Search

4,6-Bis(3,5-dimethyl-1H-pyrazol-1-yl)-N-phenyl-1,3,5-triazin-2-amine (PTA-1), N-(4-bromophenyl)-4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazin-2-amine (PTA-2) and 4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-N-(4-methoxyphenyl)-1,3,5-triazin-2-amine (PTA-3) were synthesized and characterized. Their corrosion inhibition of carbon C-steel in 0.25 M H2SO4 was studied by electrochemical impedance. The inhibition efficiency (IE%) of triazine was superior due to the cumulative inhibition of triazine core structure and pyrazole motif. Potentiodynamic polarizations suggested that s-triazine derivatives behave as mixed type inhibitors. The IE% values were 96.5% and 93.4% at 120 ppm for inhibitor PTA-2 and PTA-3 bearing –Br and –OCH3 groups on aniline, respectively. While PTA-1 without an electron donating group showed only 79.0% inhibition at 175 ppm. The adsorption of triazine derivatives followed Langmuir and Frumkin models. The values of adsorption equilibrium constant K°ads and free energy change ΔG°ads revealed that adsorption of inhibitor onto steel surface was favoured. A corrosion inhibition mechanism was proposed suggesting the presence of physical and chemical interactions. Density functional theory computational investigation corroborated nicely with the experimental results. Monte Carlo simulation revealed that the energy associated with the metal/adsorbate arrangement dE ads/dN i, for both forms of PTA-2 and PTA-3 with electron donating groups (−439.73 and −436.62 kcal mol−1) is higher than that of PTA-1 molecule (−428.73 kcal mol−1). This aligned with experimental inhibition efficiency results.

Significant efforts are continuously exerted by the scientific community to explore new strategies to design materials with high nonlinear optical responses. An effective approach is to design alkalides based on Janus molecules. Herein, we present a new approach to remarkably boost the NLO response of alkalides by stacking the Janus molecules. Alkalides based on stacked Janus molecule, M-n-M' (where n = 2 & 3 while M and M′ are Li/Na/K) are studied for structural, energetic, electrical, and nonlinear optical properties. The thermodynamic stability of the designed complexes is confirmed by the energetic stabilities, which range between -14.07 and -28.77 kcal/mol. The alkalide character of alkali metals-doped complexes is confirmed by the NBO charge transfer and HOMO(s) densities. The HOMO densities are located on the doped alkali metal atoms, indicating their alkalide character. The absorptions in UV–Vis and near IR region confirm the deep ultraviolet transparency of the designed complexes. The maximum first static and dynamic hyperpolarizabilities of 5.13 × 107 and 6.6 × 106 au (at 1339 nm) confirm their high NLO response, especially for K-2-M′ complexes. The NLO response of alkalides based on stacked Janus molecules is 1–2 orders of magnitude higher than the alkalide based on Janus monomer. The high values of dc-Kerr and electric field-induced response e.g., max ∼107 and 108 au, respectively have been obtained. These findings suggest that our designed complexes envision a new insight into the rational design of stable high NLO performance materials.

The designing of new materials having outstanding nonlinear optical (NLO) response is much needed for use in latest optics. Herein, the geometric, electronic and NLO properties of alkali and alkaline earth metals doped C6O6Li6 (alk-C6O6Li6-alkearth, alkearth = Ca, Mg, Be and alk = K, Na, Li) electrides is studied via quantum chemical approach. The interaction energies (Eint) are examined to illustrate their thermodynamic stability. The strong interaction energy of -39.99 kcal mol-1 is observed for Ca–C6O6Li6–Li electride in comparison to others. Frontier molecular orbitals (FMOs) energy gap of considered complexes is changed due to the electronic density shifting between metals and C6O6Li6 surface, which notifies the semi conducting properties of these electrides. The FMOs isodensities and natural bond orbital (NBO) charge analysis are performed to justify charge transfer between dopants and complexant. UV–Visible study also confirmed the application of these electrides as deep ultra-violet laser devices. NLO response is studied through calculation of first hyperpolarizability (βo). The highest βo value of 1.68 × 105 au is calculated for Mg–C6O6Li6–K electride. NLO response is further rationalized by three- and two-level models approach.

