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1.
Genome Res ; 34(3): 498-513, 2024 04 25.
Artigo em Inglês | MEDLINE | ID: mdl-38508693

RESUMO

Hydractinia is a colonial marine hydroid that shows remarkable biological properties, including the capacity to regenerate its entire body throughout its lifetime, a process made possible by its adult migratory stem cells, known as i-cells. Here, we provide an in-depth characterization of the genomic structure and gene content of two Hydractinia species, Hydractinia symbiolongicarpus and Hydractinia echinata, placing them in a comparative evolutionary framework with other cnidarian genomes. We also generated and annotated a single-cell transcriptomic atlas for adult male H. symbiolongicarpus and identified cell-type markers for all major cell types, including key i-cell markers. Orthology analyses based on the markers revealed that Hydractinia's i-cells are highly enriched in genes that are widely shared amongst animals, a striking finding given that Hydractinia has a higher proportion of phylum-specific genes than any of the other 41 animals in our orthology analysis. These results indicate that Hydractinia's stem cells and early progenitor cells may use a toolkit shared with all animals, making it a promising model organism for future exploration of stem cell biology and regenerative medicine. The genomic and transcriptomic resources for Hydractinia presented here will enable further studies of their regenerative capacity, colonial morphology, and ability to distinguish self from nonself.


Assuntos
Genoma , Hidrozoários , Animais , Hidrozoários/genética , Evolução Molecular , Transcriptoma , Células-Tronco/metabolismo , Masculino , Filogenia , Análise de Célula Única/métodos
2.
Nature ; 590(7845): 284-289, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33461212

RESUMO

Lungfishes belong to lobe-fined fish (Sarcopterygii) that, in the Devonian period, 'conquered' the land and ultimately gave rise to all land vertebrates, including humans1-3. Here we determine the chromosome-quality genome of the Australian lungfish (Neoceratodus forsteri), which is known to have the largest genome of any animal. The vast size of this genome, which is about 14× larger than that of humans, is attributable mostly to huge intergenic regions and introns with high repeat content (around 90%), the components of which resemble those of tetrapods (comprising mainly long interspersed nuclear elements) more than they do those of ray-finned fish. The lungfish genome continues to expand independently (its transposable elements are still active), through mechanisms different to those of the enormous genomes of salamanders. The 17 fully assembled lungfish macrochromosomes maintain synteny to other vertebrate chromosomes, and all microchromosomes maintain conserved ancient homology with the ancestral vertebrate karyotype. Our phylogenomic analyses confirm previous reports that lungfish occupy a key evolutionary position as the closest living relatives to tetrapods4,5, underscoring the importance of lungfish for understanding innovations associated with terrestrialization. Lungfish preadaptations to living on land include the gain of limb-like expression in developmental genes such as hoxc13 and sall1 in their lobed fins. Increased rates of evolution and the duplication of genes associated with obligate air-breathing, such as lung surfactants and the expansion of odorant receptor gene families (which encode proteins involved in detecting airborne odours), contribute to the tetrapod-like biology of lungfishes. These findings advance our understanding of this major transition during vertebrate evolution.


Assuntos
Adaptação Fisiológica/genética , Evolução Biológica , Peixes/genética , Marcha/genética , Genoma/genética , Pulmão , Vertebrados/genética , Ar , Nadadeiras de Animais/anatomia & histologia , Animais , Teorema de Bayes , Cromossomos/genética , Extremidades/anatomia & histologia , Feminino , Peixes/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Genes Homeobox/genética , Genômica , Humanos , Elementos Nucleotídeos Longos e Dispersos/genética , Pulmão/anatomia & histologia , Pulmão/fisiologia , Camundongos , Anotação de Sequência Molecular , Filogenia , Respiração , Olfato/fisiologia , Sintenia , Vertebrados/fisiologia , Órgão Vomeronasal/anatomia & histologia
3.
Small ; : e2400259, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38624171

RESUMO

Organic polymer photocatalysts have achieved significant progress in photocatalytic hydrogen evolution, while developing the integrated organic polymers possessing the functions of photosensitizer, electron transfer mediator, and catalyst simultaneously is urgently needed and presents a great challenge. Considering that chalcogenoviologens are able to act as photosensitizers and electron-transfer mediators, a series of chalcogenoviologen-containing platinum(II)-based supramolecular polymers is designed, which exhibited strong visible light-absorbing ability and suitable bandgap for highly efficient photocatalytic hydrogen evolution without the use of a cocatalyst. The hydrogen evolution rate (HER) increases steadily with the decrease in an optical gap of the polymer. Among these "all-in-one" polymers, Se-containing 2D porous polymer exhibited the best photocatalytic performance with a HER of 3.09 mmol g-1 h-1 under visible light (>420 nm) irradiation. Experimental and theoretical calculations reveal that the distinct intramolecular charge transfer characteristics and heteroatom N in terpyridine unit promote charge separation and transfer within the molecules. This work could provide new insights into the design of metallo-supramolecular polymers with finely tuned components for photocatalytic hydrogen evolution from water.

