Format

Send to

Choose Destination
See comment in PubMed Commons below
J Mol Model. 2014 Mar;20(3):2154. doi: 10.1007/s00894-014-2154-3. Epub 2014 Feb 22.

A B3LYP and MP2(full) theoretical investigation on the cooperativity effect between hydrogen-bonding and cation-molecule interactions and thermodynamic property in the 1: 2 (Na⁺: N-(Hydroxymethyl)acetamide) ternary complex.

Author information

1
College of Mining Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.

Abstract

The cooperativity effects between the O/N-H∙∙∙O hydrogen-bonding and Na⁺∙∙∙O cation-molecule interactions in the 1: 2 (Na⁺: N-(Hydroxymethyl)acetamide) systems were investigated at the B3LYP/6-311++G**, MP2(full)/6-311++G** and MP2(full)/aug-cc-pvtz levels. The thermodynamic cooperativity calculations were also carried out for two pathways of the ternary-complex formation. The result shows that, in most ternary complexes, the O/N-H∙∙∙O and Na⁺∙∙∙O interactions are weakened in comparison with those in binary systems, leading to the anti-cooperativity effects, in particular in the complexes in which only the Na⁺∙∙∙O interactions exist. Shifts of electron density confirm the existence of anti-cooperativity. The increase of favorable enthalpic contribution leads to the positive cooperativity effect with negative ΔG(coop.) on forming the ternary complex by initial N-(Hydroxymethyl)acetamide dimer followed by addition of Na⁺. In forming the ternary complex by Na⁺∙∙∙N-(Hydroxymethyl)acetamide with the second N-(Hydroxymethyl)acetamide unit, the large unfavorable entropy change leads to the negative cooperativity effect with positive ΔG(coop.). The ternary complex is more easily formed by the pathway in which Na⁺ binds to N-(Hydroxymethyl)acetamide dimer.

PMID:
24562861
DOI:
10.1007/s00894-014-2154-3
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Springer
    Loading ...
    Support Center