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The aerospace and automobile sectors are widely utilized the polymer composites. The composite materials, like unidirectional glass fiber reinforced polymer (UD-GFRP), is difficult to machine due to its anisotropic that is non-homogeneous character and such material requires special cutting tools. The proposed work is going to examine the tool wear, quality of the surface and forces generated in the various stages of inputs given to the machining of unidirectional glass fiber reinforced polymer (UD-GFRP) composites. The assessment of the machining incorporates tool wear investigations, surface roughness investigations and quality of material by varying input parameters. The Taguchi optimization technique with experimental design of L9 orthogonal array employed. The parameters range identified by trail runs and observations of conducted machining utilized for optimization. The Turning process parameters of cutting velocity or speed, rate of tool movement or feed rate and cutting depth on composite part or depth of cut were considered. The other factors, like tool material i.e., Poly-Crystalline Diamond (PCD) tool, its cutting regime (dry), profile of cutting tool are considered as constant parameters. The responses, like tool wear, surface finish, and cutting force, were measured against various input parameters, while machining the composite (UD-GFRP) composite part. The objective of this research is to establish relationship among various operating parameters to achieve desired results. That is major focus of the work on the economic condition for getting better values based on setting of input parameters.

Objective: To study the prevalence and incidence of seizures in patients prescribed clozapine. Methods: The treatment records of 222 patients commenced on clozapine were retrospectively reviewed during the period of January 2007 to June 2014 to evaluate the prevalence of seizures before and after starting clozapine. Results: The majority of patients commenced on clozapine were male (65%), single (65%), and unemployed (57%). The mean (± standard deviation) dose of clozapine was 277.9 ± 102.5 mg/day. A history of seizure was present in 6 patients who were also prescribed antiepileptic medication; of these 6 patients, only 1 case had recurrence of seizure while taking clozapine due to poor compliance with ongoing antiepileptic medication. The incidence rate of new-onset seizure with clozapine was 6% (12/216). Most patients who developed seizures were male, aged between 24 and 41 years, and had a long duration of illness (≥ 10 years). The risk of seizure was associated with the dose of clozapine used: 3% (5/159) with dose up to 300 mg/day, 8% (4/49) with 325 to 500 mg/day, and 38% (3/8) in those receiving > 500 mg/day. More than half of the patients (7/12) who developed seizures while prescribed clozapine were managed with reduction in the dose of clozapine. In one-third of cases (4/12) an antiepileptic medication was added and in 1 case, clozapine was stopped. All patients who continued on clozapine remained seizure-free at follow-up that ranged from 6 months to 4 years. Conclusion: The incidence of seizures with clozapine was 6% and the risk of seizures increased with higher doses. [ABSTRACT FROM AUTHOR]

The reduction of CO2 to synthetic fuels is a valuable strategy for energy storage. However, the formation of energy-dense liquid fuels such as methanol remains rare, particularly under low-temperature and -pressure conditions that can be coupled to renewable electricity sources via electrochemistry. Here, a multicatalyst system pairing an electrocatalyst with a thermal organometallic catalyst is introduced, which enables the reduction of CO2 to methanol at ambient temperature and pressure. The cascade methanol synthesis proceeds via CO2 reduction to formate by electrocatalyst [Cp*Ir(bpy)Cl]+ (Cp* = pentamethylcyclopentadienyl, bpy = 2,2'-bipyridine), Fischer esterification of formate to isopropyl formate catalyzed by trifluoromethanesulfonic acid (HOTf), and thermal transfer hydrogenation of isopropyl formate to methanol facilitated by the organometallic catalyst (H-PNP)Ir(H)3 (H-PNP = HN(C2H4PiPr2)2). The isopropanol solvent plays several crucial roles: activating formate ion as isopropyl formate, donating hydrogen for the reduction of formate ester to methanol via transfer hydrogenation, and lowering the barrier for transfer hydrogenation through hydrogen bonding interactions. In addition to reporting a method for room-temperature reduction of challenging ester substrates, this work provides a prototype for pairing electrochemical and thermal organometallic reactions that will guide the design and development of multicatalyst cascades., (© 2024 Wiley‐VCH GmbH.)

Six rhenium hydride complexes, [(6,6'-R 2 -bpy)Re(CO) 3 H] (bpy = 2,2'-bipyridine, R = OEt, OMe, NHMe, Me, F, Br), were synthesized. These complexes insert CO 2 to form rhenium formate complexes of the type [(6,6'-R 2 -bpy)Re(CO) 3 {OC(O)H}]. All the rhenium formate species were characterized using X-ray crystallography, which revealed that the bpy ligand is not coplanar with the metal coordination plane containing the two nitrogen donors of the bpy ligand but tilted. A solid-state structure of [(6,6'-Me 2 -bpy)Re(CO) 3 H] determined using MicroED also featured a tilted bpy ligand. The kinetics of CO 2 insertion into complexes of the type [(6,6'-R 2 -bpy)Re(CO) 3 H] were measured experimentally and the thermodynamic hydricities of [(6,6'-R 2 -bpy)Re(CO) 3 H] species were determined using theoretical calculations. A Brønsted plot constructed using the experimentally determined rate constants for CO 2 insertion and the calculated thermodynamic hydricities for [(6,6'-R 2 -bpy)Re(CO) 3 H] revealed a linear free energy relationship (LFER) between thermodynamic and kinetic hydricity. This LFER is different to the previously determined relationship for CO 2 insertion into complexes of the type [(4,4'-R 2 -bpy)Re(CO) 3 H]. At a given thermodynamic hydricity, CO 2 insertion is faster for complexes containing a 6,6'-substituted bpy ligand. This is likely in part due to the tilting observed for systems with 6,6'-substituted bpy ligands. Notably, the 6,6'-(NHMe) 2 -bpy ligand could in principle stabilize the transition state for CO 2 insertion via hydrogen bonding. This work shows that if only the rate of CO 2 insertion into [(6,6'-(NHMe) 2 -bpy)Re(CO) 3 H] is compared to [(4,4'-R 2 -bpy)Re(CO) 3 H] systems, the increase in rate could be easily attributed to hydrogen bonding, but in fact all 6,6'-substituted systems lead to faster than expected rates.

ConspectusDespite the plethora of metal catalyzed reactions for CO 2 utilization that have been developed in academic laboratories, practical systems remain elusive. The understanding of the elementary steps in catalysis is a proven method to improve catalytic performance. In many catalytic cycles for CO 2 utilization, the insertion of CO 2 into a metal-element σ-bond, such as hydrides, alkyls, amides, or hydroxides, is a crucial step. However, despite the many demonstrations of CO 2 insertion, there are a paucity of kinetic studies, and information about the reaction mechanism has been predominantly elucidated from computational investigations. In this Account, kinetic studies on CO 2 insertion into late transition metal-element σ-bonds performed by my group are summarized, along with their implications for catalysis.A common pathway for CO 2 insertion into a metal hydride involves a two-step mechanism. The first step is nucleophilic attack on CO 2 by the hydride to generate an H-bound formate, followed by rearrangement to form an O-bound formate product. Kinetic studies on systems in which both the first and second steps are proposed to be rate-determining, known as inner-sphere and outer-sphere processes, respectively, show that insertion rates increase as (i) the ligand trans to the hydride becomes a stronger donor, (ii) the ancillary ligand becomes more electron-donating, and (iii) the Dimroth-Reichardt parameter of the solvent increases. However, the magnitude of these effects is generally smaller for inner-sphere processes because there is less buildup of charge in the key transition state. For similar reasons, the presence of Lewis acids only increases the rate of outer-sphere processes. These results suggest it may be possible to experimentally differentiate between inner- and outer-sphere processes.The insertion of CO 2 into a metal-alkyl bond results in the formation of a C-C bond, which is important for the generation of fuels from CO 2 . For square planar Group 10 complexes, the presence of a strong donor ligand trans to the alkyl group is critical for kinetically promoting insertion. Further, the nucleophilicity of the alkyl ligand directly impacts the rate of CO 2 insertion via an S E 2 mechanism, as does the steric bulk of the complex, and the reaction solvent. In contrast to the relatively slow rates of insertion observed for metal alkyls, CO 2 insertion is rapid for metal hydroxides and amides. Although kinetics trends could be determined for hydroxides, reactions with amides are too fast for quantitative studies.Overall, the rates of insertion correlate with the nucleophilicity of the element in the metal-element σ-bond, so amide > hydroxide > hydride > alkyl. Due to the related pathways for insertion, similar trends in ligand and solvent effects are observed for insertion into different metal-element σ-bonds. Thus, the same strategies can be used to control the rates of insertion across systems. Differences in the magnitude of solvent and ligand effects are caused by variation in the amount of charge build-up on the metal in the rate-determining transition state. Likely, given that CO 2 is related to organic molecules such as aldehydes, ketones, and amides, the results described in this Account are general to a wider range of substrates.

The synthesis of a new homogeneous reductant based on 4,4'- t Bu 2 -2,2'-bipyridine, t Bu-OED 4 , is reported. t Bu-OED 4 was prepared on a multigram scale in two steps from inexpensive and commercially available starting materials, with no chromatography required for purification. t Bu-OED 4 has a reduction potential of -1.33 V (vs Ferrocenium/Ferrocene) and is soluble in a range of common organic solvents. We demonstrate that t Bu-OED 4 can facilitate Ni/Co dual-catalyzed C(sp 2 )-C(sp 3 ) cross-electrophile coupling reactions and is highly functional group tolerant. t Bu-OED 4 is expected to be a valuable addition to the set of homogeneous reductants available for organic transformations., Competing Interests: Competing Financial Interests The authors declare no competing financial interests. Declaration of interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

A family of 4,4'- t Bu 2 -2,2'-bipyridine ( tBu bpy) ligands with substituents in either the 6-position, 4,4'- t Bu 2 -6-Me-bpy ( tBu bpy Me ), or 6 and 6'-positions, 4,4'- t Bu 2 -6,6'-R 2 -bpy ( tBu bpy R2 ; R = Me, i Pr, s Bu, Ph, or Mes), was synthesized. These ligands were used to prepare Ni complexes in the 0, I, and II oxidation states. We observed that the substituents in the 6 and 6'-positions of the tBu bpy ligand impact the properties of the Ni complexes. For example, bulkier substituents in the 6,6'-positions of tBu bpy better stabilized ( tBu bpy R2 )Ni I Cl species and resulted in cleaner reduction from ( tBu bpy R2 )Ni II Cl 2 . However, bulkier substituents hindered or prevented coordination of tBu bpy R2 ligands to Ni 0 (cod) 2 . In addition, by using complexes of the type ( tBu bpy Me )NiCl 2 and ( tBu bpy R2 )NiCl 2 as precatalysts for different XEC reactions, we demonstrated that the 6 or 6,6' substituents lead to major differences in catalytic performance. Specifically, while ( tBu bpy Me )Ni II Cl 2 is one of the most active catalysts reported to date for XEC and can facilitate XEC reactions at room temperature, lower turnover frequencies were observed for catalysts containing tBu bpy R2 ligands. A detailed study on the catalytic intermediates ( tBu bpy)Ni(Ar)I and ( tBu bpy Me2 )Ni(Ar)I revealed several factors that likely contributed to the differences in catalytic activity. For example, whereas complexes of the type ( tBu bpy)Ni(Ar)I are low spin and relatively stable, complexes of the type ( tBu bpy Me2 )Ni(Ar)I are high-spin and less stable. Further, ( tBu bpy Me2 )Ni(Ar)I captures primary and benzylic alkyl radicals more slowly than ( tBu bpy)Ni(Ar)I, consistent with the lower activity of the former in catalysis. Our findings will assist in the design of tailor-made ligands for Ni-catalyzed transformations., Competing Interests: Competing Financial Interests The authors declare no competing financial interests.

