Why nursing students do not report workplace bullying during clinical practice: A mixed methods systematic review.

BACKGROUND: Workplace bullying in clinical nurse education significantly threatens students' well-being and professional development. Despite its prevalence, many incidents go unreported, exacerbating the issue and compromising the quality of care. A significant gap exists in the literature regarding comprehensive mixed-methods systematic reviews on unreported bullying incidents among nursing students. This review aims to address this knowledge gap and propose effective strategies to tackle this pervasive problem. AIM: This mixed-methods systematic review aimed to explore the factors influencing the non-reporting of workplace bullying incidents among nursing students during clinical practice. DESIGN: Mixed-methods systematic review. REVIEW METHODS AND DATA SOURCES: An extensive literature search was conducted across ten databases, including PubMed, Cochrane, Embase, Web of Science, CINAHL, PsycINFO, Scopus, Chinese Biomedical, China National Knowledge Internet, and WANFANG, from database inception to November 1, 2023. Google Scholar and reference lists of included studies were also searched. Studies were selected based on eligibility criteria regarding population, phenomena of interest, and context. Two researchers independently assessed study quality, with disagreements resolved by a third reviewer. Relevant data were extracted and synthesized using the Joanna Briggs Institute's convergent integrated approach, ensuring a comprehensive integration of qualitative and quantitative findings. RESULTS: Twenty-one studies met the inclusion criteria, comprising six qualitative, twelve quantitative, and three mixed-methods studies. Four integrated themes emerged from nursing students' perspectives on reasons for not reporting workplace bullying during clinical practice: (i) fear and concerns related to reporting, (ii) concerns about professional image, (iii) barriers and challenges in reporting, and (iv) perceived ineffectiveness of reporting. CONCLUSIONS: This systematic review provides valuable insights into nursing students' perspectives on the non-reporting of workplace bullying incidents during clinical practice. Understanding these reasons enables stakeholders to collaboratively develop interventions to create a safer and more supportive environment for nursing students, ultimately enhancing quality care and the well-being of healthcare professionals.

Design, synthesis and biological evaluation of thieno[3,2-c]pyrazol-urea derivatives as potent glycogen synthase kinase 3ß inhibitors based on the DFG-out conformation.

Glycogen synthase kinase 3ß (GSK-3ß) is a potential therapeutic target for the treatment of a variety of human diseases. Here, we report the design and synthesis of a series of thieno[3,2-c]pyrazol-urea derivatives and evaluation of their GSK-3ß inhibitory activity. Among these analogues, the compound without substitution on terminal phenyl ring (3a) was found to be the most potent GSK-3ß inhibitor with an IC50 of 74.4 nM, while substitution on the terminal phenyl (3b-3p) led to decreased potency, independent of the position, size, or electronic properties of the substituents. Kinase selectivity assay revealed that 3a showed good selectivity over a panel of kinases, but was less selective over CDK1, CDK2 and CDK5. Additionally, the pharmacological properties of the synthesized compounds were investigated computationally by the SwissADME and the results showed that most of the compounds have good ADME profiles.

Prevalence of involuntary treatment among community-living older persons with dementia: A systematic review.

OBJECTIVE: This systematic review and meta-analysis aimed to ascertain the prevalence of involuntary treatment among community-living older persons with dementia and explore associated factors. METHODS: We comprehensively searched seven electronic databases (PubMed, Embase, Cochrane Library, Web of Science, CINAHL, PsycINFO, and Scopus) from their inception to October 17, 2023, with an update conducted on April 1, 2024. Meta-analysis synthesized prevalence estimates of involuntary treatment and its three subcategories, with 95% confidence intervals. RESULTS: This study included 11 research papers involving 12,136 community-dwelling individuals with cognitive impairment and dementia from 19 countries. The pooled prevalence of involuntary treatment among community-dwelling older persons with dementia was 45.2% (95% CI: 33.7-60.5%). Subcategories included physical restraints (9.8%, 95% CI: 5.1-18.8%), psychotropic medication (19.1%, 95% CI: 13.6-26.9%), and non-consensual care (34.3%, 27.6-42.7%). Factors influencing involuntary treatment were categorized as caregiver-related and care recipient-related. CONCLUSION: This study underscores the prevalent use of involuntary treatment among community-dwelling older persons with dementia, emphasizing its association with specific caregiver and care recipient factors. Addressing these findings underscores the importance of proactive measures and targeted interventions to improve the quality of care for this vulnerable population.

