Luminescence quenching studies of [Ru(dMeObpy)3]2+ complex using the quinone derivative-effect of micelles

Quinones are considered a class of organic compounds having a quinonoid group and are the ultimate electron acceptors. Due to this property, they have favourable redox potential and the ability to form stable hydrogen bonds. Luminescence quenching is one of the most important techniques used to get information regarding the structure and dynamics of a luminophore. A variety of transition metal complexes have been synthesized and studied to comprehend the quinones' electron-accepting characteristics. Among these, Ru(II) polypyridyl complexes have widespread applications in electron transfer reactions due to their well-defined photophysical and photochemical stability. The reaction of excited state Tris(4,4'-dimethoxy-2,2'-bipyridine)ruthenium(II)tetrafluoroborate [Ru(dMeObpy)3](BF4)2 complex with quinones was investigated through photoinduced electron transfer reaction in homogeneous and microheterogenous medium. The luminescence quenching technique has been used to study this reaction. The complex has an absorbance maximum of 448 nm in aqueous medium. The quenching rate constants were deduced using the Stern-Volmer equation. The interaction between the complex and the quinones in a cationic micellar medium, cetyltrimethylammonium bromide (CTAB), was analyzed based on electrostatic interaction and hydrophobicity. The plot between RTlnkq vs. reduction potential of the quinones, as well as the transient absorption spectra, confirmed the oxidative nature of quenching of the ruthenium complex in the presence of quinones. The quenching constant values are influenced by many factors, such as the nature of the ligand, medium, size, and structure of quenchers, and electron transfer distance between the donor and the acceptor. The formation of Ru3+ species is confirmed by its characteristic absorption at 600 nm

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

3D Nanoporous FeAl-KIT-5 with a cage type pore structure: a highly efficient and stable catalyst for hydroarylation of styrene and arylacetylenes

A novel bimetallic nanoporous FeAl-KIT-5 catalyst with a cage type porous structure and a high surface area has been prepared for the hydroarylation of styrene and arylacetylenes to afford 1,1-diarylalkanes and 1,1-diarylalkenes, respectively. The catalyst was found to be highly active, and selective, affording a high yield of substituted alkanes and alkenes. The catalyst also showed much higher activity as compared to those of other nanoporous catalysts such as AlSBA-15, AlKIT-5, and FeKIT-5, and can be reused several times without much loss of its activity

Mesoporous and hexagonally ordered CuAl-SBA-15-catalyzed tandem C-C and C-O bond formation between phenols and allylic alcohols

A novel mesoporous catalyst, CuAl-SBA-15, with a hexagonally ordered porous structure prepared via a soft-templating approach in a highly acidic medium is used for tandem C-C and C-O bond formation between phenols and allylic alcohols to afford a variety of dihydrobenzopyrans in good yields. The catalyst is also found to be highly active for the synthesis of vitamin E and can be recycled several times without significant loss of its activity

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

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