Karlin Group Tridentate Model Compounds

Oxygenation rates were first examined for the system [Cu (R-XYL-H)]2+. In the model described here, two bis [2-(2-pyridyl)ethyl] amine (PY2) units are linked by a xylyl spacer group (R = H). Although initially proposed as a crude hemocyanin model, this system now is studied as a model for tyrosinase and is an example of hydrocarbon oxygenation taking place under mild conditions—that is, 1 atm 02 

A thorough kinetic and thermodynamic analysis of this model system (small positive or negative enthalpies of formation are canceled by more negative entropies of formation) led Karlin s group to conclude that the stability of dioxygen binding is driven by favorable enthalpies, but unfavorable reaction entropies preclude observation of Cu2-02 at room temperatures.412 

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