Understanding the CO capture reaction through electronic structure analysis of four-membered-ring group-13/N- and B/group-15-based Lewis acid-base pairs.

Incomplete combustion yields a significant byproduct, known for its high toxicity to humans: gas phase carbon monoxide (CO). This study utilized several advanced theoretical methods to examine the factors contributing to the activation energy involved in CO capture by a frustrated Lewis pair (FLP) and to forecast the potential success of the CO capture reaction. The current theoretical findings indicate that among the four-membered-ring Group-13/N-FLP and B/Group-15-FLP molecules, only the B/N-based FLP-type molecule effectively captures CO, considering both thermodynamics and kinetics.

Rambutan seed waste-derived nitrogen-doped carbon dots with l-aspartic acid for the sensing of Congo red dye.

In this study, new nitrogen-doped carbon dots (N-CDs) were prepared by utilizing rambutan seed waste and l-aspartic acid as dual precursors (carbon and nitrogen sources) through a hydrothermal treatment method. The N-CDs showed blue emission in solution under UV light irradiation. Their optical and physicochemical properties were examined UV-vis, TEM, FTIR spectroscopy, SEM, DSC, DTA, TGA, XRD, XPS, Raman spectroscopy, and zeta potential analyses.

Aqueous Suzuki couplings mediated by a hydrophobic catalyst.

The catalytic activity of [(PhP--CH)N]PdCl in aerobic aqueous Suzuki couplings is described. Though hydrophobic, this molecular catalyst is competent in cross-coupling reactions of arylboronic acids with a variety of electronically activated, unactivated, and deactivated aryl iodides, bromides, and chlorides upon heating in aqueous solutions under aerobic conditions to give biphenyl derivatives without the necessity of amphiphiles even in the presence of an excess amount of mercury.

Anti-Inflammatory, Antiallergic and COVID-19 Main Protease (M) Inhibitory Activities of Butenolides from a Marine-Derived Fungus .

Amid the current COVID-19 pandemic, the emergence of several variants in a relatively high mutation rate (twice per month) strengthened the importance of finding out a chemical entity that can be potential for developing an effective medicine. In this study, we explored ethyl acetate (EtOAc) extract of a marine-derived fungus afforded three butenolide derivatives, butyrolactones I, VI and V (-), two naphtho--pyrones, TMC-256 A1 () and rubrofusarin B () and methyl -hydroxyphenyl acetate (). Structure identification was unambiguously determined based on exhaustive spectral analyses including 1D/2D NMR and mass spectrometry.

Mechanistic insights into the insertion and addition reactions of group 13 analogues of the six-membered N-heterocyclic carbenes: interplay of electrophilicity, basicity, and aromaticity governing the reactivity.

Three fundamental concepts (aromaticity/basicity/electrophilicity), being heavily used in modern chemistry, have been applied in this work to study the chemical reactivity of six-membered-ring group 13 N-heterocyclic carbenes (G13-6-Rea; G13 = group 13 elements) using density functional theory (BP86-D3(BJ)/def2-TZVP). G13-6-Rea is isolobal to benzene. Two model reactions have been used in the present study: the insertion reaction of G13-6-Rea with methane and the [1 + 2] cycloaddition reaction of G13-6-Rea with ethene.

A novel one-pot synthesis of flavones.

In this paper, a one-pot facile route for the BiCl/RuCl-mediated synthesis of functionalized flavones is described, including: (i) intermolecular -acylation of substituted phenols with cinnamoyl chlorides, and (ii) intramolecular cyclodehydrogenation of the resulting -hydroxychalcones. The reaction conditions are discussed herein.

Phosphorescent MoS quantum dots as a temperature sensor and security ink.

Currently, few phosphorescent materials (PMs) possess a long phosphorescence lasting time and have potential for application in chemical sensors. Herein, we disclose that the incorporation of few-layer molybdenum disulfide quantum dots (FL-MoS QDs) into poly(vinyl alcohol) (PVA) matrices leads to the emission of bright green phosphorescence with a long lasting time of 3.0 s and a phosphorescence quantum yield of 20%.

Physical organic studies and dynamic covalent chemistry of picolyl heterocyclic amino aminals.

A dynamic covalent system of the picolyl heterocyclic amino aminals has been studied. The aminals are characterized as a metastable species and easily switch to other forms external stimuli. The solvent, temperature, acid-base and substituent effects have been examined to evaluate the dynamic covalent system.

In(OTf)-catalyzed intramolecular hydroarylation of α-phenylallyl β-ketosulfones - synthesis of sulfonyl 1-benzosuberones and 1-tetralones.