A Co II -porphyrin complex (1) with an appended aza-crown ether for Lewis acid (LA) binding was synthesized and characterized. NMR spectroscopy and electrochemistry show that cationic group I and II LAs ( i.e. , Li + , Na + , K + , Ca 2+ , Sr 2+ , and Ba 2+ ) bind to the aza-crown ether group of 1. The binding constant for Li + is comparable to that observed for a free aza-crown ether. LA binding causes an anodic shift in the Co II /Co I couple of between 10 and 40 mV and also impacts the Co III /Co II couple. The magnitude of the anodic shift of the Co II /Co I couple varies linearly with the strength of the LA as determined by the p K a of the corresponding metal-aqua complex, with dications giving larger shifts than monocations. The extent of the anodic shift of the Co II /Co I couple also increases as the ionic strength of the solution decreases. This is consistent with electric field effects being responsible for the changes in the redox properties of 1 upon LA binding and provides a novel method to tune the reduction potential. Density functional theory calculations indicate that the bound LA is 5.6 to 6.8 Å away from the Co II ion, demonstrating that long-range electrostatic effects, which do not involve changes to the primary coordination sphere, are responsible for the variations in redox chemistry. Compound 1 was investigated as a CO 2 reduction electrocatalyst and shows high activity but rapid decomposition., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A high-surface-area p -type porous Si photocathode containing a covalently immobilized molecular Re catalyst is highly selective for the photoelectrochemical conversion of CO 2 to CO. It gives Faradaic efficiencies of up to 90% for CO at potentials of -1.7 V (versus ferrocenium/ferrocene) under 1 sun illumination in an acetonitrile solution containing phenol. The photovoltage is approximately 300 mV based on comparisons with similar n -type porous Si cathodes in the dark. Using an estimate of the equilibrium potential for CO 2 reduction to CO under optimized reaction conditions, photoelectrolysis was performed at a small overpotential, and the onset of electrocatalysis in cyclic voltammograms occurred at a modest underpotential. The porous Si photoelectrode is more stable and selective for CO production than the photoelectrode generated by attaching the same Re catalyst to a planar Si wafer. Further, facile characterization of the porous Si-based photoelectrodes using transmission mode FTIR spectroscopy leads to highly reproducible catalytic performance.

In recent years, considerable progress has been made in the conversion of biomass into renewable chemicals, yet the range of value-added products that can be formed from biomass remains relatively small. Herein, we demonstrate that molecules available from biomass serve as viable starting materials for the synthesis of phosphine ligands, which can be used in homogeneous catalysis. Specifically, we prepared renewable analogues of Beller's ligand (di(1-adamantyl)- n -butylphosphine, cataCXium® A), which is widely used in homogeneous catalysis. Our new renewable phosphine ligands facilitate Pd-catalysed Suzuki-Miyaura, Stille, and Buchwald-Hartwig coupling reactions with high yields, and our catalytic results can be rationalized based on the stereoelectronic properties of the ligands. The new phosphine ligands generate catalytic systems that can be applied for the late-stage functionalization of commercial drugs., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The insertion of CO 2 into metal alkyl bonds is a crucial elementary step in transition metal-catalyzed processes for CO 2 utilization. Here, we synthesize pincer-supported palladium complexes of the type ( t Bu PBP)Pd(alkyl) ( t Bu PBP = B(NCH 2 P t Bu 2 ) 2 C 6 H 4 - ; alkyl = CH 2 CH 3 , CH 2 CH 2 CH 3, CH 2 C 6 H 5 , and CH 2 -4-OMe-C 6 H 4 ) and ( t Bu PBP)Pd(C 6 H 5 ) and compare the rates of CO 2 insertion into the palladium alkyl bonds to form metal carboxylate complexes. Although, the rate constant for CO 2 insertion into ( t Bu PBP)Pd(CH 2 CH 3 ) is more than double the rate constant we previously measured for insertion into the palladium methyl complex ( t Bu PBP)Pd(CH 3 ), insertion into ( t Bu PBP)Pd(CH 2 CH 2 CH 3 ) occurs approximately one order of magnitude slower than ( t Bu PBP)Pd(CH 3 ). CO 2 insertion into the benzyl complexes ( t Bu PBP)Pd(CH 2 C 6 H 5 ) and ( t Bu PBP)Pd(CH 2 -4-OMe-C 6 ) is significantly slower than any of the n-alkyl complexes, and CO 4 ) is significantly slower than any of the n-alkyl complexes, and CO 2 does not insert into the palladium phenyl bond of ( t Bu PBP)Pd(C 6 H 5 ). While ( t Bu PBP)Pd(CH 2 CH 3 ) and ( t Bu PBP)Pd(CH 2 CH 2 CH 3 ) are resistant to β-hydride elimination, we were unable to synthesize complexes with n -butyl, iso-propyl, and tert -butyl ligands due to β-hydride elimination and an unusual reductive coupling, which involves the formation of new C-B bonds. This reductive process also occurred for ( t Bu PBP)Pd(CH 2 C 6 H 5 ) at elevated temperature and a related process involving the formation of a new H-B bond prevented the isolation of ( t Bu PBP)PdH. DFT calculations provide insight into the relative rates of CO 2 insertion and indicate that steric factors are critical. Overall, this work is one of the first comparative studies of the rates of CO 2 insertion into different metal alkyl bonds and provides fundamental information that may be important for the development of new catalysts for CO 2 utilization., Competing Interests: The authors declare no competing financial interests., (This journal is © The Royal Society of Chemistry.)

