Torsional isomers in methylated aminoethanols - A jet-FT-IR study

2004 ◽  
Vol 82 (6) ◽  
pp. 1006-1012 ◽  
Author(s):  
Yaqian Liu ◽  
Corey A Rice ◽  
Martin A Suhm

Jet-FT-IR spectra of aminoethanol (AE), N-methylaminoethanol (MAE), and N,N-dimethylaminoethanol (DMAE) are presented and compared to gas-phase and matrix isolation IR, microwave, and quantum chemical data. The intramolecular O-H···N hydrogen bond gives rise to characteristically shifted O-H stretching bands and torsional difference bands in the monomer spectra. It stabilizes one out of 14 diastereomeric monomer conformations of AE and DMAE and two out of 27 diastereomeric MAE conformations. The latter two correspond to torsional or N-inversional isomers, the interconversion of which is hindered by the intramolecular hydrogen bond. Their energy difference is found to be <1.2 kJ/mol. The intermolecular aggregation patterns of the three aminoethanols are quite distinct and non-monotonic, as suggested by their O-H stretching fingerprints.Key words: aminoethanol, IR spectroscopy, conformation, hydrogen bond, supersonic jet.

In the article the results of the quantum chemical study of copper (II) solvato-complexes with acetonitrile (AN), tetrafluoroborate anion (BF4–) and 3-hydroxyflavone (flv) of the composition [Cu(AN)6]2+, [Cu(BF4)(AN)5]+, [Cu(flv)(AN)5]2+, [Cu(flv)(BF4)(AN)4]+ are presented. Calculations were done using density function theory (DFT) on the M06-2X/6-311++G(d,p) level of theory. Obtained results were interpreted in terms of complexes geometry and topology of electron density distribution using non-covalent interactions (NCI) approach. It was shown that flv molecule is a monodentate ligand in copper (II) complexes and coordinates central atom via carbonyl oxygen. Intramolecular hydrogen bond that exists in an isolated flv molecule was found to be broken upon [Cu(flv)(AN)5]2+ complex formation. In [Cu(flv)(AN)5]2+ complex, a significant rotation of phenyl ring over the planar chromone fragment was spotted as a consequence of intramolecular hydrogen bond breaking. Upon inclusion of BF4– anion to the first solvation shell of Cu2+, an intracomplex hydrogen bond was formed between hydrogen atom of hydroxyl group of flv molecule and the closest fluorine atom of BF4– anion. NCI analysis had shown that a hydrogen bond between hydrogen atom of hydroxyl group of flv molecule and the closest fluorine atom of BF4– anion is significantly stronger than intramolecular hydrogen bond in an isolated flv molecule. In addition, flexible phenyl ring of flv molecule in [Cu(flv)(BF4)(AN)4]+ complex was found to be internally stabilized by the weak van der Waals attraction between oxygen atoms of chromone ring and phenyl hydrogens. These evidences led to a conclusion that [Cu(flv)(BF4)(AN)4]+ complex is more stable, comparing to the in [Cu(flv)(AN)5]2+ complex.


Synthesis ◽  
2020 ◽  
Vol 52 (15) ◽  
pp. 2224-2232
Author(s):  
Boris A. Trofimov ◽  
Nina K. Gusarova ◽  
Nina I. Ivanova ◽  
Kseniya O. Khrapova ◽  
Pavel A. Volkov ◽  
...  

Tertiary α-hydroxyphosphine oxides have been synthesized via the catalyst- and solvent-free reaction between available secondary phosphine oxides and aliphatic, aromatic and heteroaromatic ketones at 20–62 °C in near to 96–98% yield. The developed method meets the requirements of green chemistry and the PASE (pot, atom, step economy) paradigm. According to quantum-chemical calculations at the B3LYP/6-311++G(d,p) level, the synthesized hydroxyphosphine oxides feature a weak (≈3 kcal·mol–1) O−H···O=P intramolecular hydrogen bond.


Author(s):  
Anastasia Filtschew ◽  
Pablo Beato ◽  
Søren Birk Rasmussen ◽  
Christian Hess

The role of platinum on the room temperature NOx storage mechanism and the NOx desorption behavior of ceria was investigated by combining online FT-IR gas-phase analysis with in situ Raman...


1994 ◽  
Vol 13 (5) ◽  
pp. 1569-1574 ◽  
Author(s):  
Philip G. Harrison ◽  
David M. Podesta
Keyword(s):  
Ft Ir ◽  

1995 ◽  
Vol 14 (7) ◽  
pp. 3507-3515 ◽  
Author(s):  
Philip G. Harrison ◽  
Ashley C. Torr
Keyword(s):  
Ft Ir ◽  

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