Treponema pallidum protein Tp0136 promotes angiogenesis to facilitate the dissemination of Treponema pallidum.

The incompletely eliminated Treponema pallidum (T. pallidum) during primary syphilis chancre infection can result in the progression of secondary, tertiary, or latent syphilis in individuals, suggesting that T. pallidum has successfully evaded the immune response and spread to distant sites. The mechanism underlying the dissemination of T. pallidum is unclear. Here, a syphilitic rabbit model dorsal-injected with recombinant Tp0136 protein or Tp0136 antibody subcutaneously was used to demonstrate the role of Tp0136 protein in promoting the dissemination of T. pallidum to the testis and angiogenesis in vivo; vascular endothelial cell line HMEC-1 was employed to display that Tp0136 protein enhances the angiogenesis. Furthermore, the three-dimensional microfluidic angiogenesis system showed that the angiogenesis would heighten vascular permeability. Then transcriptome sequencing analysis, in conjunction with cell-level validation, elucidated the critical role of the PI3K-AKT signaling pathway in the promotion of angiogenesis by Tp0136 protein, resulting in heightened permeability. These findings elucidate the strategy employed by T. pallidum in evading immune clearance.

Insight into the Metal-Involving Chalcogen Bond in the PdII/PtII-Based Complexes: Comparison with the Conventional Chalcogen Bond.

The metal-involving Ch···M chalcogen bond and the conventional Ch···O chalcogen bond between ChX2 (Ch = Se, Te; X = CCH, CN) acting as a Lewis acid and M(acac)2 (M = Pd, Pt; Hacac = acetylacetone) acting as a Lewis base were studied by density functional theory calculations. It has been observed that the nucleophilicity of the PtII complexes is higher than that of the corresponding PdII complexes. As a result, the PtII complexes tend to exhibit a more negative interaction energy and larger orbital interaction. The strength of the chalcogen bond increases with the increase of the chalcogen atom and the electronegativity of the substituent on the Lewis acid and vice versa. The metal-involving chalcogen bond shows a typical weak closed-shell noncovalent interaction in the (HCC)2Ch···M(acac)2 complexes, while it exhibits a partially covalent nature in the (NC)2Ch···M(acac)2 complexes. The conventional Ch···O chalcogen bond displays the character of a weak noncovalent interaction, and its strength is generally weaker than that of metal-involving Ch···M interactions. It could be argued that the metal-involving chalcogen bond is primarily determined by the correlation term, whereas the conventional chalcogen bond is mainly governed by the electrostatic interaction.

Hypervalent Chalcogen Bonds Catalysis on the Intramolecular Aza-Michael Reaction of Aminochalcone: Catalytic Performance and Chalcogen Bond Properties.

Chalcogen bond (ChB) catalysis, as a new type in the field of non-covalent bond catalysis, has become a hot research topic in the field of organocatalysis in recent years. In the present work, we investigated the catalytic performance of a series of hypervalent ChB catalysis based on the intramolecular Aza-Michael reaction of aminochalcone. The reaction includes the carbon-nitrogen bond coupling step (key step) and the proton transfer step. The catalytic performance of mono-dentate pentafluorophenyl chalcogen bond donor ChB1 was comparable to that of bis-dentate chalcogen bond donor ChB4, and stronger than that of mono-dentate chalcogen bond donors ChB2 and ChB3. The formation of the chalcogen bond between the catalyst and the carbonyl oxygen atom of the reactant, causing the charge rearrangement of the reactant and C(1) charge of the -C-Ph group to become more positive, thereby the ChB catalysis promoted the nucleophile reaction. The electron density of the chalcogen bond of the pre-complex, the most positive electrostatic potentials of the catalyst, and the NPA charge of the key atom are proportional to the Gibbs energy barrier of the C-N bond coupling process, which provides an idea to predict the catalytic activity of the ChB catalysis.

