The excited-state properties in a series of coumarin solar cell dyes are investigated with a long-range-corrected (LC) functional which asymptotically incorporates Hartree-Fock exchange. Using time-dependent density functional theory (TDDFT), we calculate excitation energies, oscillator strengths, and excited-state dipole moments in each of the dyes as a function of the range-separation paramet...

Viruses have evolved specialized mechanisms to efficiently transport nucleic acids and other biomolecules into specific host cells. They achieve this by performing a coordinated series of complex functions, resulting in delivery that is far more efficient than existing synthetic delivery mechanisms. Inspired by these natural systems, we describe a process for synthesizing chemically defined mol...

Confined environments can be used to alter the selectivity of a reaction by influencing the organization of the reactants, altering the mobility of trapped molecules, facilitating one reaction pathway or selectively stabilizing the products. This manuscript utilizes a series of potentially photoreactive guests to interrogate the utility of the one-dimensional nanochannels of a porous host to ab...

OBJECTIVE This paper examines policy processes regarding why the USA and Norway have not regulated coumarin in tobacco. DESIGN A qualitative analysis of all tobacco industry documents regarding coumarin since the 1950s from the 1998 US Master Settlement Agreement and subsequent legal settlements. Additional data were collected from newspaper reports, general internet search engines, journal a...

Coumarin, a simple, commodity chemical isolated from beans in 1820, has, to date, only yielded one solid state structure. Here, we report a rich polymorphism of coumarin grown from the melt. Four new metastable forms were identified and their crystal structures were solved using a combination of computational crystal structure prediction algorithms and X-ray powder diffraction. With five crysta...

durum wheat is one of the most important cereals that culture in the west of iran and dry land from long time. in order to study of chemical stress on germination of iranian durum wheat by coumarin in 5 levels (0, 10, 20, 30, 45 mg/l), an experiment was conducted in randomized complete design as factorial with three replications on 20 iranian durum wheat, which involve two genotypes as control ...

Photocaged fluorescent molecules are important research tools for tracking molecular dynamics with high spatiotemporal resolution in biological systems. We have designed and synthesized a new class of caged coumarin fluorophores. These coumarin cages displayed more than 200-fold fluorescence enhancement after UV photolysis. Remarkably, the uncaging cross section of a 1-(2-nitrophenyl)ethyl (NPE...

A series of novel thiazolidinones have been synthesized by reaction of various Schiff bases of coumarin with thioglycolic acid. The reaction of 4-hydroxy coumarin with POCl3 yielded 4chloro coumarin 2 and 4-chloro-3, 4', 3', 4"-tercoumarin 2a. Compound 2 was reacted with pphenylene diamine to yield 4-[(4-aminophenyl)amino]-2H-chromen-2-one.Various Schiff bases of coumarin were synthesized by co...

The results of a brief investigation of the amplified spontaneous emission and lasing characteristics of Coumarin 540 dye in as many as ten different solvents are reported. It has been found that C 540 dye solutions contained within a rectangular quartz cuvette give laser emission with well resolved equally spaced modes when pumped with a 476 nm beam. The modes were found to originate from the ...