From Delocalization to Disruption: The Role of Aromaticity in -Heterocyclic Carbenes' Reactions with Diazoalkane and Diazoester.

Aromaticity is a fundamental force shaping molecular stability and reactivity, yet its dynamic role along reaction coordinates remains poorly understood. In this study, we unveil how dynamic changes in aromatic character govern the reactivity of 5-ItBu with diazoalkanes and diazoesters through a multifaceted computational approach. By integrating electronic, magnetic, structural, and energetic aromaticity descriptors, we demonstrate that the retention of aromaticity along the reaction path markedly lowers activation barriers, while its disruption imposes significant energetic penalties.

The critical helping hand of water: theory shows the way to obtain elusive, granular information about kinetic asymmetry driven systems.

Kinetic asymmetry is crucial in chemical systems where the selective synthesis of one product over another, or the acceleration of specific reaction(s) is necessary. However, obtaining precise information with current experimental methods about the behavior of such systems as a function of time, substrate concentration and other relevant factors, is not possible. Computational chemistry provides a powerful means to address this problem.

Unified Photoredox-Catalyzed Aerobic Oxidative Dynamic Kinetic Asymmetric Transformation for C-N Atropoisomers Mediated by Chiral Organophosphites.

The synthesis of anilides with a chiral C(═O)-N axis has relied on direct installation of the chiral C(sp)-N(sp) bond or enantioselective modification of the peripheral groups. However, these methods are constrained by the size and type of functional groups compatible with each strategy. Herein, we report a dynamic kinetic asymmetric transformation (DYKAT) for the aerobic oxidation of iminium ions to access C(═O)-N axial chirality that addresses those limitations.

Pushing the Boundaries of Pnictogen-Bonding Organocatalysis: A Clash of Sb(III) versus Bi(III).

The σ-hole-mediated noncovalent organocatalysis involving the pnictogen (Pn) elements has thus far been explored mostly from nitrogen to antimony, with antimony identified as the most effective catalyst. Herein, density functional theory calculations have been carried out to demonstrate that tri-aryl (Ar)-substituted bismuth(III) complexes can outperform their antimony counterparts in both anion (Cl) binding and catalytic activity. Using a range of computational methods, a good correlation between the σ-hole strength, chloride binding affinity, and the reaction barrier is established.

Magnesium-Catalyzed Primary, Secondary, and Tertiary Amide Hydroboration.

Catalytic hydroboration of amides is highly important because the resultant amines are commonly found in natural products, pharmaceuticals, agrochemicals, dyes, and other applications. In comparison to the conventional reduction of amides using (over)stoichiometric reductants, hydroboration of amides using magnesium compounds represents a green and sustainable approach because magnesium is both Earth abundant and environmentally benign. However, there is only one report on magnesium-catalyzed deoxygenative hydroboration of secondary and tertiary amides.

Manganese(I)-catalyzed dehydrogenative borylation of terminal alkynes.

Compounds containing carbon-boron bonds serve as valuable intermediates for constructing more complex molecules by transforming these bonds into other carbon-element bonds. The catalytic dehydrogenative borylation of carbon-hydrogen bonds using HBpin presents an appealing method for synthesizing carbon-boron bonds. While this approach has been extensively explored with noble metals for various types of carbon-hydrogen bonds, its application with manganese-based catalysts remains rare.

Correction: Uncovering diverse reactivity of NHCs with diazoalkane: C-H activation, C[double bond, length as m-dash]C bond formation, and access to N-heterocyclic methylenehydrazine.

[This corrects the article DOI: 10.1039/D4SC05740F.].

Palladium(II)-Catalyzed Desymmetrization of 2-Alkynylbenzoate-Tethered Cyclohexadienones for the Synthesis of Polycyclic Compounds.

Pd-catalyzed cascade cyclization of 2-alkynylbenzoate-tethered cyclohexadienone was developed for the single step synthesis of isocoumarin-fused dihydrochromenones. This highly atom economical method proceeds via 6- cyclization of -butyl benzoate with a tethered alkyne. By modulating the reaction solvent and metal catalyst, the methodology was diverted for the purposeful synthesis of either of the tetra-substituted alkenes.

Unlocking Thermodynamic Enolate for Kinetically Controlled Desymmetrizing Vinylogous (4+1) Carbospiroannulation.

An unprecedented thermodynamically unfavorable (4+1) deysmmetrizing spiroannulation through a thermodynamic enolate intermediate, enabling a single-step synthesis of ubiquitous scaffolds such as all-carbon chiral spirocycles, is disclosed. In this spiroannulation, we present a vinylogous organocatalytic enantioselective desymmetrizing (4+1) cycloaddition approach involving alkylidene malononitrile and cyclopent-1,3-dienone. This carbospiroannulation method produces functionally enriched spiro[4,4]nonane structures with three stereocenters, has presented good-to-high yields and enantiomeric ratios.

