THERMODYNAMIC PARAMETERS FOR POLYETHER ADDUCTS WITH NEUTRAL MOLECULES

Thermodynamic parameters for the interaction of neutral molecules with cyclic and acyclic polyethers in benzene solvent have been determined by calorimetry. Although triethylene glycol dimethyl ether loses more entropy upon adduct formation with malononitrile than does 12-crown-4, similar enthalpies of formation indicate that the electron-donating abilities of the oxygen atoms of cyclic or acyclic ethers are comparable. Thus, no macrocyclic effect is observed for 12-crown-4 when compared to its analogous acyclic ether. The interactions of malononitrile and acetonitrile with ethers seem to depend on the collective action of the oxygen atoms in the ethers. Dimethyltin dichloride binds to a specific oxygen site.