This shift may indicate that the 2:1 complex eventually dissociates into a 1:1 complex, suggesting that the binding constant for the latter is higher than that of the former. Further, the absorbance data at λmax centered between 400 and 450 nm of the respective charge transfer bands were plotted against the titrated metal concentrations, and the curves were fitted using 1:1 and 2:1 binding models in Bindfit, 39 allowing us to determine the respective association constants (Table ). Interestingly, the logβ2 values for the DpC-Fe(II) complexes were nearly 3fold lower than that of the Dp44mT-Fe(II), suggesting that steric hindrance from the cyclohexyl ring in DpCs might be negatively affecting the binding when forming a 2:1 complex. On the other hand, the logKa values for all the 1:1 Cu(II) complexes were similar. Clearly, positioning of the linker did not influence metal binding as the derivatives exhibited binding comparable to their corresponding regioisomers. Furthermore, the azide-functionalized DpTs showed binding constants comparable to the unmodified DpTs, indicating that azidefunctionalization and the presence of a diastereomeric mixture do not impair chelation.