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Molecular structure of 2-(hydroxyimino)propanohydroxamic acid in solid state and DMSO solution.
Agnieszka Kaczor1, Leonard M Proniewicz
1Faculty of Chemistry, Jagiellonian University, ul. Ingardena 3, 30-060 Krakow, Poland.
Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
|November 22, 2005
Summary
The study reveals that 2-(hydroxyimino)propanohydroxamic acid (hpha) forms distinct structures in DMSO solution and solid state. In DMSO, hpha exists as a cluster with solvent molecules, while in solid form, it predominantly exists as a dimer.
Area of Science:
- * Computational chemistry and spectroscopy.
- * Investigating molecular structures and interactions in different phases.
Background:
- * Understanding the behavior of 2-(hydroxyimino)propanohydroxamic acid (hpha) is crucial for its applications.
- * Previous studies may not have fully elucidated its structural forms in various environments.
Purpose of the Study:
- * To determine the predominant molecular structures of hpha in DMSO-d6 solution and in the solid state.
- * To compare the structural differences between hpha in solution and solid phases using spectroscopic and computational methods.
Main Methods:
- * Measurement of 1H and 13C NMR spectra in DMSO-d6.
- * Calculation of chemical shifts and vibrational spectra using B3LYP functional with various basis sets (6-311++G(d,p) and 6-31+G(d)).
- * Analysis of experimental and calculated IR and Raman spectra.
Main Results:
- * Experimental data in DMSO-d6 solution supported the formation of a cluster of hpha with three DMSO molecules, with all labile protons hydrogen-bonded to the solvent.
- * Calculations indicated that this cluster is energetically stabilized (84-106 kJ mol-1) compared to dimeric structures in solution.
- * In the solid state, hpha predominantly forms dimers, specifically a zEe-keto dimer stabilized by symmetric hydrogen bonds.
Conclusions:
- * The molecular structure of hpha differs significantly between DMSO solution and the solid state.
- * In DMSO, hpha forms stable clusters with solvent molecules, whereas in the solid state, dimeric structures prevail.
- * Computational modeling accurately predicts and explains the observed structural preferences in different environments.