Effect of substituent on the UV-Vis spectra: an extension from disubstituted to multi-substituted benzylideneanilines

Wang, Linyan; Cao, Chao‐Tun; Cao, Chenzhong

doi:10.1002/poc.3533

Cited by 17 publications

(28 citation statements)

References 24 publications

(22 reference statements)

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“…There may be some other structural factors that should be taken into consideration. According to Cao et al the excited‐state substituent constant

σ_{CC}^{ex}

has good correlation to the UV absorption energy, so we employed

σ_{CC}^{ex} ((), X)

σ_{CC}^{ex} ((), Y)

together with σ R (X), σ R (Y), and ∆ σ 2 to regress against ν max , and obtained Equation 4.

\begin{matrix} left \\ ν_{max} = 41787.2448 + 9591.8304 σ_{normalR} (normalX) + 10271.7014 σ_{normalR} (normalY) ‐ 3429.7239 Δ σ^{2} ‐ 1700.9048 σ_{CC}^{ex} (normalX) ‐ 953.1234 σ_{CC}^{ex} (normalY) \\ R = 0.9508 S = 1294.62 F = 58.37 n = 37 \end{matrix}

…”

Section: Resultsmentioning

confidence: 99%

“…Based on the previous reports and the analysis of the structures of 2,5‐disubstituted pyrimidines, we try to characterize the effects of substituent on the UV absorption energy with several molecular descriptors, such as Hammett parameter ( σ ), the cross interaction of substituents (Δ σ 2 ) , the electronegativity parameter ( χ ), the excited‐state substituent constant (

σ_{CC}^{ex}

), and the indicator variable of halogens ( D ). The definitions or calculations of each descriptors were introduced as follows.…”

Section: Experiments and Calculation Methodsmentioning

confidence: 99%

“…The excited‐state substituent constant

σ_{CC}^{ex}

is a molecular descriptor describing the stability of the excited state . It has been widely applied to the quantitative structure‐property relationship study of the ultraviolet maximum absorption, the NMR chemical shifts, and the reduction potentials . Here, we also take

σ_{CC}^{ex}

into consideration to correlate the UV absorption energy.…”

Section: Experiments and Calculation Methodsmentioning

confidence: 99%

“…Because the molecular orbital energies are affected by the substituents in molecule, the substituent effects on the UV absorption energy have been widely investigated. For example, Cao has investigated the substituent effect on the UV absorption energies of 1,4‐disubstituted benzenes and benzylideneaniline derivatives with imine bridge group (C═N) . Praveen has studied the effect of substituent on the UV‐visible absorption and photostability of liquid crystals.…”

Section: Introductionmentioning

confidence: 99%

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Substituent effects on the UV absorption energy of 2,5‐disubstituted pyrimidines

Yuan

Chen

et al. 2018

J of Physical Organic Chem

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Pyrimidine-containing molecules have been extensively investigated in organic light emitting devices (OLEDs), solar cells, liquid crystals, and so on due to their perfect photoelectric properties. Ultraviolet (UV) absorption is one of the interesting photoelectric properties. Systematical study of the substituent effects on the UV absorption energy of pyrimidine derivatives will guide to design functional molecules with specific photoelectric properties. In this paper, thirty-seven 2-X-5-Y pyrimidines with various substituents (X/Y=NH 2 , CH 3 , OCH 3 , NMe 2 , CF 3 , NO 2 , Cl, Br, I) were synthesized, and their UV spectra were recorded in anhydrous ethanol. The maximum absorption wavelength λ max (nm) were obtained and converted to wavenumber ν max (cm -1 ) (ν max = 1/λ max ) for quantitative structure-property relationship study. Hammett parameters (σ, σ F , σ R ), electronegativity (χ), the excited-state substituent effect parameter (σ ex CC ), and the heavy atom effect indicator (D) were employed as descriptors characterizing the molecular structure. By stepwise regression, a 5-descriptor linear regression model was built as ν max = 35 864.8122 + 6743.7901σ R (X) + 8587.9937σ R (Y) − 2042.7280Δσ 2 + 1106.0034D(X) + 1451.8873χ(X) (R = 0.9861, S = 693.70, ARD = 1.49%, F = 218.68, R cv = 0.9775, S cv = 881.25, ARD cv = 1.82%, n = 37). The model is proved of good stability and predictive performance by leave-one-out cross validation. Compared with the benzylideneaniline derivatives with C═N bridge group, the substituent effects on the UV absorption energy of 2,5-disubstituted pyrimidines are quite different and much more complex. KEYWORDS 2,5-disubstituted pyrimidine, quantitative structure-property relationship, substituent effect, UV absorption

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“…There may be some other structural factors that should be taken into consideration. According to Cao et al the excited‐state substituent constant

σ_{CC}^{ex}

has good correlation to the UV absorption energy, so we employed

σ_{CC}^{ex} ((), X)

σ_{CC}^{ex} ((), Y)

together with σ R (X), σ R (Y), and ∆ σ 2 to regress against ν max , and obtained Equation 4.