4.
Chem Rev ; 122(1): 565-788, 2022 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-34850633

RESUMO

This review surveys recent progress in the chemistry of polycyclic heteroaromatic molecules with a focus on structural diversity and synthetic methodology. The article covers literature published during the period of 2016-2020, providing an update to our first review of this topic (Chem. Rev. 2017, 117 (4), 3479-3716).


Assuntos
Compostos Heterocíclicos , Compostos Policíclicos , Compostos Heterocíclicos/química
5.
Pediatr Transplant ; 28(3): e14759, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38623871

RESUMO

BACKGROUND: Invasive fungal disease (IFD) is a frequent complication in pediatric lung transplant recipients, occurring in up to 12% of patients in the first year. Risk factors for infection include impaired lung defenses and intense immunosuppressive regimens. While most IFD occurs from Aspergillus, other fungal conidia are continuously inhaled, and infections with fungi on a spectrum of human pathogenicity can occur. CASE REPORT: We report a case of a 17-year-old lung transplant recipient in whom Irpex lacteus and Rhodotorula species were identified during surveillance bronchoscopy. She was asymptomatic and deemed to be colonized by Irpex lacteus and Rhodotorula species following transplant. 2 years after transplantation, she developed a fever, respiratory symptoms, abnormal lung imaging, and histological evidence of acute and chronic bronchitis on transbronchial biopsy. After developing symptoms concerning for a pulmonary infection and graft dysfunction, she was treated for a presumed IFD. Unfortunately, further diagnostic testing could not be performed at this time given her tenuous clinical status. Despite the initiation of antifungal therapy, her graft function continued to decline resulting in a second lung transplantation. CONCLUSIONS: This case raises the concern for IFD in lung transplant recipients from Irpex species. Further investigation is needed to understand the pathogenicity of this organism, reduce the incidence and mortality of IFD in lung transplant recipients, and refine the approach to diagnosis and manage the colonization and isolation of rare, atypical fungal pathogens in immunocompromised hosts.


Assuntos
Infecções Fúngicas Invasivas , Transplante de Pulmão , Polyporales , Rhodotorula , Adolescente , Feminino , Humanos , Antifúngicos/uso terapêutico , Broncoscopia , Pulmão , Transplante de Pulmão/efeitos adversos , Transplantados
6.
Eur Surg Res ; 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38412840

RESUMO

INTRODUCTION: Laparoscopic sleeve gastrectomy (LSG) is associated with postoperative gastroesophageal reflux disease (GERD) and erosive esophagitis (EE). The role of crural repair during LSG is still controversial. The preoperative laxity of the gastroesophageal junction (GEJ), graded by the Hill's classification, is more predictive for postoperative GERD and EE after LSG than the presence of a hiatal hernia seen on endoscopy. Thus, the authors hypothesize that a concomitant crural repair in a specific subgroup of patients with a lax GEJ (Hill's III) may reduce the incidence of postoperative GERD and EE. METHODS: A double-blinded, randomized controlled trial of patients with Hill's III GEJ undergoing LSG will be randomized to a concomitant crural repair (experimental) versus LSG alone (control). Primary outcome measures will be presence of EE at 1-year. Secondary outcome measures will include proton pump inhibitor use, postoperative complications, operative time, blood loss, quality of life, GERD and gastrointestinal symptoms. CONCLUSION: Conflicting crural repair results may be explained by differences in preoperative GEJ laxity. Patients with a frank hiatal hernia and patulous GEJ (Hill's IV) have a very high, while patients with an apposed GEJ (Hill's I, Hill's II) have a low incidence of postoperative GERD and EE respectively. Thus, the authors hypothesize that patients with a lax GEJ without frank hiatal hernia (Hill's III), might benefit from a crural repair. This study results can potentially highlight the clinical importance of preoperative endoscopic evaluation of the GEJ in all patients planned for LSG, to determine which subgroup patients may benefit from a crural repair. (Clinicaltrials.gov: NCT05330910, Registered 15-April-2022).

