Photolytic -Selective Amino Pyridylation of Aryl Isocyanates with -Amino Pyridinium Ylides for the Synthesis of -Arylsulfonyl Ureas.

Herein, we report an expedient synthesis of aryl sulfonyl ureas and from -amino pyridinium ylides and aryl isocyanates. -Aminopyridinium ylides are synthesized via blue light-emitting diode irradiation of pyridine/isoquinoline and appropriate iminoiodinanes. The strategy involved a hitherto unknown carboamination of imine moieties (of aryl isocyanates) via a three-component reaction of pyridine derivatives/isoquinoline , -aryl sulfonyl iminoiodinanes , and numerous aryl isocyanates at room temperature in 2-methyl tetrahydrofuran to afford the target compounds in moderate to excellent yields.

Ambipolar macrocycle derived from spiro-xanthene and carbazole: synthesis, structure-property relationships, electronic properties and host-guest investigation.

For the first time, we present the detailed synthesis, photophysical, electrochemical, host-guest and charge transport properties of spiro[fluorene-9,9'-xanthene] (SFX) and carbazole macrocycle SPS-NR-02. The electron and hole transport values measured using the space charge limited current (SCLC) method resulted in ambipolar charge transport with an electron to hole mobility ratio of 0.39.

Design of Isoindigo-Based Small-Molecule Donors for Bulk Heterojunction Organic Solar Cell Applications in Combination with Nonfullerene Acceptors.

The development of small-molecule organic solar cells with the required efficiency depends on the information obtained from molecular-level studies. In this context, 39 small-molecule donors featuring isoindigo as an acceptor moiety have been meticulously crafted for potential applications in bulk heterojunction organic solar cells. These molecules follow the D-A-D-A-D and D-A-π-D-π-A-D framework.

Bioengineering of CuO structured macro-biotemplate for the ultra-efficient and selective hand-retrieval of glyphosate from agro-farms.

Glyphosate (Gly) is a massively utilized toxic herbicide exceeding its statutory restrictions, causing adverse environmental and health impacts. Engineered nanomaterials, even though are integral to remediate Gly, their practical use is limited due to time and energy driven purifications, and negative environmental impacts. Here, a 3D wide area (~1.

Metal-free synthesis of -sulfonyl imines from benzyl alcohol derivatives and iminoiodinanes mechanochemistry.

An expedient and operationally convenient mechanochemical synthesis of aryl/heteroaryl -sulfonyl imines is reported by reacting iminoiodinanes with numerous aryl/heteroaryl benzyl alcohols in ball milling apparatus (RETSCH 400™) with three 5 mm stainless steel (ss) balls in a 5 mL stainless steel (ss) reaction jar. CHCl ( = 0.2-0.

Theoretical Insights into the Optical and Excited State Properties of Donor-Phenyl Bridge-Acceptor Containing Through-Space Charge Transfer Molecules.

A comparative new strategy to enhance thermally activated delayed fluorescence (TADF) of through-space charge transfer (CT) molecules in organic light-emitting diodes (OLEDs) is investigated. Generally, TADF molecules adopt a twisted donor and acceptor structure to get a sufficiently small Δ and a higher value of the spin-orbit coupling matrix element (SOCME). However, molecules containing donor-phenyl bridge-acceptor (D-p-A) units and featuring π-stacked architectures have intramolecular CT contribution through space and exhibit high TADF efficiency.

Theoretical studies on donor-acceptor based macrocycles for organic solar cell applications.

We have designed a series of new conjugated donor-acceptor-based macrocyclic molecules using state-of-the-art computational methods. An alternating array of donors and acceptor moieties in these macrocycle molecules are considered to tune the electronic and optical properties. The geometrical, electronic, and optical properties of newly designed macrocyclic molecules are fully explored using various DFT methods.

Engineering colloidally stable, highly fluorescent and nontoxic Cu nanoclusters reaction parameter optimization.

Metal nanoclusters (NCs) composed of the least number of atoms (a few to tens) have become very attractive for their emerging properties owing to their ultrasmall size. Preparing copper nanoclusters (Cu NCs) in an aqueous medium with high emission properties, strong colloidal stability, and low toxicity has been a long-standing challenge. Although Cu NCs are earth-abundant and inexpensive, they have been comparatively less explored due to their various limitations, such as ease of surface oxidation, poor colloidal stability, and high toxicity.

