NH3(g) = [M(H2O)NH3]+(g) + H2O(g) (eq 2). Additional DFT calculations for eq 2 were carried out omitting corrections for RE. These indicated, in the absence of RE, virtually no change in the log K1(NH3) value for H+, a small decrease for Cu+, and a larger decrease for Ag+. There would, however, be a very large decrease in the log K1(NH3) value for Au(I) from 9.8 (RE included) to 1.6 (RE omitted). These results suggest that much of "soft" acid behavior in aqueous so...

show abstract

“…Each case builds on the tendency of the ionic species in which the complexed guest species induces a carboxylic acid groups to occupy axial positions on the macroperturbation in the electronic state of the host molecule. Perturcyclic periphery (22). In case of type A this would lead to capbations can be detected by absorption or emission spectroscopy ping across the face of the macrocycle; hence, this type is to define chromoionophores (1, 2) or fluoroionophores (2), respectively.…”

Section: Thomas M F~e Smentioning

confidence: 99%

Photoionophores derived from crown ether polycarboxylic acids: synthesis, ion binding, and spectroscopic characterization

Fyles¹,

Suresh²

1994

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

Three types of potential photoionophores based on polycarboxylic acid crown ethers were prepared, and their cation complexation behaviours and spectroscopic properties were surveyed. The first type were neutral macropolycyclic hosts prepared by capping across the faces of the crown ether with aromatic diamine chromophores. The second were bis-crown ether carboxylates bearing a bridging aromatic chromophore. The third type appended an additional chromophore-donor site on the crown ether carboxylic acid framework. Cation complexation was examined by potentiometric titration. The neutral ligands were rather poor hosts for alkali metal cations. The other two types of crown ether carboxylates showed a combination of size selectivity and electrostatic stabilization, leading to significant and selective ion binding in water. Ligands of the third type also exhibited cation-dependent absorption spectra in neutral and basic aqueous solution. No significant alkali metal or alkaline earth cation-induced perturbation of the emission spectra was uncovered, but a sodium-and cesium-dependent long wavelength emission enhancement was observed in one of the neutral ligand systems. Photoionophores are selective complexing agents for specific phores investigated. Each case builds on the tendency of the ionic species in which the complexed guest species induces a carboxylic acid groups to occupy axial positions on the macroperturbation in the electronic state of the host molecule. Perturcyclic periphery (22). In case of type A this would lead to capbations can be detected by absorption or emission spectroscopy ping across the face of the macrocycle; hence, this type is to define chromoionophores (1, 2) or fluoroionophores (2), respectively. In principle, ion-selective complexing agents could be modified by addition of a suitable chromophore to yield a functional photoionophore with the selectivity of the unmodified ion-binding host. For alkali metal and alkaline earth cations several examples of this strategy are reported for crown ether (2-12), cryptand (13,14), hemispherand (15), calixarene (16,17), and cyclophane hosts (18). Phenols ( l , 4 , 12), polycyclic aromatic (3, 13, 18), and heteroaromatic chromophores (5, 8,9, 11) have all been exploited. Despite the successes, there is still a need for photoionophores for alkali metal cations that could be used in aqueous solution over a range of pH values (10). The majority of the known photoionophores are either insoluble in water, insensitive to alkali metal cations, or pH sensitive.This paper evaluates several potential photoionophores referred to as captand. The additional arms above and below the macrocyclic plane place the chromophore in proximity to a bound cation and define a three-dimensional cavity (23, 24).Type B is akin to other bis-crown ethers (25), with the additional feature that the chromophore lies between the rings. The crown ethers are expected to act as independent carboxylate crown ethers. Type C unites several themes in crown ether chemistry: lariat ether structu...

show abstract

Solid-state chemistry of polycarboxylate crown ether cation complexes: cooperative binding of water and metal ions by flexible chorands

Cited by 10 publications

References 13 publications

Structural studies of tetrazoles. Crystal and molecular structure and ab initio calculations of 1-phenyl-1H-tetrazole-5-thiolate, as its [diaqua(18-crown-6)sodium] salt: An anionic tetrazole free of direct metal interactions

Structural studies of tetrazoles. Crystal and molecular structure and ab initio calculations of 1-phenyl-1H-tetrazole-5-thiolate, as its [diaqua(18-crown-6)sodium] salt: An anionic tetrazole free of direct metal interactions

Density Functional Theory-Based Prediction of the Formation Constants of Complexes of Ammonia in Aqueous Solution: Indications of the Role of Relativistic Effects in the Solution Chemistry of Gold(I)

Photoionophores derived from crown ether polycarboxylic acids: synthesis, ion binding, and spectroscopic characterization

Contact Info

Product

Resources

About