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Introduction: This study aims to investigate the psychosocial characteristics of suicide deaths in Korea according to population inflow and outflow, and to identify high-risk suicide groups by regional type in order to establish tailored suicide prevention plans for each region., Methods: The analysis included 4193 suicide deaths from four regional types in Korea. The data source was a comprehensive survey of suicide deaths through police investigation records from the Korean government. The analysis involved collecting demographic variables, suicide-related variables, and stress variables at the time of death for suicide deaths in each region and conducting cross-analysis and multinomial logistic regression analysis., Results: Across all regions, factors such as male gender, unemployment, hanging in one's own home, and mental health problems were prevalent. However, in population-inflow urban areas, early-middle age and economic problems were higher, in population-outflow urban areas, late-middle age and economic problems were more prominent. Additionally, in both inflow and outflow rural areas, there was a relatively higher proportion of old age and physical health problems., Conclusions: This study is significant for confirming common and specific factors influencing suicide in each region, and for proposing considerations when formulating tailored suicide prevention plans for local communities., (© 2024 The Author(s). Suicide and Life‐Threatening Behavior published by Wiley Periodicals LLC on behalf of American Association of Suicidology.)

Two o -carboranes with (i) 9,9-dimethyl-9 H -xanthene and (ii) spiro[fluorene-9,9'-xanthene] moieties ( XTC and sXTC , respectively) were prepared and characterized. Single X-ray crystallography analysis revealed the presence of intermolecular hydrogen bonds in XTC crystals. Although both compounds did not exhibit emission in tetrahydrofuran solutions at 298 K, intense bluish emission was observed in the solid states and frozen tetrahydrofuran solutions at 77 K. According to the results of theoretical calculations, this emission originated from an intramolecular charge transfer (ICT) transition with the o -carborane moiety. The absolute quantum efficiency (Φ em ) of the ICT-based emission in the film state equaled 49% for XTC and 20% for sXTC but was as high as 90% for the crystals of both compounds. The crystal structures of XTC and sXTC revealed that the o -carboranyl-appended phenyl plane was orthogonal (85-89°) to the carbon-carbon bonding axis in the o -carborane, indicating the existence of a strong exo -π-interaction, which was identified as the structural basis for the ICT-based transition. These results implied that the intermolecular structural effect of XTC in the randomly aggregated solid state (film) helped maintain the above orthogonality and, hence, the high efficiency from the ICT radiative mechanism. Thus, we concluded that the ICT radiative efficiency of o -carboranyl luminophores in the aggregated solid state can be controlled by specific intermolecular interactions and that the molecular geometric design inducing this feature can be important for developing highly efficient carboranyl luminophores.

Objective: Given the high suicide risk among people with schizophrenia and other mental disorders and the significance of intervention in the daily life setting, tailored gatekeeper training is necessary for families of people with mental disorders. This study evaluated the effectiveness of a suicide prevention education program for families of people with mental disorders (SPEM-F), developed by the Korea Foundation for Suicide Prevention., Methods: Fifty-nine family members of people with mental disorders were recruited from eight community psychiatric rehabilitation centers in Korea and enrolled in a cluster randomized controlled trial. Four facilities were randomized to the experimental group (n=30) and four to the control group (n=29). The study parameters were measured at baseline, post-intervention, and 1-month follow-up; the effects of SPEM-F (90 minutes, conducted offline) were analyzed using repeated-measures analysis of variance. The dependent variables were suicide-related knowledge, attitude, self-efficacy, preventive behavioral intention, and family problem-solving communication., Results: The experimental group showed significant increases in suicide-related knowledge (p<0.001), self-efficacy (p<0.05), and preventive behavioral intention (p<0.01) compared with the control group until the 1-month follow-up, including an upward trend in improved family problem-solving communication (p=0.069)., Conclusion: The results confirm that SPEM-F is an effective evidence-based gatekeeper training program for families of people with mental disorders, as it focuses on knowledge, self-efficacy, preventive behavioral intention, and communication improvement. As families of people with mental disorders including schizophrenia, are both highly motivated and close to people at high risk for suicide, SPEM-F can effectively promote suicide prevention and gatekeeper activities.