Stereoselective Addition of Alkynes to Ketenimines: Copper/Amine Catalyzed Sulfonyl Azide-Alkyne Cycloaddition Reactions for the Synthesis of ()-1,3-Enynes.

Herein, we report a copper/amine catalyzed stereoselective addition of alkynes to ketenimine intermediates generated in situ from the sulfonyl azide-alkyne cycloaddition cascade for the stereoselective synthesis of ()-1,3-enynes. Significantly, for the first-time, enamine intermediates generated in the copper-catalyzed sulfonyl azide-alkyne cycloaddition reactions have been successfully trapped and isolated as the products. Density functional theory computations have also been performed and found to be consistent with the observed experimental stereoselectivity.

Blue LED Mediated Intramolecular C-H Functionalization and Cyclopropanation of Tryptamines: Synthesis of Azepino[4, 5-b]indoles and Natural Product Inspired Polycyclic Indoles.

We report a novel blue LED mediated intramolecular C-H functionalization of tryptamine derivatives to generate azepino[4, 5-b]indoles () in moderate to good yields. By altering the substitution at the tryptamine nitrogen, intramolecular cyclopropanation is achieved in high yields under the same reactions condition to provide natural product inspired polycyclic indoles (), which are further transformed to spiropiperidino ( and ) indoles in decent yields. The mechanism of formation of the compounds was investigated through DFT studies.

Twisted Eigen Can Induce Proton Transfer at a Hydrophobic-Hydrophilic Interface.

The investigation of proton localization at a hydrophobic-hydrophilic interface is an important problem in chemical and materials sciences. In this study, protonated benzene (i.e.

Fused Pyrazine- and Carbazole-Containing Azaacenes: Synthesis and Properties.

A new family of azaacenes has been designed and synthesized by incorporating the electron-withdrawing sp -hybridized nitrogen of pyrazine and electron-donating nitrogen of carbazole in a molecular skeleton. Two different conjugated lengths of 8-ring aza-nonacene and 10-ring aza-undecene have been achieved by an efficient condensation reaction. The unique optoelectronic properties of these molecules were investigated using both experimental and theoretical techniques.

Harnessing Autoxidation of Aldehydes: Iodoarene Catalyzed Synthesis of Substituted 1,3,4-Oxadiazole, in the Presence of Molecular Oxygen.

Isobutyraldehyde underwent auto-oxidation in the presence of molecular oxygen to generate an acyloxy radical under a "metal-free" environment. They were subsequently exploited to afford hypervalent iodines with -anisolyl iodide which generated substituted 1,3,4-oxadiazoles in moderate to excellent yields from '-arylidene acetohydrazides. The reaction strategy tolerated diverse substitution on the hydrazide substrates.

Directing-Group-Assisted Manganese-Catalyzed Cyclopropanation of Indoles.

The first manganese-catalyzed cyclopropanation of indoles is reported in moderate to excellent yield with methyl-2-diazo-2-arylacetates. This new strategy involved acetyl (COCH) as the directing group and exhibited exceptional functional group tolerance. In the absence of stereodirecting groups the desired products were obtained as a mixture of diastereomers (7:3 → 8:2).

Cobalt-Catalyzed, Hydroxyl-Assisted C-H Bond Functionalization: Access to Diversely Substituted Polycyclic Pyrans.

Highly efficient oxidative annulation of alkynes furnished diversely substituted pyran[2,3,4- de]chromene-2-one derivatives and related polycycles in moderate to high yield. The reaction is catalyzed by nontoxic, air-stable, and inexpensive Cp*Co(CO)I catalyst. The hydroxyl moiety at the substrate acts as the directing group for the C-H bond activation.

Synthesis and properties of isoindigo and benzo[1,2-b:4,5-b']bis[b]benzothiophene oligomers.

A well-defined series of long and soluble isoindigo thienoacene oligomers have been synthesized from a novel electron deficient building block: benzo[1,2-b:4,5-b']bis[b]benzothiophene bislactams. Extension of the π-conjugated systems facilitates control of the optical, electronic and device characteristics.

Co-operativity in non-covalent interactions in ternary complexes: a comprehensive electronic structure theory based investigation.

The structure and stability of various ternary complexes in which an extended aromatic system such as coronene interacts with ions/atoms/molecules on opposite faces of the π-electron cloud were investigated using ab initio calculations. By characterizing the nature of the intermolecular interactions using an energy decomposition analysis, it was shown that there is an interplay between various types of interactions and that there are co-operativity effects, particularly when different types of interactions coexist in the same system. Graphical abstract Weak OH-π, π-π and van der Waals-π ternary systems are stabilized through dispersion interactions.