A new series of alkaline earthides based on Cryptand [2.2.2] (C222) containing nine complexes is designed by carefully placing alkali metals and alkaline earth metals inside and outside the C222 complexant, respectively i.e., M1(C222)M2 (M1 = Li, Na, K; M2 = Be, Mg, Ca). The designed complexes are reasonably stable both electronically and thermodynamically, as revealed through their vertical ionization potentials (VIPs) and interaction energies, respectively. Moreover, the true alkaline earthide nature of the complexes is confirmed through NBO and FMO analyses showing the negative charges and HOMOs over the alkaline earth metals, respectively. The further validity of true earthide characteristic is represented graphically by the spectra of partial density of states (PDOS). HOMO-LUMO gaps of the compounds are also very small (from 2.23 to 2.83 eV) when compared with pure cage's (C222) H-L gap i.e., 5.63 eV. All these features award these complexes with very small values of transition energies (ΔE) ranging from 0.68 to 2.06 eV ultimately resulting in remarkably high hyperpolarizability values up to 2.7 × 105 au (for Na+(C222)Mg−). Furthermore, applying external electric field (EEF) on the complexes enhances hyperpolarizability further. A remarkable increase of 1000 folds has been seen when hyperpolarizability of K+(C222)Ca− is calculated after EEF application i.e., from 8.79 × 104 au to 2.48 × 107 au; when subjected to 0.001 au external electric field.

Switchable nonlinear optical (NLO) materials have widespread applications in electronics and optoelectronics. Thermo-switches generate many times higher NLO responses as compared to photo-switches. Herein, we have investigated the geometric, electronic, and nonlinear optical properties of spiropyranes thermochromes via DFT methods. The stabilities of close and open isomers of selected spiropyranes are investigated through relative energies. Electronic properties are studied through frontier molecular orbitals (FMOs) analysis. The lower HOMO-LUMO energy gap and lower excitation energy are observed for open isomers of spiropyranes, which imparts the large first hyperpolarizability value. The delocalization of π-electrons, asymmetric distribution and elongated conjugation system are dominant factors for high hyperpolarizability values of open isomers. For deep understanding, we also analyzed the frequency-dependent hyperpolarizability and refractive index of considered thermochromes. The NLO response increased significantly with increasing frequency. Among all those compounds, the highest refractive index value is observed for the open isomer of the spiropyran 1 (1.99 × 10−17 cm2/W). Molecular absorption analysis confirmed the electronic excitation in the open isomers compared to closed isomers. The results show that reversible thermochromic compounds act as excellent NLO molecular switches and can be used to design advanced electronics.

The toxicity of transition metals, including copper(II), manganese(II), iron(II), zinc(II), hexavalent chromium, and cobalt(II), at elevated concentrations presents a significant threat to living organisms. Thus, the development of efficient sensors capable of detecting these metals is of utmost importance. This study explores the utilization of two-dimensional nitrogenated holey graphene (C2N) nanosheet as a sensor for toxic transition metals. The C2N nanosheet’s periodic shape and standard pore size render it well suited for adsorbing transition metals. The interaction energies between transition metals and C2N nanosheets were calculated in both gas and solvent phases and were found to primarily result from physisorption, except for manganese and iron which exhibited chemisorption. To assess the interactions, we employed NCI, SAPT0, and QTAIM analyses, as well as FMO and NBO analysis, to examine the electronic properties of the TM@C2N system. Our results indicated that the adsorption of copper and chromium significantly reduced the HOMO–LUMO energy gap of C2N and significantly increased its electrical conductivity, confirming the high sensitivity of C2N towards copper and chromium. The sensitivity test further confirmed the superior sensitivity and selectivity of C2N towards copper. These findings offer valuable insight into the design and development of sensors for the detection of toxic transition metals.