\begin{matrix} left \\ ν_{max} = 41787.2448 + 9591.8304 σ_{normalR} (normalX) + 10271.7014 σ_{normalR} (normalY) ‐ 3429.7239 Δ σ^{2} ‐ 1700.9048 σ_{CC}^{ex} (normalX) ‐ 953.1234 σ_{CC}^{ex} (normalY) \\ R = 0.9508 S = 1294.62 F = 58.37 n = 37 \end{matrix}

…”

Section: Resultsmentioning

confidence: 99%

σ_{CC}^{ex}

), and the indicator variable of halogens ( D ). The definitions or calculations of each descriptors were introduced as follows.…”

Section: Experiments and Calculation Methodsmentioning

confidence: 99%

“…The excited‐state substituent constant

σ_{CC}^{ex}

σ_{CC}^{ex}

into consideration to correlate the UV absorption energy.…”

Section: Experiments and Calculation Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Substituent effects on the UV absorption energy of 2,5‐disubstituted pyrimidines

Yuan

Chen

et al. 2018

J of Physical Organic Chem

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“…When the reaction was completed, the crude product was cooled to room temperature and solidi ed. White lamellar crystals of the title compound were obtained by recrystallizing with ethanol [3].…”

Section: Source Of Materialsmentioning

confidence: 99%

Crystal structure of N-(3,4-dichlorobenzylidene)-4-methylaniline, C₁₄H₁₁Cl₂N

Yuan

Chen

Wang

2017

Zeitschrift Für Kristallographie - New Crystal Structures

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C14H11Cl 2 N, monoclinic, P21/c (no. 14), a = 6.1494 ( CCDC no.: 1525722The title crystal structure is shown in the gure. Tables 1 and 2 contain details of the measurement method and a list of the atoms including atomic coordinates and displacement parameters. Source of materialThe product was synthesized by solvent-free method [1,2]. The raw materials 3,4-dichlorobenzaldehyde (98%) and pmethylaniline (98%) were purchased from J&K SCIENTIFIC LTD. Equimolar 3,4-dichlorobenzaldehyde and p-nitroaniline were stirred uniformly at rst. Then, the mixture was placed

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Influences of polarizability effect of alkyl group and homoring competition effect of substituents on the NMR spectra of salen‐type Schiff base

Wei¹,

Cao²

2021

Magnetic Reson in Chemistry

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Salen-type Schiff bases are a kind of important compounds and are widely used. In order to explore the effect of alkyl groups and substituents attached to aromatic ring on the chemical shifts, 63 title compounds were synthesized.Their 1 H NMR and 13 C NMR spectra were obtained; and the effects of the alkyl chain length and substituents on the chemical shifts (δ H (CH N), δ C (CH N), δ H (OH), and δ C (C OH)) were studied. The results show that (1) the alkyl polarizability effect index (PEI) has an important influence on the chemical shifts of the above four atoms, with the increase of PEI, the values of δ H (CH N) and δc(CH N) decrease, and the values of δ H (OH) and δ C (C OH) increase. (2) The influence of substituent X attached to aromatic ring on the chemical shift is related to its position by taking OH or CH N as reference. As for the effect of substituent on the chemical shifts, the effect of Hammett constant σ(X) OH and excited-state substituent parameter σ ex CC X ð Þ OH with OH as reference are different from that ofσ(X) CH N and σ ex CC X ð Þ CH N with CH N as reference, and there is a "homoring competition effect" of the substituent.(3) The effect of the cross-interaction between X and OH on the chemical shift is also significantly different due to the different position of X. Quantitative correlation equations against chemical shifts were built for the four atoms, and the stability and prediction ability of the obtained equations were confirmed by leave-one-out cross validation.

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Effect of substituent on the UV-Vis spectra: an extension from disubstituted to multi-substituted benzylideneanilines

Cited by 17 publications

References 24 publications

Substituent effects on the UV absorption energy of 2,5‐disubstituted pyrimidines

Substituent effects on the UV absorption energy of 2,5‐disubstituted pyrimidines

Crystal structure of N-(3,4-dichlorobenzylidene)-4-methylaniline, C₁₄H₁₁Cl₂N

Influences of polarizability effect of alkyl group and homoring competition effect of substituents on the NMR spectra of salen‐type Schiff base

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Effect of substituent on the UV-Vis spectra: an extension from disubstituted to multi-substituted benzylideneanilines

Cited by 17 publications

References 24 publications

Substituent effects on the UV absorption energy of 2,5‐disubstituted pyrimidines

Substituent effects on the UV absorption energy of 2,5‐disubstituted pyrimidines

Crystal structure of N-(3,4-dichlorobenzylidene)-4-methylaniline, C14H11Cl2N

Influences of polarizability effect of alkyl group and homoring competition effect of substituents on the NMR spectra of salen‐type Schiff base

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Crystal structure of N-(3,4-dichlorobenzylidene)-4-methylaniline, C₁₄H₁₁Cl₂N