Binding Constants by Microcalorimetric and Spectroscopic Measurements

FIGURE 1.13 Typical (a) calorimetric, (b) CDM, and (c) UV titrations of tBuCQD (SO) with (i )-DNB-Leu (SA) in methanol at 25°C. In panel (a) the heat effects measured after successive addition of (i )-DNB-Leu solution are depicted, while in (b) and (c) the CDM and UV spectra, respectively, monitored at different ratios of total SA and SO, [SA]x/[SO]x concentrations are shown (note, subscript T stands for total molar amount in the reaction solution). (Reproduced from J. Lah et al., J. Phys. Chem. B, 105 1670 (2001). With permission.) 

Binding Constants Kfj for (R)-and (5)-DNB-Leu Binding to the Chiral Selectors tBuCQN, tBuCQD, QN, and QD Determined from the Calorimetric, UV, and CDM Titration Curves in Methanol solutions at 25°C  

Source Reproduced from J. Lah, N.M. Maier, W. Lindner, and G Vesnaver, J. Phys. Chem. B, 105 1670 (2001). 

Somewhat larger deviations are seen for the UV spectrophotometrically derived constants. However, the intrinsic binding selectivities as assessed from the ratio of the binding constants for the corresponding enantiomers was a reasonable match between UV and ITC, at least what the carbamate selectors is concerned. 

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