A structurally stable, 3d-4f heterometallic coordination polymer has been solvothermally synthesised and evaluated for its accomplished materials properties. The light absorption activity in the visible band was higher for unique Ce-Fe MOF than that of the homometallic Ce-MOF or Fe- MOF. The intimate overlap of two different metal clusters in heterometallic environmental induced the formation of low line conduction orbital, which ultimately lowered the transition energy. The heterometallic acquired an additional sensitisation from a Fe-μ3-oxo cluster that had vibrantly enhanced the light uptake activity. The vacancy created in the 6s, 5d orbital of Ce in Ce-Fe MOF contributed to the photo-excitation of electrons and reduced the recombination time. This distinct intramolecular arrangement assisted the exciton trapping characteristic. Also, the presence of multiple metal cores in the framework aided to confine the increased number of excitons for a redox reaction. The solar photocatalysis study with acetaminophen revealed these improved materialistic features by degrading it 94.6% with a rate constant of 0.0137 min−1. The recycle studies confirmed the robust stability of the synthesised MOF. 相似文献
Here, a simple and novel approach is reported for developing a new class of transparent chemical vapor sensors with a low power consumption, high sensitivity, good selectivity, and excellent environmental stability by depositing multiwalled carbon nanotubes on prepatterned polymer substrates using supramolecular assembly. The patterned polymer substrates were fabricated from block copolymers, whereas the supramolecular assembly between the carbon nanotubes and block copolymer is utilized for the selective localization of carbon nanotubes at the block copolymer–air interface. The thin film devices made from the block copolymer and carbon nanotubes are highly transparent (transmittance > 90%) and respond to a wide range of solvents of different polarity, both hydrophilic and hydrophobic, with good selectivity and fast response time.
Charge-transfer (CT) or electron donor-acceptor (EDA) complex formation between organic donors and acceptors has been extensively
studied by spectrophotometry and other methods. High performance thin layer chromatography (HPTLC), although extensively used
for the identification and quantification of drugs and explosives, has not been used until now to determine the extent of
association and the association constants KDA of charge transfer or EDA complexes between donor (D) and acceptor (A). This paper describes the use of the HPTLC technique
with scanning densitometry to identify and determine the association constants KDA of charge-transfer complexes of N,N-diethylaniline (DEA) with different nitro explosives, namely 1,4-dinitrobenzene (DNB),
2,4-dinitrotoluene (DNT) and 2,4,6-trinitrotoluene (TNT), in chloroform. Advantages of the HPTLC method are highlighted. The
association constants KDA of the complexes determined using the HPTLC method have been verified and validated spectrophotometrically when the concentrations
of D and A are in their stoichiometric ratio. The thermodynamics of the complex formation reaction were obtained spectrophotometrically
from measurements of the association constants KDA at five different temperatures ranging from 293 to 313 K, when D and A are in their stoichiometric ratio and also when A≫D. 相似文献
AbstractRhodium-catalyzed intermolecular [3?+?2+2] cycloaddition reactions of bis(methylenecyclopropanes) with different alkynes are described. The rhodium-catalyzed [3?+?2+2] cycloadditions resulted in the formation of functionalized 5–7–3 spirocyclic carbocycles in moderate yields with excellent regio- and chemo-selectivity. 相似文献
Poly(3-hexyl thiophene) (P3HT) organically modified montmorillonite (om-MMT) polymer nanocomposites (PNCs) are prepared in the melt-cooled state. Hierarchical structures up to third order, namely, side chain mesomorph formation followed by the interchain lamellar structure of P3HT and finally its intercalation within the clay tactoids are observed. The structures are supported by transmission electron microscopy (TEM) and wide-angle X-ray scattering (WAXS) experiments. The TGA curves show two-stage degradation corresponding to those of the side chain and main chain of P3HT, and both temperatures decrease with an increase in clay concentration in the PNCs. The melting points of PNCs have increased by 2-3 degrees C higher than that of P3HT. The glass-transition temperature (Tg) and beta-transition temperature (Tbeta), measured by DMA, increase with an increase in clay concentration. The storage modulus (G) of PNCs has also increased more dramatically than that of P3HT. The UV-vis spectra of the PNCs show a blue shift in the pi-pi* absorption peak of the conjugated chain, but the photoluminescence spectra showed a red shift with an increase in the clay concentration. The quantum yield of the photoluminescence process also increases in the melt-cooled PNCs, and this is in sharp contrast to that of solvent cast PNCs where photoluminescence quenching was observed. Fibrillar network structure of the solvent cast PNCs promotes energy transfer of the charge carriers, but its absence in the melt-cooled films inhibits such energy transfer, increasing the quantum yield. The room-temperature dc conductivity of the PNCs decreased by an order compared to that of P3HT in both the doped and undoped states. The I-V characteristic curve shows semiconducting behavior, and it slowly transforms into insulator with increasing clay concentration. 相似文献
The study of electrogenerated chemiluminescence (ECL) in aqueous and non-aqueous media with tetraphenylborate anion as a co-reactant is reported. The obtained results indicate that tetraphenylborate acts according to an oxidative reduction scheme and forms a strong reducer after being homogeneously oxidized by a radical cation or dication of luminophore. Spectral measurements prove that light emission originates from the luminophore present in solution and practically no emission occurs when only tetraphenylborate ion is oxidized at the electrode. Since the tetraphenylborate ion is a well known analytical reactant and precipitates a number of metal and organic cations its electrochemiluminescent detection can be used for their assay. It can also be applied as an efficient co-reactant for electrogenerated chemiluminescence excitation both in aqueous and non-aqueous media. 相似文献