Loneliness and social isolation among informal carers of individuals with dementia: A systematic review and meta-analysis.

OBJECTIVES: This systematic review and meta-analysis aimed to determine the prevalence of loneliness and social isolation among informal carers of individuals with dementia and to identify potential influencing factors. METHODS: We conducted a comprehensive search across 10 electronic databases, including PubMed, Cochrane, Embase, Web of Science, PsycINFO, CINAHL, Scopus, Chinese Biomedical, China National Knowledge Internet, and WANFANG. Our search strategy covered the inception of the databases up to September 16, 2023, with an updated search conducted on March 8, 2024. Prevalence estimates of loneliness and social isolation, presented with 95% confidence intervals, were synthesized through meta-analysis. Subgroup analyses and meta-regression were employed to explore potential moderating variables and heterogeneity. RESULTS: The study encompassed 27 research papers involving 11,134 informal carers from 17 different countries. The pooled prevalence of loneliness among informal carers of individuals with dementia was 50.8% (95% CI: 41.8%-59.8%), while the pooled prevalence of social isolation was 37.1% (95% CI: 26.7%-47.6%). Subgroup analyses and meta-regression indicated that various factors significantly influenced the prevalence of loneliness and social isolation. These factors included the caregiving setting, study design, the intensity of loneliness, geographical location (continent), data collection time, and the choice of assessment tools. CONCLUSIONS: This study underscores the substantial prevalence of loneliness and social isolation among informal carers of individuals with dementia. It suggests that policymakers and healthcare providers should prioritize the development of targeted interventions and support systems to alleviate loneliness and social isolation within this vulnerable population.

Pressure and temperature dependent kinetics and the reaction mechanism of Criegee intermediates with vinyl alcohol: a theoretical study.

Criegee intermediates (CIs), the key intermediates in the ozonolysis of olefins in atmosphere, have received much attention due to their high activity. The reaction mechanism of the most simple Criegee intermediate CH2OO with vinyl alcohol (VA) was investigated by using the HL//M06-2X/def2TZVP method. The temperature and pressure dependent rate constant and product branching ratio were calculated using the master equation method. For CH2OO + syn-VA, 1,4-insertion is the main reaction channel while for the CH2OO + anti-VA, cycloaddition and 1,2-insertion into the O-H bond are more favorable than the 1,4-insertion reaction. The 1,4-insertion or cycloaddition intermediates are stabilized collisionally at 300 K and 760 torr, and the dissociation products involving OH are formed at higher temperature and lower pressure. The rate constants of the CH2OO reaction with syn-VA and anti-VA both show negative temperature effects, and they are 2.95 × 10-11 and 2.07 × 10-13 cm3 molecule-1 s-1 at 300 K, respectively, and the former is agreement with the prediction in the literature.

Cationic Hypervalent Chalcogen Bond Catalysis on the Povarov Reaction: Reactivity and Stereoselectivity.

Chalcogen bond catalysis, particularly cationic hypervalent chalcogen bond catalysis, is considered to be an effective strategy for organocatalysis. In this work, the cationic hypervalent chalcogen bond catalysis for the Povarov reaction between N-benzylideneaniline and ethyl vinyl ether was investigated by density functional theory (DFT). The catalytic reaction involves the cycloaddition process and the proton transfer process, and the rate-determining step is the cycloaddition process. Cationic hypervalent tellurium derivatives bearing CF3 and F groups exhibit superior catalytic activity. For the rate-determining step, the Gibbs free energy barrier decreases as the positive electrostatic potential of the chalcogen bond catalysts increases. More importantly, the Gibbs free energy barrier has a strong linear correlation with the electrostatic energy of the chalcogen bond in the catalyst-substrate complex. Furthermore, the catalytic reactions include the endo pathway and exo pathway. The C-H⋅⋅⋅π interaction between the substituent of the ethyl vinyl ether and the aryl ring of the N-benzylideneaniline contributes to the endo-selectivity of the reaction. This research contributes to a deeper understanding of chalcogen bond catalysis, providing insights for designing chalcogen bond catalysts with high performance.

