Esketamine-A quick-acting novel antidepressant without the disadvantages of ketamine.

Esketamine, which is an S-enantiomer of ketamine, is better than conventional antidepressants and even better than R-ketamine. This article discusses the mechanism of action of Esketamine, how different it is from other antidepressants, its side effect profile, indications for use, various routes of administration and the review of existing literature on Esketamine.

Choline chloride-based deep eutectic solvents as effective electrolytes for dye-sensitized solar cells.

Electrolytes for dye-sensitized solar cells remain a challenge for large-scale production and commercialization, hindering the wide application of solar cells. We have developed two new electrolyte-based deep eutectic solvents using a mixture of choline chloride with urea and with ethylene glycol for dye-sensitized solar cells. The prominent features of the two deep eutectic solvent electrolytes are simple preparation for large-scale production with inexpensive, available, and nontoxic starting materials and biodegradability.

Cultural and Structural Humility and Addressing Systems of Care Disparities in Mental Health Services for Black, Indigenous, and People of Color Youth.

This article draws into focus the role of cultural and structural humility in shaping a mental health system that can address the mental health disparities for BIPOC youths. In an era of growing diversity in the United States population and a calling out of racism and discrimination on an interpersonal and systemic level, the commitment to a lifelong engagement of cultural awareness and an openness to reflect and critique, is whereby mutual partnerships between professionals, patients, and clinician themselves can strengthen. This hallmark tenet of cultural humility is actively being adopted into community programs and academic health care institutions as ways to improve the mental health understanding and needs of BIPOC youths.

Double Fence Porphyrins that are Compatible with Cobalt(II/III) Electrolyte for High-Efficiency Dye-Sensitized Solar Cells.

A series of new double fence porphyrin dyes bJS1-bJS3, with eight long alkoxyl chains attached to four β-phenyl groups, have been designed and synthesized. The single fence meso-substituted counterparts mJS1-mJS3 were also prepared as reference dyes. Dyes bJS1-bJS3 and mJS1-mJS3 exhibit power conversion efficiencies of 8.

-Butylpyridine Coordination with [Cu(dmp)] Redox Couple and Its Connection to the Stability of the Dye-Sensitized Solar Cell.

Cu(I)/(II) complex redox couples in dye-sensitized solar cell (DSSC) are of particular interest because of their low reorganization energy between Cu(I) and Cu(II), which minimizes the potential loss during sensitizer regeneration, thus allowing the open-circuit voltage of the device to go over 1.0 V. However, Cu(I)/(II)-based redox couples are reported to coordinate with 4--butylpyridine (TBP), which is a standard additive in the electrolyte, and this is believed to account for the poor durability of a Cu(I)/(II)-based DSSCs.

1-Alkenyl-3-methylimidazolium trifluoromethanesulfonate ionic liquids: novel and low-viscosity ionic liquid electrolytes for dye-sensitized solar cells.

Dye-sensitized Solar Cells (DSCs) based on ruthenium complex N719 as sensitizer have received much attention due to their affordability and high efficiency. However, their best performance is only achieved when using volatile organic solvents as electrolyte solutions, which are unstable under prolonged thermal stress. Thus, we developed a new series of 1-alkenyl-3-methylimidazolium trifluoromethanesulfonate ionic liquids used as robust DSC electrolytes.

The photolysis of α-hydroperoxycarbonyls.

In this work, we theoretically elucidated the mechanism and predicted the major products of the photolysis of α-hydroperoxycarbonyls, known to be products of the atmospheric oxidation of biogenic volatile organic compounds (BVOC) and components of secondary organic aerosol (SOA) in rural and remote areas. Using 2-hydroperoxypropanal OCHCH(OOH)CH as a model compound, we show that the likely major photolysis mechanism is a fast 1,5 H-shift in the initially excited singlet S state followed by spontaneous elimination of singlet oxygen to yield an enol HOCH[double bond, length as m-dash]CHCH, while intersystem crossing (ISC) to the triplet T state and C-C scission into HC˙O + HOOC˙HCH followed by expulsion of a hydroxyl radical from the unstable HOOC˙HCH is another product channel. The direct S reaction was found to occur at such a high rate that the quantum yield in atmospheric conditions is expected to approach unity.

Theoretically derived mechanisms of HPALD photolysis in isoprene oxidation.

In this work we identified and theoretically quantified two photolysis mechanisms of HPALDs (hydroperoxy aldehydes) that result from the isomerization of peroxy radicals in the atmospheric oxidation of isoprene at low/moderate NO. As a first photolysis mechanism, we show that a fraction of the initially excited S-state HPALDs isomerizes by a near-barrierless 1,5 H-shift at a rate approaching 10 s - competing with the ∼equally fast intersystem crossing to the T triplet state - forming an unstable biradical that spontaneously expels an OH (hydroxyl) radical. A second mechanism is shown to proceed through the activated T triplet biradical - formed from S - undergoing a concerted ring-closure and OH-expulsion, yielding an oxiranyl-type co-product radical that quickly ring-opens to enoxy radicals.

The reaction of methyl peroxy and hydroxyl radicals as a major source of atmospheric methanol.

