On the solvation of L-aspartic acid

Abstract

We use molecular statics and dynamics to study the stability of L-aspartic acid both in vacuo and solvated by polar and non-polar molecules using density functional theory in the generalized gradient approximation. We find that structures stable in vacuo are unstable in aqueous solution and vice versa. From our simulations we are able to come to some conclusions about the mechanism of stabilisation of zwitterions by polar protic solvents, water and methanol.

Notes

 †Dedicated, with gratitude, to Professor R. M. Lynden-Bell on the occasion of her retirement.

 ‡It is usual in the literature to refer to this form as ‘neutral’. We prefer the term ‘non-charge-separated’ which, while also non-precise, emphasizes that both n and z ₁ are charge neutral compared to the singly deprotonated molecules that we also consider here.