Aromaticity in heterocyclic molecules containing divalent sulfur

1988 ◽  
Vol 53 (9) ◽  
pp. 2023-2054 ◽  
Author(s):  
Milan Randić ◽  
Sonja Nikolić ◽  
Nenad Trinajstić
Keyword(s):  
Sulfur Atom ◽  
Positional Isomers ◽  
Heterocyclic Molecules ◽  
Resonance Energies ◽  
Conjugated Circuits ◽  
Divalent Sulfur

The conjugated circuits model is applied to heterocycles containing divalent sulfur. A novel parametrization is introduced for 4n + 2 and 4n conjugated circuits containing a single sulfur atom. The relative aromatic stabilities of a number of heterocyclic systems containing divalent sulfur are studied. Comparison is made whenever possible with earlier reported resonance energies of these compounds, obtained by using Huckel MO and SCF π-MO models, and appropriate reference structures. Special attention is given to positional isomers. An explanation of the differences amongst such isomers is given.

scholarly journals Combinatorics of Edge Symmetry: Chiral and Achiral Edge Colorings of Icosahedral Giant Fullerenes: C80, C180, and C240

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1308
Author(s):  
Krishnan Balasubramanian
Keyword(s):  
Equivalence Classes ◽  
Group Symmetry ◽  
Irreducible Representations ◽  
Inversion Method ◽  
High Symmetry ◽  
Edge Colorings ◽  
Edge Group ◽  
Resonance Energies ◽  
Conjugated Circuits ◽  
Cycle Indices

We develop the combinatorics of edge symmetry and edge colorings under the action of the edge group for icosahedral giant fullerenes from C80 to C240. We use computational symmetry techniques that employ Sheehan’s modification of Pόlya’s theorem and the Möbius inversion method together with generalized character cycle indices. These techniques are applied to generate edge group symmetry comprised of induced edge permutations and thus colorings of giant fullerenes under the edge symmetry action for all irreducible representations. We primarily consider high-symmetry icosahedral fullerenes such as C80 with a chamfered dodecahedron structure, icosahedral C180, and C240 with a chamfered truncated icosahedron geometry. These symmetry-based combinatorial techniques enumerate both achiral and chiral edge colorings of such giant fullerenes with or without constraints. Our computed results show that there are several equivalence classes of edge colorings for giant fullerenes, most of which are chiral. The techniques can be applied to superaromaticity, sextet polynomials, the rapid computation of conjugated circuits and resonance energies, chirality measures, etc., through the enumeration of equivalence classes of edge colorings.

Conjugated circuits and resonance energies of benzenoid hydrocarbons

1976 ◽  
Vol 38 (1) ◽  
pp. 68-70 ◽  
Author(s):  
Milan Randić
Keyword(s):  
Benzenoid Hydrocarbons ◽  
Resonance Energies ◽  
Conjugated Circuits

Applying the conjugated circuits method to Clar structures of [n]phenylenes for determining resonance energies

2011 ◽  
Vol 13 (46) ◽  
pp. 20644 ◽  
Author(s):  
Milan Randić ◽  
Alexandru T. Balaban ◽  
Dejan Plavšić
Keyword(s):  
Resonance Energies ◽  
Conjugated Circuits ◽  
Clar Structures

ChemInform Abstract: HUECKEL MOLECULAR ORBITAL PI-RESONANCE ENERGIES, HETEROCYCLES CONTAINING DIVALENT SULFUR

1973 ◽  
Vol 4 (33) ◽  
pp. no-no
Author(s):  
B. ANDES JUN. HESS ◽  
L. J. SCHAAD
Keyword(s):  
Molecular Orbital ◽  
Resonance Energies ◽  
Divalent Sulfur

scholarly journals Hypervalent Nonbonded Interactions of a Divalent Sulfur Atom. Implications in Protein Architecture and the Functions

Molecules ◽  
2012 ◽  
Vol 17 (6) ◽  
pp. 7266-7283 ◽  
Author(s):  
Michio Iwaoka ◽  
Noriyoshi Isozumi
Keyword(s):  
Sulfur Atom ◽  
Nonbonded Interactions ◽  
Protein Architecture ◽  
Divalent Sulfur

Hueckel molecular orbital .pi.-resonance energies. Heterocycles containing divalent sulfur

1973 ◽  
Vol 95 (12) ◽  
pp. 3907-3912 ◽  
Author(s):  
B. Andes. Hess ◽  
L. J. Schaad
Keyword(s):  
Molecular Orbital ◽  
Resonance Energies ◽  
Divalent Sulfur

ChemInform Abstract: Aromaticity in Heterocyclic Molecules Containing Divalent Sulfur

ChemInform ◽  
1989 ◽  
Vol 20 (1) ◽  
Author(s):  
M. RANDIC ◽  
S. NIKOLIC ◽  
N. TRINAJSTIC
Keyword(s):  
Heterocyclic Molecules ◽  
Divalent Sulfur

Halogen bonding to a divalent sulfur atom: an experimental study of the interactions of CF3X (X = Cl, Br, I) with dimethyl sulfide

2011 ◽  
Vol 13 (21) ◽  
pp. 10204 ◽  
Author(s):  
Dieter Hauchecorne ◽  
Alessio Moiana ◽  
Benjamin J. van der Veken ◽  
Wouter A. Herrebout
Keyword(s):  
Experimental Study ◽  
Sulfur Atom ◽  
Dimethyl Sulfide ◽  
Halogen Bonding ◽  
Divalent Sulfur

On the photoelectron and ultraviolet spectra of molecules containing a divalent sulfur atom and a carbonyl group separated by a methylene group

1976 ◽  
Vol 54 (19) ◽  
pp. 3026-3030 ◽  
Author(s):  
P. R. Olivato ◽  
H. Viertler ◽  
B. Wladislaw ◽  
K. C. Cole ◽  
C. Sandorfy
Keyword(s):  
Carbonyl Group ◽  
Absorption Spectra ◽  
Sulfur Atom ◽  
Lone Pair ◽  
Ultraviolet Absorption ◽  
Photoelectron Spectra ◽  
Ultraviolet Spectra ◽  
Methylene Group ◽  
Divalent Sulfur

Photoelectron spectra show that in CH3SCH2COCH3 the sulfur and carbonyl lone pair orbitals [Formula: see text] are both stabilized with respect to the compounds containing S or CO only. This is in keeping with the observed values of the basicity constants. The ultraviolet absorption spectra contain the expected [Formula: see text] and [Formula: see text] bands and give evidence for a significant amount of mixing between the excited orbitals.

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