Electronic and nonlinear optical properties of endohedral metallofullerenes are presented. The endohedral metallofullerenes contain transition metal encapsulated in inorganic fullerenes X12Y12 (X = B, Al & Y = N, P). The endohedral metallofullerenes (endo-TM@X12Y12) possess quite interesting geometric and electronic properties, which are the function of the nature of the atom and the size of fullerene. NBO charge and frontier molecular orbital analyses reveal that the transition metal encapsulated Al12N12 fullerenes (endo-TM@Al12N12) are true metalides when the transition metals are Ni, Cu and Zn. Endo-Cr@Al12N12 and endo-Co@Al12N12 are at the borderline between metalides and electrides with predominantly electride characteristics. The other members of the series are excess electron systems, which offer interesting electronic and nonlinear optical properties. The diversity of nature possessed by endo-TM@Al12N12 is not prevalent for other fullerenes. Endo-TM@Al12P12 are true metalides when the transition metals are (Cr-Zn). HOMO-LUMO gaps (EH-L) are reduced significantly for these endohedral metallofullerenes, with a maximum percent decrease in EH-L of up to 70%. Many complexes show odd–even oscillating behavior for EH-L and dipole moments. Odd electron species contain large dipole moments and small EH-L, whereas even electron systems have the opposite behavior. Despite the decrease in EH-L, these systems show high kinetic and thermodynamic stabilities. The encapsulation of transition metals is a highly exergonic process. These endo-TM@X12Y12 possess remarkable nonlinear optical response in which the first hyperpolarizability reaches up to 2.79 × 105 au for endo-V@Al12N12. This study helps in the comparative analysis of the potential nonlinear optical responses of electrides, metalides and other excess electron systems. In general, the potential nonlinear optical response of electrides is higher than metalides but lower than those of simple excess electron compounds. The higher non-linear optical response and interesting electronic characteristics of endo-TM@Al12N12 complexes may be promising contenders for potential NLO applications.

Zigzag molecular nanobelts have recently captured the interest of scientists because of their appealing aesthetic structures, intriguing chemical reactivities, and tantalizing features. In the current study, first-row transition metals supported on an H6-N3-belt[6]arene nanobelt are investigated for the electrocatalytic properties of these complexes for the hydrogen dissociation reaction (HDR). The interaction of the doped transition metal atom with the nanobelt is evaluated through interaction energy analysis, which reveals the significant thermodynamic stability of TM-doped nanobelt complexes. Electronic properties such as frontier molecular orbitals and natural bond orbitals analyses are also computed, to estimate the electronic perturbation upon doping. The highest reduction in the HOMO–LUMO energy gap compared to the bare nanobelt is seen in the case of the Zn@NB catalyst (4.76 eV). Furthermore, for the HDR reaction, the Sc@NB catalyst displays the best catalytic activity among the studied catalysts, with a hydrogen dissociation barrier of 0.13 eV, whereas the second-best catalytic activity is observed for the Zn@NB catalyst (0.36 eV). It is further found that multiple active sites, i.e., the presence of the metal atom and nitrogen atom moiety, help to facilitate the dissociation of the hydrogen molecule. These key findings of this study enhance the understanding of the relative stability, electronic features, and catalytic bindings of various TM@NB catalysts.

Carbon-based polynuclear clusters are designed and investigated for geometric, electronic, and nonlinear optical (NLO) properties at the CAM-B3LYP/6-311++G(d,p) level of theory. Significant binding energies per atom (ranging from −162.4 to −160.0 kcal mol−1) indicate excellent thermodynamic stabilities of these polynuclear clusters. The frontier molecular orbital (FMOs) analysis indicates excess electron nature of the clusters with low ionization potential, suggesting that they are alkali-like. The decreased energy gaps (EH-L) with increased alkali metals size revael the improved electrical conductivity (σ). The total density of state (TDOS) study reveals the alkali metals’ size-dependent electronic and conductive properties. The significant first and second hyperpolarizabilities are observed up to 5.78 × 103 and 5.55 × 106 au, respectively. The βo response shows dependence on the size of alkali metals. Furthermore, the absorption study shows transparency of these clusters in the deep-UV, and absorptions are observed at longer wavelengths (redshifted). The optical gaps from TD-DFT are considerably smaller than those of HOMO-LUMO gaps. The significant scattering hyperpolarizability (βHRS) value (1.62 × 104) is calculated for the C3 cluster, where octupolar contribution to βHRS is 92%. The dynamic first hyperpolarizability β(ω) is more pronounced for the EOPE effect at 532 nm, whereas SHG has notable values for second hyperpolarizability γ(ω).

