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IR and NMR spectra, intramolecular hydrogen bonding and conformations of para-tert-butyl-aminothiacalix[4]arene in solid state and chloroform solution
- Source :
- Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 75:872-879
- Publication Year :
- 2010
- Publisher :
- Elsevier BV, 2010.
-
Abstract
- It is demonstrated that dissolution of aminothiacalix[4]arene in chloroform results in transformation of 1,3-alternate conformation, adopted in single-crystal and bulk polycrystalline solids, to the pinched-cone form. This conformer is stabilised by the intramolecular hydrogen bonds of two distal amino-groups acting as H-donors with another two amino moieties that appear as H-acceptors. The H-bonds cause quite small (ca. 10-20 cm(-1)) red shift of the IR bands of the NH(2) stretching vibrations, which suggests rather weak NHcdots, three dots, centeredN hydrogen bonding. This latter is sufficient to stabilize the pinched-cone conformation in the chloroform solution, but the energy gap between the pinched-cone and other conformations is small, and solid-state intermolecular forces easily overcome it, leading to realisation of the 1,3-alternate conformer. The comparison of the DFT computed and experimental vibrational and NMR spectra demonstrates good quality of present quantum-chemical computations, allows complete interpretation of the spectra and reveals simple IR and NMR spectroscopic markers of the conformers of aminothiacalix[4]arenes.
- Subjects :
- Models, Molecular
Magnetic Resonance Spectroscopy
Spectrophotometry, Infrared
Band gap
Molecular Conformation
Analytical Chemistry
chemistry.chemical_compound
Computational chemistry
Spectroscopy, Fourier Transform Infrared
Instrumentation
Dissolution
Conformational isomerism
Spectroscopy
Chloroform
Molecular Structure
Hydrogen bond
Intermolecular force
Hydrogen Bonding
Atomic and Molecular Physics, and Optics
Solutions
NMR spectra database
Crystallography
Models, Chemical
chemistry
Intramolecular force
Quantum Theory
Calixarenes
Subjects
Details
- ISSN :
- 13861425
- Volume :
- 75
- Database :
- OpenAIRE
- Journal :
- Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
- Accession number :
- edsair.doi.dedup.....e3eee8fec81fb861a04540a91d0a3070