A new Cu(II) complex of an asymmetrically dicondensed Schiff base (H2L = N-(2-hydroxyacetophenylidene)-N′-salicylidene-1,3-propanediamine) derived from 1,3-propanediamine, salicylaldehyde, and o-hydroxyacetophenone has been synthesized. Using this complex, [CuL] (1), as a metalloligand, two trinuclear Cu-Mn complexes, [(CuL)2Mn(N3)(H2O)](ClO4)·H2O (2) [(CuL)2Mn(NCS)2] (3), have prepared. Single-crystal structural analyses reveal that complexes 2 3 both the same bent {(CuL)2Mn}2+ unit in...

Cu-doped TiO2 photocatalysts [Cu-(1 to 10) atom %] synthesized by the sol–gel method and thoroughly characterized using several techniques were evaluated for photocatalytic reduction of CO2 under ambient conditions. These converted reactant mixture moisture selectively into methane oxygen visible irradiation without use any sacrificial agent. The Cu dopant considerably lowered bandgap TiO2, thereby making it feasible doped absorb light in region. Beyond 1% doping materials far superior as...

Abstract A compact naphthalenediimide (NDI)–2,2,6,6‐tetramethylpiperidinyloxy (TEMPO) dyad has been prepared with the aim of studying radical‐enhanced intersystem crossing (EISC) and formation high spin states as well electron polarization (ESP) dynamics. Compared previously reported radical–chromophore dyads, present system shows a very triplet state quantum yield ( Φ T =74 %), long‐lived τ =8.7 μs), fast EISC (1/ k =338 ps), absorption in red spectral region. Time‐resolved paramagnetic...

Generation of electron spin polarization (ESP) during the bimolecular quenching an excited chromophore by a free radical is generally explained radical-triplet pair mechanism, which capable giving magnitudes ESP arising from singlet or triplet chromophore. When and are covalently linked, although there several mechanisms to explain observed spin-polarized paramagnetic resonance signals under variety experimental conditions in different chromophore-radical systems, no schemes that allow...

Quenching of excited states by a free radical is generally studied in systems where these two are separate entities freely moving liquid solution. Random diffusive encounters bring them together to cause the quenching and leave spins polarized. In dynamics radical-triplet pair mechanism generation electron spin polarization (ESP), distance-dependent exchange interaction plays crucial role. To investigate how distance between molecule influences ESP, we have covalently linked naphthalene...

Electron spin systems with non-Boltzmann distributions are commonly observed in photophysical and photochemical processes involving free radicals. Understanding the origin of electron polarization (ESP) reveals detailed insight into spin-dependent interactions occurring these processes. The ability to transfer ESP nuclear spins solvent produce large is itself an active area research field called dynamic (DNP). Harnessing such fields demands a magnitude importantly on radicals that stable. In...

We propose a new, more efficient, and potentially cost effective, solid-state nuclear spin hyperpolarization method combining the cross-effect mechanism electron optical in rotating solids. first demonstrate solid state at low temperatures field then investigate its dependence to obtain optimal condition for high-field hyperpolarization. The results are incorporated into advanced magic-angle spinning dynamic polarization (MAS-DNP) numerical simulations that show optically pumped MAS-DNP...

Amide-functionalized carbon nanotubes (CNTs) enhanced the sorption efficiency of trivalent f elements. Different isotherm models were employed to understand mechanism. Sorption proceeded via physisorption, and confirmed IR spectroscopy. The Electron Paramagnetic Resonance (EPR) spectra Gd3+ sorbed on CNT also showed no perturbation local environment sorption, again revealing physisorption. Analysis kinetics through Lagergren's first-order kinetics, intraparticle diffusion model,...

The synthesis and structural characterization of the hitherto unreported multiply bonded paramagnetic dirhenium(<sc>iii</sc>,<sc>ii</sc>) nitrobenzoate complexes have been reported.

Enhancing the polarization of spin levels at room temperature is one active research areas in magnetic resonance. Generation electron hyperpolarization involves a complex interplay electronic and processes. In this work, optimization crucial (ESP) generating parameters synthesis radical–chromophore adduct are described. The ESP synthesized about 550 times equilibrium temperature, which possibly maximal value for chromophore–nitroxyl system. present work highlights role photophysical...

Breaking the maximum enhancement barrier of 660 at room temperature in a conventional dynamic nuclear polarization (DNP) experiment has immense potential practical applications. Optical DNP experiments with radical-chromophore (RC) adducts, which harnesses hyperpolarized radicals, instead thermalized offers powerful way to achieve this. Typical and NMR experiments, however, are carried out high magnetic fields about 5-10 T, whereas large electron spin hyperpolarization (ESP) demonstrated RC...

Splitting of spectral lines is generally associated with corresponding splitting appropriate energy levels. However, here we report our observation the splittings hyperfine in time-resolved EPR spectrum a stable free radical that participates quenching an excited molecule. The observed does not arise from any levels radical, nor due to Torrey oscillations but culmination detailed interplay photophysical and magnetic resonance dynamics process. In particular, sequential singlet triplet states...

Liquid water (LW) existence in pure ice below 273 K has been a controversial aspect primarily because of the lack experimental evidence. Recently, electron paramagnetic resonance (EPR) used to study deeply supercooled rapidly frozen polycrystalline ice. The same technique can also be probe presence LW that formed through more conventional, slow cooling one. In this context, present aims emphasize case an external involving techniques such as EPR, results are influenced by binary phase (BP)...

Obtaining a subcellular resolution for biological samples doped with stable radicals at room temperature (RT) is long-sought goal in electron paramagnetic resonance imaging (EPRI). The spatial current EPRI methods constrained either because of low spin polarization RT or the experimental limitations associated field gradients and radical linewidth. Inspired by recent demonstration large hyperpolarization chromophore-nitroxyl probe molecules, present work proposes novel optically...

The present phosphor K2Ca(SO4)2, doped by dysprosium and europium, is synthesized the solid-state diffusion method. doping concentration varied from 0.1 to 0.5 mol% weight. A studied for X-ray powder diffraction, surface morphology analytical scanning electron microscopy analyzed energy-dispersive spectroscopy. prepared Dy Eu, has been characterized thermoluminescence (TL) glow curve, showing maximum peak temperatures at 176°C 200°C, respectively. TL intensity of K2Ca(SO4)2: Eu was compared...

For the triplet mechanism (TM) of electron spin polarisation in photochemically generated free radicals to dominate, chemical reaction has be very fast and capable competing with spin-lattice relaxation process triplet. This is a well-established condition. Here we report counter example polarisation, where this condition appears violated, dominant characteristic TM observed, even when reacts slowly. The system studied photoreduction 4,4′-dihydroxy-benzophenone (DHBP) 2-propanol producing...

Time-resolved EPR studies of the hydrogen abstraction reaction photoexcited xanthone in 2-propanol were carried out as a function concentration and sample temperature. The temperature was varied from 22°C to about −30°C, 0.2 4.0 mM. At low or concentration, observed spectra ketyl radical propan-2-olyl could be simulated superposition hyperfine-independent component due emissive triplet mechanism hyperfine-dependent S–T0 pair mechanism. However, with an increase xanthone, relative...