Aromatic character of fluorinated pyridines

Tokatlı, Ahmet; Akyürekli, Salih

doi:10.1007/s11224-012-0097-9

Cited by 12 publications

(4 citation statements)

References 43 publications

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“…Others significantly contracted geometries are the PyF 3 o and PyF 4 derivatives. Similar trends are found in the B3LYP/6–311++G(d,p) results published by Tokath and Akyürekli …”

Section: Resultssupporting

confidence: 90%

Substitution effect on the intermolecular halogen and hydrogen bonds of the σ‐bonded fluorinated pyridine···XY/HX complexes (XY = F₂, Cl₂, ClF; HX = HF, HCl)

Sládek

Punyain

Ilčin

et al. 2014

Int J of Quantum Chemistry

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Optimal structures, electronic and thermodynamic properties of the title complexes are presented. The stability of the hydrogen bonded systems is enhanced by the increasing dipole moments whereas in the halogen bonded systems it is also affected by the atom size in the diatomics. The consecutive addition of fluorine atoms to the pyridine moiety results in the decrease of the interaction energy for both types of the investigated bonds. The substitution on the meta sites in pyridine leads to more stable complexes than the substitution in the ortho position.The role of substitution on electric polarization and electrostatic forces is estimated by the symmetry-adapted perturbation theory energy decomposition. The predicted Gibbs free energies of the complexes of mono fluorinated pyridines with HCl, HF, and ClF are from 212 to 222 kJ mol 21 at 200 K. The possible experimental identification of the complexes with respect to the vibrational modes is discussed.

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“…Others significantly contracted geometries are the PyF 3 o and PyF 4 derivatives. Similar trends are found in the B3LYP/6–311++G(d,p) results published by Tokath and Akyürekli …”

Section: Resultssupporting

confidence: 90%

Substitution effect on the intermolecular halogen and hydrogen bonds of the σ‐bonded fluorinated pyridine···XY/HX complexes (XY = F₂, Cl₂, ClF; HX = HF, HCl)

Sládek

Punyain

Ilčin

et al. 2014

Int J of Quantum Chemistry

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“…The Dw is defined as: Dw = w zz -(w xx + w yy )/2, where w zz is the out-of-plane component, while w xx and w yy are the in-plane components of the diamagnetic susceptibility. 62 Similar to NICS, aromatic clusters possess negative Dw. Our Dw calculations were performed using the same theoretical level as used in NICS calculations.…”

mentioning

confidence: 98%

Observation of d–p hybridized aromaticity in lanthanum-doped boron clusters

Cheng

Berkdemir

Castleman

2014

Phys. Chem. Chem. Phys.

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The concept of aromaticity has been advanced beyond the framework of organic chemistry, and multiple aromaticity (σ, π, and δ) has been observed to account for the highly symmetric structures or unusual stability of the clusters. In the present study, the electronic structures and chemical bonding of small monolanthanum boride clusters are investigated using photoelectron imaging spectroscopy and first principles electronic structure calculations. Accurate electron affinities of 1.32 ± 0.04 and 1.13 ± 0.06 eV for the neutral LaB2 and LaB3 clusters are obtained by the vibrationally-resolved photoelectron spectra of the LaB2(-) and LaB3(-) clusters, respectively. It is shown that LaB2(-) and LaB3 exhibit enhanced stability in their respective cluster series, as evidenced from the calculated removal energies and HOMO-LUMO gaps. Molecular orbital analysis discloses that these two clusters possess doubly aromatic characters (σ and π), responsible for their enhanced stability. Interestingly, unlike conventional σ-, π-, and δ-aromaticity formed by the delocalization of unhybridized p or d orbitals, the σ and π delocalized molecular orbitals shown here are formed through the effective overlap between the 5d atomic orbital of the La atom and the p orbitals of the remaining boron atoms, representing an intriguing d-p hybridized aromaticity.