In(OTf)-catalyzed intramolecular hydroarylation of α-phenylallyl β-ketosulfones provides sulfonyl 1-benzosuberones and 1-tetralones in moderate to good yields in refluxing (CHCl) under open-vessel and easy-operation reaction conditions. A plausible mechanism is proposed and discussed. This highly regioselective protocol provides an atom-economic ring-closure route.

A computational study to determine whether substituents make E[triple bond, length as m-dash]nitrogen (E = B, Al, Ga, In, and Tl) triple bonds synthetically accessible.

This study theoretically determines the effect of substituents on the stability of the triple-bonded L-E[triple bond, length as m-dash]N-L (E = B, Al, Ga, In, and Tl) compound using the M06-2X/Def2-TZVP, B3PW91/Def2-TZVP, and B3LYP/LANL2DZ+dp levels of theory. Five small substituents (F, OH, H, CH and SiH) and four large substituents (SiMe(SiBu), SiPrDis, Tbt ([double bond, length as m-dash] CH-2,4,6-{CH(SiMe)}) and Ar* ([double bond, length as m-dash]CH-2,6-(CH-2,4,6-i-Pr))) are used. Unlike other triply bonded L-E[triple bond, length as m-dash]P-L, L-E[triple bond, length as m-dash]As-L, L-E[triple bond, length as m-dash]Sb-L and L-E[triple bond, length as m-dash]Bi-L molecules that have been studied, the theoretical findings for this study show that both small (but electropositive) ligands and bulky substituents can effectively stabilize the central E[triple bond, length as m-dash]N triple bond.

The mechanistic investigations of photochemical decarbonylations and oxidative addition reactions for M(CO) (M = Fe, Ru, Os) complexes.

The mechanisms for the photochemical CO-dissociation and the oxidative addition reactions are studied theoretically using three model systems: M(CO) (M = Fe, Ru, and Os) and the CASSCF/Def2-SVP (fourteen-electron/ten-orbital active space) and MP2-CAS/Def2-SVP//CASSCF/Def2-SVP methods. The structures of the intersystem crossings and the conical intersections, which play a decisive role in these CO photo-extrusion reactions, are determined. The intermediates and the transition structures in either the singlet or triplet states are also computed, in order to explain the reaction routes.

Corroboration of Zn(ii)-Mg(ii)-tertiary structure interplays essential for the optimal catalysis of a phosphorothiolate thiolesterase ribozyme.

The TW17 ribozyme, a catalytic RNA selected from a pool of artificial RNA, is specific for the Zn-dependent hydrolysis of a phosphorothiolate thiolester bond. Here, we describe the organic synthesis of both guanosine α-thio-monophosphate and the substrates required for selecting and characterizing the TW17 ribozyme, and for deciphering the catalytic mechanism of the ribozyme. By successively substituting the substrate originally conjugated to the RNA pool with structurally modified substrates, we demonstrated that the TW17 ribozyme specifically catalyzes phosphorothiolate thiolester hydrolysis.

A model study on the photodecarbonyl reaction of (η-CH)M(CO) (M = Co, Rh, Ir).

The group 9 organometallic complexes η-CpM(CO) (M = Co, Rh, and Ir) and Si(CH)(H) have been considered as a model system to study their photochemical decarbonyl reactions as well as the Si-H bond activation reactions using the CASSCF and MP2-CAS computational methods. For the cobalt complex, three kinds of reaction pathways, which result in the same oxidative addition product, are investigated. Our theoretical finding demonstrated that after the photoirradiation, η-CpCo(CO) loses one CO ligand without any difficulty to form either the triplet ([η-CpCo(CO)]) or singlet ([η-CpCo(CO)]) species.

The mechanistic investigations of photochemical carbonyl elimination and oxidative addition reactions of (η-CH)M(CO), (M = Mn and Re) complexes.

We used computational methods to explore the mechanisms of the photochemical decarbonylation and the Si-H bond activation reaction of the group 7 organometallic compounds, η-CpM(CO) (M = Mn and Re). The energies of both conical intersections and the intersystem crossings, which play a decisive role in these photo-activation reactions, are determined. Both intermediates and transition states in either the singlet or triplet states are also computed to furnish a mechanistic interpretation of the whole reaction paths.

Photochemical isomerization reactions of acrylonitrile. A mechanistic study.

The mechanisms for the photochemical isomerization reactions are determined theoretically using the acrylonitrile model molecule. The CASSCF (twelve-electron/eleven-orbital active space) and MP2-CAS methods are respectively used with the 6-311G(d,p) and 6-311++G(3df,3pd) basis sets. The structure of the conical intersection that plays a prominent role in the photoisomerization of acrylonitrile is obtained.