Implicating the Role of Au-H Bonds in Photochemical N Fixation by Ruthenium-Doped Gold Clusters.

Dinitrogen fixation through the Nitrogen Reduction Reaction (NRR) under mild conditions without the use of sacrificial agents has its share of formidable hurdles. It has been shown recently that Ru-doped Au nanoclusters can reduce N molecules to NH only in the presence of UV-Vis light in aqueous medium. Herein, using theoretical techniques (Density Functional Theory), we shed light on the mechanistic avenues traversed to achieve this prodigious chemical feat.

Phosphite mediated molecular editing switch to -C-H alkylation of isoquinolines: emergence of a distinct photochemical [1,3] N to C rearrangement.

The isoquinoline core is present in one of the largest subsets of bioactive natural products. The multifunctional isoquinoline core exerts diverse bioactivity, resulting in the development of numerous isoquinoline-based drugs and molecules that are currently under clinical trials. We developed a new approach for phosphite-mediated [1,2] alkyl migration for an overall -C-H alkylation -alkylation of isoquinoline.

Insight into the MOBu (M=Na, K)-Mediated Dehydrogenation of Dimethylamine-Borane and Transfer Hydrogenation of Nitriles to Primary Amines.

Selective synthesis of primary amines from nitriles is challenging in synthetic chemistry due to the possible en-route generation of various amines and imines. Herein, we report a practical and operationally simple MOBu-mediated (M=Na, K) transfer hydrogenation of nitriles to the corresponding primary amines with a relatively unexplored sacrificial hydrogen source (dimethylamine borane). The strategy encompasses a broad substrate scope under transition metal-free conditions and does not require any solvent.

Photocatalytic Synthesis of β-Keto Primary Chlorides by Selective Chlorocarbonylation of Olefins.

Functionalized primary alkyl chlorides are precursors to a plethora of scaffolds but their access from chemical feedstocks remains challenging. Herein, we report a concise dual Ni/photoredox catalytic protocol for regioselective chlorocarbonylation of unactivated alkenes that enables rapid access to β-keto primary chlorides. The catalytic process features an extensive substrate scope, scalability and functional group tolerance.

Enantioselective Amination of 3-Substituted-2-benzofuranones via Non-covalent N-Heterocyclic Carbene Catalysis.

Herein, an efficient method for asymmetric α-amination of 2-benzofuranones with N-heterocyclic carbene (NHC) catalysis is reported. The process is based on non-covalent interaction of NHC with substrate, facilitating the formation of a chiral ion-pair that encompasses enolate and azolium salt. The activated enolate adds to an electrophilic amine source with sufficient facial control to furnish an enantioenriched product having an amine substituted quaternary stereocenter.

Eliminating all bonds from the ground state gives rise to ionic bonding in high-spin states of heterodiatomics.

Understanding chemical bonding in second-row diatomics has been central to elucidating the basics of bonding itself. Bond strength and the number of bonds are the two factors that decide the reactivity of molecules. While bond strengths have been theoretically computed accurately and experimentally determined, the number of bonds is a more contentious issue, especially for complicated multi-reference systems like C.

Curious Behavior of Fe-As Chemical Interactions and Nucleation of Clusters in Aqueous Medium.

The simultaneous presence of Fe and As ions in groundwater (higher ppb or lower ppm level concentrations at circumneutral pH) as well as in acid mine drainages (AMDs)/industrial wastewater (up to few thousand ppm concentration at strongly acidic pH) are quite common. Therefore, understanding the chemical interactions prevalent between Fe and As ions in aqueous medium leading to nucleation of ionic clusters/solids, followed by aggregation and growth, is of great environmental significance. In the present work, we attempt to probe the nucleation process of Fe-As clusters in solutions of various concentrations and pHs (from AMD to groundwater-like) using a combination of experimental and theoretical techniques.

Inept N Activation of Tri-Nuclear Nickel Complex with Labile Sulfur Ligands Facilitates Selective N H Formation in Electrocatalytic Conversion of N.

Conversion of N to the energy vector N H under benign conditions is highly desirable. However, such N fixation processes are extremely rare. It has been recently reported that N to N H conversion can be achieved electrochemically by using a trinuclear [Ni (S C H ) ] complex (named as [Ni S ] ).

Metal-Ligand Cooperativity in Mn -Catalysed N-Formylation of Secondary Amides and Lactams Using CO at Room Temperature.