V-series nerve agents are very lethal to health and cause the inactivation of acetylcholinesterase which leads to neuromuscular paralysis and, finally, death. Therefore, rapid detection and elimination of V-series nerve agents are very important. Herein, we have carried out a theoretical investigation of carbon nitride quantum dots (C2N) as an electrochemical sensor for the detection of V-series nerve agents, including VX, VS, VE, VG, and VM. Adsorption of V-series nerve agents on C2N quantum dots is explored at M05-2X/6-31++G(d,p) level of theory. The level of theory chosen is quite adequate in systems describing non-bonding interactions. The adsorption behavior of nerve agents is characterized by interaction energy, non-covalent interaction (NCI), Bader’s quantum theory of atoms in molecules (QTAIM), frontier molecular orbital (FMO), electron density difference (EDD), and charge transfer analysis. The computed adsorption energies of the studied complexes are in the range of −12.93 to −17.81 kcal/mol, which indicates the nerve agents are physiosorbed onto C2N surface through non-covalent interactions. The non-covalent interactions between V-series and C2N are confirmed through NCI and QTAIM analysis. EDD analysis is carried out to understand electron density shifting, which is further validated by natural bond orbital (NBO) analysis. FMO analysis is used to estimate the changes in energy gap of C2N on complexation through HOMO-LUMO energies. These findings suggest that C2N surface is highly selective toward VX, and it might be a promising candidate for the detection of V-series nerve agents.

A novel approach was carried to prepare trans-CuCl2L2 complex with the ligand L, (E)-(4-chlorophenyl)-N-(3-phenyl-4H-1,2,4-triazol-4-yl)methanimine which was formed in situ during the reaction of CuCl2 with 4-(4-chlorobenzylideneamino)-5-phenyl-2H-1,2,4-triazole-3(4H)-thione. The synthesized compounds were characterized by applying various spectroscopic techniques. The crystal structure of the complex was unambiguously determined using X-ray analysis indicating square planar geometry. Intermolecular H-bonds govern the supramolecular structure of the copper complex. Aromatic rings are stacked in an offset packing due to occurrence of π–π interactions. The structure is further corroborated with a detailed computational investigation. A thione–thiol tautomerism for the triazole compound was also studied. The Schiff base 1,2,4-triazole copper chloride complex is expected to have high anticancer activity.

Currently, hydrogen is recognized as the best alternative for fossil fuels because of its sustainable nature and environmentally friendly processing. In this study, hydrogen dissociation reaction is studied theoretically on the transition metal doped carbon nitride (C2N) surface through single atom catalysis. Each TMs@C2N complex is evaluated to obtain the most stable spin state for catalytic reaction. In addition, electronic properties (natural bond orbital NBO & frontier molecular orbital FMO) of the most stable spin state complex are further explored. During dissociation, hydrogen is primarily adsorbed on metal doped C2N surface and then dissociated heterolytically between metal and nitrogen atom of C2N surface. Results revealed that theFe@C2N surface is the most suitable catalyst for H2 dissociation reaction with activation barrier of 0.36 eV compared with Ni@C2N (0.40 eV) and Co@C2N (0.45 eV) complexes. The activation barrier for H2 dissociation reaction is quite low in case of Fe@C2N surface, which is comparatively better than already reported noble metal catalysts.

