ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpin-polarized electron paramagnetic resonance spectra of radical pairs in micelles: observation spin-spin interactionsGerhard L. Closs, Malcolm D. E. Forbes, and James R. NorrisCite this: J. Phys. Chem. 1987, 91, 13, 3592–3599Publication Date (Print):June 1, 1987Publication History Published online1 May 2002Published inissue 1 June 1987https://pubs.acs.org/doi/10.1021/j100297a026https://doi.org/10.1021/j100297a026research-articleACS...

An all-atom 5 nanosecond molecular dynamics simulation of a water-solvated micelle containing 60 sodium dodecyl sulfate monomers was performed. Structural properties such as the radius gyration, eccentricity, micellar size, accessible surface area, dihedral angle distribution, carbon atom and orientation toward center mass were evaluated. The results indicate stable system over duration simulation. Evaluation structure motion counterions show (1) long equilibration time (1 nanosecond) is...

Amide and ester coupling reactions of ω-functionalized monolayer-protected gold cluster molecules (MPCs) are an exceptionally efficient avenue to a diverse variety polyfunctionalized MPCs starting from small subset materials. In this paper, have been employed produce 13 bearing multiple copies structural groups. Detailed features three the products highlighted: (a) stepwise deprotection result in MPC surrounded by ca. eight pendant tripeptides, (b) preliminary Steady-State Electron...

Can't fight the SEEPR: Simultaneous electrochemical electron paramagnetic resonance reveals that a molecule containing nitronyl nitroxide (NN) radical (structure and red layer) is redox-active, with switchability between oxidized reduced states. An organic NN device utilizes dual p- n-type properties in memory device.

Using a 5 ns explicit atom molecular dynamics simulation of 60 monomer sodium dodecyl sulfate micellar system containing 7579 TIP3P water molecules, the behavior in different electrostatic environments was examined. Structural evaluation revealed that penetration molecules into micelle restricted to headgroup region, leaving 12 Å water-free hydrocarbon core. Water near exhibit distortion water−water hydrogen bonding network due oxygen−water bond formation. The dynamic implications this are...

The emitting metal-to-ligand charge transfer (MLCT) excited state of [Ru(bpy)2(bpz)]2+ (bpy is 2,2'-bipyridine; bpz 2,2'-bipyrazine) reductively quenched by hydroquinone (H2Q) proton-coupled electron (PCET), most likely concerted electron−proton (EPT). identity the transient products ([Ru(bpy)2(bpzH•)]2+ and HQ•) kinetics their formation disappearance have been established steady-state emission time-resolved emission, absorption, EPR measurements. protonated, reduced complex...

The simultaneous, concerted transfer of electrons and protons—electron-proton (EPT)—is an important mechanism utilized in chemistry biology to avoid high energy intermediates. There are many examples thermally activated EPT ground-state reactions excited states following photoexcitation thermal relaxation. Here we report application ultrafast excitation with absorption Raman monitoring detect a photochemically driven process (photo-EPT). In this process, both protons transferred during the...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpin and reaction dynamics in flexible polymethylene biradicals as studied by EPR, NMR, optical spectroscopy, magnetic field effects. Measurements mechanisms of scalar electron spin-spin couplingGerhard L. Closs, Malcolm D. E. Forbes, Piotr PiotrowiakCite this: J. Am. Chem. Soc. 1992, 114, 9, 3285–3294Publication Date (Print):April 1, 1992Publication History Published online1 May 2002Published inissue 1 April...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolvent-free cyclization of linear dienes using olefin metathesis and the Thorpe-Ingold effectMalcolm D. E. Forbes, Jasson T. Patton, Tanya L. Myers, Heather Maynard, Dennis W. Smith Jr., Gregory R. Schulz, Kenneth B. WagenerCite this: J. Am. Chem. Soc. 1992, 114, 27, 10978–10980Publication Date (Print):December 1, 1992Publication History Published online1 May 2002Published inissue 1 December...

Spin and conformational dynamics in symmetric alkyne-bridged multi[copper(II) porphyrin] structures have been studied toluene solution at variable temperature using steady-state electron paramagnetic resonance (EPR) spectroscopy. Comparison of the dimer EPR spectra to those Cu porphyrin monomers shows evidence an isotropic exchange interaction (Javg) these biradicaloid structures, manifested by a significant line broadening spectra. The extent depends on molecular structure temperature,...