Halogen Bond Catalysis: A Physical Chemistry Perspective.

As important noncovalent interactions, halogen bonds have been widely used in material science, supramolecular chemistry, medicinal chemistry, organocatalysis, and other fields. In the past 15 years, halogen bond catalysis has become a developed field in organocatalysis for the catalysts' advantages of being environmentally friendly, inexpensive, and recyclable. Halogen bonds can induce various organic reactions, and halogen bond catalysis has become a powerful alternative to the fully explored hydrogen bond catalysis. From a physical chemistry view, this perspective provides an overview of the latest progress and key examples of halogen bond catalysis via activation of the lone pair systems of organic functional group, π systems, and metal complexes. The research progresses in halogen bond catalysis by our group were also introduced.

The levels and related factors of posttraumatic growth among nurses: A systematic review and meta-analysis.

WHAT IS KNOWN ON THE SUBJECT?: Nurses often encounter traumatic events in their clinical practice. Trauma can have both negative effects, such as post-traumatic stress disorder and positive effects, such as growth and positive emotions. Posttraumatic growth is beneficial for nurses, as it contributes to positive mental health outcomes and increases life satisfaction. WHAT THE PAPER ADDS TO EXISTING KNOWLEDGE?: Our study confirms that nurses commonly experience posttraumatic growth after being exposed to traumatic events, and the level of growth is moderate. We have identified individual, work-related, and social and organizational factors that may influence the occurrence of posttraumatic growth among nurses. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Our findings provide valuable insights for interventions aimed at promoting posttraumatic growth among nurses. It is crucial to consider individual factors, work-related factors, and social and organizational factors when designing these interventions. By addressing these factors, healthcare professionals can support nurses in coping with trauma and facilitate their posttraumatic growth. ABSTRACT: INTRODUCTION: While the negative effects of trauma on nurses have been well-documented, it is equally important to focus on ways to promote posttraumatic growth (PTG) among nurses. AIM: This study aims to explore the levels and related factors of PTG among nurses. METHOD: A comprehensive search was conducted across nine databases up to 26 December 2022. The pooled mean score for PTG was calculated and presented with a 95% confidence interval. Subgroup and meta-regression analyses were performed to identify potential moderators of PTG among nurses. RESULTS: A total of 55 studies, involving 35,621 nurses from 11 countries and regions, were included in this review. The pooled scores of the PTG indicated that nurses experienced a moderate level of PTG (55.69, 95% CI: 50.67-60.72). DISCUSSION: Nurses commonly experience PTG following exposure to traumatic events, with a moderate level of PTG. Our systematic review highlights the potential determinants of PTG among nurses, including individual, work-related, and social and organizational factors. IMPLICATIONS FOR PRACTICE: Targeting these factors in interventions can provide nurses with the necessary resources and support to effectively cope with stress and trauma, and potentially facilitate PTG.

Mechanism and Stereoselectivity Control of Terminal Alkyne Dimerization Activated by a Zr/Co Heterobimetallic Complex: A DFT Study.

Heterobimetallic complexes have recently garnered considerable attention in organic synthesis owing to their high activity and selectivity, which surpass those of monometallic complexes. In this study, the detailed mechanisms of terminal alkyne dimerization activated by the heterobimetallic Zr/Co complex, as well as the different stereoselectivities of Me3SiC≡CH and PhC≡CH dimerization, were investigated and elucidated by using density functional theory calculations. After excluding the three-molecule reaction and outer-sphere mechanisms, the inner-sphere mechanism was determined as the most optimal process. The inner-sphere mechanism involves four processes: THF dissociation and coordination of the first alkyne; ligand migration and C-H activation; N2 dissociation and insertion of the second alkyne; and reductive elimination. The stereoselectivity between the E-/Z- and gem-isomers is determined by the C-C coupling mode of the two alkynes and that of the E- and Z-isomers is determined by the sequence of the C-C coupling and hydrogen migration in the reductive elimination process. Me3SiC≡CH dimerization yields only an E-isomer owing to the large differences in the distortion and interaction energies, whereas PhC≡CH dimerization produces an E-, Z-, and gem-isomers owing to the reduced interaction energy differences.

