Effect of Macrocyclic Ligand Constraints upon the Kinetics of Complex Formation and Dissociation and Metal Ion Exchange. Copper(II) Complexes with Cyclohexanediyl Derivatives of the Cyclic Tetrathiaether [14]aneS4 in 80% Methanol

Aronne, Luciana; Yu, Qiuyue; Ochrymowycz, L. A.; Rorabacher, D. B.

doi:10.1021/ic00111a036

Cited by 13 publications

(24 citation statements)

References 2 publications

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“…(1.) Their rigidity prevents a folding that is necessary for the usual step-wise coordination of a macrocyclic ligand (176)(177)(178)(179)(180). Therefore, the formation rate is slow and the corresponding activation energy is large.…”

Section: A Complex Synthesismentioning

confidence: 99%

Bispidine Coordination Chemistry

Comba

Kerscher

Schiek

2007

Progress in Inorganic Chemistry

142

198

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Section: A Complex Synthesismentioning

confidence: 99%

Bispidine Coordination Chemistry

Comba

Kerscher

Schiek

2007

Progress in Inorganic Chemistry

142

198

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“…Modification of ligand structure has also been used to change the rate and kinetic parameters of metal complexes. − In general, one expects the ligand p K a to affect the rate of complex formation if the reaction occurs by an associative mechanism or by a dissociative mechanism where the lability is determined by the leaving group. A variety of vanadium(V) complexes and their complex formation rates have been examined in detail. − All show similar rates of complex formation.…”

Section: Introductionmentioning

confidence: 99%

Vanadium(V) Complexes of Polydentate Amino Alcohols: Fine-Tuning Complex Properties

Crans

Boukhobza

1998

J. Am. Chem. Soc.

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In aqueous solution, the stability, the structure, and the lability of 12 vanadium(V) complexes were determined and related to the amino alcohol ligand properties. The amino alcohols were chosen to maintain a five-coordinate vanadium geometry in the vanadium complex and were based on diethanolamine as the parent ligand. Apparent and composite stability constants were determined for all 12 complexes. Selected complexes were further examined to determine solution structure, lability, and thermodynamic properties. We empirically show that the formation constants for the series of 12 complexes, when plotted as a function of the pK a value for the protonated amino alcohol, generate a curve that initially increases as the pK a value increases and then decreases as the pK a value continues to increase. The observed associations suggest that the electron-donating capacity of the amino alcohol plays a major role in complex stability; however, metal coordination number, sterics in the amino alcohol, and solvation also are found to affect the stability. Determination of the thermodynamic parameters of selected complexes showed that the enthalpic component was the major contributor to the stability of the complex, but that the entropic component opposed this term. A series of studies was conducted to examine whether the lability of these complexes varied from the parent complexes. Unfortunately, the variation in the lability of these complexes was much less than the variation in complex stability. In summary, these studies describe quantitatively the variation in complex stability and lability as the structure of amino alcohol is modified and explain why some complexes show less stability than predicted on the basis of the pK a value. In short, this study provides valuable information for the design of additional vanadium complexes with specific properties.

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“…Finally, their electron-donating ability is one of the factors influencing relative stabilities and rates of formation of complexes formed between these ligands and various metal ions . The generalizations regarding macrocyclic complexation behavior must, however, take into account ligand−solvent interactions . Although the macrocyclic effect had been known for a long time some of its details are still unclear.…”

Section: Introductionmentioning

confidence: 99%