7.
J Adolesc ; 96(4): 771-788, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38287896

RESUMO

INTRODUCTION: College transition is often regarded as the most stressful phase of life by college students. Hence, it is necessary to find ways to help them adjust more smoothly to this transition. Hope, as conceptualized by C. R. Snyder, has been widely studied as a predictor of optimal functioning and has been shown to be associated with better adjustment among college students. This study aimed to shed light on the role of hope in college transition by examining its unique reciprocal relationships with an array of important psychosocial resources and emotional well-being among first-year college students. METHODS: Data were collected from a sample of Hong Kong college freshmen (N = 433, Medianage = 18 years old, 63.7% female) at two time points. At each time point, participants completed self-reported measures tapping into their levels of hope, psychosocial resources, and emotional well-being. Psychological resources included general and academic self-efficacy, meaning in life, and optimism. Social resources included secure attachment, perceived school environment, and social support. Emotional well-being was operationalized as positive and negative emotions. Cross-lagged panel models were constructed and tested by path analyses. RESULTS: When autoregression and the effects of other variables were controlled, a greater sense of hope uniquely predicted higher levels of general and academic self-efficacy, greater presence of life meanings, more secure attachment, and more positive and fewer negative emotions. On the other hand, higher levels of meaning in life (both presence and search) and social support uniquely predicted greater hope. Academic hope and presence of life meanings reciprocally predicted one another, whereas other significant cross-lagged relationships were unidirectional. CONCLUSIONS: The findings suggest interventions that promote hope can be useful in helping college freshmen adjust to the new college environment by enhancing their psychosocial resources and emotional well-being. Such interventions would be more effective if they included elements that boost meaning in life and social support, which are expected to further enhance the perceptions of hope.


Assuntos
Esperança , Apoio Social , Estudantes , Humanos , Feminino , Estudantes/psicologia , Masculino , Adolescente , Universidades , Hong Kong , Adulto Jovem , Autoeficácia , Emoções , Adaptação Psicológica
8.
Chem Soc Rev ; 52(2): 454-472, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36594823

RESUMO

The design and development of functional materials with real-life applications are highly demanding. Understanding and controlling inter- and intra-molecular interactions provide opportunities to design new materials. A judicious manipulation of the molecular structure significantly alters such interactions and can boost selected properties and functions of the material. There is burgeoning evidence of the beneficial effects of non-covalent interactions (NCIs), showing that manipulating NCIs may generate functional materials with a wide variety of physical properties leading to applications in catalysis, drug delivery, crystal engineering, etc. This prompted us to review the implications of NCIs on the molecular packing, optical properties, and applications of functional π-conjugated materials. To this end, this tutorial review will cover different types of interactions (electrostatic, π-interactions, metallophilic, etc.) and their impact on π-conjugated materials. Attempts have also been made to delineate the effects of weak interactions on opto-electronic (O-E) applications.

9.
Int J Mol Sci ; 25(2)2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38256142

RESUMO

To reduce the mortality and morbidity associated with cancer, new cancer theranostics are in high demand and are an emerging area of research. To achieve this goal, we report the synthesis and characterization of piperazine-linked 1,8-naphthalimide-arylsulfonyl derivatives (SA1-SA7). These compounds were synthesized in good yields following a two-step protocol and characterized using multiple analytical techniques. In vitro cytotoxicity and fluorescent cellular imaging of the compounds were assessed against non-cancerous fibroblast (3T3) and breast cancer (4T1) cell lines. Although the former study indicated the safe nature of the compounds (viability = 82-95% at 1 µg/mL), imaging studies revealed that the designed probes had good membrane permeability and could disperse in the whole cell cytoplasm. In silico studies, including molecular docking, molecular dynamics (MD) simulation, and ADME/Tox results, indicated that the compounds had the ability to target CAIX-expressing cancers. These findings suggest that piperazine-linked 1,8-naphthalimide-arylsulfonyl derivatives are potential candidates for cancer theranostics and a valuable backbone for future research.


