Substituent Effects on NMR Spectroscopy of 2,2-Dimethylchroman-4-one Derivatives: Experimental and Theoretical Studies

Iguchi, Daniela; Ravelli, Davide; Erra‐Balsells, Rosa; Bonesi, Sergio M.

doi:10.3390/molecules25092061

Cited by 4 publications

(3 citation statements)

References 33 publications

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“…In general, Hammett’s substituent constant determines the relative electronic effects of any given substituents on the electron density of the reaction center under consideration . Numerous studies suggested that Hammett parameters can be correlated with the NMR chemical shift values. − Accordingly, the chemical shift values of N–H protons of indole ( 1a ), 3-Me-indole ( 1b ), indole 3-carboxaldehyde ( 1d ), and 3-cyano indole ( 1c ) (from their 1 H NMR spectra) were compared with their initial rate of N–H insertion to the phenyl diazoester. It was observed that the more electron-donating the C3 substituent (of the indole) is, the more upfield the N–H protons are and consequently the slower is the rate of the reaction [Figure A].…”

Section: Resultsmentioning

confidence: 99%

Blue LED-Mediated N–H Insertion of Indoles into Aryldiazoesters at Room Temperature in Batch and Flow: Reaction Kinetics, Density Functional Theory, and Mechanistic Study

2021

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Mild blue light-mediated N–H insertion of indole and its derivatives into aryldiazoesters has been reported in a batch and flow strategy to afford the corresponding N-alkylated product in moderate-to-excellent yield. Detailed high-performance liquid chromatography-based reaction kinetics measurements, control experiments, and kinetic isotope effect reveal that 3-substituted indoles with electron-withdrawing groups such as −CN and −CHO facilitated the product formation, whereas the electron-donating group retarded the process. The neutral indole performed in between them. Furthermore, Hammett plot and density functional theory-based transition-state optimization studies showed substantial correlation of the electronic nature of the substituents at the C3 position of indoles with the rate of the N–H insertion reaction. The strategy was utilized to synthesize a key intermediate for the natural product (−)-psychotrimine.

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Section: Resultsmentioning

confidence: 99%

Blue LED-Mediated N–H Insertion of Indoles into Aryldiazoesters at Room Temperature in Batch and Flow: Reaction Kinetics, Density Functional Theory, and Mechanistic Study

2021

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“…Hammett proposed his theory long ago from experimental observations 18,19 resting on the idea that the electron‐donating or electron‐withdrawing power of a substituent in an aromatic molecule can be quantified and the corresponding values of the Hammett's constants used in any type of these systems. This original idea and its extensions afterward have provided the basis for the quantitative rationalization of structure‐reactivity in organic chemistry 21 and a plethora of other chemical phenomena ranging from RMN effects, 26 characterizations of different catalytic of Au nanoparticles on different supports, 27 metal–organic frameworks (MOFs), 28 non‐covalent interactions, 29 and photophysical properties of dyes, 30 among others. In this work, we use HT to explore correlations between optoelectronic properties and device parameters of the DPPs.…”

Section: Theoretical and Computational Methodsmentioning

confidence: 99%

A Hammett's analysis of the substituent effect in functionalized diketopyrrolopyrrole (DPP) systems: Optoelectronic properties and intramolecular charge transfer effects

Monteiro-de-Castro

Borges

2023

J Comput Chem

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Diketopyrrolopyrrole (DPP) systems have promising applications in different organic electronic devices. In this work, we investigated the effect of 20 different substituent groups on the optoelectronic properties of DPP‐based derivatives as the donor ()‐material in an organic photovoltaic (OPV) device. For this purpose, we employed Hammett's theory (HT), which quantifies the electron‐donating or ‐withdrawing properties of a given substituent group. Machine learning (ML)‐based , , , , , , , and Hammett's constants previously determined were used. Mono‐ (DPP‐X1) and di‐functionalized (DPP‐X2) DPPs, where X is a substituent group, were investigated using density functional theory (DFT), time‐dependent DFT (TDDFT), and ab initio methods. Several properties were computed using CAM‐B3LYP and the second‐order algebraic diagrammatic construction, ADC(2), an ab initio wave function method, including the adiabatic ionization potential (), the electron affinity (), the HOMO‐LUMO gaps (), and the maximum absorption wavelengths (), the first excited state transition 1S0→ 1S1 energies () (the optical gap), and exciton binding energies. From the optoelectronic properties and employing typical acceptor systems, the power conversion efficiency (), open‐circuit voltage (), and fill factor () were predicted for a DPP‐based OPV device. These photovoltaic properties were also correlated with the machine learning (ML)‐based Hammett's constants. Overall, good correlations between all properties and the different types of constants were obtained, except for the constants, which are related to inductive effects. This scenario suggests that resonance is the main factor controlling electron donation and withdrawal effects. We found that substituent groups with large values can produce higher photovoltaic efficiencies. It was also found that electron‐withdrawing groups (EWGs) reduced and considerably compared to the unsubstituted DPP‐H. Moreover, for every decrease (increase) in the values of a given optoelectronic property of DPP‐X1 systems, a more significant decrease (increase) in the same values was observed for the DPP‐X2, thus showing that the addition of the second substituent results in a more extensive influence on all electronic properties. For the exciton binding energies, an unsupervised machine learning algorithm identified groups of substituents characterized by average values (centroids) of Hammett's constants that can drive the search for new DDP‐derived materials. Our work presents a promising approach by applying HT on molecular engineering DPP‐based molecules and other conjugated molecules for applications on organic optoelectronic devices.

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“…These relationships are frequently mentioned as linear free-energy relationships (LFER). The LFER has often been used to cover the whole correlation study in organic chemistry [1][2][3]. Modern studies show that Hammett parameters can be correlated with the reaction rates, equilibrium constants, IR frequencies, UV absorption and NMR chemical shifts [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Effect of Substituent on the 13C NMR Chemical Shifts of Substituted 26-Member [2+2] Macrocyclic Compounds

Radhakrishnan,

Senthilkumar

2023

ajc

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A series of substituted symmetrical 14,15,34,35,94,95,114,115-octamethoxy-2,10-bis(4-methoxyphenyl)-4,8,12,16-tetraaza-1,3,9,11(1,2),6,14(1,4)-hexabenzenacyclohexadecaphane-4,7,12,15-tetraene compounds (macrocyclic compounds) have been prepared by condensation of various substituted benzaldehyde with 1,2-dimethoxy benzene followed by nitration, reduction and cyclization with terephthaldehyde. Isolated substituted compounds were characterized by UV, IR, NMR and Mass spectrometric technics. Investigation of substituents effect and mode of transmission of electronic effects have been carried out by 13C NMR chemical shifts measurement and correlated it with LFER parameters in substituted macrocyclic compounds.

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Substituent Effects on NMR Spectroscopy of 2,2-Dimethylchroman-4-one Derivatives: Experimental and Theoretical Studies

Cited by 4 publications

References 33 publications

Blue LED-Mediated N–H Insertion of Indoles into Aryldiazoesters at Room Temperature in Batch and Flow: Reaction Kinetics, Density Functional Theory, and Mechanistic Study

Blue LED-Mediated N–H Insertion of Indoles into Aryldiazoesters at Room Temperature in Batch and Flow: Reaction Kinetics, Density Functional Theory, and Mechanistic Study

A Hammett's analysis of the substituent effect in functionalized diketopyrrolopyrrole (DPP) systems: Optoelectronic properties and intramolecular charge transfer effects

Effect of Substituent on the 13C NMR Chemical Shifts of Substituted 26-Member [2+2] Macrocyclic Compounds

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