Eleven 2,2'-bipyridine (bpy) ligands functionalized with attachment groups for covalent immobilization on silicon surfaces were prepared. Five of the ligands feature silatrane functional groups for attachment to metal oxide coatings on the silicon surfaces, while six contain either alkene or alkyne functional groups for attachment to hydrogen-terminated silicon surfaces. The bpy ligands were coordinated to Re(CO) 5 Cl to form complexes of the type Re(bpy)(CO) 3 Cl, which are related to known catalysts for CO 2 reduction. Six of the new complexes were characterized using X-ray crystallography. As proof of principle, four molecular Re complexes were immobilized on either a thin layer of TiO 2 on silicon or hydrogen-terminated silicon. The surface-immobilized complexes were characterized using X-ray photoelectron spectroscopy, IR spectroscopy, and cyclic voltammetry (CV) in the dark and for one representative example in the light. The CO stretching frequencies of the attached complexes were similar to those of the pure molecular complexes, but the CVs were less analogous. For two of the complexes, comparison of the electrocatalytic CO 2 reduction performance showed lower CO Faradaic efficiencies for the immobilized complexes than the same complex in solution under similar conditions. In particular, a complex containing a silatrane linked to bpy with an amide linker showed poor catalytic performance and control experiments suggest that amide linkers in conjugation with a redox-active ligand are not stable under highly reducing conditions and alkyl linkers are more stable. A conclusion of this work is that understanding the behavior of molecular Re catalysts attached to semiconducting silicon is more complicated than related complexes, which have previously been immobilized on metallic electrodes.

The kinetics of hydride transfer from Re( R bpy)(CO) 3 H (bpy = 4,4'-R-2,2'-bipyridine; R = OMe, t Bu, Me, H, Br, COOMe, CF 3 ) to CO 2 and seven different cationic N-heterocycles were determined. Additionally, the thermodynamic hydricities of complexes of the type Re( R bpy)(CO) 3 H were established primarily using computational methods. Linear free-energy relationships (LFERs) derived by correlating thermodynamic and kinetic hydricities indicate that, in general, the rate of hydride transfer increases as the thermodynamic driving force for the reaction increases. Kinetic isotope effects range from inverse for hydride transfer reactions with a small driving force to normal for reactions with a large driving force. Hammett analysis indicates that hydride transfer reactions with greater thermodynamic driving force are less sensitive to changes in the electronic properties of the metal hydride, presumably because there is less buildup of charge in the increasingly early transition state. Bronsted α values were obtained for a range of hydride transfer reactions and along with DFT calculations suggest the reactions are concerted, which enables the use of Marcus theory to analyze hydride transfer reactions involving transition metal hydrides. It is notable, however, that even slight perturbations in the steric properties of the Re hydride or the hydride acceptor result in large deviations in the predicted rate of hydride transfer based on thermodynamic driving forces. This indicates that thermodynamic considerations alone cannot be used to predict the rate of hydride transfer, which has implications for catalyst design.

Background: Systematic reviews conducted on sleep disturbances in attention deficit hyperactivity disorder (ADHD) have found inconsistent results due to the presence of several moderating variables which were not controlled for in previous studies. The aim of this study was to examine sleep disturbances in children with ADHD compared to their typically developing peers after controlling for moderating variables (age, sex, medication status, body mass index, and psychiatric and medical comorbidities). Methods: ADHD was diagnosed using DSM-IV-TR criteria (Diagnostic and Statistical Manual of Mental Disorders) and Conners’ Parent Rating Scales. Children recruited (aged 6−12 years) for the ADHD group (n = 40) met the following criteria: IQ > 80, unmedicated, and no psychiatric or medical comorbidities. The control group consisted of age- and sex-matched typically developing peers (n = 40). Sleep was assessed subjectively (through parent reported questionnaires and sleep logs) and objectively (using video polysomnography). Results: 65% of children with ADHD had a sleep disorder, as compared to 17% of controls. The ADHD group reported more sleep disturbances and disorders, both on subjective measures and objective measures. Conclusions: Sleep disturbances and primary sleep disorders in children with ADHD exist independent of moderating variables and differences in sleep assessment methods, thereby bolstering support for previously documented literature on the ADHD and sleep connection.

Many contemporary organic transformations, such as Ni-catalyzed cross-electrophile coupling (XEC), require a reductant. Typically, heterogeneous reductants, such as Zn 0 or Mn 0 , are used as the electron source in these reactions. Although heterogeneous reductants are highly practical for preparative-scale batch reactions, they can lead to complications in performing reactions on process scale and are not easily compatible with modern applications, such as flow chemistry. In principle, homogeneous organic reductants can address some of the challenges associated with heterogeneous reductants and also provide greater control of the reductant strength, which can lead to new reactivity. Nevertheless, homogeneous organic reductants have rarely been used in XEC. In this Perspective, we summarize recent progress in the use of homogeneous organic electron donors in Ni-catalyzed XEC and related reactions, discuss potential synthetic and mechanistic benefits, describe the limitations that inhibit their implementation, and outline challenges that need to be solved in order for homogeneous organic reductants to be widely utilized in synthetic chemistry. Although our focus is on XEC, our discussion of the strengths and weaknesses of different methods for introducing electrons is general to other reductive transformations.

