The structure of glycine-water H-bonded complexes

✍ Scribed by Harold Basch; Walter J. Stevens

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 472 KB
• Volume: 169
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(90)85201-m

✦ Synopsis

Hydrogen-bond energies and geometric structures for the 1: 1 cyclic complexes of water with the three possible conformers of glycine have been determined. Ab initio gradient optimization at the self-consistent field (SCF) level in a double-zeta plus polarization-functions basis set was followed by single-point post-SCF second-order Msller-Plesset (MP2) calculations for the lowest energy structures. The most stable complex involves a doubly hydrogen-bonded arrangement of water with the carboxyl group of glycine monomer I, which is also the lowest energy conformer of the glycine monomer. The calculated MP2 binding energy of I I .O kcal/mol (uncorrected for basis set superposition which is expected to be small) is substantial and this complex should be observed experimentally. MP2 reduces the shorter SCF geometry optimized H-bond length by =: 0. I A.