Global prevalence of bullying and associated factors among nursing students during clinical practice: A systematic review and meta-analysis.

OBJECTIVE: This meta-analysis aims to estimate the global prevalence of bullying among nursing students during clinical practice and identify associated factors. DESIGN: Systematic review and meta-analysis. REVIEW METHODS AND DATA SOURCES: We conducted a comprehensive literature search across ten databases (PubMed, Cochrane, Web of Science, Embase, CINAHL, PsycINFO, Scopus, Chinese Biomedical, China National Knowledge Internet, and WANFANG) from their inception to January 3, 2023. Two researchers independently screened potentially eligible studies, extracted data, and assessed study quality. Data were analyzed using random-effects or fixed-effects models. Subgroup analyses and meta-regression explored the influence of participant and study characteristics on bullying prevalence. Publication bias and sensitivity analyses were also performed. RESULTS: We included 28 studies (N = 9511) from 13 countries on five continents. The pooled estimate of bullying prevalence among nursing students during clinical practice was 65.60 % (95 % CI 55. 75 to 74.27), with no evidence of publication bias (t = 1.51, p-value = 0.14). Subgroup and moderator analyses highlighted the impact of country, continent, publication year, and assessment tool on bullying prevalence. CONCLUSION: Nursing students face a high prevalence of bullying during clinical practice. Addressing this issue in nursing education requires prioritizing associated factors, fostering a culture of safety, providing effective training, and promoting individual resilience. These actions can prevent and mitigate bullying, creating a supportive and empowering learning environment for future nurses.

Halogen bond catalysis of the [4+2] cycloaddition reaction of 2-alkenylindoles: catalytic modes and stereoselectivity.

Halogen bond donor catalysts have been widely used in organic reactions because they are environmentally friendly, inexpensive and recyclable. The [4+2] cycloaddition reaction is a key reaction in organic synthesis because of its ease of use, fast speed, and wide range of applications. In this work, halogen bond catalysis in the [4+2] cycloaddition reaction between 2-alkenylindoles was investigated based on DFT calculations. There are two modes of I⋯π halogen bond catalysis: either on the ethenyl of 2-alkenylindole (mode A) or on the five-membered ring of 2-alkenylindole (mode B). Both modes involve two steps: the formation of carbon-carbon bonds and the formation of six-membered rings. Gibbs free energy barriers were determined to investigate the stereoselectivity of the endo pathway and exo pathway. For mode A, the exo products were more easily generated when the substituent R = H, and the N-H⋯π interaction promoted high endo selectivity in the case of the substituent R = Ph. For mode B, an increasing proportion of endo products can be obtained in the order of catalyst I2, IBr and ICl. The π⋯π interaction of the substituent R = Ph promotes the [4+2] cycloaddition reaction, which is consistent with the experimental observation that R = Ph has a higher yield than R = H. The study of different catalytic modes and stereoselectivity would provide new ideas for the further study of the [4+2] cycloaddition reaction.

A Real-Time and Robust Neural Network Model for Low-Measurement-Rate Compressed-Sensing Image Reconstruction.

Compressed sensing (CS) is a popular data compression theory for many computer vision tasks, but the high reconstruction complexity for images prevents it from being used in many real-world applications. Existing end-to-end learning methods achieved real time sensing but lack theory guarantee for robust reconstruction results. This paper proposes a neural network called RootsNet, which integrates the CS mechanism into the network to prevent error propagation. So, RootsNet knows what will happen if some modules in the network go wrong. It also implements real-time and successfully reconstructed extremely low measurement rates that are impossible for traditional optimization-theory-based methods. For qualitative validation, RootsNet is implemented in two real-world measurement applications, i.e., a near-field microwave imaging system and a pipeline inspection system, where RootsNet easily saves 60% more measurement time and 95% more data compared with the state-of-the-art optimization-theory-based reconstruction methods. Without losing generality, comprehensive experiments are performed on general datasets, including evaluating the key components in RootsNet, the reconstruction uncertainty, quality, and efficiency. RootsNet has the best uncertainty performance and efficiency, and achieves the best reconstruction quality under super low-measurement rates.

