Electrochromic single and two-core viologen derivatives and optical articles containing them

The present invention relates to a group of novel electrochromic materials. More specifically, it relates to electrochromic materials based on either single or two-core viologen systems and the use of these viologen systems as a variable transmittance medium for the manufacture of an optical article, such as an ophthalmic lens

Electrochromic two-core viologen derivatives and optical articles containing them

The present invention relates to a group of novel electrochromic materials. More specifically, it relates to electrochromic materials having two-core viologens and the use of these two-core viologens as a variable transmittance medium for the manufacture of an optical article, such as an ophthalmic lens

Extending Human Perception of Electromagnetic Radiation to the UV Region through Biologically Inspired Photochromic Fuzzy Logic (BIPFUL) Systems.

Photochromic Fuzzy Logic Systems have been designed that extend human visual perception into the UV region. The systems are founded on a detailed knowledge of the activation wavelengths and quantum yields of a series of thermally reversible photochromic compounds. By appropriate matching of the photochromic behaviour unique colour signatures are generated in response differing UV activation frequencies

Inhibition of the photochromic behaviour of a 3,3-diphenyl-3H-pyrano[3,2-f]quinoline ligand by coordination to Ag(I) ions

The synthesis and characterisation of a photoresponsive 3,3-diphenyl-3H-pyrano[3,2-f]quinoline ligand which contains both quinoline and thiazole N-donor moieties is described. This ligand acts as a bidentate N-donor ligand and the solid-state structure of a Ag(I) complex is reported. Whereas the free ligand exhibits typical photochromic behaviour, coordination with Ag(I) results in complete inhibition of the photochromic response. However, excitation wavelength dependent emission spectra demonstrated an increase in fluorescence response of the new Ag(I) complex

The first structural and spectroscopic characterisation of a ring-opened form of a 2H-naphtho[1,2-b]pyran: a novel photomerocyanine

Heating 4-methoxy-1-naphthol with a 1,1-diarylprop-2-yn-1-ol gave the 2,2-diaryl-6-methoxy-2H-naphtho[1,2-b]pyran together with the novel merocyanine, (E)-2-[30,30-bis(aryl)allylidene]-4-methoxynaphthalen- 1(2H)-one. Brief UV-irradiation of the pyran favoured the formation of the (Z)-merocyanine with longer irradiation and/or acidic conditions favouring the (E)-isomer

Synthesis of the 5-thiorotenoid system from thiochroman-3-one

Base-induced cyclisation of the diketones 10(X = H or F), prepared in a two-step sequence from thiochroman-3-one, affords 6H,12H-[1]benzothiopyrano[3,4-b][1]benzopyran-12-ones 11. Reduction with diisobutylaluminium hydride affords a separable mixture of the cis- and trans-5-thiorotenoids. Dieckmann cyclisation of ethyl 2-(ethoxycarbonylmethylthio)phenylethanoate affords a mixture of 4-ethoxycarbonyl- and 2-ethoxycarbonyl-thiochroman-3-ones. Attempts to prepare a thiorotenoid by condensation of these β-keto esters with 4-methoxyphenol resulted in formation of the novel bis[1]benzothiopyrano[3,2-b:4′,3′-e]pyran ring system

Expedient syntheses of the rotenoid and thiorotenoid systems

A simple four-step synthesis of a 6,6-disubstituted 6a,12a-dihydro-6H,12H-[1]benzopyrano[3,4,-b]-[1]benzopyran-12-one 6 from a chroman-4-one 3 is described. Application of the synthetic strategy to a thiochroman-4-one leads to the 5-thiorotenoid system

Enamino ketones as precursors of functionalised 2H-thiopyrans and thiopyrano[2,3-c]- and [3,2-b]-benzothiopyrans

Oxo enamino ketones obtained by treating active methylene compounds with N,N-dimethylformamide dimethyl acetal yield novel 2H-thiopyrans in a regioselective one pot thionation–[4 + 2]-cycloaddition sequence. Application of similar methodology to thiochroman-3-ones affords novel thiopyrano[2,3-c][1]benzothiopyrans and the [3,2-b] isomers