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Intramolecular charge transfer (ICT) is an important photochemical process. In contrast to those in singlet manifold, triplet ICT states were less studied. In this paper, the lowest excited triplet state (T) of 4‑amino‑4'‑nitrobiphenyl (NH-Bp-NO) was recorded with nanosecond transient absorption spectroscopy in acidic acetonitrile and alcoholic solutions. By employing the Kamlet-Taft model to analyze the correlation between absorption maxima and alcohol solvent properties including polarity/polarizability, abilities of hydrogen bond donating and hydrogen bond accepting, hydrogen bond configuration in the ground state (S) and T was resolved. The results suggest that the hydrogen bond between amino H and alcohol is dominant in S, while in T, hydrogen bonds between amino H and alcohol, between nitro O and alcohol have comparable contribution. By examination of the 1‑naphthol quench effect on T, the hydrogen bond between nitro O and alcohol was confirmed present. Theoretical calculation results on the model of NH-Bp-NO-(MeOH) also indicate that hydrogen bonds between amino H and alcohol, between nitro O and alcohol are both much stronger in T than in S. In acidic acetonitrile solution, in S of NH-Bp-NO the amino group is protonated with pK of 4.5, meanwhile in T the nitro group is much easier to be protonated than in S. Its conjugated acid was measured to have a pK of 3.1.
This article was published in the following journal.
Name: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy
The reactions of the three triplet ground state arylcarbenes diphenylcarbene 1, fluorenylidene 2, and dibenzo-cycloheptadienylidene 3 with the Lewis acids H2O, ICF3, and BF3 were studied under the con...
Due to the reversal in electron counts for aromaticity and antiaromaticity in the closed-shell singlet state (normally ground state, S0) and lowest ππ* triplet state (T1 or T0), as given by Hückel'...
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Aromaticity can be a useful concept for predicting the behavior of excited states. Here we show that π-conjugated porphyrin nanorings exhibit size-dependent excited-state global aromaticity and antia...
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The Veterans Health Administration (VHA) has stated the need for a brief screening instrument that can assist with the triage of the enormous number of returning OEF/OIF veterans with conc...
To determine the effectiveness of combining different concentrations of hydrogen peroxide and carbamide used during tooth bleaching.
This study suggested that hydrogen has a potential as an effective and safe therapeutic agent on cGVHD.
The purpose of this study is to compare the clinical performance of three dental adhesive systems used to bond Class V cavity fillings in adult teeth.
There have been many adjunctive treatments for the additional clinical benefits to scaling and root planing (SRP) in the treatment of chronic periodontitis. Topical hydrogen peroxide (HP) ...
UNSATURATED FATTY ACIDS that contain at least one double bond in the trans configuration, which results in a greater bond angle than the cis configuration. This results in a more extended fatty acid chain similar to SATURATED FATTY ACIDS, with closer packing and reduced fluidity. HYDROGENATION of unsaturated fatty acids increases the trans content.
Emission of LIGHT when ELECTRONS return to the electronic ground state from an excited state and lose the energy as PHOTONS. It is sometimes called cool light in contrast to INCANDESCENCE. LUMINESCENT MEASUREMENTS take advantage of this type of light emitted from LUMINESCENT AGENTS.
Type III intermediate filament proteins that assemble into neurofilaments, the major cytoskeletal element in nerve axons and dendrites. They consist of three distinct polypeptides, the neurofilament triplet. Types I, II, and IV intermediate filament proteins form other cytoskeletal elements such as keratins and lamins. It appears that the metabolism of neurofilaments is disturbed in Alzheimer's disease, as indicated by the presence of neurofilament epitopes in the neurofibrillary tangles, as well as by the severe reduction of the expression of the gene for the light neurofilament subunit of the neurofilament triplet in brains of Alzheimer's patients. (Can J Neurol Sci 1990 Aug;17(3):302)
Organic compounds containing a carbon-nitrogen double bond where a NITROGEN atom can be attached to HYDROGEN or an alkyl or aryl group.
Hydrogen. The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight 1. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.