Experiences and perspectives of nurses infected with COVID-19: A qualitative systematic review and meta-synthesis.

This qualitative systematic review aims to comprehensively understand the experiences and perspectives of nurses infected with COVID-19, addressing a significant gap in the current literature. Following the JBI meta-synthesis approach, a rigorous search was conducted across nine electronic databases and references until January 16, 2023. Seventeen eligible studies underwent quality assessment using the JBI critical checklist. Data were synthesized using standardized tools, and the ConQual tool evaluated confidence in the findings. Seven key findings emerged, providing valuable insights into emotional experiences, adaptation to COVID-19 challenges, influence of support systems, coping strategies, posttraumatic growth perceptions, and effects on professional identity and career advancement. The findings highlight emotional toll, adaptive strategies, and professional implications for nurses. Moreover, they emphasize the importance of support systems, coping mechanisms, and posttraumatic growth in promoting nurses' well-being and resilience. These insights have practical implications for targeted interventions and support mechanisms to enhance infected nurses' well-being and improve healthcare outcomes.

USF1 modulates transcription and cellular functions by regulating multiple transcription factors in Huh7 cells.

Liver cancer, including hepatocellular carcinoma (HCC), is a malignant tumor that has high rates of metastasis and mortality worldwide. Upstream transcription factor 1 (USF1) is a canonical transcription factor (TF) and is associated with the pathogenesis of several cancers, but its biological functions and molecular targets in HCC remain unclear. Huh7 cells that overexpress USF1 were used with whole transcriptome profiling through RNA sequencing and chromatin immunoprecipitation (ChIP) sequencing methods to investigate the downstream targets of USF1. Reverse transcription-quantitative PCR was then used to validate the downstream targets. The results showed that USF1 significantly regulates 350 differentially expressed genes (DEGs). The upregulated DEGs were primarily protein-coding genes enriched in immune and inflammation response pathways, while the downregulated DEGs were mainly coding long non-coding (lnc)RNAs, indicating the regulatory function of USF1. It was also demonstrated that USF1 directly binds to the promoter region of 2,492 genes, which may be involved in the viral progression and cell proliferation pathways. By integrating these two datasets, 16 overlapped genes were detected, including downregulated lncRNA-NEAT1 and upregulated TF-ETV5. The downregulated lncRNA-NEAT1 showed reverse expression pattern and prognosis result compared with that of USF1 in patients with liver cancer, while upregulated TF-ETV5 showed consistent results with USF1. Promoter region motif analysis indicated that ETV5 has more binding motifs and genes than USF1 itself for USF1-regulated DEGs, indicating that USF1 may indirectly modulate gene expression by regulating ETV5 expression in Huh7 cells. The study also validated the direct interaction between USF1 and the promoter of ETV5 using ChIP-qPCR. In summary, the results demonstrated that USF1 binds to the promoter region of thousands of genes and affects a large part of DEGs indirectly. Downstream genes, including lncRNA-NEAT1 and TF-ETV5, may also have potential functions in the regulated network by USF1 and have potential functions in the progression of HCC. The present findings suggested that USF1 and its downstream targets could be potential targets for HCC therapy in the future.

Gold(III) derivatives as the noncovalent interaction donors: theoretical study of the π-hole regium bonds.

