The Unusual Transformation of an Aromatic 1H-Imidazole into a Non-Aromatic 2H-Imidazole

Hoz, Antonio de la; Sánchez-Migallón, Ana; Mateo, María del Carmen; Prieto, Pilar; Infantes, Lourdes; Elguero, José

doi:10.1007/s11224-005-4467-4

Cited by 13 publications

(2 citation statements)

References 4 publications

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“…It is well recognized that pyrrole and its N derivatives exhibit prototropic tautomerism [9,21,22,57,[76][77][78][79][80][81][82][83][84][85][86][87][88]. The labile proton can move from one site to the other according to 1,3-or 1,5-shift.…”

Section: Homed Application To Tautomeric Azoles and Phospholesmentioning

confidence: 99%

Application of the Extended HOMED (Harmonic Oscillator Model of Aromaticity) Index to Simple and Tautomeric Five-Membered Heteroaromatic Cycles with C, N, O, P, and S Atoms

Raczyńska

2019

Symmetry

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The geometry-based HOMA (Harmonic Oscillator Model of Aromaticity) descriptor, based on the reference compounds of different delocalizations of n- and π-electrons, can be applied to molecules possessing analogous bonds, e.g., only CC, only CN, only CO, etc. For compounds with different heteroatoms and a different number of CC, CX, XX, and XY bonds, its application leads to some discrepancies. For this reason, the structural descriptor was modified and the HOMED (Harmonic Oscillator Model of Electron Delocalization) index defined. In 2010, the HOMED index was parameterized for compounds with C, N and O atoms. For parametrization, the reference molecules of similar delocalizations of n- and π-electrons were employed. In this paper, the HOMED index was extended to compounds containing the CP, CS, NN, NP, PP, NO, NS, PO, and PS bonds. For geometrical optimization of all reference molecules and of all investigated heterocompounds, the same quantum–chemical method {B3LYP/6-311+G(d,p)} was used to eliminate errors of the HOMED estimation. For some tautomeric systems, the Gn methods were also employed to confirm tautomeric preferences. The extended HOMED index was applied to five-membered heterocycles, simple furan and thiophene, and their N and P derivatives as well as for tautomeric pyrrole and phosphole and their N and P derivatives. The effects of additional heteroatom(s) in the ring on the HOMED values for furan are parallel to those for thiophene. For pyrroles, aromaticity dictates the tautomeric preferences. An additional N atom in the ring only slightly affects the HOMED values for the favored and well delocalized NH tautomers. Significant changes take place for their rare CH forms. When intramolecular proton-transfer is considered for phosphole and its P derivatives, the PH tautomers seem to be favored only for 1,2,3-triphosphole/1,2,5-triphosphole and for 1,2,3,5-tetraphosphole. For other phospholes, the CH forms have smaller Gibbs energies than the PH isomers. For phosphazoles, the labile proton in the favored form is linked to the N atom. The PH forms have smaller HOMED indices than the NH tautomers but higher than the CH ones.

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Section: Homed Application To Tautomeric Azoles and Phospholesmentioning

confidence: 99%

Application of the Extended HOMED (Harmonic Oscillator Model of Aromaticity) Index to Simple and Tautomeric Five-Membered Heteroaromatic Cycles with C, N, O, P, and S Atoms

Raczyńska

2019

Symmetry

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“…It is an aromatic planarring molecule that exists in two equivalent tautomeric forms (1H-and 3H-imidazole) (Kale et al, 2016;Verma et al, 2013). On the contrary, the third isomer (2H-imidazole) is non-aromatic due to the absence of a sextet of π-electrons (Hoz et al, 2005). Imidazole is an amphoteric compound and consequently susceptible to both electrophilic and nucleophilic reactions (Kale et al, 2016;Verma et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Ultra-Efficient Removal of Mercury from Contaminated Water using Selected Phenylimidazole Derivatives

Živković

2024

Water Air Soil Pollut

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Heterocycles, including imidazole derivatives, are important chemicals due to their structural similarity to active natural molecules. This study explored the utilization of phenylimidazole derivatives for mercury removal from aqueous solutions. Three derivatives were tested, including one harboring a sulfhydryl functional group, thus offering distinct mercury-binding capabilities. Mercury binding experiments revealed modest mercury binding by two derivatives. However, extraordinary efficiency of mercury binding by the sulfhydryl-bearing compound was demonstrated through a reduction in mercury concentrations in pure water by 43-fold in just 15 min and decreasing below the analytical detection limit with prolonged exposure (30 min). Moreover, the ultra-efficiency of mercury binding was demonstrated by a capability to reduce mercury concentrations even in highly contaminated environmental water sample by a factor exceeding 1200-fold in 20 h, using minimal amounts of the compound. This phenylimidazole derivative exhibited comparable efficiency in binding mercury from authentic environmental water samples, hinting at practical applications for real-world remediation efforts. Kinetic investigations showed a pseudo-first order reaction with a rate constant of 0.26 min−1 and half-life of 2.69 min that governs mercury binding to this phenylimidazole derivative. These findings underscore the potential of the sulfhydryl-containing phenylimidazole derivative, as swift and effective binding material for aqueous mercury removal. Its rapid action, coupled with binding efficiency, suggests a promising material for addressing mercury contamination in highly contaminated environmental water samples.

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How Aromaticity Affects the Chemical and Physicochemical Properties of Heterocycles: A Computational Approach

Alkorta¹,

Elguero²

2008

Topics in Heterocyclic Chemistry

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The Unusual Transformation of an Aromatic 1H-Imidazole into a Non-Aromatic 2H-Imidazole

Cited by 13 publications

References 4 publications

Application of the Extended HOMED (Harmonic Oscillator Model of Aromaticity) Index to Simple and Tautomeric Five-Membered Heteroaromatic Cycles with C, N, O, P, and S Atoms

Application of the Extended HOMED (Harmonic Oscillator Model of Aromaticity) Index to Simple and Tautomeric Five-Membered Heteroaromatic Cycles with C, N, O, P, and S Atoms

Ultra-Efficient Removal of Mercury from Contaminated Water using Selected Phenylimidazole Derivatives

How Aromaticity Affects the Chemical and Physicochemical Properties of Heterocycles: A Computational Approach

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