A Mn catalyst featuring redox-active tridentate phenalenyl (PLY) ligand has been used for catalytic N-formylation of secondary amides and lactams under 1 atm CO as a C source at room temperature for the first time. The protocol is applicable to a wide range of secondary amides including heterocycles, bio-active cinnamide derivatives and the diversification of therapeutic molecules. In-depth mechanistic investigations based on experimental outcomes and DFT calculations suggested an unconventional metal-ligand cooperation, where a ligand-centred radical plays a crucial role in initiating the reaction process.

Impact of the Hydrogen-Bonding Functional Group on Hydrogelation of Amphiphilic Naphthalene-diimide Derivatives and Nonspecific Protein Adsorption.

This manuscript reports the effect of hydrogen-bonding functionality on the supramolecular assembly of naphthalene-diimide (NDI)-derived amphiphilic building blocks in water. All the molecules contain a central NDI chromophore, functionalized with a hydrophilic oligo-oxyethylene (OE) wedge in one arm and a phenyl group on the opposite arm. They differ by a single H-bonding functionality, which links the NDI chromophore and the phenyl moiety.

Room-Temperature Synthesis of 1,3,5-Tri()aryl Benzene from Nitroalkenes Using Pd(OAc): Complete Mechanistic and Theoretical Studies.

Herein, a room-temperature catalytic pathway for 1,3,5-tri()aryl derivatives from nitroalkenes using simple Pd(OAc) is presented. This newly developed C-C bond-forming methodology takes place in a cascade manner with the initial pallado-Morita-Baylis-Hillman (MBH) type adduct. The broad substrate scopes, functional group tolerance, and different aryl-substituted benzene derivatives make this methodology more attractive.

Metal-Thiolate Framework for Electrochemical and Photoelectrochemical Hydrogen Generation.

Hydrogen has evolved as the cleanest and most sustainable fuel, produced directly from naturally abundant water resources. Generation of hydrogen by electrochemical or photoelectrochemical splitting of water has been conceived as the most effective method for hydrogen production. Herein, a robust solid metal-thiolate framework (MTF-1) was obtained by hydrothermal crystallization of the reaction mixture consisting of 1,3,5-triazine-2,4,6-trithioltrisodium salt and Cu under mild synthesis conditions.

The Role of Copper Salts and O in the Mechanism of C≡N Bond Activation for Facilitating Nitrogen Transfer Reactions.

C≡N bond scission can be a potential avenue for the functionalization of chemical bonds. We have conducted a computational study, using density functional theory (DFT) and ab initio multireference CASSCF methods, to unravel the intricate mechanistic pathways traversed in the copper-promoted, dioxygen-assisted reaction for the formation of aryl isocyanate species from aryl aldehyde. This aryl isocyanate species acts as an active species for C≡N bond cleavage of coordinated cyanide anion enabling nitrogen transfer to various aldehydes.

The curious saga of dehydrogenation/hydrogenation for chemical hydrogen storage: a mechanistic perspective.

Hydrogen storage is an indispensable component of hydrogen-based fuel economy. Chemical hydrogen storage relies on the development of lightweight compounds which can deliver high weight percentage of H at moderate temperatures through dehydrogenation and can be recovered from the dehydrogenated mass by hydrogenation for reuse. In this feature article we primarily discuss the mechanistic underpinnings of the catalytic dehydrogenation of ammonia-borane, a potential candidate for hydrogen storage and the challenges associated with its regeneration from the dehydrogenated mass.

Reduced graphene oxide (rGO) aerogel: Efficient adsorbent for the elimination of antimony (III) and (V) from wastewater.

3D porous, thin sheet-like rGO aerogel was fabricated to explore its antimony (Sb) removal potential from wastewater. Langmuir isothermal and pseudo-second-order kinetic model best-suited the adsorption process. The maximum adsorption capacities were 168.

Unraveling the stability of cyclobutadiene complexes using aromaticity markers.

Cyclobutadiene (CBD) is the paradigmatic antiaromatic molecule but is known to form highly stable aromatic complexes, e.g. CBD-Fe(CO)3.

Externally Regulated Specific Molecular Recognition Driven Pathway Selectivity in Supramolecular Polymerization.

This article reveals 4-dimethylaminopyridine (DMAP) regulated pathway selectivity in the supramolecular polymerization of a naphthalene-diimide derivative (NDI-1), appended with a carboxylic acid group. In decane, NDI-1 produces ill-defined aggregate (Agg-1) due to different H-bonding motifs of the -COOH group. With one mole equivalent DMAP, the NDI-1/DMAP complex introduces new nucleation condition and exhibits a cooperative supramolecular polymerization producing J-aggregated fibrillar nanostructure (Agg-2).

