Synthesis and crystal structures of a series of Schiff bases: a photo-, solvato- and acidochromic compound

Jiménez‐Sánchez, Arturo; Rodríguez, Mario; Métivier, Rémi; Ramos‐Ortíz, Gabriel; Maldonado, José Luis; Réboles, Netzahualcoyotl; Farfán, Norberto; Nakatani, Keitaro; Santillán, Rosa

doi:10.1039/c3nj00895a

Cited by 33 publications

(20 citation statements)

References 66 publications

(19 reference statements)

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“…The Lippert-Mataga equation (shown in Supplementary Material) is widely used to evaluate the dipole moment changes of the dyes with photoexcitation [ 33 , 34 ]; the emission of the chromophores, especially, is strongly dependent on solvent polarity. As shown in Figure 2 , the Lippert-Mataga plots exhibit a linear behavior; this means no specific interaction exists between the solvent and the chromophores, except for the polarizability as modeled [ 35 , 36 ]. The slop of the fitting line is related to the dipole moment change between the ground and excited states ( μ e − μ g ).…”

Section: Resultsmentioning

confidence: 99%

A Series of Imidazole Derivatives: Synthesis, Two-Photon Absorption, and Application for Bioimaging

Zhu

Xiao

Zhao

et al. 2015

BioMed Research International

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A new series of D-π-A type imidazole derivatives have been synthesized and characterized. Two corresponding imidazolium salts (iodine and hexafluorophosphate) were prepared from the imidazole compound. Their electron-withdrawing ability can be largely tunable by salt formation reaction or ion exchange. UV-vis absorption and single-photon fluorescence spectra have been systematically investigated in different solvents. The two-photon cross sections (δ 2PA) of the imidazole derivatives are measured by two-photon excited fluorescence (2PEF) method. Compared with those of T-1 (107 GM) and T-3 (96 GM), T-2 (imidazolium iodine salt) has a large two-photon absorption (2PA) cross section value of 276 GM. Furthermore, the cytotoxicity and applications in bioimaging for the imidazole derivatives were carried out. The results showed that T-1 can be used as a lysosomal tracker with high stability and water solubility within pHs of 4–6, while T-2 and T-3 can be used as probes for cell cytoplasm.

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Section: Resultsmentioning

confidence: 99%

A Series of Imidazole Derivatives: Synthesis, Two-Photon Absorption, and Application for Bioimaging

Zhu

Xiao

Zhao

et al. 2015

BioMed Research International

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“…Similar bathochromic shifts in substrate absorbance have been observed for other iminium ion-forming organocatalysts 31 and enzymes. 26 , 32 Spectroscopic titration studies with a Schiff-base adduct of 1a in organic solvents 33 suggest that the species formed between 1a and Lys-167 is likely protonated. Additionally, after chemically reducing DERA-MA in the presence of 1a with NaBH 3 CN, ESI-MS analysis revealed that compared to unmodified DERA-MA, the observed major peak increased by + 117 Da, corresponding to the covalent modification of the protein with one molecule of the reduced Schiff-base adduct of 1a (calcd.…”

Section: Results and Discussionmentioning

confidence: 99%

Unlocking Asymmetric Michael Additions in an Archetypical Class I Aldolase by Directed Evolution

Kunzendorf

Velde

et al. 2021

ACS Catal.

