An obvious observation from Table is that the reaction becomes more exothermic along with slightly lower ∆G ‡ , resulting in faster reaction rates as we move from gas phase to increase the polarity of the solvents. This might be explained through stabilization of the TS and the product state via stronger electrostatic interaction with a highly polar solvent. [a] The tautomerization reaction was studied from P(V)2w → P(III)2w.