Continuous studies are being carried out to explore new methods and carrier surfaces for target drug delivery. Herein, we report the covalent triazine framework C6N6 as a drug delivery carrier for fluorouracil (FU) and nitrosourea (NU) anti-cancer drugs. FU and NU are physiosorbed on C6N6 with adsorption energies of −28.14 kcal/mol and −27.54 kcal/mol, respectively. The outcomes of the non-covalent index (NCI) and quantum theory of atoms in molecules (QTAIM) analyses reveal that the FU@C6N6 and NU@C6N6 complexes were stabilized through van der Waals interactions. Natural bond order (NBO) and electron density difference (EDD) analyses show an appreciable charge transfer from the drug and carrier. The FU@C6N6 complex had a higher charge transfer (−0.16 e−) compared to the NU@C6N6 complex (−0.02 e−). Frontier molecular orbital (FMO) analysis reveals that the adsorption of FU on C6N6 caused a more pronounced decrease in the HOMO-LUMO gap (EH-L) compared to that of NU. The results of the FMO analysis are consistent with the NBO and EDD analyses. The drug release mechanism was studied through dipole moments and pH effects. The highest decrease in adsorption energy was observed for the FU@C6N6 complex in an acidic medium, which indicates that FU can easily be off-loaded from the carrier (C6N6) to a target site because the cancerous cells have a low pH compared to a normal cell. Thus, it may be concluded that C6N6 possesses the therapeutic potential to act as a nanocarrier for FU to treat cancer. Furthermore, the current study will also provide motivation to the scientific community to explore new surfaces for drug delivery applications.

The corrosion inhibition effect of the three extracts from Harmal roots (HRE), leaves (HLE), and flowers (HFE) were studied for carbon steel corrosion inhibition in 0.25 M H2SO4 solution. The electrochemical impedance study indicated that the three types of extracts decreased corrosion effectively through a charge transfer mechanism. Harmal roots and leaf extracts showed inhibition values of 94.1% and 94.2%, while it was 88.7% for Harmal flower extract at the inhibitor concentration of 82.6 ppm. Potentiodynamic polarization data revealed that Harmal extracts acted through predominant cathodic type inhibition. Both the corrosion current density and corrosion rate decreased significantly in the presence of Harmal extracts compared to blank solution. The corrosion rate (mpy) value was 63.3, 86.1, and 180.7 for HRE, HLE, and HFE, respectively. The adsorption-free energy change ΔGads (kJ·mol−1) values calculated from the Langmuir adsorption isotherm plots were for HRE (−35.08), HLE (−33.17), and HFE (−33.12). Thus, corrosion inhibition occurred due to the adsorption of Harmal extract on the carbon steel surface via the chemisorption mechanism. Moreover, a computational investigation using B3LYP/6-311G++(d,p) basis set in both gaseous and aqueous phases was performed for the major alkaloids (1–8) present in the Harmal extract.

Trefoil factor 1 (TFF1) is a protein secreted by the gastric mucosa that protects against gastric tumourigenesis. Here, the authors show that TFF1 inhibits the oncogenic inflammatory response and IL-6-mediated STAT3 activation by interfering with the binding of IL6 to its receptor IL6Rα.

In this work it is demonstrated that enantiomerically enriched N-alkyl 2-oxazolinylazetidines undergo exclusive α-lithiation, and that the resulting lithiated intermediate is chemically stable but configurationally labile under the given experimental conditions that afford enantioenriched N-alkyl-2,2-disubstituted azetidines. Although this study reveals the configurational instability of the diastereomeric lithiated azetidines, it points out an interesting stereoconvergence of such lithiated intermediates towards the thermodynamically stable species, making the overall process highly stereoselective (er > 95:5, dr > 85:15) after trapping with electrophiles. This peculiar behavior has been rationalized by considering the dynamics at the azetidine nitrogen atom, the inversion at the C-Li center supported by in situ FT-IR experiments, and DFT calculations that suggested the presence of η3-coordinated species for diastereomeric lithiated azetidines. The described situation contrasted with the demonstrated stability of the smaller lithiated aziridine analogue. The capability of oxazolinylazetidines to undergo different reaction patterns with organolithium bases supports the model termed “dynamic control of reactivity” of relevance in organolithium chemistry. It has been demonstrated that only 2,2-substituted oxazolinylazetidines with suitable stereochemical requirements could undergo C=N addition of organolithiums in non-coordinating solvents, leading to useful precursors of chiral (er > 95:5) ketoazetidines.

