6533b82cfe1ef96bd128eadd
RESEARCH PRODUCT
Local aromaticity in polyacenes manifested by individual proton and carbon shieldings: DFT mapping of aromaticity
ŁUkasz GajdaTeobald KupkaMagdalena GajdaTapas Karsubject
NICSProtonchemistry.chemical_element010402 general chemistrypolyacenes01 natural sciencesMolecular physicschemistry.chemical_compoundPhysics::Atomic and Molecular ClustersHOMAGeneral Materials ScienceReactivity (chemistry)Physics::Chemical PhysicsBenzenenuclear shieldingAceneHarmonic oscillator010405 organic chemistrymolecular modelingChemical shiftAromaticityGeneral Chemistryaromaticity0104 chemical scienceschemistryCarbondescription
Exponential dependencies between locally calculated geometric and magnetic indexes of aromaticity, harmonic oscillator model of aromaticity (HOMA) and nucleus independent chemical shifts (NICS)(0), NICS(1) and NICS(1)zz, and the number of conjugated benzene rings in linear acenes, from benzene to decacene were observed at B3LYP/6-311+G** level of theory. Correlations between HOMA and NICS indexes showed exponential dependencies and were fitted with simple three-parameter function. Similar correlations between both indexes of aromaticity and proton and carbon nuclear isotropic shieldings of individual acene rings were observed. Contrary to proton data, the predicted 13 C nuclear isotropic shieldings of carbon atoms belonging to inner rings in polyacenes were less shielded, indicating lower aromaticity and therefore, higher reactivity.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2019-11-21 | Magnetic Resonance in Chemistry |