Novel Red‐Emitting Copper(I) Complexes with Pyrazine and Pyrimidinyl Ancillary Ligands for White Light‐Emitting Electrochemical Cells

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Bifunctional (Cyclopentadienone) Iron-Tricarbonyl Complexes: Synthesis, Computational Studies and Application in Reductive Amination

Reductive amination under hydrogen pressure is a valuable process in organic chemistry to access amine derivatives from aldehydes or ketones. Knolker's complex has been shown to be an efficient iron catalyst in this reaction. To determine the influence of the substituents on the cyclopentadienone ancillary ligand, a series of modified Knolker's complexes was synthesised and fully characterised. These complexes were also transformed into their analogous acetonitrile iron-dicarbonyl complexes. Catalytic activities of these complexes were evaluated and compared in a model reaction. The scope of this reaction is also reported. For mechanistic insights, deuterium-labelling experiments and DFT calculations were undertaken and are also presented

Design Rule Hidden from The Eye in S/N-Bridged Ancillary Ligands for Copper(I) Complexes Applied to Light-Emitting Electrochemical Cells

Enhancing low-energy emitting Cu(I)-ionic transition metal complexes (iTMCs) light-emitting electrochemical cells (LECs) is of utmost importance towards Cu(I)-iTMC-based white-emitting LECs. Here, the ancillary ligand design includes (i) extension of &amp; pi;-systems and (ii) insertion of S-bridge between heteroaromatics rings. This led to two novel heteroleptic Cu(I)-iTMCs: 2-(pyridin-2-yl-l2-azanyl)quinoline (CuN2) and 2-(naphthalen-2-ylthio)quinoline (CuS2) as N&amp;lt;^&amp;gt;N and bis[(2-diphenylphosphino)phenyl] ether as P&amp;lt;^&amp;gt;P, exhibiting improved photoluminescence quantum yields (&amp; phi;) and thermally activated delayed fluorescence processes compared to their reference Cu(I)-iTMCs: di(pyridin-2-yl)-l2-azane (CuN1) and di(pyridin-2-yl)sulfane (CuS1). Despite CuS2 stands out with the highest &amp; phi; (38% vs 17 / 14 / 1% for CuN1 / CuN2 / CuS1), only CuN2-LECs show the expected enhanced performance (0.35 cd A(-1) at luminance of 117 cd m(-2)) compared to CuN1-LECs (0.02 cd A(-1) at6 cd m(-2)), while CuS2-LECs feature low performances (0.04 cd A(-1) at 10 cd m(-2)). This suggests that conventional chemical design rules are not effective towards enhancing device performance. Herein, nonconventional multivariate statistical analysis and electrochemical impedance spectroscopy studies allow to rationalize the mismatch between chemical design and device performance bringing to light a hidden design rule: polarizability of the ancillary ligand is key for an efficient Cu(I)-iTMC-LECs. All-in-all, this study provides fresh insights for the design of Cu-iTMCs fueling research on sustainable ion-based lighting sources.Funding Agencies|European Union [956923]; CNRS (Centre National de la Recherche Scientifique); LABEX SynOrg [ANR-11-LABX-0029]; Normandie University; Projekt DEAL; Ministere de lEnseignement Superieur et de la Recherche; Region Normandie; Graduate School of Research XL-Chem [ANR-18-EURE-0020 XL-Chem]</p

Diversity-Oriented Synthesis of Spiropyrrolo[1,2- a ]isoquinoline Derivatives via Diastereoselective and Regiodivergent Three-Component 1,3-Dipolar Cycloaddition Reactions: In Vitro and in Vivo Evaluation of the Antidiabetic Activity of Rhodanine Analogues