Medical hydrogel applications have expanded rapidly over the past decade. Implantation in patients by noninvasive injection is preferred, but this requires solidification from a low viscosity solution to occur vivo via an applied stimuli. Transdermal photo-cross-linking of acrylated biopolymers with photoinitiators and lights offers mild, spatiotemporally controlled trigger. However, current short wavelength initiators limit curing depth efficacy because they do not absorb within optical...

Viologen-tetraarylborate ion-pair complexes were prepared and investigated by steady-state time-resolved spectroscopic techniques such as fluorescence femtosecond transient absorption. The results highlight a charge transfer transition that leads to changes in the viologen structure excited singlet state. Femtosecond absorption reveals formation of excited-state stimulated emission bands assigned planar (kobs < 1012 s-1) twisted ∼ 1010 structures between two pyridinium groups ion. An...

The creation of ordered arrays qubits that can be interfaced from the macroscopic world is an essential challenge for development quantum information science (QIS) currently being explored by chemists and physicists. Recently, porous metal–organic frameworks (MOFs) have arisen as a promising solution to this they allow atomic-level spatial control molecular subunits comprise their structures. To date, no organic qubit candidates been installed in MOFs despite structural variability promise...

Abstract— Steady‐state and time‐resolved electron paramagnetic resonance (TREPR) experiments are described. Comparison of the TREPR continuous wave method to other time domain EPR techniques such as Fourier transform (FT‐EPR) is made, advantages disadvantages each presented. The role played by several mechanisms chemically induced dynamic spin polarization (CIDEP) in appearance spectra explained. using higher frequency spectrometers than standard X‐band (9.5 GHz) presented discussed....

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEPR spectroscopy of electron spin-polarized biradicals in liquid solutions: technique, spectral simulation, scope, and limitationsGerhard L. Closs Malcolm D. E. ForbesCite this: J. Phys. Chem. 1991, 95, 5, 1924–1933Publication Date (Print):March 1, 1991Publication History Published online1 May 2002Published inissue 1 March 1991https://pubs.acs.org/doi/10.1021/j100158a009https://doi.org/10.1021/j100158a009research-articleACS PublicationsRequest...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTObservation of medium chain length polymethylene biradicals in liquid solutions by time resolved EPR spectroscopyGerhard L. Closs and Malcolm D. E. ForbesCite this: J. Am. Chem. Soc. 1987, 109, 20, 6185–6187Publication Date (Print):September 1, 1987Publication History Published online1 May 2002Published inissue 1 September 1987https://pubs.acs.org/doi/10.1021/ja00254a050https://doi.org/10.1021/ja00254a050research-articleACS PublicationsRequest...

The proton-coupled electron transfer (PCET) reaction between the bpz-based photoexcited 3MLCT state of [RuII(bpy)2(bpz)]2+ (bpy = 2,2′-bipyridine, bpz 2,2′-bipyrazine) and a series substituted hydroquinones (H2Q) has been studied by transient absorption (TA) time-resolved paramagnetic resonance (TREPR) spectroscopy at X-band. When is carried out in CH3CN/H2O mixed solvent system with unsubstituted hydroquinone, neutral semiquinone radical (4a) its conjugate base, anion (4b), are both...

Substituted triphenylamine (TPA) radical cations show great potential as oxidants and spin-containing units in polymer magnets. Their properties can be further tuned by supramolecular assembly. Here, we examine how the of photogenerated cations, intrinsic to TPA macrocycles, are altered upon their self-assembly into one-dimensional columns. These macrocycles consist two TPAs methylene ureas, which drive assembly porous organic materials. Advantageously, activation crystals undergo guest...

Time-resolved electron paramagnetic resonance (TREPR) data collected during the photodegradation of iso-α-acids (isohumulones), principal bittering agents from hops in beer, are presented and discussed, and, data, photophysics leading to free-radical production as primary step photodecomposition towards development “skunky” beer explained. During laser flash photolysis at 308 nm toluene/methylcyclohexane (1:1), TREPR spectra exhibit net emissive signals that strongly spin polarized by...

Intramolecular electron transfer (IET) from tyrosine to tryptophan cation radicals is investigated using time resolved chemically induced dynamic nuclear polarization (CIDNP) spectroscopy in combination with laser flash photolysis. In both the tryptophan-tyrosine dipeptide and denatured state of hen lysozyme aqueous solution, transformation TrpH+ → TyrO by IET leads an increase radical concentration, growth CIDNP signal, fast decay CIDNP, inversion phase photosensitizing dye, 2,2′-dipyridyl....