Abstract: This invention relates to a dye donor element for laser-induced thermal dye transfer comprising a support having thereon a dye layer comprising an image dye in a binder and an infrared-absorbing material associated therewith, and wherein the infrared-absorbing material is a telluro- or seleno-squarylium dye having the following formula: ##STR1## wherein: R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each independently represents hydrogen or a substituted or unsubstituted alkyl, aryl or hetaryl group;R.sub.5 and R.sub.6 each independently represents hydrogen, halogen, cyano, alkoxy, aryloxy, acyloxy, aryloxycarbonyl, alkoxycarbonyl, sulfonyl, carbamoyl, acyl, acylamido, alkylamino, arylamino, or a substituted or unsubstituted alkyl, aryl or hetaryl group;X represents Se or Te; andY represents O, S, Se, Te, TeCl.sub.2 or TeBr.sub.2, with the proviso that when X and Y are both Se and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each represents t-butyl, then R.sub.5 and R.sub.

Abstract: A process for detecting the presence of living cells suspended in an aqueous medium preferably at a nearly neutral pH, which comprises:(a) reducing a tellurapyrylium Te(IV) dihydroxide (TPDH) with cells, optionally while using a substituted benzoquinone electron transfer agent to assist the reduction, thereby producing a change in light absorbance and(b) sensing the change in absorbance to detect or quantify the presence of the cells.The light absorbance change comprises the appearance of a new spectral peak from the product formed by reduction of the Te(IV) dihydroxide. The new peak has a high extinction coefficient in the near infrared region of the electromagnetic spectrum, i.e., away from the spectral region where some biological components cause spectral interference. Consequently, detection methods provided by this invention have a high degree of sensitivity and are comparatively free from spectral interference caused by materials commonly present in biological materials.

Abstract: There are disclosed pyrylium salts and a method of using them medicinally in photodynamic therapy for increasing the survival time of animals affected with glioma or mammary carcinoma. The salts are seleno- or telluropyrylium compounds having a singlet oxygen quantum efficiency of at least 0.005 when exposed as described at wavelengths between about 650 and 1000 nanometers.

Abstract: Unsymmetrical tellurapyrylium dyes can be ungraded in purity by separating them from symmetrical analogs produced as co-products. The procedure employed for the purification comprises an oxidative halogenation, followed by a fractional crystallization, and a reduction to regenerate the tellurapyrylium dye.

Abstract: There are disclosed certain pyrylium salts and a method of making them. The dyes are useful both medicinally in photodynamic therapy and in photoconductive compositions, photoresist and lithographic compositions or optical recording discs. The salts are mixed seleno- or telluropyrylium compounds having a singlet oxygen quantum efficiency of at least 0.005 when exposed as described at wavelengths between about 650 and 1000 nanometers, and a Lewis base anion.

Abstract: Novel 4H-tellurin compounds are disclosed. The compounds are useful as electron-accepting sensitizers for electron-donating photoconductive-compositions.

Abstract: Telluropyrylium dyes are useful as infrared absorbing dyes in recording elements.

Abstract: Novel Z-3-trihalochalcogenpropenone compounds selected from the group consisting of Z-3-trihaloseleniumpropenone and Z-3-trihalotelluriumpropenone and methods of making such compounds are disclosed. The Z-3-trihalochalcogenpropenone compounds are useful as sensitizers in electrophotographic compositions and elements.

Abstract: Novel chalcogenopentalene compounds having a tellurium atom in the 6a position, and methods of making chalcogenopentalenes having a tellurium or a selenium atom in the 6a position are disclosed. The chalcogenopentalene compounds are useful as sensitizers in electrophotographic compositions and elements containing an electron donor and as charge emitters in multilayer photoconductive elements.

Abstract: The present invention discloses novel substituted benzotelluropyrones and a novel method for making such compositions. The compositions are useful as intermediates for making benzotelluropyrylium and benzotelluropyrylium diketonate electron dye sensitizers for electron donating photoconductive compositions and elements.

Abstract: The present invention discloses novel mononuclear telluropyrone compositions of matter and a method for making such compositions. The compositions are useful intermediates for making telluropyrylium electron accepting dye sensitizers for photoconductive compositions.

Abstract: Novel benzotelluropyrylium diketonate dyes are disclosed. The dyes are useful in improving the performance of electron donating photoconductive compositions and elements. Methods for making the dye sensitizers are also disclosed.

Abstract: Novel telluropyrylium dyes are disclosed. The dyes are useful as electron accepting sensitizers for electron donating photoconductive compositions. Novel methods making the dyes are also disclosed.

Abstract: 1,2-oxachalcogenol-1-ium salts are presented. A novel method for making the salts is also presented. The salts are useful in improving the quantum efficiency of organic photoconductive compositions containing organic donor compounds having photoconductive properties.