Assuntos
Naftalimidas , Neoplasias , Humanos , Simulação de Acoplamento Molecular , Piperazina , Imagem Molecular
10.
Angew Chem Int Ed Engl ; 63(22): e202403660, 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38465907

RESUMO

Luminescent organic radicals, especially those with photoactivated circularly polarized luminescence (CPL) features, hold great significance for cutting-edge optoelectronic applications, but their development still remains a challenge. In this study, we propose a novel strategy to achieve photoactivated CPL radicals by bonding two phosphine centers within an axial chiral system, yielding a compound of R/S-5,5-bis(diphenylphosphino)-4,4'-bibenzo[d][1,3]dioxole (R/S-BDP). The photoactivated R/S-BDP molecules in polymer matrix display a robust quantum yield of 19.8 % and a dissymmetry factor (glum) of 1.2×10-4, marking this work as the first example of photoactivated CPL radicals. Furthermore, the glum is improved to 1.0×10-2 by using a liquid crystal as host. Experimental and theoretical analyses reveal that R/S-BDP molecules, endowed with double phosphine cores in axial chirality, offer a direct way for intramolecular electron transfer upon photoirradiation. This leads to the generation of radical ionic pairs, which subsequently trigger the donor-acceptor arrangement through intermolecular electron transfer, thereby resulting in stable radical emission. The extended photoactivated BDP-F exhibits a remarkably high quantum efficiency of 57.8%. Ultimately, the distinctive photo-responsive CPL radical luminescence has been successfully used for information displays and anti-counterfeiting.

11.
Clin Infect Dis ; 2023 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-37596856

RESUMO

BACKGROUND: Sepsis surveillance using electronic health record (EHR)-based data may provide more accurate epidemiologic estimates than administrative data, but experience with this approach to estimate population-level sepsis burden is lacking. METHODS: This was a retrospective cohort study including all adults admitted to publicly-funded hospitals in Hong Kong between 2009-2018. Sepsis was defined as clinical evidence of presumed infection (clinical cultures and treatment with antibiotics) and concurrent acute organ dysfunction (≥2 point increase in baseline SOFA score). Trends in incidence, mortality, and case fatality risk (CFR) were modelled by exponential regression. Performance of the EHR-based definition was compared with 4 administrative definitions using 500 medical record reviews. RESULTS: Among 13,550,168 hospital episodes during the study period, 485,057 (3.6%) had sepsis by EHR-based criteria with 21.5% CFR. In 2018, age- and sex-adjusted standardized sepsis incidence was 759 per 100,000 (relative +2.9%/year [95%CI 2.0, 3.8%] between 2009-2018) and standardized sepsis mortality was 156 per 100,000 (relative +1.9%/year [95%CI 0.9,2.9%]). Despite decreasing CFR (relative -0.5%/year [95%CI -1.0, -0.1%]), sepsis accounted for an increasing proportion of all deaths (relative +3.9%/year [95%CI 2.9, 4.9%]). Medical record reviews demonstrated that the EHR-based definition more accurately identified sepsis than administrative definitions (AUC 0.91 vs 0.52-0.55, p < 0.001). CONCLUSIONS: An objective EHR-based surveillance definition demonstrated an increase in population-level standardized sepsis incidence and mortality in Hong Kong between 2009-2018 and was much more accurate than administrative definitions. These findings demonstrate the feasibility and advantages of an EHR-based approach for widescale sepsis surveillance.

12.
Emerg Infect Dis ; 29(12): 2550-2553, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37885046

RESUMO

In Singapore, 10 captive lions tested positive for SARS-CoV-2 by real-time PCR. Genomic analyses of nanopore sequencing confirmed human-to-animal transmission of the SARS-CoV-2 Delta variant. Viral genomes from the lions and zookeeper shared a unique spike protein substitution, S:A1016V. Widespread SARS-CoV-2 transmission among humans can increase the likelihood of anthroponosis.


Assuntos
COVID-19 , Leões , Animais , Humanos , Singapura/epidemiologia , SARS-CoV-2/genética , COVID-19/veterinária
13.
Emerg Infect Dis ; 29(12): 2580-2583, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37708842

RESUMO

We detected African swine fever virus (ASFV) from a wild boar in Singapore. In <72 hours, we confirmed and reported ASFV p72 genotype II, CD2v serogroup 8, and IGR-II variant by using a combination of real-time PCR and whole-genome sequencing. Continued biosurveillance will be needed to monitor ASFV in Singapore.


