In recent work, there has been considerable speculation about the atmospheric reaction of methylenimine (CH₂NH), because this compound is highly reactive, soluble in water, and sticky, thus posing severe experimental challenges. In this work, we have revisited the kinetics of the OH + CH₂NH reaction assisted by a single water molecule. The potential energy surfaces (PESs) for the water-assisted OH + CH₂NH reaction were calculated using the CCSD(T)//BH&HLYP/aug-cc-pVTZ levels of theory. The rate coefficients for the bimolecular reaction pathways CH₂NH⋯H₂O + OH and CH₂NH + H₂O⋯HO were computed using canonical variational transition state theory (CVT) with small curvature tunneling correction. The reaction without water has four elementary reaction pathways, depending on how the hydroxyl radical approaches CH₂NH. In all cases, the reaction begins with the formation of a single pre-reactive complex before producing abstraction and addition products. When water is added, the products of the reaction do not change, and the reaction becomes quite complex, yielding four different pre-reactive complexes and eight reaction pathways. The calculated rate coefficient for the OH + CH₂NH (water-free) reaction at 300 K is 1.7 × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ and for OH + CH₂NH (water-assisted), it is 5.1 × 10⁻¹⁴ cm³ molecule⁻¹ s⁻¹. This result is similar to the isoelectronic analogous reaction OH + CH₂O (water-assisted). In general, the effective rate coefficients of the water-assisted reaction are 2∼3 orders of magnitude smaller than water-free. Our results show that the water-assisted OH + CH₂NH reaction cannot accelerate the reaction because the dominated water-assisted process depends parametrically on water concentration. As a result, the overall reaction rate coefficients are smaller.

In this work, we used quantum chemical methods and chemical kinetic models to answer the question of whether or not formaldehyde (CH₂O) and ammonia (NH₃) can be produced from gas phase hydration of methylenimine (CH₂NH). The potential energy surfaces (PESs) of CH₂NH + H₂O → CH₂O + NH₃ and CH₂NH + 2H₂O → CH₂O + NH₃ + H₂O reactions were computed using CCSD(T)/6–311++G(3d,3pd)//M06-2X/6–311++G(3d,3pd) level. The temperature-and pressure-dependent rate constants were calculated using variational transition state theory (VTST), microcanonical variational transition state theory $$(\mu VTST)$$(μVTST) and Rice–Ramsperger–Kassel–Marcus/master equation (RRKM/ME) simulations. The PES along the reaction path forming a weakly bound complex (CH₂NH⋯H₂O) was located using VTST and $$\mu$$μ VTST, however, the PES along the tight transition state was characterized by VTST with small curvature tunneling (SCT) approach. The results show that the formation of CH₂NH + H₂O → CH₂NH⋯H₂O is pressure -and temperature-dependent. The calculated atmospheric lifetimes of CH₂NH⋯H₂O (~ 8 min) are too short to undergo secondary bimolecular reactions with other atmospheric species. Our results suggest that the formation of CH₂O and NH₃ likely to occur in the combustion of biomass burning but the rate of formation CH₂O and NH₃ is predicted to be negligible under atmospheric conditions. When a second water molecule is added to the reaction, the results suggest that the rates of formation of CH₂O and NH₃ remain negligible.

Microbial resistance to antibiotics is an urgent and worldwide concern. Several pyrazole-derived hydrazones were synthesized by using benign reaction conditions. Several of these molecules are potent growth inhibitors of drug-resistant strains of Staphylococcus aureus and Acinetobacter baumannii with minimum inhibitory concentration values as low as 0.39 μg/mL. Furthermore, these molecules are nontoxic to human cells at high concentrations. Some of these molecules were tested for their ability to disrupt the bacterial membrane by using the SYTO-9/propidium iodide (BacLight) assay.

The lower charge mobility of organic semiconductors relative to that of inorganic semiconductors is a thorny problem that still has not been resolved. Here, a new type of arrangement of grid-shaped organic semiconductors with extremely low values of internal reorganization energies (IREs) for both hole (0.056 eV) and electron (0.078 eV) transfer processes has been designed and investigated by density functional theory (DFT) calculations. The structural, thermodynamic and electronic properties of grid spirofluorene (GSF) consisting of four spirobifluorenes have been discussed thoroughly. Our analyses of these unique grid structures indicate that they possess a stringent structure and very weak ring strain energy, and may be easily synthesized in the laboratory. Interestingly, GSF1, GSF2, and GSF9 possess both small hole and lower electron transfer reorganization energies (<0.1 eV), which may originate from their rigid molecular structures. The large π conjugated system in which all of the frontier molecular orbitals are homogeneously delocalized over the entire molecules is another important characteristic of these GSFs. This work reveals that the gridization method is a novel strategy for obtaining materials with low hole and electron transfer reorganization energies.

The gas phase reaction between CH ₂ O and NH ₃ is an important reaction in cold interstellar clouds, combustion chemistry and organic chemistry.