Comprehending the quadruple bonding conundrum in C from excited state potential energy curves.

The question of quadruple bonding in C has emerged as a hot button issue, with opinions sharply divided between the practitioners of Valence Bond (VB) and Molecular Orbital (MO) theory. Here, we have systematically studied the Potential Energy Curves (PECs) of low lying high spin sigma states of C, N, Be and HC[triple bond, length as m-dash]CH using several MO based techniques such as CASSCF, RASSCF and MRCI. The analyses of the PECs for the Σ (with 2 + 1 = 1, 3, 5, 7, 9) states of C and comparisons with those of relevant dimers and the respective wavefunctions were conducted.

Understanding the Role of Aromaticity and Conformational Changes in Bond Dissociation Processes of Photo-Protecting Groups.

Photoremovable protecting groups (PPGs) provide spatial and temporal control over the release of various chemicals. Using surface hopping studies with multireference electronic structure methods we have unravelled the nuclear and the electronic events at play. Furthermore, the electronic changes along the reaction path were probed using excited state aromaticity quantifiers and orbital analysis.

Frustrated Lewis Acid-Base-Pair-Catalyzed Amine-Borane Dehydrogenation.

Metal-free catalysis by sterically encumbered Lewis Acid-Base pairs, popularly known as frustrated Lewis pairs (), is gaining importance by the day due to its promise of providing a greener alternative to transition-metal-based catalysis. One of the stumbling blocks in achieving catalytic dehydrogenation of amine-boranes is catalyst deactivation by the reaction product. Herein, we have theoretically investigated the routes of a dimethylxanthene-derived B,P--catalyzed dehydrogenation of dimethylamine-borane , a rare instance which avoids catalyst inhibition by the reaction product.

Understanding the Role of Solvents and Spin-Orbit Coupling in an Oxygen-Assisted S 2-Type Oxidative Transmetalation Reaction.

The aerial oxidation of Pd to Pd has emerged as an integral component of sustainable catalytic C-H functionalization processes. However, a proper understanding of the factors that control the viability of this oxidative process remains elusive. An investigation of the intricate mechanism of the transmetalation reaction of the aerial oxidative transformation of [(Me tacn)Pd Me ] (Me tacn=N,N',N''-trimethyl-1,4,7-triazacyclononane) to [(Me tacn)Pd Me ] has been conducted by using DFT, along with multireference methods, such as second-order n-electron valence-state perturbation theory (NEVPT2) with complete active space self-consistent field theory (CASSCF).

Unraveling the Microscopic Origin of Triplet Lasing from Organic Solids.

We present a heuristic mechanism for the origin of the unusual triplet lasing from (E)-3-(((4-nitrophenyl)imino)methyl)-2H-thiochroman-4-olate·BF.We demonstrate that whereas the moderate lifetime (1.03 μs) of the first triplet state (T) prohibits triplet-triplet annihilation, the relatively faster S → T intersystem crossing and the 10 times smaller reverse intersystem crossing effectively help achieve population inversion in the T state.

Mono- and dinuclear oxidovanadium(v) complexes of an amine-bis(phenolate) ligand with bromo-peroxidase activities: synthesis, characterization, catalytic, kinetic and computational studies.

The mono- and dinuclear oxidovanadium(v) complexes [VO(L)(Cl)] (1) and [LVO(μ-O)VO(L)] (2) of ONNO donor amine-bis(phenolate) ligand (HL) were readily synthesized by the reaction between HL and VCl.(THF) or VO(acac) in MeOH or MeCN, respectively, and then characterized through mass spectroscopy, H-NMR and FTIR techniques. Both the complexes possess distorted octahedral geometry around each V centre.

Understanding the Unexpected Product Distribution in the Aerial Oxidation of Carbene-Stabilized Diphosphorus Complex.

Oxidation of nonmetallic singlet molecules by oxygen has its own share of intricacies. Herein, by means of DFT and ab initio techniques, mechanistic details of the aerial oxidation of an N-heterocyclic carbene (NHC) stabilized diphosphorus complex are revealed. This particular oxidation process is known to produce an unexpected P-P bond containing diphosphorus tetroxide complex, instead of the more thermodynamically stable oxo-bridged (P-O-P) compound.