Assuntos
Vírus da Febre Suína Africana , Sus scrofa , Animais , Suínos , Singapura/epidemiologia , Vírus da Febre Suína Africana/genética , Genótipo , Reação em Cadeia da Polimerase em Tempo Real
14.
Thorax ; 78(7): 674-681, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35981883

RESUMO

BACKGROUND: Tuberculosis (TB) is a preventable and curable disease, but mortality remains high among those who develop sepsis and critical illness from TB. METHODS: This was a population-based, multicentre retrospective cohort study of patients admitted to all 15 publicly funded Hong Kong adult intensive care units (ICUs) between 1 April 2008 and 31 March 2019. 940 adult critically ill patients with at least one positive Mycobacterium tuberculosis (MTB) culture were identified out of 133 858 ICU admissions. Generalised linear modelling was used to determine the impact of delay in TB treatment on hospital mortality. Trend of annual Acute Physiology and Chronic Health Evaluation (APACHE) IV-adjusted standardised mortality ratio (SMR) over the 11-year period was analysed by Mann-Kendall's trend test. RESULTS: ICU and hospital mortality were 24.7% (232/940) and 41.1% (386/940), respectively. Of those who died in the ICU, 22.8% (53/232) never received antituberculosis drugs. SMR for ICU patients with TB remained unchanged over the study period (Kendall's τb=0.37, p=0.876). After adjustment for age, Charlson comorbidity index, APACHE IV, albumin, vasopressors, mechanical ventilation and renal replacement therapy, delayed TB treatment was directly associated with hospital mortality. In 302/940 (32.1%) of patients, TB could only be established from MTB cultures alone as Ziehl-Neelsen staining or PCR was either not performed or negative. Among this group, only 31.1% (94/302) had concurrent MTB PCR performed. CONCLUSIONS: Survival of ICU patients with TB has not improved over the last decade and mortality remains high. Delay in TB treatment was associated with higher hospital mortality. Use of MTB PCR may improve diagnostic yield and facilitate early treatment.


Assuntos
Estado Terminal , Tuberculose , Adulto , Humanos , Estado Terminal/terapia , Estudos Retrospectivos , Unidades de Terapia Intensiva , Mortalidade Hospitalar , Resultado do Tratamento
15.
Clin Chem ; 69(2): 189-201, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36576350

RESUMO

BACKGROUND: Nuclear-derived cell-free DNA (cfDNA) molecules in blood plasma are nonrandomly fragmented, bearing a wealth of information related to tissues of origin. DNASE1L3 (deoxyribonuclease 1 like 3) is an important player in shaping the fragmentation of nuclear-derived cfDNA molecules, preferentially generating molecules with 5 CC dinucleotide termini (i.e., 5 CC-end motif). However, the fragment end properties of microbial cfDNA and its clinical implication remain to be explored. METHODS: We performed end motif analysis on microbial cfDNA fragments in plasma samples from patients with sepsis. A sequence context-based normalization method was used to minimize the potential biases for end motif analysis. RESULTS: The end motif profiles of microbial cfDNA appeared to resemble that of nuclear cfDNA (Spearman correlation coefficient: 0.82, P value 0.001). The CC-end motif was the most preferred end motif in microbial cfDNA, suggesting that DNASE1L3 might also play a role in the fragmentation of microbe-derived cfDNA in plasma. Of note, differential end motifs were present between microbial cfDNA originating from infection-causing pathogens (enriched at the CC-end) and contaminating microbial DNA potentially derived from reagents or the environment (nearly random). The use of fragment end signatures allowed differentiation between confirmed pathogens and contaminating microbes, with an area under the receiver operating characteristic curve of 0.99. The performance appeared to be superior to conventional analysis based on microbial cfDNA abundance alone. CONCLUSIONS: The use of fragmentomic features could facilitate the differentiation of underlying contaminating microbes from true pathogens in sepsis. This work demonstrates the potential usefulness of microbial cfDNA fragmentomics in metagenomics analysis.


Assuntos
Ácidos Nucleicos Livres , Sepse , Humanos , DNA/genética , Sepse/diagnóstico , Fragmentação do DNA
16.
J Med Virol ; 95(8): e28993, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37526404

RESUMO

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is estimated to affect 0.4%-2.5% of the global population. Most cases are unexplained; however, some patients describe an antecedent viral infection or response to antiviral medications. We report here a multicenter study for the presence of viral nucleic acid in blood, feces, and saliva of patients with ME/CFS using polymerase chain reaction and high-throughput sequencing. We found no consistent group-specific differences other than a lower prevalence of anelloviruses in cases compared to healthy controls. Our findings suggest that future investigations into viral infections in ME/CFS should focus on adaptive immune responses rather than surveillance for viral gene products.


