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Biomedical subjects

Neil R Branda

Publications and source records attributed to Neil R Branda.

15 recordsLinked to original sources
PubMed2005

Synthesis and coordination chemistry of a photoswitchable bis(phosphine) ligand.

A 1,2-dithienylethene compound bearing bis(phosphine) groups (1o) represents a new class of photoresponsive ligands where there are steric and electronic differences between two photogenerated isomers. The coordination chemistry of this ligand class is demonstrated by preparing a gold(I) complex (2o) and a phosphine selenide (3o).

Journal Article↗
PubMed2005

Reactivity-gated photochromism of 1,2-dithienylethenes for potential use in dosimetry applications.

[reaction: see text] A novel molecular switching system based on reactivity-gated photochromism operates because a butadiene undergoes a [4 + 2] cycloaddition reaction with a dienophile to produce the photoresponsive 1,2-dithienylethene backbone. The reversible change in color when samples are irradiated with appropriate wavelengths of light occurs only after the Diels-Alder cycloaddition reaction takes place.

Bridged Bicyclo Compounds↗
PubMed2005

Chiral discrimination in photochromic helicenes.

A photoresponsive dithienylethene derivative bearing chiral pinene-based arms underwent a stereoselective photoinduced cyclization reaction to produce greater than 98% of a single diastereomer. The magnitude of the optical rotation changed as much as Delta[alpha]373 = 8698 degrees upon alternate irradiation with 400 nm and greater than 434 nm light.

Journal Article↗
PubMed2003

Novel photochromic compounds based on the 1-thienyl-2-vinylcyclopentene backbone.

[reaction: see text] A new class of photochromic compounds based on the hexatriene backbone has been developed. The backbone, composed of a thiophene ring, a perfluorocyclopentene ring, and a trisubstituted olefin, undergoes reversible ring-opening and ring-closing photoisomerization reactions when irradiated with ultraviolet and visible light, respectively.

Journal Article↗
PubMed2003

Electrochromism in photochromic dithienylcyclopentenes.

Both photochromic and unprecedented electrochromic properties have been observed for a class of 1,2-bis(3-thienyl)cyclopentene derivatives bearing either a thiophene or a phenyl group attached to the reactive carbon centers. These compounds can be interconverted between their colorless ring-open and colored ring-closed states using UV and visible light, respectively. They can also be catalytically transformed from their ring-closed states to their ring-open states through electrochemical or chemical oxidation.

Journal Article↗
PubMed2003

Synthesis, spectral and electrochemical investigations of bichromophoric pentads possessing tetraazaporphyrin and (bipy)2RuII/(phen)2RuII moieties.

Four (bipy)2RuII and (phen)2RuII moieties have been attached to the magnesium tepraazaporphyrin periphery by exploiting thioether coordination to obtain pentads 1 and 2 respectively. These molecules exhibit strong inter-chromophore electronic interaction as reflected by the changes in their spectral and oxidation potential shifts.

Journal Article↗
PubMed2002

Protons as the triggers to regulate hydrogen-bonding receptors.

[reaction: see text] The protonation of alkylamines in two novel receptors results in intramolecular host-guest associations between the resulting ammonium ions and crown ether macrocycles. These interactions result in conformational changes of the receptors and prevent them from acting as hydrogen bond complements for uracil and carboxylate guest species.

Journal Article↗