The surface functionalization of two-dimensional (2D) materials with organic electron donors (OEDs) is a powerful tool to modulate the electronic properties of the material. Here we report a novel molecular dopant, Me-OED, that demonstrates record-breaking molecular doping to MoS 2 , achieving a carrier density of 1.10 ± 0.37 × 10 14 cm -2 at optimal functionalization conditions; the achieved carrier density is much higher than those by other OEDs such as benzyl viologen and an OED based on 4,4'-bipyridine. This impressive doping power is attributed to the compact size of Me-OED, which leads to high surface coverage on MoS 2 . To confirm, we study t Bu-OED, which has an identical reduction potential to Me-OED but is significantly larger. Using field-effect transistor measurements and spectroscopic characterization, we estimate the doping powers of Me- and t Bu-OED are 0.22-0.44 and 0.11 electrons per molecule, respectively, in good agreement with calculations. Our results demonstrate that the small size of Me-OED is critical to maximizing the surface coverage and molecular interactions with MoS 2 , enabling us to achieve unprecedented doping of MoS 2 .

The insertion of carbon dioxide into metal element σ-bonds is an important elementary step in many catalytic reactions for carbon dioxide valorization. Here, the insertion of carbon dioxide into a family of group 10 alkyl complexes of the type ( R PBP)M(CH 3 ) ( R PBP = B(NCH 2 PR 2 ) 2 C 6 H 4 - ; R = Cy or t Bu; M = Ni or Pd) to generate κ 1 -acetate complexes of the form ( R PBP)M{OC(O)CH 3 } is investigated. This involved the preparation and characterization of a number of new complexes supported by the unusual R PBP ligand, which features a central boryl donor that exerts a strong trans -influence, and the identification of a new decomposition pathway that results in C-B bond formation. In contrast to other group 10 methyl complexes supported by pincer ligands, carbon dioxide insertion into ( R PBP)M(CH 3 ) is facile and occurs at room temperature because of the high trans -influence of the boryl donor. Given the mild conditions for carbon dioxide insertion, we perform a rare kinetic study on carbon dioxide insertion into a late-transition metal alkyl species using ( t Bu PBP)Pd(CH 3 ). These studies demonstrate that the Dimroth-Reichardt parameter for a solvent correlates with the rate of carbon dioxide insertion and that Lewis acids do not promote insertion. DFT calculations indicate that insertion into ( t Bu PBP)M(CH 3 ) (M = Ni or Pd) proceeds via an S E 2 mechanism and we compare the reaction pathway for carbon dioxide insertion into group 10 methyl complexes with insertion into group 10 hydrides. Overall, this work provides fundamental insight that will be valuable for the development of improved and new catalysts for carbon dioxide utilization., Competing Interests: The authors declare no competing financial interests., (This journal is © The Royal Society of Chemistry.)

A novel pincer ligand, iPr PN Ph P [PhN(CH 2 CH 2 P i Pr 2 ) 2 ], which is an analogue of the versatile MACHO ligand, iPr PN H P [HN(CH 2 CH 2 P i Pr 2 ) 2 ], was synthesized and characterized. The ligand was coordinated to ruthenium, and a series of hydride-containing complexes were isolated and characterized by NMR and IR spectroscopies, as well as X-ray diffraction. Comparisons to previously published analogues ligated by iPr PN H P and iPr PN Me P [CH 3 N(CH 2 CH 2 P i Pr 2 ) 2 ] illustrate that there are large changes in the coordination chemistry that occur when the nitrogen substituent of the pincer ligand is altered. For example, ruthenium hydrides supported by the iPr PN Ph P ligand always form the syn isomer (where syn/anti refer to the relative orientation of the group on nitrogen and the hydride ligand on ruthenium), whereas complexes supported by iPr PN H P form the anti isomer and complexes supported by iPr PN Me P form a mixture of syn and anti isomers. We evaluated the impact of the nitrogen substituent of the pincer ligand in catalysis by comparing a series of iPr PN R P (R = H, Me, Ph)-ligated ruthenium hydride complexes as catalysts for formic acid dehydrogenation and carbon dioxide (CO 2 ) hydrogenation to formate. The iPr PN Ph P-ligated species is the most active for formic acid dehydrogenation, and mechanistic studies suggest that this is likely because there are kinetic advantages for catalysts that operate via the syn isomer. In CO 2 hydrogenation, the iPr PN Ph P-ligated species is again the most active under our optimal conditions, and we report some of the highest turnover frequencies for homogeneous catalysts. Experimental and theoretical insights into the turnover-limiting step of catalysis provide a basis for the observed trends in catalytic activity. Additionally, the stability of our complexes enabled us to detect a previously unobserved autocatalytic effect involving the base that is added to drive the reaction. Overall, by modifying the nitrogen substituent on the MACHO ligand, we have developed highly active catalysts for formic acid dehydrogenation and CO 2 hydrogenation and also provided a framework for future catalyst development.

The syntheses of four new tunable homogeneous organic reductants based on a tetraaminoethylene scaffold are reported. The new reductants have enhanced air stability compared to current homogeneous reductants for metal-mediated reductive transformations, such as cross-electrophile coupling (XEC), and are solids at room temperature. In particular, the weakest reductant is indefinitely stable in air and has a reduction potential of -0.85 V versus ferrocene, which is significantly milder than conventional reductants used in XEC. All of the new reductants can facilitate C(sp 2 )-C(sp 3 ) Ni-catalyzed XEC reactions and are compatible with complex substrates that are relevant to medicinal chemistry. The reductants span a range of nearly 0.5 V in reduction potential, which allows for control over the rate of electron transfer events in XEC. Specifically, we report a new strategy for controlled alkyl radical generation in Ni-catalyzed C(sp 2 )-C(sp 3 ) XEC. The key to our approach is to tune the rate of alkyl radical generation from Katritzky salts, which liberate alkyl radicals upon single electron reduction, by varying the redox potentials of the reductant and Katritzky salt utilized in catalysis. Using our method, we perform XEC reactions between benzylic Katritzky salts and aryl halides. The method tolerates a variety of functional groups, some of which are particularly challenging for most XEC transformations. Overall, we expect that our new reductants will both replace conventional homogeneous reductants in current reductive transformations due to their stability and relatively facile synthesis and lead to the development of novel synthetic methods due to their tunability.

