| Popis: |
Selectively C-deuteriated N-acetylglycine trimer and tetramer acid types have been synthesized, and their two crystalline modifications, solid-A and solid-B [which correspond in structure to polyglycine (PG) II and I, respectively] have been prepared. Raman scattering spectra have been measured for a series of these glycine oligomers, and the CH 2 - and CD 2 -characteristic modes have been investigated in detail. Assignment of the CH 2 -characteristic bands to each CH 2 group in the oligomers has been carried out successfully. In particular, the results obtained from the CD 2 stretch region show that N- and C-terminal glycine residues for the PGI- and PGII-type trimers and tetramers are all in very similar environments and that the glycine residues which are sandwiched between the two terminal residues are also in a similar environment for both the trimers and the tetramers. |
