Infrared and Raman spectroscopic characterization of the hydrogen-bonding network in l-serine crystal |
| |
Affiliation: | 1. Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal;2. Department of Biochemistry, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106-4935, USA |
| |
Abstract: | The IR spectra (4000–400 cm−1) of neat and isotopically substituted (ND/OD ≤ 10% D and ≅30% D) polycrystalline l-serine (α-amino-β-hydroxypropionic acid; HO–CH2–CH(NH3)+–COO−) were recorded in the temperature range 300–10 K and assigned. The isotopic-doping/low-temperature methodology, which allows for decoupling of individual proton vibrational modes from the crystal bulk vibrations, was used for estimating the lengths and energies of the different H-bonds present in l-serine crystal. To this end, the frequency shifts observed in both the NH/OH stretching and out-of-plane bending spectral regions (relatively to reference values for these vibrations in non-hydrogen-bonded l-serine molecules) were used, together with previously developed empirical correlations between these spectral parameters and the H-bond properties. In addition, the room-temperature Raman spectrum (4000–150 cm−1) of a single crystal of neat l-serine was also recorded and interpreted. A systematic comparison was made between the spectroscopic data obtained currently for l-serine and previously for dl-serine, revealing that the vibrational spectra of the two crystals reflect well the different characteristics of their hydrogen-bond networks, and also correlate accurately with the different susceptibility of the two crystals to pressure-induced strain. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|