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Interanionic (-)O-H...O(-) interactions: a solid-state and computational study of the ring and chain motifs.
1Department of Chemistry G. Ciamician Univeristy of Bologna, Italy. dbraga@ciam.unibo.it
Chemistry (Weinheim an Der Bergstrasse, Germany)
|February 24, 2001
Summary
This study investigates interanionic (-)O-H...O(-) interactions in various anions, revealing that ring and chain motifs have different stabilities. These interactions are crucial bonding forces, especially in crystalline structures.
Area of Science:
- Physical Chemistry
- Solid-State Chemistry
- Crystallography
Background:
- Investigates the (-)O-H...O(-) interaction in monodeprotonated carbonic, oxalic, squaric, and croconic acids.
- Analyzes ring (RING) and chain (CHAIN) hydrogen bond motifs in these anions.
Purpose of the Study:
- To theoretically and experimentally investigate the geometry, energy, and occurrence of RING and CHAIN motifs.
- To understand the nature of interanionic (-)O-H...O(-) interactions in vacuum and condensed phases.
- To examine the stability of RING and CHAIN motifs in gas and crystal phases.
Main Methods:
- Theoretical calculations (ab initio)
- Experimental analysis
- Database searching (CSD and ICSD)
Main Results:
- Hydrogen carbonates primarily form RINGs, while hydrogen oxalates form CHAINs.
- Hydrogen squarates and croconates can form both RING and CHAIN motifs.
- Interaction energy is dominated by electrostatics; RINGs are metastable in gas but stable in crystals, while CHAINs are unstable.
Conclusions:
- (-)O-H...O(-) interactions act as stabilizing bonding interactions rather than intermolecular hydrogen bonds.
- The Madelung field stabilizes RING motifs in crystals.
- Short O...O contacts arise from charge compression in polyatomic anions bridged by alkali cations.