Investigating the visible range photoresponse of an organic single-crystal analogue of the green fluorescent protein.

The growing demand for lightweight, flexible, semi-transparent and low-cost photodetectors (PDs) in wearable electronics and optical communication systems has prompted studies to investigate organic materials as feasible alternatives to conventional inorganic PDs. However, modern organic PDs often face responsivity, detectivity, and photoresponse speed limitations, particularly in the visible range. Here, we present the photoresponse of an organic single-crystal analogue of the green fluorescent protein (GFP) chromophore photodetector, fabricated on a silicon nitride substrate.

Ce[N(SiMe)](THF)-Catalyzed Hydroboration of CO, Esters and Epoxides with Pinacolborane: Selective Synthesis of Methanol in Multigram Scale.

In this work, we have reduced CO with HBpin to afford borylated methanol product selectively in ~99 % yield using Ce[N(SiMe)](THF) as a catalyst. This led to multigram scale isolation of methanol obtained from CO reduction via the hydrolysis of borylated methanol, this establishes the potential of Ce[N(SiMe)](THF) as an efficient homogeneous catalyst for the bulk scale methanol synthesis. A practical application of this catalytic system was also shown by reducing CO-containing motorbike exhaust efficiently and selectively.

Studies on the Stereoselective Synthesis of Sacubitril via a Chiral Amine Transfer Approach.

We present a comprehensive account of our efforts directed towards the synthesis of sacubitril, a neprilysin inhibitor used in combination with valsartan and marketed as Entresto™. Our initial approach to the formal synthesis of sacubitril employed a chiral pool strategy, utilizing (S)-pyroglutamic acid as a key building block and Cu(I)-mediated Csp-Csp cross-coupling as a key transformation. Further investigations led to the development of chiral amine transfer (CAT) reagents-based stereoselective synthesis.

A Pair of Dinuclear Fe(II) Enantiomers: Syntheses and Structures of ΛΔ/ΔΛ-Bis(Dihydridoborate) Complexes.

In our effort to establish a direct synthetic approach for bis(dihydridoborate) complexes of first-row transition metals, we have investigated the reactivity of [Cp*Fe(dppe)Cl] (dppe =1,2-bis(diphenylphosphino)ethane) with Na[BHL] (L =2-mercaptopyridine (mp) and 2-mercaptobenzothiazole (mbz)) that led to the formation of iron(II) dihydridoborate complexes, [Cp*Fe{κ-S,H,H-(HBH(L))}] 1 a-b (L=mp (1 a) and L=mbz (1 b)). Further, in an attempt to isolate the bis(dihydridoborate) complex of iron by the insertion of borane into the κ-N,S-chelated iron complex, [(dppe)Fe{κ-N,S-(mp)}] (2), we have isolated and structurally characterized a rare example of dimeric iron bis(dihydridoborate) complex, [Fe{κ-S,H,H-(HBH(mp))}], ΛΔ/ΔΛ-3 as pair of enantiomers. Interestingly, these enantiomers ΛΔ/ΔΛ-3 have two trans-[Fe{κ-S,H,H-(HBH(mp))}] moieties bridged through sulfur atoms of 2-mercaptopyridinyl ligands, where the iron centres are hepta-coordinated.

Unprecedented C-F bond cleavage in perfluoronaphthalene during cobaltocene reduction.

The C-F bond activation of perfluoronaphthalene by 5-SIDipp led to the formation of dicationic salts with two fluorides (3·2HF2 ) or heptafluorodiborate (3·2B2F7) as counter-anions. The anion exchange reaction of 3·2B2F7 with NBuPF afforded a highly luminescent 3·2PF6. The addition of cobaltocene in the reaction mixture of 5-SIDipp and perfluoronaphthalene led to a distinct Co(I) species.

Uncovering diverse reactivity of NHCs with diazoalkane: C-H activation, C[double bond, length as m-dash]C bond formation, and access to N-heterocyclic methylenehydrazine.

N-heterocyclic carbenes (NHCs) have attracted significant attention due to their strong σ-donating capabilities, as well as their transition-metal-like reactivity towards small molecules. However, their interaction with diazoalkanes remains understudied. In this manuscript, we explore the reactivity of a series of stable carbenes, encompassing a wide range of electronic properties, with MeSiCHN.

Rational Monomer Design for the Synthesis of Conjugated Polymers by Direct Heteroarylation Polymerization.

This study focuses on the design concepts that contribute to the C-H activation in bithiophene-flanked monomers incorporating naphthalene diimide (NDI), perylene diimide (PDI), and fluorene (FLU) and their polymerization by direct heteroarylation. Density functional theory (DFT) calculations reveal distinct energy requirements for C-H bond abstraction, which is dictated by the electron-withdrawing strength of the central aromatic core flanked by bithiophene. These provide insights into the reactivity of each monomer for C-H bond activation.

Germylene Mediated Reductive C-C and C-N Coupling of an Isocyanide and its Device Application.

