Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Más filtros




Base de datos
Intervalo de año de publicación
1.
Chemistry ; 28(39): e202200310, 2022 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-35482818

RESUMEN

Artificial light-driven splitting of water into hydrogen involves multiple links to emulate natural photosynthesis, including light absorption, electron or energy transfer, surface catalysis et al., in which, the mass transportation of sacrificial reagent and reactant is always ignored. Metal-organic cage (MOC) of Pd6 Ru8 (MOC-16), assembling multiple photosensitive Ru and catalytic Pd concomitant with directional electron transfer between them, provides an opportunity to explore the environmental effects from the view point of mass transportation without disturbance of other links. Zr-MOF of UiO-66 is used as a matrix to heterogenize MOC-16 and a series of characterizations are carried out to unravel the composition, structure and optical properties. The intact MOC-16 remains with long-term photo-stability and the outstanding photocatalytic activity is obtained by virtue of a long-lived triplet state. Three matrixes of ZIF-8, ZIF-8 derived carbonate CZIF, and UiO-66 are intercompared for mass transfer based on wettability and porous structure. Water molecule directly takes part in the formation of H2 catalyzed by MOC-16@UiO-66, evidenced by a kinetic isotope effect, in addition to the proton delivery thanks to the hydrophilic nature of UiO-66. The porous structure of UiO-66 is essential for the permeation of sacrificial reagent to serve as two-electron donor, in sharp contrast as one-electron donor in nonporous CZIF matrix. These results highlight the importance of microenviroment surrounding molecular catalysts in view of the heterogenization of molecular catalysts, meanwhile, providing a prominent guidance on how to choose 3D support to bridge the homogenous and heterogenous system.

2.
J Am Chem Soc ; 141(33): 13057-13065, 2019 08 21.
Artículo en Inglés | MEDLINE | ID: mdl-31343866

RESUMEN

Application of a molecular catalyst in artificial photosynthesis is confronted with challenges such as rapid deactivation due to photodegradation or detrimental aggregation in harsh conditions. In this work, a metal-organic cage [Pd6(RuL3)8]28+ (MOC-16), characteristic of a photochemical molecular device (PMD) concurrently integrating eight Ru2+ light-harvesting centers and six Pd2+ catalytic centers for efficient homogeneous H2 production, is successfully heterogenized through incorporation into a metal-organic framework (MOF) of ZIF-8 and then transformed into a carbonate matrix of Znx(MeIm)x(CO3)x (CZIF), leading to hybridized MOC-16@CZIF. This MOC@MOF integrated photocatalyst inherits a highly efficient and directional electron transfer in the picosecond domain of MOC-16 and possesses one order increased microsecond magnitude of the triplet excited-state electron in comparison to that of the primitive MOC-16. The carbonate CZIF matrix endows MOC-16@CZIF with water wettability, serving as a proton relay to facilitate proton delivery by virtue of H2O as proton carriers. Electron transfer during the photocatalytic process is also enhanced by infiltration of a sacrificial agent of BIH into the CZIF matrix to promote conductivity, owing to its strong reducing ability to induce free charge carriers. These synergistic effects contribute to the extra high activity for H2 generation, making the turnover frequency of this heterogeneous MOC-16@CZIF photocatalyst maintain a level of ∼0.4 H2·s-1, increased by 50-fold over that of a homogeneous PMD. Meanwhile, it is robust enough to tolerate harsh reaction conditions, presenting an unprecedented heterogenization example of homogeneous PMD with a MOF-derived matrix to mimic catalytic features of a natural photosystem, which may shed light on the design of multifunctional PMD@MOF materials to expand the number of molecular catalysts for practical application in artificial photosynthesis.

3.
Dalton Trans ; 48(13): 4370-4374, 2019 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-30860527

RESUMEN

The first OCP adducts of aluminium and gallium are reported. The complexes are supported by sterically encumbered salen ligands and reveal a selective binding to O and P, respectively. Their reactivity with diazaphosphenium Lewis acids and N-heterocyclic carbene Lewis bases is described, in addition to cycloaddition reactions with s-tetrazines.

4.
Angew Chem Int Ed Engl ; 57(19): 5512-5515, 2018 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-29508510

RESUMEN

A simple synthesis of sodium 2-phosphanaphthalene-3-olate (1) based on the extrusion of N2 from phthalazine using Na[OCP] is reported. This heterocycle can be readily functionalized at the negatively charged oxygen center using a variety of electrophilic substrates. The coordination chemistry of both 1 and its neutral derivatives was explored, revealing their facile use as P-donor ligands for late-transition-metal complexes.

5.
Zhonghua Nan Ke Xue ; 15(5): 449-51, 2009 May.
Artículo en Chino | MEDLINE | ID: mdl-19514560

RESUMEN

OBJECTIVE: To evaluate the effect and safety of transurethral prostatectomy with the bipolar plasmakinetic technique (PKRP) in the treatment of benign prostate hyperplasia (BPH). METHODS: A total of 712 BPH patients underwent transurethral prostatectomy with the bipolar plasmakinetic technique. The patients averaged 70.6 years of age and 52 g (range 35-102 g) in estimated prostate weight preoperatively. Comparative analyses were made on the maximum urine flow rate (Qmax), residual urine volume and scores on IPSS and QOL obtained pre- and post-operatively. RESULTS: The operations lasted 20-120 minutes (mean 51 min), the resected tissues weighed 15-96 g (mean 46 g), and no transurethral resection syndrome (TURS) occurred. The catheters were removed 4 -5 days after surgery. The patients were followed up for 1 -52 months (mean 27.6 mo). Obvious reduction was observed in the average Qmax from 4.7 ml/s preoperatively to 19. 1 ml/s postoperatively, in the mean IPSS score from 26.6 to 5. 8, and in the mean QOL score from 5.4 to 1.7, all with significant differences (P < 0.01). CONCLUSION: Transurethral prostatectomy with the bipolar plasmakinetic technique is a safe and effective means for the treatment of BPH.


Asunto(s)
Hiperplasia Prostática/cirugía , Resección Transuretral de la Próstata/métodos , Anciano , Anciano de 80 o más Años , Humanos , Masculino , Persona de Mediana Edad , Resultado del Tratamiento
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA