Ab initio calculation of through-space magnetic shielding of linear polycyclic aromatic hydrocarbons (acenes): Extent of aromaticity

Martin, Ned H.; Caldwell, Brian W.; Carlson, Katie P.; Teague, Matthew R.

doi:10.1016/j.jmgm.2008.10.007

Cited by 12 publications

(7 citation statements)

References 40 publications

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“…188,189 By visualizing the iso-chemical-shielding surfaces (ICSS), they obtain a 3D map of the magnetic shielding function that shows anisotropic and ring-current effects. The ICSS visualization method has been employed in a variety of aromaticity studies [190][191][192][193][194][195][196][197][198][199] and has recently been reviewed. 200…”

Section: Through Space Currentsmentioning

confidence: 99%

Calculations of magnetically induced current densities: theory and applications

Sundholm

Fliegl

Berger

2016

WIREs Comput Mol Sci

322

543

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A review of computational studies of magnetically induced current density susceptibilities in molecules and their relation to experiments is presented. The history of the investigation of magnetically induced current densities and ring currents in molecules is briefly covered. The theoretical development of relativistic and nonrelativistic computational approaches for computing current densities in closed-shell and open-shell molecules is discussed and different state of the art methods to interpret calculated current densities are reviewed. Numerical integration approaches to assess global, semilocal, and local aromatic properties of multiring molecules are presented and demonstrated on free-base trans-porphyrin. We show that numerical integration of the current density combined with guiding visualization techniques of the current flow is a powerful tool for studies of the aromatic character of complicated molecular structures such as annelated aromatic and antiaromatic rings. Representative applications are reported illustrating the importance of careful current density studies for organic and inorganic chemistry. The applications include calculations of current densities and current strengths for aromatic, antiaromatic, and nonaromatic molecules of different kind. Current densities in spherical, cylindrical, tetrahedral, toroidal, and Möbius-twisted molecules are discussed. The aromatic character, current pathways, and current strengths of porphyrins are briefly highlighted. Aromatic properties of inorganic molecules are assessed based on current density calculations. Current strengths as a noninvasive tool to determine strengths of hydrogen bonds are discussed.

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Section: Through Space Currentsmentioning

confidence: 99%

Calculations of magnetically induced current densities: theory and applications

Sundholm

Fliegl

Berger

2016

WIREs Comput Mol Sci

322

543

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“…Nuclear Independent Chemical Shift (NICS) at GIAO/B3LYP/6-311++G** [38][39][40][41][42][43] and magnetic susceptibilities at CSGT/B3LYP/6-311++G** level of theory [44][45][46][47][48] in 1angstrom upper than thiophene ring were calculated and listed in Table 6. Negative values of NICS represent the magnetic shielding and electric Table 4 B3LYP/6-311++G** calculated IR absorption frequencies in cm À1 (intensities in km/mol) for thiophene and fluorothiophenes.…”

Section: Nics Analysismentioning

confidence: 99%

Theoretical study on the electronic, structural, properties and reactivity of a series of mono-, di-, tri- and tetrafluorothiophenes as monomers for new conducting polymers

Jameh‐Bozorghi

Beigi

2011

Journal of Fluorine Chemistry

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“…It is well known that polycyclic aromatic hydrocarbons have substantial through-space NMR shielding effects above the molecular plane [5,8,9]. In addition, the magnetic consequences of some fused aromatic-antiaromatic ring systems have been explored employing NICS [10,11] or a grid of NICS represented visually as isochemical shielding surfaces (ICSS) [12].…”

Section: Introductionmentioning

confidence: 99%

Computed NMR Shielding Effects over Fused Aromatic / Antiaromatic Hydrocarbons

Martin¹,

Teague²,

Mills³

2010

Symmetry

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Through-space isotropic NMR shielding values of a perpendicular diatomic hydrogen probe moved in a 0.5 Å grid 2.5 Å above several polycyclic aromatic/antiaromatic ring and aromatic/aromatic hydrocarbons were computed with Gaussian 03 at the GIAO HF/6-31G(d,p) level. Combinations of benzene fused with cyclobutadiene, with the tropylium ion, and with the cyclopentadienyl anion were investigated. Subtraction of the isolated H 2 isotropic value gave shielding increments (∆σ), which, when plotted against Cartesian coordinates of the probe over each hydrocarbon, gave representations of threedimensional isotropic shielding increment surfaces. The results are related to the degree of bond length alternation, the extent of π electron delocalization, and (for the ions) the NPA charge distribution. The shielding increment data are compared to NICS(1) values computed at the same level; both indicate the degree of aromaticity or antiaromaticity of the component rings.

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Ab initio calculation of through-space magnetic shielding of linear polycyclic aromatic hydrocarbons (acenes): Extent of aromaticity

Cited by 12 publications

References 40 publications

Calculations of magnetically induced current densities: theory and applications

Calculations of magnetically induced current densities: theory and applications

Theoretical study on the electronic, structural, properties and reactivity of a series of mono-, di-, tri- and tetrafluorothiophenes as monomers for new conducting polymers

Computed NMR Shielding Effects over Fused Aromatic / Antiaromatic Hydrocarbons

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