We have demonstrated a unique reductive coupling of 4-iodophenyl isocyanide, facilitated by a perimidine-based N-heterocyclic germylene (NHGe), which yields a bis-spirogerma compound featuring simultaneous C-C and C-N bond formation. This reaction, which leads to the oxidation of germanium from +2 to +4, represents a significant departure from previously documented isocyanide-germylene interactions. The product exhibits extensive conjugation across its bicyclic CGeN framework, conferring distinct photophysical properties, including prominent orange luminescence in both solution and solid states.

Depolymerization of Waste Polycarbonates to Value-Added Products.

Additive free aminolysis method developed for the depolymerization/upcycling of polycarbonates. We report here chemical recycling of polycarbonate under ambient conditions to get its monomer bisphenol A, monoaminocarbamate and biscarbamates in 1 : 2 : 1 ratio respectively. By employing the secondary amine as the aminating reagent, facilitates the depolymerization to work under additive/catalyst free conditions.

Unveiling the Inverse Sandwich Complexes of XeO: A Computational Exploration.

Our study introduces the design of inverse sandwich (iSw) complexes incorporating a noble gas compound: xenon trioxide (XeO). Through comprehensive computational analyses, we have investigated the critical factors influencing their stability by employing a variety of state-of-the-art computational tools. We demonstrated that the coordination number of xenon in the iSw complex of XeO with 18-crown-6 is influenced by the presence of a rare, weakly stabilizing Xe···Xe interaction between the XeO molecules.

Taming XeO with Aza-Crowns: Computational Studies into σ-Hole Mediated Host-Guest Interactions.

Various aza-crowns with different sizes and substituents have been explored computationally as potential hosts for stabilizing the explosive guest xenon trioxide (XeO) through σ-hole-mediated aerogen bonding interactions. Interestingly, aza-crowns demonstrate superior binding towards XeO compared to their oxygen and thio counterparts. However, unlike the latter cases, where the binding was found to be increasingly favorable with the increase in the size of the crowns, aza-crowns exhibit a variable size preference for XeO, peaking with aza-15-crown-5, and reducing thereafter with increase in crown size.

Brønsted Acid-Promoted Cyclodimerization of α,β-Unsaturated γ-Ketoesters: Construction of Fused Pyrano-ketal-lactones and γ-Ylidene-butenolides.

Unprecedented MsOH-promoted diastereoselective cascade dimerization and intramolecular lactonization of readily accessible α,β-unsaturated γ-ketoesters are presented. The results obtained in this work, control experiments, and density functional theory (DFT) calculations suggested that the initial enolization and to isomerization/equilibration of olefin (C=C) of substrate α,β-unsaturated γ-ketoesters give a -isomer preferentially over an -isomer. Subsequently, the -isomer undergoes intermolecular annulation with α,β-unsaturated γ-ketoesters via domino Michael addition/ketalization/lactonization steps to furnish fused tetracyclic pyrano-ketal-lactone.

Effect of Position of Donor Units and Alkyl Groups on Dye-Sensitized Solar Cell Device Performance: Indoline-Aniline Donor-Based Visible Light Active Unsymmetrical Squaraine Dyes.

Indoline (In) and aniline (An) donor-based visible light active unsymmetrical squaraine (SQ) dyes were synthesized for dye-sensitized solar cells (DSSCs), where the position of An and In units was changed with respect to the anchoring group (carboxylic acid) to have In-SQ-An-COH and An-SQ-In-COH sensitizers, . Linear or branched alkyl groups were functionalized with the N atom of either In or An units to control the aggregation of the dyes on TiO. exhibit an isomeric π-framework where the squaric acid unit is placed in the middle, where and dyes possess the anchoring group connected with the An donor, and , , and dyes having the anchoring group connected with the In donor.

Size Matters: Computational Insights into the Crowning of Noble Gas Trioxides.

In pursuit of enhancing the stability of the highly explosive and shock-sensitive compound XeO, we performed quantum chemical calculations to investigate its possible complexation with electron-rich crown ethers, including 9-crown-3, 12-crown-4, 15-crown-5, 18-crown-6, and 21-crown-7, as well as their thio analogues. Furthermore, we expanded our study to other noble gas trioxides (NgO), namely, KrO and ArO. The basis set superposition error (BSSE) corrected interaction energies for these adducts range from -13.

Far-red active unsymmetrical squaraine dyes containing N-arylated indoline donors for dye sensitized solar cells.

Squaraine dyes possess sharp far-red active transition with high extinction coefficient and form aggregates on TiO surface. Aggregation of dyes on TiO has been considered as a detrimental factor for DSSC device performance, which can be controlled by appending alkyl groups to the dye structures. Hence by integrating alkylated (alkyl groups with both in-plane and out-of-plane) aryl group with indoline moiety to make it compatible with other electrolytes and for controlling the dye-aggregation, a series of squaraine acceptor-based dyes SQA4-6 have been designed and synthesized.