In this study, we found that the electronic effects of the functional groups on aromatic units attached to o -carboranyl species can enhance the efficiency of intramolecular charge transfer (ICT)-based radiative decay processes. Six o -carboranyl-based luminophores having attached functionalized biphenyl groups with CF 3 , F, H, CH 3 , C(CH 3 ) 3 , and OCH 3 substituents were prepared and fully characterized by multinuclear magnetic resonance spectroscopy. In addition, their molecular structures were determined by single-crystal X-ray diffractometry, which revealed that the distortion of the biphenyl rings and the geometries around the o -carborane cages were similar. All compounds exhibited ICT-based emissions in the rigid state (solution at 77 K and film). Intriguingly, the quantum efficiencies (Φ em ) of five compounds (that of the group with CF 3 could not be measured because of its extremely weak emissions) in the film state increased gradually as the electron-donating power of the terminal functional group modifying the biphenyl moiety increased. Furthermore, the nonradiative decay constants ( k nr ) for the group with OCH 3 were estimated to be one-tenth of those for the group with F, whereas the radiative decay constants ( k r ) for the five compounds were similar. The dipole moments (μ) calculated for the optimized first excited state (S 1 ) structures gradually increased, from that of the group with CF 3 to that of the group with OCH 3 , implying that the inhomogeneity of the molecular charge distribution was enhanced by electron donation. The electron-rich environment formed as a result of electron donation led to efficient charge transfer to the excited state. Both experimental and theoretical findings revealed that the electronic environment of the aromatic moiety in o -carboranyl luminophores can be controlled to accelerate or interrupt the ICT process in the radiative decay of excited states.

Herein, we prepared an o -carborane compound (9biAT) linked to a 9,9'-bianthracene moiety at each C9-position. The compound exhibited reddish emission in solid and solution states. The solvatochromism effect and theoretical calculation results for the excited (S 1 ) state of 9biAT verified that the emission was attributed to ICT transition. In particular, the structural rigidity and the orthogonal geometry around the carborane enhanced ICT-based emission in the solution state at 298 K, resulting in a considerably high quantum efficiency ( Φ em = 86%) in cyclohexane. In addition, both the Φ em value and radiative decay constant ( k r ) gradually decreased with an increase in the polarity of the organic solvent. Theoretical modelling of the charge distribution in the S 1 -optimised geometry revealed that charge recombination in the radiative-relaxation process upon ICT transition could be delayed under polar conditions. Consequently, a high Φ em value in the solution state at room temperature can be obtained by maintaining molecular rigidity and controlling the polarity of the environment.

Novel bipyridine-based heterocyclic building block, 3,10-dichloro-benzo[f][1,10]phenanthroline and its Ruthenium(II) complex have been synthesized and fully characterized. The synthesized Ru(II)-complex is highly luminescent displaying emission at 590 nm with quantum yield of ∼0.8 in methanol. Ru(II) complex showed photocytotoxicity upon 400 nm blue light irradiation. Mechanistic study revealed that photoactivated Ru(II) complex generates reactive radical species which can damage the protein inside the cells and induce cell death even with short irradiation time., Competing Interests: Declaration of Competing Interest 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., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The efficiency of intramolecular charge transfer (ICT)-based emission on π-aromatic-group-appended closo-ortho -carboranyl luminophores is known to be affected by structural fluctuations and molecular geometry, but investigation of this relationship has been in progress to date. In this study, four naphthyl-based bis- o -carboranyl compounds, in which hydrogen ( 15CH and 26CH ) or trimethysilyl groups ( 15CS and 26CS ) were appended at the o -carborane cage, were synthesized and fully characterized. All the compounds barely displayed an emissive trace in solution at 298 K; however, 15CH and 26CH distinctly exhibited a dual emissive pattern in rigid states (in solution at 77 K and in films), attributed to locally excited (LE) and ICT-based emission, while 15CS and 26CS showed strong ICT-based greenish emission. Intriguingly, the molecular structures of the four compounds, analyzed by single X-ray crystallography, showed that the C-C bond axis of the o -carborane cage in the trimethysilyl group-appended compounds 15CS and 26CS were more orthogonal to the plane of the appended naphthyl group than those in 15CH and 26CH . These features indicate that 15CS and 26CS present an efficient ICT transition based on strong exo -π-interaction, resulting in a higher quantum efficiency (Φ em ) for ICT-based radiative decay than those of 15CH and 26CH . Moreover, the 26CS structure revealed most orthogonal geometry, resulting in the highest Φ em and lowest k nr values for the ICT-based emission. Consequently, all the findings verified that efficient ICT-based radiative decay of aromatic group-appended o -carboranyl luminophores could be achieved by the formation of a specific geometry between the o -carborane cage and the aromatic plane.

