Enthalpy- vs Entropy-Driven Complexation of Homoallylic Alcohols by Rhodium(I) Complexes
2011-11-28T00:00:00Z (GMT) by
The thermodynamics of binding between several homoallylic alcohols and simple olefinic Rh(I) compounds was examined with 1H NMR spectroscopy and isothermal titration calorimetry (ITC). 1H NMR titrations revealed moderate binding of these alcohols with [Rh(COD)2]+ (1) and [Rh(COD)(CH3CN)2]+ (3), but weaker binding with [Rh(NBD)2]+ (2). ITC indicated that the complexation with [Rh(COD)2]+ is mainly governed by enthalpy, whereas binding with [Rh(COD)(CH3CN)2]+ is entirely driven by entropy. The thermodynamic parameters for the homoallylic alcohol binding of Rh(I) complexes 1–3 are consistent with crystallographic data.