Intestinal Parasitic Infections (IPIs) are a major public health problem worldwide, especially among children with a need for periodical evaluation of prevalence and risk factors to adopt an appropriate prevention strategy. This cross-sectional prospective study was conducted to identify prevalence, risk factors, characteristics, and impact of IPIs on school children in different regions of Jeddah, Saudi Arabia. Children were recruited from randomly selected schools. Questionnaires were distributed to students and filled by their parents to collect relevant information about sociodemographic, environmental, and hygienic living conditions. Stool samples and anthropometric measurements as indicators of nutritional status were collected from students who agreed to participate in the study. Fecal samples were examined by direct smear and formol-ether concentration method. Out of 581 collected stool samples, only 31 (5.3%) samples were positive for IPIs especially Blastocystis hominis (10 samples) and Giardia lamblia (six samples). The only two significant risk factors associated with IPIs were drinking water from tanks [odds ratio (OR): 3.35, 95% confidence interval (CI): 1.60–6.99, p = 0.001] and washing hands with only water (OR: 2.63, 95% CI: 1.17–5.93, p = 0.03). There was no significant impact of IPIs on growth parameters or level of children’s academic performance.

We introduced and studied a new generalization of the Burr type X distribution. Some of its properties were derived and numerically analyzed. The new density can be “right-skewed” and symmetric with “unimodal” and many “bimodal” shapes. The new failure rate can be “increasing,” “bathtub,” “J-shape,” “decreasing,” “increasing-constant-increasing,” “reversed J-shape,” and “upside-down (reversed U-shape).” The usefulness and flexibility of the new distribution were illustrated by means of four asymmetric bimodal right- and left-heavy tail real lifetime data.

In this article, the theoretical and mathematical study of peristaltic transport of a Jeffrey fluid in a rectangular duct with compliant walls is discussed. The constitutive equations are simplified under the implementation of low Reynolds number and long wavelength approximations. The analytical solution of the resulting equations is evaluated by Eigen function expansion method. The graphical aspects of all the parameters of interest are also analyzed. The graphs of velocity for two and three dimensional flow are plotted. The trapping bolus phenomenon is also discussed though streamlines.

Background/Aim: The objective was to evaluate the sero-prevalence of hepatitis B surface antigen (HBsAg) and IgM antibodies to hepatitis core antigen in Balochistan Province of Pakistan. Design of the study: A cross-sectional, population-based study. Place and time of the study: The study was conducted in Balochistan from 1 st January 2004 to 31 st December, 2008. The screening areas included Barkhan, Eashani, Khuzdar, Kodi Zikriani, Kohlu, Rakhni and Turbat. Materials and Methods: A total of 15,260 subjects were enrolled; 11,900 (78%) agreed to undergo screening. Fresh serum samples were tested for the presence of hepatitis B surface antigen and IgM antibodies to hepatitis B core antigen. Results: HBsAg was detected in 1166 (9.8%) while anti-HBc IgM was found in 117 (10.0%). HBsAg positivity was seen in 875 (12.7%) males and 291 (5.8%) females. The prevalence of hepatitis B in Balochistan varies from 3.3% in Khuzdar to 17.0% in Kodi Zikriani. Conclusions: It is utmost important to educate the public, to take proper measures to control the spread of infection and vaccination in order to interrupt transmission of this threatening public health problem in Balochistan province of Pakistan.

The molecular heterogeneity of renal cell carcinoma (RCC) complicates the therapeutic interventions for advanced metastatic disease and thus its management remains a significant challenge. This study investigates the role of the lncRNA CDKN2B-AS1 and miR-141-3p interactions in the progression and metastasis of kidney cancer. Human renal cancer cell lines (ACHN and Caki1), normal RPTEC cells, tissue cohorts, and a series of in vitro assays and in vivo mouse model were used for this study. An overexpression of CDKN2B-AS1 was observed in RCC compared to normal samples in TCGA and our in-house SFVAMC tissue cohorts. Reciprocally, we observed reduced expression of miR-141 in RCC compared to normal in the same cohorts. CDKN2B-AS1 shares regulatory miR-141 binding sites with CCND1 and CCND2 genes. Direct interactions of CDKN2B-AS1/miR-141/Cyclin D1-D2 were confirmed by RNA immunoprecipitation and luciferase reporter assays indicating that CDKN2B-AS1/miR-141/Cyclin D1-D2 acts as a ceRNA network in RCC. Functionally, attenuation of CDKN2B-AS1 and/or overexpression of miR-141 inhibited proliferation, clonogenicity, migration/invasion, induced apoptosis in vitro and suppressed tumor growth in xenograft mouse model. Further, overexpression of CDKN2B-AS1 is positively correlated with poor overall survival of RCC patients. Expression of miR-141 also robustly discriminated malignant from non-malignant tissues and its inhibition in normal RPTEC cells induced pro-cancerous characteristics. CDKN2B-AS1 attenuation or miR-141 overexpression decreased CCND1/CCND2 expression, resulting in reduced RAC1/pPXN that are involved in migration, invasion and epithelial-mesenchymal transition. This study, for the first time, deciphered the role of CDKN2B-AS1/miR-141/Cyclin D axis in RCC and highlights this network as a promising therapeutic target for the regulation of EMT driven metastasis in RCC.

