Hydrogen‐bonding interactions in fully deuterated α‐glycine at high pressures

Recent spectroscopic investigations of various amino acids report intriguing high‐pressure and low‐temperature behavior of NH 3 + groups and their influence on various hydrogen bonds in the system. In particular, the variation of the intensity of NH 3 + torsional mode at different temperatures and pressures has received much attention. We report here the first in situ Raman investigations of fully deuterated α‐glycine up to ∼20 GPa. The discontinuous changes in COO − and ND 3 + modes across ∼3 GPa indicate subtle structural rearrangements in fully deuterated α‐glycine. The decrease in the intensity of ND 3 + torsional mode is found to be similar to that of undeuterated α‐glycine. The pressure‐induced stiffening of ND and CD 2 stretching modes are discussed in the context of changes in the hydrogen‐bonding interactions. Copyright © 2011 John Wiley & Sons, Ltd.