Assuntos
Síndrome de Fadiga Crônica , Humanos , Síndrome de Fadiga Crônica/epidemiologia , Saliva , Viroma , Fezes
17.
Chemistry ; 29(37): e202300376, 2023 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-37062705

RESUMO

Two novel nona-coordinated Eu(III) complexes [Eu(btfa)3 (Ph-TerPyr)] (Eu-1) and [Eu(NTA)3 (Ph-TerPyr)] (Eu-2) have been synthesized and characterized. The structure of the complexes was elucidated by density functional theory (DFT) methods. The experimental photophysical properties of the complexes were investigated and complemented with theoretical calculations. Effective energy transfer (ET) pathways for the sensitized red luminescence is discussed. The complexes were tested as emitting layers (EML) in organic light emitting diodes (OLEDs). At the optimum doping concentration of 4 wt.%, the double-EML OLEDs of Eu-1 exhibited red electroluminescence (EL) with an EQE of 4.0 % and maximum brightness (B)=1179 cd/m2 , maximum current efficiency (ηc )=5.64 cd/A, and maximum power efficiency (ηp )=4.78 lm/W at the current density (J) of 10 mA/cm2 . Interestingly, the double-EML OLEDs of Eu-2 at the optimum concentration of 3 wt.%, displayed an outstanding EL performance with EQE of 7.32 % and B=838 cd/m2 , ηc =10.19 cd/A and ηp =10.33 lm/W at J=10 mA/cm2 . The EL performance of this device is among the best reported for devices incorporating a europium complex as a red emitter.

18.
J Org Chem ; 88(17): 12502-12518, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37579226

RESUMO

A copper-catalyzed aerobic oxidative/decarboxylative phosphorylation of aryl acrylic acids with P(III)-nucleophiles via the Michaelis-Arbuzov rearrangement for the synthesis of ß-ketophosphine oxides, ß-ketophosphinates, and ß-ketophosphonates is reported. The present reaction could be conducted effectively without the use of a ligand and a base. Various kinds of aryl acrylic acids and P(III)-nucleophiles are tolerated in the transformation, generating the desired ß-keto-organophosphorus compounds as a valuable class of phosphorus-containing intermediates with good to excellent yields. In addition, the possible mechanism and kinetic studies for the reaction have been explored by step-by-step control experiments and competitive experiments, and the results proved that this transformation may follow second-order chemical kinetics as well as involve a radical process.

19.
J Org Chem ; 88(23): 16196-16215, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37955519

RESUMO

A simple and efficient method for the ruthenium-catalyzed 1,6-hydroalkylation of para-quinone methides (p-QMs) with ketones via the in situ activation of C(sp3)-H bonds has been disclosed. Without the need for preactivation of the substrates and oxidant, a broad range of p-QMs and ketones are well tolerated, producing the expected 1,6-hydroalkylation products with moderate to good yields. Step-by-step control experiments and DFT calculation were conducted systematically to gain insights for the plausible reaction mechanism. This finding may have potential application in the selective diarylmethylation of ketones at the α-C position in organic synthesis.

20.
Inorg Chem ; 62(3): 1202-1209, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36622043

RESUMO

The excited-state manipulation of the phosphorescent iridium(III) complexes plays a vital role in their photofunctional applications. The development of the molecular design strategy promotes the creative findings of novel iridium(III) complexes. The current molecular design strategies for iridium(III) complexes mainly depend on the selective cyclometalation of the ligands with the iridium(III) ion, which is governed by the steric hindrance of the ligand during the cyclometalation. Herein, a new molecular design strategy (i.e., random cyclometalation strategy) is proposed for the effective excited-state manipulation of phosphorescent cyclometalated iridium(III) complexes. Two series of new and separable methoxyl-functionalized isomeric iridium(III) complexes are accessed by a one-pot synthesis via random cyclometalation, resulting in a dramatic tuning of the phosphorescence peak wavelength (∼57 nm) and electrochemical properties attributed to the high sensitivity of their excited states to the position of the methoxyl group. These iridium(III) complexes show intense phosphorescence ranging from the yellow (567 nm) to the deep-red (634 nm) color with high photoluminescence quantum yields of up to 0.99. Two deep-red emissive iridium(III) complexes with short decay lifetimes are further utilized as triplet emitters to afford efficient solution-processed electroluminescence with reduced efficiency roll-offs.

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