Methyl peroxy, a key radical in tropospheric chemistry, was recently shown to react with the hydroxyl radical at an unexpectedly high rate. Here, the molecular reaction mechanisms are elucidated using high-level quantum chemical methodologies and statistical rate theory. Formation of activated methylhydrotrioxide, followed by dissociation into methoxy and hydroperoxy radicals, is found to be the main reaction pathway, whereas methylhydrotrioxide stabilization and methanol formation (from activated and stabilized methylhydrotrioxide) are viable minor channels.

Atmospheric Vinyl Alcohol to Acetaldehyde Tautomerization Revisited.

The atmospheric oxidation of vinyl alcohol (VA) produced by photoisomerization of acetaldehyde (AA) is thought to be a source of formic acid (FA). Nevertheless, a recent theoretical study predicted a high rate coefficient k1(298 K) of ≈10(-14) cm(3) molecule(-1) s(-1) for the FA-catalyzed tautomerization reaction 1 of VA back into AA, which suggests that FA buffers its own production from VA. However, the unusually high frequency factor implied by that study prompted us to reinvestigate reaction 1 .

Fast (E)-(Z) Isomerization Mechanisms of Substituted Allyloxy Radicals in Isoprene Oxidation.

Unusually rapid (E) ⇌ (Z) isomerization mechanisms are proposed and theoretically quantified for substituted allyloxy radicals, R'RC═CH-CH2O(•), with R and R' alkyl or oxygenated substituents, termed below β,γ-enoxy radicals. These conversions are shown to occur by a sequence of (i) ring closure to nearly isoergic oxiranyl-C(•)RR' radicals, (ii) internal rotation of the oxiranyl-moiety over 180°, and (iii) oxiranyl-ring reopening to yield the (E) ⇌ (Z)-isomerized oxy radicals. The barriers for all three steps were computed at the CCSD(T)/aug-cc-pVTZ//QCISD/6-311(d,p) level of theory to be only ≈5 ± 2 kcal mol(-1), and the rate constants at 298 K for the overall reactions were evaluated using transition-state theory to be in the range of 10(8)-10(9) s(-1).

Hydroxyl radical recycling in isoprene oxidation driven by hydrogen bonding and hydrogen tunneling: the upgraded LIM1 mechanism.

The Leuven isoprene mechanism, proposed earlier to aid in rationalizing the unexpectedly high hydroxyl radical (OH) concentrations in isoprene-rich, low-nitric-oxide (NO) regions ( Peeters ; et al. Phys. Chem.

Absolute rate coefficient of the gas-phase reaction between hydroxyl radical (OH) and hydroxyacetone: investigating the effects of temperature and pressure.

The rate coefficient (k1) of the reaction between hydroxyl radical and hydroxyacetone, which remained so far controversial, was determined over the temperature range 290-500 K using pulsed-laser photolysis coupled to pulsed-laser induced fluorescence (PLP-PLIF). Hydroxyl radical was generated by pulsed photolysis of H2O2 at 248 nm. The results show that at a pressure of 50 Torr He, the rate coefficient obeys a negative temperature dependence k1(T) = (1.

Decomposition pathways of the neutral and protonated formamide in some lower-lying excited states.

Unimolecular decompositions of neutral (NH2CHO) and protonated (NH3CHO(+)) formamide, an active precursor of biomolecules in prebiotic chemistry, are investigated in the ground (S0) and first triplet (T1) and singlet (S1) excited states. Different decomposition channels including the homolytic bond dissociations, dehydration, decarbonylation, dehydrogenation, etc., are explored using coupled-cluster theory (CCSD(T)/CBS method) for both S0 and T1 states and RASPT2(18,15)/6-31G(d,p) computations for the S1 state.

Theoretical study of the decomposition of formamide in the presence of water molecules.

Formamide (NH2CHO, FM) has been considered an active key precursor in prebiotic chemistry on early Earth. Under certain conditions such as dry lagoons, FM can decompose to produce reactants that lead to formation of more complex biomolecules. Specifically, FM decomposition follows many reactive channels producing small molecules such as H2, CO, H2O, HCN, HNC, NH3, and HNCO with comparable energy barriers in the range of 73-82 kcal/mol.

Experimental and theoretical study of the reaction of the ethynyl radical with nitrous oxide, C2H + N2O.

We investigated the rate constants and reaction mechanism of the gas phase reaction between the ethynyl radical and nitrous oxide (C(2)H + N(2)O) using both experimental methods and electronic structure calculations. A pulsed-laser photolysis/chemiluminescence technique was used to determine the absolute rate coefficient over the temperature range 570 K to 836 K. In this experimental temperature range, the measured temperature dependence of the overall rate constants can be expressed as: k(T) (C(2)H + N(2)O) = 2.

Hydrazine bisalane is a potential compound for chemical hydrogen storage. A theoretical study.