Ni II cyclam (cyclam = 1,4,8,11-tetraazacyclotetradecane) is an efficient catalyst for the selective reduction of CO 2 to CO. A crucial elementary step in the proposed catalytic cycle is the coordination of CO 2 to a Ni I cyclam intermediate. Isolation and spectroscopic characterization of this labile Ni I species without solvent has proven to be challenging, however, and only partial IR spectra have previously been reported using multiple photon fragmentation of ions generated by gas-phase electron transfer to the Ni II cyclam dication at 300 K. Here, we report a chemical reduction method that efficiently prepares Ni I cyclam in solution. This enables the Ni I complex to be transferred into a cryogenic photofragmentation mass spectrometer using inert-gas-mediated electrospray ionization. The vibrational spectra of the 30 K ion using both H 2 and N 2 messenger tagging over the range 800-4000 cm -1 were then measured. The resulting spectra were analyzed with the aid of electronic structure calculations, which show strong method dependence in predicted band positions and small molecule activation. The conformational changes of the cyclam ligand induced by binding of the open shell Ni I cation were compared with those caused by the spherical, closed-shell Li I cation, which has a similar ionic radius. We also report the vibrational spectrum of a Ni I cyclam complex with a strongly bound O 2 ligand. The cyclam ligand supporting this species exhibits a large conformational change compared to the complexes with weakly bound N 2 and H 2 , which is likely due to significant charge transfer from Ni to the coordinated O 2 .

The synthesis of triarylmethanes via Pd-catalyzed Suzuki-Miyaura reactions between diarylmethyl 2,3,4,5,6-pentafluorobenzoates and aryl boronic acids is described. The system operates at mild conditions and has a broad substrate scope, including the coupling of diphenylmethanol derivatives that do not contain extended aromatic substituents. This is significant as these substrates, which result in the types of triarylmethane products that are prevalent in pharmaceuticals, have not previously been compatible with systems for diarylmethyl ester coupling. Further, the reaction can be performed stereospecifically to generate stereo-inverted products. On the basis of DFT calculations, it is proposed that the oxidative addition of the diarylmethyl 2,3,4,5,6-pentafluorobenzoate substrate occurs via an S N 2 pathway, which results in the inverted products. Mechanistic studies indicate that oxidative addition of the diarylmethyl 2,3,4,5,6-pentafluorobenzoate substrates to (IPr)Pd(0) results in the selective cleavage of the O-C(benzyl) bond in part because of a stabilizing η 3 -interaction between the benzyl ligand and Pd. This is in contrast to previously described Pd-catalyzed Suzuki-Miyaura reactions involving phenyl esters, which involve selective cleavage of the C(acyl)-O bond, because there is no stabilizing η 3 -interaction. It is anticipated that this fundamental knowledge will aid the development of new catalytic systems, which use esters as electrophiles in cross-coupling reactions., Competing Interests: Competing Financial Interests The authors declare no competing financial interests.

Objective: The present study is a large case series evaluating the benefits of transcranial direct current stimulation (tDCS) in treatment-resistant obsessive compulsive disorder (OCD)., Methods: We reviewed the charts of 32 patients with treatment-resistant OCD who received 10-20 sessions of anodal pre-SMA tDCS., Results: Overall, 9 (28 %) showed at least partial response to tDCS at the end of 10-20 sessions [responders = 8 (25 %), partial responders = 1 (3%)]. Two out of three partial responders at the end of 10 sessions had response at the end of 20 sessions., Conclusions: tDCS may benefit a proportion of patients with treatment-resistant OCD., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Psoriasis is a chronic inflammatory dermatosis associated with psychological morbidity. Very few studies have evaluated stigma among caregivers of patients with psoriasis., Objective: This study aimed to evaluate the prevalence of stigma and its correlates among the caregivers of patients with psoriasis., Methodology: Forty-nine caregivers of patients with psoriasis were evaluated on psoriasis adapted version of caregiver of people with mental illness (CPMI) to assess internalized stigma, Explanatory Model Interview Catalogue Stigma Scale, Family Burden Inventory (FBI), Multidimensional aspect of perceived social support scale (PSS), Cognitive behavioral avoidance scale (CBAS), and Coping checklist., Results: Majority of the caregivers were either spouse (42.8%) or parents (36.7%) of the patients. The caregivers were involved in the care of the patients for a mean duration of 6.5(SD; 4.8) years. On CPMI, the mean score was highest for the affective domain (3.1), this was followed by affective (2.9), and behavioral (2.9) domain. Very few (12.2%) caregivers reported significantly high caregiver burden. A higher level of stigma was associated with more often use of avoidance coping. Presence of higher social support was associated with higher level of stigma as assessed by using CPMI. A higher level of caregiver burden in all the domains of FBI was associated with higher level of stigma., Conclusion: Stigma is highly prevalent among the caregivers of patients with psoriasis. These findings suggest that there is an urgent need to identify the stigma and address the same., Competing Interests: There are no conflicts of interest., (Copyright: © 2021 Indian Dermatology Online Journal.)

The prevalence of transition metal-mediated hydride transfer reactions in chemical synthesis, catalysis, and biology has inspired the development of methods for characterizing the reactivity of transition metal hydride complexes. Thermodynamic hydricity represents the free energy required for heterolytic cleavage of the metal-hydride bond to release a free hydride ion, H - , as determined through equilibrium measurements and thermochemical cycles. Kinetic hydricity represents the rate of hydride transfer from one species to another, as measured through kinetic analysis. This tutorial review describes the common methods for experimental and computational determination of thermodynamic and kinetic hydricity, including advice on best practices and precautions to help avoid pitfalls. The influence of solvation on hydricity is emphasized, including opportunities and challenges arising from comparisons across several different solvents. Connections between thermodynamic and kinetic hydricity are discussed, and opportunities for utilizing these connections to rationally improve catalytic processes involving hydride transfer are highlighted.

