4,7-Bis(thiolo)substituted [1,2,5]selenadiazolo[3,4-d]pyridazines: synthesis, structural, photophysical and thermotropic features

4,7-Bis(thiolo)substituted [1,2,5]selenadiazolo[3,4-d]pyridazines: synthesis, structural, photophysical and thermotropic features Full article

Journal

Tetrahedron
ISSN: 0040-4020 , E-ISSN: 1464-5416

Output data

Year: 2026, Volume: 200, Article number : 135428, Pages count : DOI: 10.1016/j.tet.2026.135428

Authors

Chmovzh Timofey N. ¹ , Rakhimkulov Dadozhon M. ^2,1 , Kalle Paulina ³ , Korshunov Vladislav M. ^4,5 , Ferulev Alexey I. ^4,5 , Mikhalchenko Ludmila V. ¹ , Taydakov Ilya V. ^6,5 , Rakitin Oleg A. ¹

Affiliations

1	N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninskiy Prosp., 119991 Moscow, Russian Federation
2	D. I. Mendeleev University of Chemistry and Technology of Russia, Miusskaya sqr., 9, Moscow 125047, Russian Federation
3	N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31 Leninsky prosp., Moscow 119991, Russia
4	Bauman Moscow State Technical University, 5/1 2-nd Baumanskaya street, 105005, Moscow, Russia
5	P. N. Lebedev Physical Institute of the Russian Academy of Sciences, 53 Leninskiy 1. Prospect, 119991 Moscow, Russia
6	G.V. Plekhanov Russian University of Economics, Stremyanny per. 36, Moscow, 117997, Russian Federation

1,2,5-Chalcogenadiazoles fused to another heterocycle are proposed for use in various fields, such as organic photovoltaics, organic light-emitting diodes, NIR dyes, non-fullerene acceptors for solar cells, dye-sensitized solar cells, and many others. The reaction of 3,6-dibromopyridazine-4,5-diamine with selenium dioxide in MeCN followed by the addition of aromatic and aliphatic thiols afforded symmetrical bis(dithiolo)-substituted and monoalkylthiol-substituted dithiolo-[1,2,5]selenadiazolo[3,4-d]pyridazines. The monoalkylthiol-substituted derivatives of this heterocyclic system were successfully converted to asymmetric [1,2,5]selenadiazolo[3,4-d]pyridazines. 4,7-Bis(thiolo)substituted [1,2,5]selenadiazolo[3,4-d]pyridazines were shown to exhibit significant polymorphism in the solid state with multiple crystal-crystalline transitions before melting. By varying the alkyl chain length (from C8 to C16) in the alkylthio derivatives of [1,2,5]selenadiazolo[3,4-d]pyridazines, it is possible to modulate the number and complexity of these transitions before melting (longer chains facilitate more transitions). It was found that the introduction of thiol instead of amine substituents in pyridizineselenadiazole molecules leads to fluorescence instead phosphorescence with a significant decrease in the quantum yield to 1.6%. It was shown that the introduction of dodecylthiol derivatives into 1,2,5-thiadiazoles fused with benzene and nitrogen heterocycles leads to the appearance of π-π* excited states. 4,7-Bis(dodecylthio)benzo[c][1,2,5]thiadiazole and 4,7-bis(dodecylthio)-[1,2,5]thiadiazolo[3,4-c]pyridine in toluene exhibit bright fluorescence with high quantum yields of 80% and 60%, respectively, which may be suitable for applications such as potential integration into polymer matrices.

Chmovzh T.N. , Rakhimkulov D.M. , Kalle P. , Korshunov V.M. , Ferulev A.I. , Mikhalchenko L.V. , Taydakov I.V. , Rakitin O.A.
4,7-Bis(thiolo)substituted [1,2,5]selenadiazolo[3,4-d]pyridazines: synthesis, structural, photophysical and thermotropic features
Tetrahedron. 2026. V.200. 135428 . DOI: 10.1016/j.tet.2026.135428 WOS Scopus OpenAlex

Submitted:	Apr 2, 2026
Accepted:	Aug 5, 2026
Published print:	Aug 7, 2026
Published online:	Aug 7, 2026

≡ Web of science:	WOS:001846603300001
≡ Scopus:	2-s2.0-105046858697
≡ OpenAlex:	W7201873467