o -Carboranyl compounds contain specific geometries, ranging from planar to orthogonally distorted biphenyl rings. Herein, 13 o -carboranyl compounds, 1HF-13PP , were synthesized and fully characterized to determine the impact of structural formation of the aromatic group appended with the o -carborane to estimate the efficiency of their radiative decay process. All the compounds exhibited significant intramolecular charge transfer (ICT)-based emission in the crystalline state at 298 K. Remarkably, increasing the distorted dihedral angles between biphenyl rings gradually decreased the emission efficiencies. Furthermore, their radiative decay constants decreased linearly with increasing dihedral angles, which demonstrated the inversely proportional relationship between these two factors. These findings distinctly suggest that the planar or distorted geometry of substituted aryl groups can strongly affect the efficiency of the ICT-based radiative process in o -carboranyl luminophores., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

In this paper, we propose a strategic molecular design of closo-o -carborane-based donor-acceptor dyad system that exhibits thermally activated delayed fluorescence (TADF) in the solution state at ambient temperature. Planar 9,9-dimethyl-9 H -fluorene-based compounds with closo - and nido-o -carborane cages appended at the C2-, C3-, and C4-positions of each fluorene moiety ( closo -type: 2FC , 3FC , 4FC , and 4FCH , and nido -type: nido - 4FC = [ nido -form of 4FC ]·[NBu 4 ]) were prepared and characterized. The solid-state molecular structure of 4FC exhibited a significantly distorted fluorene plane, which suggests the existence of severe intramolecular steric hindrance. In photoluminescence measurements, 4FC exhibits a noticeable intramolecular charge transition (ICT)-based emission in all states (solution at 298 K and 77 K, and solid states); however, emissions by other closo -compounds were observed in only the rigid state (solution at 77 K and film). Furthermore, nido - 4FC did not exhibit emissive traces in any state. These observations verify that all radiative decay processes correspond to ICT transitions triggered by closo-o -carborane, which acts as an electron acceptor. Relative energy barriers calculated by TD-DFT as dihedral angles around o -carborane cages change in closo -compounds, which indicates that the structural formation of 4FC is nearly fixed around its S 0 -optimized structure. This differs from that for other closo -compounds, wherein the free rotation of their o -carborane cages occurs easily at ambient temperature. Such rigidity in the structural geometry of 4FC results in ICT-based emission in solution at 298 K and enhancement of quantum efficiency and radiative decay constants compared to those for other closo -compounds. Furthermore, 4FC displays short-lived (∼0.5 ns) and long-lived (∼30 ns) PL decay components in solution at 298 K and in the film state, respectively, which can be attributed to prompt fluorescence and TADF, respectively. The calculated energy difference (Δ E ST ) between the first excited singlet and triplet states of the closo -compounds demonstrate that the TADF characteristic of 4FC originates from a significantly small Δ E ST maintained by the rigid structural fixation around its S 0 -optimized structure. Furthermore, the strategic molecular design of the o -carborane-appended π-conjugated (D-A) system, which forms a rigid geometry due to severe intramolecular steric hindrance, can enhance the radiative efficiency for ICT-based emission and trigger the TADF nature., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)