IR Cavity Ringdown Spectroscopy and Density Functional Theory for Jet-Cooled Pyrrole–Cyclopentanone Binary Clusters: Effect of Pseudorotation on N—H···O═C Hydrogen Bonds

The conformations of the title compounds were determined in solution (NMR and UV-Vis spectroscopy) and in the solid state (FT-IR and XRD), complemented with density functional theory (DFT) in the gas phase. The nonequivalence of the amide protons of these compounds due to the hindered rotation of the C(O)–NH2 single bond resulted in two distinct resonances of different chemical shift values in the aromatic region of their 1H-NMR spectra. Intramolecular hydrogen bonding interactions between the carbonyl oxygen and the sulfonamide hydrogen atom were observed in the solution phase and solid state. XRD confirmed the ability of the amide moiety of this class of compounds to function as a hydrogen bond acceptor to form a six-membered hydrogen bonded ring and a donor simultaneously to form intermolecular hydrogen bonded complexes of the type N–H···O=S. The distorted tetrahedral geometry of the sulfur atom resulted in a deviation of the sulfonamide moiety from co-planarity of the anthranilamide scaffold, and this geometry enabled oxygen atoms to form hydrogen bonds in higher dimensions.

Download Full-text

Binary Clusters AuPt and Au6Pt: Structure and Reactivity within Density Functional Theory

The Journal of Physical Chemistry A ◽

10.1021/jp055506o ◽

2006 ◽

Vol 110 (19) ◽

pp. 6285-6293 ◽

Cited By ~ 55

Author(s):

Wei Quan Tian ◽

Maofa Ge ◽

Fenglong Gu ◽

Toshiki Yamada ◽

Yuriko Aoki

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Functional Theory ◽

Binary Clusters

Download Full-text

6-Bromoindigo dye

Acta Crystallographica Section C Crystal Structure Communications ◽

10.1107/s0108270112006440 ◽

2012 ◽

Vol 68 (4) ◽

pp. o160-o163 ◽

Cited By ~ 1

Author(s):

David J. Szalda ◽

Keith Ramig ◽

Olga Lavinda ◽

Zvi C. Koren ◽

Lou Massa

Keyword(s):

Density Functional Theory ◽

Quantum Theory ◽

Hydrogen Bonds ◽

Density Functional ◽

Stacking Interactions ◽

Inversion Center ◽

Asymmetric Unit ◽

Functional Theory ◽

Bond Lengths ◽

Type C

6-Bromoindigo (MBI) [systematic name: 6-bromo-2-(3-oxo-2,3-dihydro-1H-indol-2-ylidene)-2,3-dihydro-1H-indol-3-one], C16H9BrN2O2, crystallizes with one disordered molecule in the asymmetric unit about a pseudo-inversion center, as shown by the Br-atom disorder of 0.682 (3):0.318 (3). The 18 indigo ring atoms occupy two sites which are displaced by 0.34 Å from each other as a result of this packing disorder. This difference in occupancy factors results in each atom in the reported model used to represent the two disordered sites being 0.08 Å from the higher-occupancy site and 0.26 Å from the lower-occupancy site. Thus, as a result of the disorder, the C—Br bond lengths in the disordered components are 0.08 and 0.26 Å shorter than those found in 6,6′-dibromoindigo (DBI) [Süsse & Krampe (1979).Naturwissenschaften,66, 110], although the distances within the indigo ring are similar to those found in DBI. The crystals are also twinned by merohedry. Stacking interactions and hydrogen bonds are similar to those found in the structures of indigo and DBI. In MBI, an interaction of the type C—Br...C replaces the C—Br...Br interactions found in DBI. The interactions in MBI were calculated quantum mechanically using density functional theory and the quantum theory of atoms in molecules.

Download Full-text

Change in Energy of Intermolecular Hydrogen Bonds Upon Excitation of Coumarin 120 in Water: A Combined Time-dependent Density Functional Theory/Effective Fragment Potential Study

Communications in Computational Chemistry ◽

10.4208/cicc.2015.v3.n1.3 ◽

2015 ◽

Vol 3 (1) ◽

pp. 18-33

Author(s):

Mariyappa Ramegowda

Keyword(s):

Density Functional Theory ◽

Hydrogen Bonds ◽

Density Functional ◽

Time Dependent ◽

Intermolecular Hydrogen Bonds ◽

Functional Theory ◽

Effective Fragment Potential ◽

Potential Study ◽

Coumarin 120 ◽

Dependent Density

Download Full-text

Structural polymorphism of pyrazinium hydrogen sulfate: extending chemistry of the pyrazinium salts with small anions

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768110019580 ◽

2010 ◽

Vol 66 (4) ◽

pp. 451-457 ◽

Cited By ~ 4

Author(s):

Armand Budzianowski ◽

Mariana Derzsi ◽

Piotr J. Leszczyński ◽

Michał K. Cyrański ◽

Wojciech Grochala

Keyword(s):

Density Functional Theory ◽

Hydrogen Bond ◽

Dipole Moment ◽

Hydrogen Bonds ◽

Dft Calculations ◽

Density Functional ◽

Hydrogen Sulfate ◽

Structural Polymorphism ◽

Functional Theory ◽

First Time

Two polymorphs (α, β) of pyrazinium hydrogen sulfate (pyzH+HSO_4^-, abbreviated as PHS) with distinctly different hydrogen-bond types and topologies but close electronic energies have been synthesized and characterized for the first time. The α-polymorph (P212121) forms distinct blocks in which the pyzH+ and HSO_4^- ions are interconnected through a network of NH...O and OH...O hydrogen bonds. The β-form (P\bar 1) consists of infinite chains of alternating pyzH+ and HSO_4^- ions connected by NH...O and OH...N hydrogen bonds. Density functional theory (DFT) calculations indicate the possible existence of a hypothetical polar P1 form of the β-polymorph with an unusually high dipole moment.

Download Full-text