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Research was conducted to examine chalcogen atom effects on the rates of hydrolysis of chalcogenopyrylium dyes. Results indicate that the qualitative ordering of the rates can be rationalized in terms of higher stability of the thiopyrylium ring relative to the selenopyrylium ring. Findings also show that the decreasing electronegativity of the chalcogen atoms as size increases would tend to stabilize the cationic charge inductively, predicting the opposite trend in stability.

The products of the hydrolysis of chalcogenopyrylium dyes at alkaline pH under both anaerobic and aerobic conditions were analyzed. The types of hydrolysis products observed were found strongly dependent on the identity of the chalcogen atoms in the pi-framework and on the presence of molecular oxygen during the hydrolysis. It was found that chalcogenopyranomes produce modest yields in aerobic reactions.

Heteroatom scrambling occurs due to the formation of unsymmetrical tris(chalcogenopyramylmethylidene)methanes during the synthesis of unsymmetrical chalcogenopyrylium dyes. The complete chalcogenopyranyl ring is involved during heteroatom scrambling and Reverse aldol reaction with dyes has no significant influence on scrambling mechanism. Dyes have found various applications in optical recording, electrophotography and thermal dye transfer. The experimental procedure for the synthesis of unsymmetrical dyes and tris(chalcogenopyramylmethylidene)methanes is discussed.

Highlights a study which investigated the impact of different chalcogen atoms on the hydrolysis rates of chalcogenopyrylium dyes. Details on dyes composed of near-infrared-absorbing chromophores; Effectiveness of the dyes as sensitizers for photodynamic therapy; Methodology used to conduct the study; Results of the study.

Presents a study on hydrolyses of chalcogenopyrylium dyes one to nine. Description of the products derived from hydrolysis of dyes one to nine at alkaline pH under both anaerobic and aerobic conditions; Indication of minor polymeric/oligomeric products; Results of the study.