Exploring the correlation between the π-electron delocalization and intramolecular hydrogen bond in malonaldehyde derivatives; a quantum chemical study

Nowroozi, Alireza; Nakhaei, Ebrahim; Masumian, Ehsan

doi:10.1007/s11224-014-0421-7

Cited by 14 publications

(6 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The resonance is one of the most important concept in describe molecular structures in the aromatic and quasiaromatic rings, that extensively studied [9,37,49,50].…”

Section: Resonance Parametersmentioning

confidence: 99%

“…In the RAHB system of NNF, amide resonance is the most important factor that determines the hydrogen bond strength in this molecule [4]. Thus, the substitution of electron withdrawing and donating groups on the RAHB ring lead to change in the resonance and make a great change in some of the IHB descriptor properties such as geometrical parameters, electron density and resonance indices, both in the ground and excited states [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A comparative study of intramolecular hydrogen bond on N-formylformamide derivatives in ground and first singlet excited state: a DFT and TD-DFT study

2019

View full text Add to dashboard Cite

Intramolecular hydrogen bond (IHB) of N-formylformamide derivatives in the both ground (GS) and first singlet excited state (S 1 ) have been investigated by DFT and TD-DFT methods with the standard basis set 6-311++G (d,p), respectively. Also the potential energy density method was used to calculate of the IHB energies in the both GS and S 1 . Our calculations show that IHB energies in the GS are much higher than the S 1 one. In order to explain this energy difference, molecular orbital analysis (MO S ) has been employed. According to the MO S , it was found that electron density on antibonding orbital (δ * O-H ) increases after excitation, which can be a reason for the weakened IHB in the S 1 . In this work, we evaluated and compared the substitution effects on the IHB strength in the both GS and S 1 by some of the IHB descriptors such as geometrical, topological and orbital charge transfer parameters. The results proved that the substitution effects on the both GS and S 1 are same. As with replacing of the halogen atoms at R 2 position the IHB energies increased while for the R 2 and R 1,2 decreased. Moreover, for the first time, various geometry-based resonance indices such as Gilli (Q and λ) parameters, original harmonic oscillator model of aromaticity, harmonic oscillator model of electron delocalization and harmonic oscillator model for heterocyclic with π-electrons delocalization were calculated and compared in the both GS and S 1 . Interestingly, it is found from the resonance indices that electron delocalization in the S 1 increased that this result is against the RAHB theory in the studied molecules. Finally, the linear equations of the IHB energies versus the IHB descriptors parameters and resonance indices in the both GS and S 1 indicate that the potential energy density is an inappropriate method for calculation of the IHB energies of the heterocyclic RAHB systems in the S 1 .

show abstract

“…The resonance is one of the most important concept in describe molecular structures in the aromatic and quasiaromatic rings, that extensively studied [9,37,49,50].…”

Section: Resonance Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A comparative study of intramolecular hydrogen bond on N-formylformamide derivatives in ground and first singlet excited state: a DFT and TD-DFT study

2019

View full text Add to dashboard Cite

show abstract

“…Hence, in the Tables 6 and 7. Recently, various indicators are examined to estimate the quasi-aromaticity character of malondialdehyde derivatives and the following order is concluded [48]:…”

Section: P-electron Delocalizationmentioning

confidence: 99%

A comparative study of two-ring resonance-assisted hydrogen bond systems

et al. 2015

View full text Add to dashboard Cite

Two-ring resonance-assisted hydrogen bond (RAHB) systems can be obtained by merging two cis enol ring of malondialdehyde with different orientations. In the present work, a comparative theoretical study of all of the possible two-ring RAHB systems, 2,3-dihydroxy-2-butene-4-dial (DBD), 1,5-dihydroxy-1,4-diene-3-pentanone (DDP) and 2-dihydroxy-methylene-propanediol (DMP), was carried out. Also, the influence of the co-existence of two RAHB rings on the molecular structures, intramolecular hydrogen bond (IMHB) and the p-electron delocalization (p-ED) was investigated. In this regard, ab initio calculations on the various equilibrium conformations of DBD, DDP and DMP at MP2/6-311??G(d,p) level of theory have been performed and the IMHB strength of model compounds by different descriptors such as geometrical, topological, molecular orbital, spectroscopic and energetic parameters was evaluated. Then, the p-ED of DBD, DDP and DMP was estimated by using a variety of indicators, such as geometrical factor of Gilli (k), the harmonic oscillator model of aromaticity, the nucleus-independent chemical shift, the para delocalization index, the average two-center index, the aromatic fluctuation index. Finally, based on the computational results, it was found that the strength of IMHB and significance of p-ED in two-ring RAHB systems are strongly related to the relative flow of p-electrons in two rings. In other words, the parallel flows of p-electrons in DMP and DDP increase the IMHB strength and p-ED, while opposite flow of p-electrons in DBD decreases the IMHB strength and p-ED.

show abstract

“…It is known that influence of such intramolecular H-bonding on the aromaticity and π-electron delocalization could be rather strong, − especially for the ortho -substituted rings with strong H-bonding between substituents. In some particular nonaromatic conjugated systems, such as malonaldehyde or malondialdehyde derivatives, the electron delocalization in the hydrogen-bonded quasi-aromatic rings could be comparable to the delocalization in the aromatic π-systems. − In the previous studies of the structure and aromaticity of the series of aminonitrobenzenes it was found that the degree of benzene ring aromaticity decreases essentially with the increasing of the number of such hydrogen bonds between amino and nitro groups, mutually enhancing each other in the nonadditive manner. The substituent effect on aromatic ring could also be strongly affected by involving the substituent into intermolecular hydrogen bonding .…”

Section: Introductionmentioning

confidence: 99%

About the Aromaticity of symm-Triaminotrinitrobenzene

et al. 2019

View full text Add to dashboard Cite

Aromaticity and structural features of the isolated symm-triaminotrinitrobenzene (TATB) were examined using the nonempirical ab initio quantum chemical method and molecular dynamics at the Car–Parrinello level. Different criteria of the aromaticity were combined with the study of conformational flexibility of molecule and analysis of the electron density distribution. It was found that the cooperative effect of the resonance-assisted hydrogen bonds results in the ultimate decreasing aromaticity of the benzene ring in TATB. Values of the HOMA index indicate that it could be classified as low-aromatic in equilibrium state at zero temperature but completely nonaromatic at room temperature. An extremely high flexibility of the molecule is also not typical for aromatic rings. The electron delocalization in H-bonded ON–CC–N–H quasi-aromatic rings was found to be greater than that in the benzene ring of TATB.

show abstract

Exploring the correlation between the π-electron delocalization and intramolecular hydrogen bond in malonaldehyde derivatives; a quantum chemical study

Cited by 14 publications

References 34 publications

A comparative study of intramolecular hydrogen bond on N-formylformamide derivatives in ground and first singlet excited state: a DFT and TD-DFT study

A comparative study of intramolecular hydrogen bond on N-formylformamide derivatives in ground and first singlet excited state: a DFT and TD-DFT study

A comparative study of two-ring resonance-assisted hydrogen bond systems

About the Aromaticity of symm-Triaminotrinitrobenzene

Contact Info

Product

Resources

About