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Updated: Aug 22, 2025

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
[1,4]Ditellurino[2,3-b:5,6-b']di-pyrazine
Donna Franklin1, Aundrea Lee1, Frank R Fronczek2
1Department of Chemistry, Lafayette, LA 70403, USA.
Abstract:
[1,4]Ditellurino[2,3-b:5,6-b']di-pyrazine represents the first reported [1,4]chalcogena[2,3-b:5,6-b']di-pyrazine containing a heavy chalcogens The asymmetric unit consists of three mol-ecules. In contrast to its sulfur analog, which is planar [Lynch et al. (1994 ▸) Cryst. Struct. Commun. 50,1470-1472], C8H4N4Te2 is folded along the Te⋯Te axis to accommodate the larger chalcogenide atoms. The dihedral angle between the two Te2C2 rings of the central ring is 57.9° (mean of three). C-Te bond lengths range from 2.1105 (16) Å to 2.1381 (17) Å, in good agreement with those predicted by their covalent radii. All Te atoms are involved in inter-molecular Te⋯N contacts, with distances in the range 2.894 (2) to 2.963 (2) Å. These result in a spiral supra-molecular assembly, forming helical columns.
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