Electronic structure calculations suggest that hydrazine bisalane (AlH(3)NH(2)NH(2)AlH(3), alhyzal) is a promising compound for chemical hydrogen storage (CHS). Calculations are carried out using the coupled-cluster theory CCSD(T) with the aug-cc-pVTZ basis set. Potential energy surfaces are constructed to probe the formation of, and hydrogen release from, hydrazine bisalane which is initially formed from the reaction of hydrazine with dialane.

Formation and hydrogen release of hydrazine bisborane: transfer vs. attachment of a borane.

The reactivity of hydrazine in the presence of diborane has been investigated using ab initio quantum chemical computations (MP2 and CCSD(T) methods with the aug-cc-pVTZ basis set). Portions of the relevant potential energy surface were constructed to probe the formation mechanism of the hydrazine diborane (BH(3)BH(3)NH(2)NH(2)) and hydrazine bisborane (BH(3)NH(2)NH(2)BH(3)). The differences between both adducts are established.

Theoretical study of formamide decomposition pathways.

The chemical transformations of formamide (NH(2)CHO), a molecule of prebiotic interest as a precursor for biomolecules, are investigated using methods of electronic structure computations and Rice-Rampserger-Kassel-Marcus (RRKM) theory. Specifically, quantum chemical calculations applying the coupled-cluster theory CCSD(T), whose energies are extrapolated to the complete basis set limit (CBS), are carried out to construct the [CH(3)NO] potential energy surface. RRKM theory is then used to systematically examine decomposition channels leading to the formation of small molecules including CO, NH(3), H(2)O, HCN, HNC, H(2), HNCO, and HOCN.

Fast reactions of hydroxycarbenes: tunneling effect versus bimolecular processes.

Different uni- and bimolecular reactions of hydroxymethylene, an important intermediate in the photochemistry of formaldehyde, as well as its halogenated derivatives (XCOH, X = H, F, Cl, Br), have been considered using high-level CCSD(T)/CBS quantum chemical methods. The Wentzel-Kramers-Brillouin (WKB) and Eckart approximations were applied to estimate the tunneling rate constant of isomerization of trans-HCOH to H(2)CO, and the WKB procedure was found to perform better in this case. In agreement with recent calculations and experimental observations [Schreiner et al.

Production of hydrogen from reactions of methane with boranes.

The reactions of methane with different hydrides have been investigated using quantum chemical calculations (MP2 and CCSD(T) methods with the aug-cc-pVnZ one-electron functions extrapolated to the basis set limits). The hydrides of the elements of the second and third row, and also GaH(3), with an electronegativity smaller than the value of hydrogen (LiH, Li(2)H(2), BeH(2), NaH, MgH(2), BH(3), AlH(3), B(2)H(6), Al(2)H(6), SiH(4), PH(4) and GaH(3)) have been considered. Reactions of CH(4) with either BH(3) or LiH are characterized by the lowest energy barriers.

The effect of the NH2 substituent on NH3: hydrazine as an alternative for ammonia in hydrogen release in the presence of boranes and alanes.

Potential energy surfaces for H(2) release from hydrazine interacting with borane, alane, diborane, dialane and borane-alane were constructed from MP2/aVTZ geometries and zero point energies with single point energies at the CCSD(T)/aug-cc-pVTZ level. With one borane or alane molecule, the energy barrier for H(2)-loss of approximately 38 or 30 kcal mol(-1) does not compete with the B-N or Al-N bond cleavage ( approximately 30 or approximately 28 kcal mol(-1)). The second borane or alane molecule can play the role of a bifunctional catalyst.

Internal energy effects on the ion/molecule reactions of ionized methyl isocyanide.

Electron ionization of methyl isocyanide in various chemical ionization conditions is reported and, depending on the energy conditions used, different ion/molecule reactions are observed. It is proposed, on the basis of combined quantum chemical (DFT) calculations and tandem mass spectrometric experiments, that a common intermediate could be a cumulenic ionized dimer dissociating in the ion source following two energy depending competitive channels, a loss of a hydrogen atom and a loss of a methyl group. Proposed structures for new cumulenic ions are supported by collision experiments in the high (collisional activation) or/and low (collision- induced dissociations) translational energy regime.

Reactions of diborane with ammonia and ammonia borane: catalytic effects for multiple pathways for hydrogen release.

High-level electronic structure calculations have been used to construct portions of the potential energy surfaces related to the reaction of diborane with ammonia and ammonia borane (B2H6 + NH3 and B2H6 + BH3NH3)to probe the molecular mechanism of H2 release. Geometries of stationary points were optimized at the MP2/aug-cc-pVTZ level. Total energies were computed at the coupled-cluster CCSD(T) theory level with the correlation-consistent basis sets.

Computational study of the release of H2 from ammonia borane dimer (BH3NH3)2 and its ion pair isomers.

High-level electronic structure calculations have been used to map out the relevant portions of the potential energy surfaces for the release of H2 from dimers of ammonia borane, BH3NH3 (AB). Using the correlation-consistent aug-cc-pVTZ basis set at the second-order perturbation MP2 level, geometries of stationary points were optimized. Relative energies were computed at these points using coupled-cluster CCSD(T) theory with the correlation-consistent basis sets at least up to the aug-cc-pVTZ level and in some cases extrapolated to the complete basis set limit.