68579-77-1Relevant articles and documents
Gas-Phase Lewis Acid-Base Interactions. An Experimental Determination of Cyanide Binding Energies from Ion Cyclotron Resonance and High-Pressure Mass Spectrometric Equilibrium Measurements
Larson, J. W.,Szulejko, J. E.,McMahon, T. B.
, p. 7604 - 7609 (2007/10/02)
Both ion cyclotron resonance and high-pressure mass spectrometric equilibrium techniques have been used to investigate the binding energies of anions to a variety of Lewis acids.From an analysis of the enthalpy changes associated with CN- binding it is evident that in cases of relatively weak binding considerable freedom of rotational motion of CN- in the complex may be retained.Ab initio calculations and experiment suggest that binding through both the N and C sites of CN- is nearly equally favorable in some cases.In contrast to results previously obtained for Bronsted acids which showed that CN- and Cl- bind nearly identically, the present data for Lewis acids show many cases where cyanide is much more favorably bound than chloride, a consequence of enhanced covalent binding of the CN- complexes.New Kroeger Drago parameters derived for CN- support the importance of covalent binding in cyanide adducts.Correlations of binding energy of anions to Lewis acids with the anion proton affinity show excellent linear relationships which may be used to predict binding energetics for new anions.