International audienceAn efficient diastereoselective route is developed to get access to novel spiropyrrolo[1,2-a]isoquinoline-oxindole skeletons by a one-potthree-component [3 + 2] cycloaddition reaction of (Z)-5-arylidene-1,3-thiazolidine-2,4-diones, isatin derivatives, and 1,2,3,4-tetrahydroisoquinoline (THIQ). Interestingly, the regioselectivity of the reaction is both temperature- and solvent-dependent, allowing the synthesis of two regioisomeric endo-dispiropyrrolo[2,1-a]isoquinolineoxindoles in excellent yield. Unprecedentedly, each isomeric dispiropyrrolo[2,1-a]isoquinolineoxindole endured retro-1,3-dipolar cycloaddition/recycloaddition reactions under thermal or catalytic conditions to regenerate the corresponding regioisomeric counterpart. In addition, DFT calculations were performed at the M062X/6-31++g(d,p) level of theory to unravel the origin of the reversal of regioselectivity and endo-stereoselectivity of the title 1,3-dipolar cycloaddition reactions. Upon treatment of Isatin, THIQ with (Z)-4-arylidene-5-thioxo-thiazolidin-2-ones as dipolarophiles, unusual rhodanine analogues were formed, along with smaller amounts of a dispirooxindole-piperazine. The structure and the relative configuration of these N-heterocycles were unambiguously assigned by spectroscopic techniques and confirmed by four single-crystal structures. In vitro and in vivo studies reveal that the novel rhodanine derivatives exert antidiabetic activity. The binding affinity with the active site of the enzyme α-amylase was studied by molecular docking. Furthermore, the bioavailability assessed through virtual ADME parameters (Absorption, Distribution, Metabolism, Elimination pharmacokinetics) and the excellent fit with the Lipinski and Veber rules predict good drug-likeness properties for a bromo-substituted 2-sulfanylidene-1,3-thiazolidin-4-one

Synthesis & Structure‐Photophysics Evaluation on 2‐N‐Aminoquinazolines – Small‐Molecule Fluorophores for Solution and Solid State

International audience2-N-aminoquinazolines were prepared through consecutive SNAr functionalization. X-ray structures display the nitrogen lone pair of the 2-N-morphilino group in conjugation with the electron deficient quinazoline core and thus representing electronic push-pull systems. 2-N-aminoquinazolines show a positive solvatochromism and are fluorescent in solution and in solid state with quantum yields up to 0.73. Increase in electron donor strength of the 2-amino substituent causes a red-shift of the intramolecular charge transfer (ICT) band (300-400 nm); whereas the photoluminescence emission maxima (350-450 nm) is also red-shifted significantly along with an enhancement in photoluminescence efficiency. HOMO-LUMO energies were estimated by a combination of electrochemical and photophysical methods and correlate well to those obtained by computational methods. ICT properties are theoretically attributed to an excitation to Rydberg-MO in SAC-CI method, which can be interpreted as n-pi* excitation. 7-Amino-2-N-morpholino-4-methoxyquinazoline responds to acidic conditions with significant increases in photoluminescence intensity revealing a new turn-on/off fluorescence probe

Synthesis and Structure‐Photophysics Evaluation of 2‐N‐Amino‐quinazolines: Small Molecule Fluorophores for Solution and Solid State

International audience2-N-aminoquinazolines were prepared through consecutive SNAr functionalization. X-ray structures display the nitrogen lone pair of the 2-N-morphilino group in conjugation with the electron deficient quinazoline core and thus representing electronic push-pull systems. 2-N-aminoquinazolines show a positive solvatochromism and are fluorescent in solution and in solid state with quantum yields up to 0.73. Increase in electron donor strength of the 2-amino substituent causes a red-shift of the intramolecular charge transfer (ICT) band (300-400 nm); whereas the photoluminescence emission maxima (350-450 nm) is also red-shifted significantly along with an enhancement in photoluminescence efficiency. HOMO-LUMO energies were estimated by a combination of electrochemical and photophysical methods and correlate well to those obtained by computational methods. ICT properties are theoretically attributed to an excitation to Rydberg-MO in SAC-CI method, which can be interpreted as n-pi* excitation. 7-Amino-2-N-morpholino-4-methoxyquinazoline responds to acidic conditions with significant increases in photoluminescence intensity revealing a new turn-on/off fluorescence probe