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Class I aldolases catalyze asymmetric aldol addition reactions and have found extensive application in the biocatalytic synthesis of chiral β-hydroxy-carbonyl compounds. However, the usefulness of these powerful enzymes for application in other C–C bond-forming reactions remains thus far unexplored. The redesign of class I aldolases to expand their catalytic repertoire to include non-native carboligation reactions therefore continues to be a major challenge. Here, we report the successful redesign of 2-deoxy- d -ribose-5-phosphate aldolase (DERA) from Escherichia coli , an archetypical class I aldolase, to proficiently catalyze enantioselective Michael additions of nitromethane to α,β-unsaturated aldehydes to yield various pharmaceutically relevant chiral synthons. After 11 rounds of directed evolution, the redesigned DERA enzyme (DERA-MA) carried 12 amino-acid substitutions and had an impressive 190-fold enhancement in catalytic activity compared to the wildtype enzyme. The high catalytic efficiency of DERA-MA for this abiological reaction makes it a proficient “Michaelase” with potential for biocatalytic application. Crystallographic analysis provides a structural context for the evolved activity. Whereas an aldolase acts naturally by activating the enzyme-bound substrate as a nucleophile (enamine-based mechanism), DERA-MA instead acts by activating the enzyme-bound substrate as an electrophile (iminium-based mechanism). This work demonstrates the power of directed evolution to expand the reaction scope of natural aldolases to include asymmetric Michael addition reactions and presents opportunities to explore iminium catalysis with DERA-derived catalysts inspired by developments in the organocatalysis field.

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“…Single crystal X-ray diffraction (SCXRD) confirmed that the imine crystal structure consists of two diaminothiophene units and one ethylenedioxythiophene group, and indicating also the E conformation of the heteroatom double bond. Sanchez et al [ 43 ] described the synthesis of Schiff bases and their photochromic behavior as an effect of intermolecular hydrogen bond formation. It was demonstrated that only Schiff’s base derivatives of phenylglycinol showed photochromism in the solid state.…”

Section: Introductionmentioning

confidence: 99%

Crystal Structure Determination of 4-[(Di-p-tolyl-amino)-benzylidene]-(5-pyridin-4-yl-[1,3,4]thiadiazol-2-yl)-imine along with Selected Properties of Imine in Neutral and Protonated Form with Camforosulphonic Acid: Theoretical and Experimental Studies

et al. 2021

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The crystal structure was determined for the first time for 4-[(di-p-tolyl-amino)benzylidene]-(5-pyridin-4-yl-[1,3,4]thiadiazol-2-yl)-imine (trans-PPL9) by X-ray diffraction. The imine crystallized in the monoclinic P21/n space group with a = 18.9567(7) Å, b = 6.18597(17) Å, c = 22.5897(7) Å, and β = 114.009(4)°. Intermolecular interactions in the PPL9 crystal were only weak C−H∙∙∙N hydrogen bonds investigated using the Hirshfeld surface. The electronic and geometric structure of the imine were investigated by the density functional theory and the time-dependent density-functional theory. The properties of the imine in neutral and protonated form with camforosulphonic acid (CSA) were investigated using cyclic voltammetry, UV–vis and 1H NMR spectroscopy. Theoretical and experimental studies showed that for the 1:1 molar ratio the protonation occured on nitrogen in pyridine in the PPL9 structure, as an effect of Brönsted acid–base interactions. Thermographic camera was used to defined defects in constructed simple devices with ITO/PPL9 (or PPL9:CSA)/Ag/ITO architecture. In conclusion, a thermally stable imine was synthesized in crystalline form and by CSA doping, a modification of absorption spectra together with reduction of overheating process was observed, suggesting its potential application in optoelectronics.

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Synthesis and crystal structures of a series of Schiff bases: a photo-, solvato- and acidochromic compound

Cited by 33 publications

References 66 publications

A Series of Imidazole Derivatives: Synthesis, Two-Photon Absorption, and Application for Bioimaging

A Series of Imidazole Derivatives: Synthesis, Two-Photon Absorption, and Application for Bioimaging

Unlocking Asymmetric Michael Additions in an Archetypical Class I Aldolase by Directed Evolution

Crystal Structure Determination of 4-[(Di-p-tolyl-amino)-benzylidene]-(5-pyridin-4-yl-[1,3,4]thiadiazol-2-yl)-imine along with Selected Properties of Imine in Neutral and Protonated Form with Camforosulphonic Acid: Theoretical and Experimental Studies

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