Palladium(II) precatalysts are used extensively to facilitate cross-coupling reactions because they are bench stable and give high activity. As a result, precatalysts such as Buchwald's palladacycles, Organ's PEPPSI species, Nolan's allyl-based complexes, and Yale's 1- tert -butylindenyl containing complexes, are all commercially available. Comparing the performance of the different classes of precatalysts is challenging because they are typically used under different conditions, in part because they are reduced to the active species via different pathways. However, within a particular class of precatalyst, it is easier to compare performance because they activate via similar pathways and are used under the same conditions. Here, we evaluate the activity of different allyl-based precatalysts, such as (η 3 -allyl)PdCl(L), (η 3 -crotyl)PdCl(L), (η 3 -cinnamyl)PdCl(L), and (η 3 -1- tert -butylindenyl)PdCl(L) in Suzuki-Miyaura reactions. Specifically, we evaluate precatalyst performance as the ancillary ligand (NHC or phosphine), reaction conditions, and substrates are varied. In some cases, we connect relative activity to both the mechanism of activation and the prevalence of the formation of inactive palladium(I) dimers. Additionally, we compare the performance of in situ generated precatalysts with commonly used palladium sources such as tris(dibenzylideneacetone)dipalladium(0) (Pd 2 dba 3 ), bis(acetonitrile)dichloropalladium(II) (Pd(CH 3 CN) 2 Cl 2 ), and palladium acetate. Our results provide information about which precatalyst to use under different conditions., Competing Interests: Competing Financial Interests This work was primarily funded by Umicore, who own the rights to all of the allyl-based precatalysts studied in this work. Additionally, NH is an inventor on patents relating to the Yale precatalyst.

A dual catalytic system for cross-electrophile coupling reactions between aryl halides and alkyl halides that features a Ni catalyst, a Co cocatalyst, and a mild homogeneous reductant is described. Mechanistic studies indicate that the Ni catalyst activates the aryl halide, while the Co cocatalyst activates the alkyl halide. This allows the system to be rationally optimized for a variety of substrate classes by simply modifying the loadings of the Ni and Co catalysts based on the reaction product profile. For example, the coupling of aryl bromides and aryl iodides with alkyl bromides, alkyl iodides, and benzyl chlorides is demonstrated using the same Ni and Co catalysts under similar reaction conditions but with different optimal catalyst loadings in each case. Our system is tolerant of numerous functional groups and is capable of coupling heteroaryl halides, di- ortho -substituted aryl halides, pharmaceutically relevant druglike aryl halides, and a diverse range of alkyl halides. Additionally, the dual catalytic platform facilitates a series of selective one-pot three-component cross-electrophile coupling reactions of bromo(iodo)arenes with two distinct alkyl halides. This demonstrates the unique level of control that the platform provides and enables the rapid generation of molecular complexity. The system can be readily utilized for a wide range of applications as all reaction components are commercially available, the reaction is scalable, and toxic amide-based solvents are not required. It is anticipated that this strategy, as well as the underlying mechanistic framework, will be generalizable to other cross-electrophile coupling reactions., Competing Interests: The authors declare no competing financial interest.

Objective: A substantial proportion of severely ill patients with obsessive-compulsive disorder (OCD) do not respond to serotonin reuptake inhibitors (SRIs) and are unable to practice cognitive behavioral therapy (CBT) on an out-patient basis. We report the short-term (at discharge) and long-term (up to 2 years) outcome of a multimodal inpatient treatment program that included therapist-assisted intensive CBT with adjunctive pharmacotherapy for severely ill OCD patients who are often resistant to SRIs and are either unresponsive or unable to practice outpatient CBT., Methods: A total of 420 patients, admitted between January 2012 and December 2017 were eligible for the analysis. They were evaluated using the Mini International Neuropsychiatric Interview, the Yale-Brown Obsessive Compulsive Scale (YBOCS), and the Clinical Global Impression (CGI) scale. All patients received 4 to 5 therapist-assisted CBT sessions per week along with standard pharmacotherapy. Naturalistic follow-up information at 3, 6, 12, and 24 months were recorded., Results: At baseline, patients were mostly severely ill (YBOCS = 29.9 ± 4.5) and nonresponsive to ≥2 SRIs (83%). Mean duration of inpatient stay was 42.7 ± 25.3 days. At discharge, there was a significant decline in the mean YBOCS score (29.9 ± 4.5 vs. 18.1 ± 7.7, P < .001, Cohen's d = 1.64); 211/420 (50%) were responders (≥35% YBOCS reduction and CGI-I≤2) and an additional 86/420 (21%) were partial responders (25% to 35% YBOCS reduction and CGI-I≤3). Using latent class growth modeling of the follow-up data, 4 distinct classes were identified, which include "remitters" (14.5%), "responders" (36.5%), "minimal responders" (34.7%), and "nonresponders" (14.6%). Shorter duration of illness, better insight, and lesser contamination/washing symptoms predicted better response in both short- and long-term follow-up., Conclusion: Intensive, inpatient-based care for OCD may be an effective option for patients with severe OCD and should be considered routinely in those who do not respond with outpatient treatment.