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“…Consequently, various descriptors continually came into being en masse. These descriptors or evaluation methods for aromaticity include but are not limited to, A j , [31] HOMA, [32–36] HOMED, [37–39] HOMHED, [21] ∑ΔN, [40] HOSE, [41–43] Bird index, [45–48] A Poz , [49] RAHB, [50–57] Huckel rule, [12,58] NICS, [59–61] NICSS ZZ , [62] AdNDP, [63] ICSS, [64,65] NICS‐rate, [66] Δχ, [11] Λ, [67] AICD, [68] möbius aromaticity rule, [69,70] Baird rule, [71] MRE method, [72,73] MCBO/MCI, [74–78] ELF, [79–82] PDI, [83] LOL, [84,85] ATI, [86] CLRK, [87] FUL, [88] RCP, [89] Shannon aromaticity, [90] ELI, [91] EFG method, [92] pEDA/sEDA [93] …“The problem is that not all of them give the same ordering by aromaticity of a series of rings or molecules adding confusion to the field”, as said as Miquel Solà, [9] many times the apparent contradictions were found among different descriptors [94] . To circumvent the aporia, the so‐called multidimensional character of aromaticity was proposed in an ad hoc way [95–101] .…”

Section: Introductionmentioning

confidence: 99%

The σ+π dual aromaticity of typical bi‐tetrazole ring molecule TKX‐50

Yang,

Dong,

et al. 2024

ChemPhysChem

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Two complexes of dihydroxylammonium 5,5´‐bistetrazole‐1,1´‐diolate (TKX‐50) were employed to evaluate the aromaticity of their tetrazole rings via deep analysis such as the electronic structure, the ZZ component of the natural chemical shielding tensor (NICSZZ) and component orbitals, localized orbital locator purely contributed by σ‐orbitals (LOL‐σ) and localized orbital locator purely contributed by π‐orbitals (LOL‐π), the anisotropy of the induced current density(AICD) and the ZZ component of iso‐chemical shielding surface(ICSSZZ)of these tetrazole rings thereof. The conclusion shows: that all tetrazole rings and bi‐tetrazole rings in complexes have strong σ and a comparable strength π double aromaticity; all these magnetic shields almost symmetrically increase from the central axis to the tetrazole ring atoms; tetrazole rings in complex II show a little stronger dual aromaticity than that in complex I mainly due to the different orientation of the fragment 2 encompassing two hydroxylamine groups resulting in different effects on the contributions of σ orbitals and π orbitals to total aromaticity of tetrazole rings thereof; the difference in aromaticity is fundamentally caused by the atoms O with stronger electron‐withdrawing than atom N in fragment 2 interact with bi‐tetrazole ring through O in complex I but through N in complex II.

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Aromatic character of fluorinated pyridines

Cited by 12 publications

References 43 publications

Substitution effect on the intermolecular halogen and hydrogen bonds of the σ‐bonded fluorinated pyridine···XY/HX complexes (XY = F₂, Cl₂, ClF; HX = HF, HCl)

Substitution effect on the intermolecular halogen and hydrogen bonds of the σ‐bonded fluorinated pyridine···XY/HX complexes (XY = F₂, Cl₂, ClF; HX = HF, HCl)

Observation of d–p hybridized aromaticity in lanthanum-doped boron clusters

The σ+π dual aromaticity of typical bi‐tetrazole ring molecule TKX‐50

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Aromatic character of fluorinated pyridines

Cited by 12 publications

References 43 publications

Substitution effect on the intermolecular halogen and hydrogen bonds of the σ‐bonded fluorinated pyridine···XY/HX complexes (XY = F2, Cl2, ClF; HX = HF, HCl)

Substitution effect on the intermolecular halogen and hydrogen bonds of the σ‐bonded fluorinated pyridine···XY/HX complexes (XY = F2, Cl2, ClF; HX = HF, HCl)

Observation of d–p hybridized aromaticity in lanthanum-doped boron clusters

The σ+π dual aromaticity of typical bi‐tetrazole ring molecule TKX‐50

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Product

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Substitution effect on the intermolecular halogen and hydrogen bonds of the σ‐bonded fluorinated pyridine···XY/HX complexes (XY = F₂, Cl₂, ClF; HX = HF, HCl)

Substitution effect on the intermolecular halogen and hydrogen bonds of the σ‐bonded fluorinated pyridine···XY/HX complexes (XY = F₂, Cl₂, ClF; HX = HF, HCl)