Mechanism of water exchange on five-coordinate copper(ii) complexes

Mechanistic Insight into the Activity of Tyrosinase from Variable‐Temperature Studies in an Aqueous/Organic Solvent

“…These low values cannot be simply attributed to the susceptibility to ligand substitution of copper( II ) ions, since similar values should then be observed with catechols. Furthermore, ligand substitutions in copper( II ) model complexes are associated with much larger activation enthalpies, ranging from 25 to 85 kJ mol −1 , depending on the complex and the reaction conditions 52–54. Therefore, at least for phenolic substrates, the hypothesis of slow binding to tyrosinase is unlikely.…”

18O-Water exchange in photosystem II: Substrate binding and intermediates of the water splitting cycle

“…In a recent study of this phenomenon, a series of the d 9 Cu 2+ complexes were structurally constrained by a single 5-coordinated organic ligand in which the remaining single aqua ligand could be resolved. It was found that the Cu-complexes had either significantly reduced or entirely lost the J-T distortions and that the exchange of the aqua ligand was significantly slowed compared to hexaaquo Cu 2+ complex [71]. Fig.…”

Mechanistic Studies of Metal Aqua Ions: A Semi‐Historical Perspective

“…However, coordinated H 2 O is not invariably labilized by the entry of another ligand into the first coordination sphere as shown by 2,2'-bipyridine and 2,2',2''-terpyridine which cause only minor changes in lability, probably because their s-donation of electron density to M m is offset by pbonding-electron-density withdrawal [83]. Sometimes, other ligands may decrease H 2 O lability as does trimethyl phosphate and 3-(2-pyridyl)-5,6-bis(4-phenylsulfonic acid)-1,2,4-triazine ( 4,4'-[3-(pyridin-2-yl)-1,2,4-triazine-5,6-diyl]bis[benzenesulfonic acid) when coordinated to Cu 2 , possibly because of a decrease in coordination number [84].…”