The Poisson Topp Leone Burr XII distribution is extensively studied due to its broad relevance in analyzing censored real datasets from engineering, economics, and medicine. In this research, the distribution’s versatility is highlighted through the analysis of four specific real datasets. The study compares the Poisson Topp Leone Burr XII distribution with nine extensions of the Burr type XII distribution to determine which offers the best fit for these datasets. To evaluate the goodness-of-fit of the Poisson Topp Leone Burr XII distribution under right censoring, a modified Bagdonavicius-Nikulin ˇ goodness-of-fit test statistic is introduced and applied. This new test statistic is utilized to validate the distributional fit for the Poisson Topp Leone Burr XII distribution across the four right-censored datasets. The modified Bagdonavicius-Nikulin ˇ test statistic is employed to assess distributional validation, specifically in the context of right censoring. The application of this statistic involves analyzing each of the four censored datasets to confirm the appropriateness of the Poisson Topp Leone Burr XII distribution for these scenarios. Additionally, to support the evaluation of the modified goodness-of-fit test statistic, the Barzilai-Borwein algorithm is utilized. This algorithm is employed within a simulation study to further assess the effectiveness and reliability of the modified Bagdonavicius-Nikulin test statistic, thereby ensuring robust validation of ˇ the Poisson Topp Leone Burr XII distribution against the observed real datasets. [ABSTRACT FROM AUTHOR]

Boron functional groups are often introduced in place of aromatic carbon-hydrogen bonds to expedite small-molecule diversification through coupling of molecular fragments.sup.1-3. Current approaches based on transition-metal-catalysed activation of carbon-hydrogen bonds are effective for the borylation of many (hetero)aromatic derivatives.sup.4,5 but show narrow applicability to azines (nitrogen-containing aromatic heterocycles), which are key components of many pharmaceutical and agrochemical products.sup.6. Here we report an azine borylation strategy using stable and inexpensive amine-borane.sup.7 reagents. Photocatalysis converts these low-molecular-weight materials into highly reactive boryl radicals.sup.8 that undergo efficient addition to azine building blocks. This reactivity provides a mechanistically alternative tactic for sp.sup.2 carbon-boron bond assembly, where the elementary steps of transition-metal-mediated carbon-hydrogen bond activation and reductive elimination from azine-organometallic intermediates are replaced by a direct, Minisci.sup.9-style, radical addition. The strongly nucleophilic character of the amine-boryl radicals enables predictable and site-selective carbon-boron bond formation by targeting the azine's most activated position, including the challenging sites adjacent to the basic nitrogen atom. This approach enables access to aromatic sites that elude current strategies based on carbon-hydrogen bond activation, and has led to borylated materials that would otherwise be difficult to prepare. We have applied this process to the introduction of amine-borane functionalities to complex and industrially relevant products. The diversification of the borylated azine products by mainstream cross-coupling technologies establishes aromatic amino-boranes as a powerful class of building blocks for chemical synthesis. Selective borylation of azines--nitrogen-containing aromatic heterocycles used in the synthesis of many pharmaceuticals--is made possible by forming a radical from an aminoborane using a photocatalyst., Author(s): Ji Hye Kim [sup.1] , Timothée Constantin [sup.1] , Marco Simonetti [sup.1] , Josep Llaveria [sup.2] , Nadeem S. Sheikh [sup.3] , Daniele Leonori [sup.1] Author Affiliations: (1) Department [...]