Background: Psoriasis is a chronic inflammatory dermatosis associated with psychological morbidity. Like mental illness, it is also associated with stigma. Very few studies from India have evaluated stigma experienced by patients with psoriasis., Aim of the Study: To study stigma in patients with psoriasis (in the form of internalized stigma, perceived stigma, and social-participation-restriction stigma) and its relationship with demographic and clinical variables., Methodology: 104 patients with psoriasis assessed on the internalized stigma of mental illness scale (ISMIS), explanatory model interview catalogue stigma scale, participation scale (P-scale), perceived social support, total score of Patient Health Questionnaire (PHQ-9), Generalized Anxiety Disorder (GAD-7) scale, Dermatology Life Quality Index, and Psoriasis disability index., Results: On ISMIS, overall, 27.9% had experienced stigma. On domains, majority of the participants experienced discrimination (52.9%) followed by stigma resistance (51.9%), stereotype (26.0%), social withdrawal (24.1%), and alienation (23.1%). Majority of them reported mild restriction. As per the evaluation by a qualified psychiatrist, about 30% of the participants had at least one psychiatric diagnosis. On comparison, those with the presence of co-morbid psychiatric illness experienced a higher level of stigma on each domain of ISMIS except discrimination and stigma resistance. Lower social support was associated with higher stigma in all the domains. All the domains of ISMIS except discrimination and stigma resistance were associated with a higher level of anxiety and depression, poor quality of life, and higher disability., Conclusion: The patients with psoriasis experience a significant amount of stigma and stigma is associated with the presence of psychiatric morbidity, lower social support, higher restriction, and more disability., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Indian Dermatology Online Journal.)

Although the catalytic carboxylation of unactivated alkyl electrophiles has reached remarkable levels of sophistication, the intermediacy of (phenanthroline)Ni(I)-alkyl species-complexes proposed in numerous Ni-catalyzed reductive cross-coupling reactions-has been subject to speculation. Herein we report the synthesis of such elusive (phenanthroline)Ni(I) species and their reactivity with CO 2 , allowing us to address a long-standing question related to Ni-catalyzed carboxylation reactions.

Transcranial direct current stimulation (tDCS), a non-invasive, neuromodulatory technique, is being increasingly applied to several psychiatric disorders. In this study, we describe the side-effect profile of repeated tDCS sessions (N = 2005) that were administered to 171 patients (156 adults and 15 adolescents) with different psychiatric disorders [schizophrenia [N = 109], obsessive-compulsive disorder [N = 28], alcohol dependence syndrome [N = 13], mild cognitive impairment [N = 10], depression [N = 6], dementia [N = 2] and other disorders [N = 3]]. tDCS was administered at a constant current strength of 2 mA with additional ramp-up and ramp-down phase of 20 s each at the beginning and end of the session, respectively. Other tDCS protocol parameters were: schizophrenia and obsessive-compulsive disorder: 5-days of twice-daily 20-min sessions with an inter-session interval of 3-h; Mild cognitive impairment/dementia and alcohol dependence syndrome: at least 5-days of once-daily 20-min session; Depression: 10-days of once-daily 30 min session. At the end of each tDCS session, any adverse event observed by the administrator and/or reported by the patient was systematically assessed using a comprehensive questionnaire. The commonly reported adverse events during tDCS included burning sensations (16.2%), skin redness (12.3%), scalp pain (10.1%), itching (6.7%), and tingling (6.3%). Most of the adverse events were noted to be mild, transient and well-tolerated. In summary, our observations suggest that tDCS is a safe mode for therapeutic non-invasive neuromodulation in psychiatric disorders in adults as well as the adolescent population., Competing Interests: Declaration of Competing Interest There are no potential conflicts of interest to report for any of the authors., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The catalytic hydrogenation of amides is an atom economical method to synthesize amines. Previously, it was serendipitously discovered that the combination of a secondary amide co-catalyst with ( iPr PNP)Fe(H)(CO) ( iPr PNP = N[CH 2 CH 2 (P i Pr 2 )] 2 ), results in a highly active base metal system for deaminative amide hydrogenation. Here, we use DFT to develop an improved co-catalyst for amide hydrogenation. Initially, we computationally evaluated the ability of a series of co-catalysts to accelerate the turnover-limiting proton transfer during C-N bond cleavage and poison the ( - ), results in a highly active base metal system for deaminative amide hydrogenation. Here, we use DFT to develop an improved co-catalyst for amide hydrogenation. Initially, we computationally evaluated the ability of a series of co-catalysts to accelerate the turnover-limiting proton transfer during C-N bond cleavage and poison the ( iPr PNP)Fe(H)(CO) catalyst through a side reaction. TBD (triazabicyclodecene) was identified as the leading co-catalyst. It was experimentally confirmed that when TBD is combined with ( iPr PNP)Fe(H)(CO) a remarkably active system for amide hydrogenation is generated. TBD also enhances the activity of other catalysts for amide hydrogenation and our results provide guidelines for the rational design of future co-catalysts., (This journal is © The Royal Society of Chemistry 2020.)

The reversible activation of H 2 via a pathway involving metal-ligand cooperation (MLC) is proposed to be important in many transition metal catalyzed hydrogenation and dehydrogenation reactions. Nevertheless, there is a paucity of experimental information probing the mechanism of this transformation. Here, we present an in-depth kinetic study of the 1,2-addition of H 2 via an MLC pathway to the widely used iron catalyst [( i Pr PNP)FeH(CO)] ( 1 ) ( i Pr PNP = N(CH 2 CH 2 P i Pr 2 ) 2 - ). We report one of the first experimental demonstrations of an enhancement in rate for the activation of H 2 using protic additives, which operate as "proton shuttles". Our results indicate that proton shuttles need to be able to both simultaneously donate and accept a proton, and the best shuttles are molecules that are strong hydrogen bond donors but sufficiently weak acids to avoid deleterious protonation of the transition metal complex. Additionally, comparison of the rate of H 2 activation via an MLC pathway between 1 and two widely used ruthenium catalysts enables more general conclusions about the role of the metal, ancillary ligand, and proton shuttles in H 2 activation. The results of this study provide guidance about the design of catalysts and additives to promote H 2 activation via an MLC pathway.