Copper-Catalyzed Ring-Expansion Cascade of Azirines with Alkynes: Synthesis of Multisubstituted Pyridines at Room Temperature.

The first intermolecular ring-expansion cascade of azirines with alkynes for the synthesis of pyridines, enabled by a copper/triethylamine catalytic system via simultaneous generation and utilization of yne-enamine and skipped-yne-imine intermediates, is reported. Experimental as well as computational mechanistic studies revealed that the role of triethylamine is crucial in deciding the reaction pathway toward the pyridine products. This process offers a novel, one-step, direct, and practical strategy for the rapid construction of highly substituted pyridines under exceedingly mild conditions, and an installed alkyne functionality.

Fused electron deficient semiconducting polymers for air stable electron transport.

Conventional semiconducting polymer synthesis typically involves transition metal-mediated coupling reactions that link aromatic units with single bonds along the backbone. Rotation around these bonds contributes to conformational and energetic disorder and therefore potentially limits charge delocalisation, whereas the use of transition metals presents difficulties for sustainability and application in biological environments. Here we show that a simple aldol condensation reaction can prepare polymers where double bonds lock-in a rigid backbone conformation, thus eliminating free rotation along the conjugated backbone.

Charge-Transfer Dynamics in the Lowest Excited State of a Pentacene-Fullerene Complex: Implications for Organic Solar Cells.

We characterize the dynamic nature of the lowest excited state in a pentacene/C complex on the femtosecond time scale, via a combination of ab initio molecular dynamics and time-dependent density functional theory. We analyze the correlations between the molecular vibrations of the complex and the oscillations in the electron-transfer character of its lowest excited state, which point to vibration-induced coherences between the (pentacene-based) local-excitation (LE) state and the complex charge-transfer (CT) state. We discuss the implications of our results on this model system for the exciton-dissociation process in organic solar cells.

High operational and environmental stability of high-mobility conjugated polymer field-effect transistors through the use of molecular additives.

Due to their low-temperature processing properties and inherent mechanical flexibility, conjugated polymer field-effect transistors (FETs) are promising candidates for enabling flexible electronic circuits and displays. Much progress has been made on materials performance; however, there remain significant concerns about operational and environmental stability, particularly in the context of applications that require a very high level of threshold voltage stability, such as active-matrix addressing of organic light-emitting diode displays. Here, we investigate the physical mechanisms behind operational and environmental degradation of high-mobility, p-type polymer FETs and demonstrate an effective route to improve device stability.

Limits for Recombination in a Low Energy Loss Organic Heterojunction.

Donor-acceptor organic solar cells often show high quantum yields for charge collection, but relatively low open-circuit voltages (V) limit power conversion efficiencies to around 12%. We report here the behavior of a system, PIPCP:PCBM, that exhibits very low electronic disorder (Urbach energy less than 27 meV), very high carrier mobilities in the blend (field-effect mobility for holes >10 cm V s), and a very low driving energy for initial charge separation (50 meV). These characteristics should give excellent performance, and indeed, the V is high relative to the donor energy gap.

Impact of Fluorine Substituents on π-Conjugated Polymer Main-Chain Conformations, Packing, and Electronic Couplings.

Taking the π-conjugated polymers PBDT[2X]T (X = H, F) as model systems, the effects of fluorine substitution on main-chain conformations, packing, and electronic couplings are examined. This combination of molecular dynamics simulations and solid-state NMR shows that a higher propensity for backbone planarity in PBDT[2F]T leads to more pronounced, yet staggered, chain stacking, which generally leads to higher electronic couplings and binding energy between neighboring chains.

Ionization Energies, Electron Affinities, and Polarization Energies of Organic Molecular Crystals: Quantitative Estimations from a Polarizable Continuum Model (PCM)-Tuned Range-Separated Density Functional Approach.

We propose a new methodology for the first-principles description of the electronic properties relevant for charge transport in organic molecular crystals. This methodology, which is based on the combination of a nonempirical, optimally tuned range-separated hybrid functional with the polarizable continuum model, is applied to a series of eight representative molecular semiconductor crystals. We show that it provides ionization energies, electron affinities, and transport gaps in very good agreement with experimental values, as well as with the results of many-body perturbation theory within the GW approximation at a fraction of the computational costs.