Except for the well-known σ-hole regium bonds formed by metal nanoparticles and M(I) (M = Cu, Ag, and Au) derivatives, the existence of π-hole regions located above and below the Au atom in gold(III) derivatives suggests that gold(III) also functions as an efficient electrophilic site. In this study, a comprehensive analysis was conducted on the electrophilicity of trichloro-(p-toluonitrilo-N)-gold(III) derivatives AuL3(NCC6H4X) (L = Cl, Br, CN; X = NH2, CH3, CF3, NC, and CN) and the nature of π-hole regium bonds in the AuL3(NCC6H4X)⋯LB (LB = NH3, N(NH3)3, CH2O, C2H2, C2H4, C6H6) and (AuCl3(NCC6H4Y))n (Y = Cl, CN, NC, NO2; n = 2, 3)) complexes. The characteristics of the π-hole regium bonds were studied with respect to the influence of ligands and substituents, the strength of intermolecular interactions between Au(III) derivatives and Lewis bases, and those in the polymers. In the case of the AuL3(NCC6H4X)⋯NH3 complexes, the strength of the regium bonds increases gradually in the order of L = Cl < Br < CN and X = NH2 < CH3 < CF3 ≈ NC < CN. The ligands (L) attached to the Au atom exert a significant effect on the strength of the π-hole regium bonds in comparison to the substituents (X) on the benzene ring. The regium bonds are primarily dominated by electrostatic interaction, accompanied by moderate contribution from polarization. Linear relationships were identified between the electrostatic energies and the local most positive potentials over the Au atom, as well as between the polarization energies and the amount of charge transfer. Most of the π-hole regium bonds in the AuL3(NCC6H4X)⋯LB complexes exhibit the characters of closed shell noncovalent interactions. In the polymers (AuCl3(NCC6H4Y))n, weak face-to-face π-π stacking interactions are also present, in addition to regium bonds. The trimers displayed a slightly negative cooperativity in comparison to the dimers.

Chalcogen Bond Catalysis with Telluronium Cations for Bromination Reaction: Importance of Electrostatic and Polarization Effects.

Recently, chalcogen bond catalysts with telluronium cations have garnered considerable attention in organic reactions. In this work, chalcogen bond catalysis on the bromination reaction of anisole with N-bromosuccinimide (NBS) with the telluronium cationic catalysts has been explored with density functional theory (DFT). The catalytic reaction is divided into two stages: the bromine transfer step and the proton transfer step. Based on the computational results, one can find the rate-determining step is the bromine transfer step. Moreover, the present study elucidates that a stronger chalcogen bond between catalysts and NBS will give better catalytic performance. Additionally, this work also clarified the importance of the electrostatic and polarization effects in the chalcogen bond between the oxygen atom of NBS and the Te atom of the catalyst in this bromination reaction. The electrostatic and polarization effects are significantly influenced by the electron-withdrawing ability of the substitution groups on the catalysts. Moreover, the structure-property relationship between the strength of chalcogen bond, electrostatic effect, polarization effect and catalytic performance are established for the design of more efficient chalcogen bond catalysts.

Iodine(I)-based and iodine(III)-based halogen bond catalysis on the Friedel-Crafts reaction: a theoretical study.

Halogen bond catalysis, especially iodine derivatives catalysis, has attracted increasing attention in recent years owing to the advantages of relatively cheap, stable, green, easy to handle, and favorable catalytic activity. To obtain insights into the catalytic mechanism and activity of halogen bond donor catalysts, iodine(I)-based and iodine(III)-based halogen bond catalysis on the Friedel-Crafts reaction were investigated in this study. The entire reaction contains several key steps: carbon-carbon bond coupling, proton transfer, hydroxyl departure, indole addition, and deprotonation process. According to the energetic span model, iodine(III)-based donor catalysts exhibit higher catalytic activity than iodine(I)-based catalysts and double cationic catalysts are more potent than single cationic ones. For halogen bond catalysis, the Gibbs energy barriers have linear relation to the electron density at the halogen bond critical points. Furthermore, the Gibbs energy barriers are also linearly related to the integral charge values of the increased region of electron density outside the oxygen atom of reactants. Therefore, the stronger halogen bond results in lower Gibbs energy barrier, and the stronger polarization further benefits the halogen bond catalysis.