Anchoring pyrazolines on a 2,2′:6′,2″-terpyridine backbone

• Published in: Journal of molecular structure 2017-11, Vol.1148, p.397-403
• Main Authors: Liu, E, Li, Li, Xiong, Hangxing, Chan, Corinna, Cheng, Jessica, Zhang, Guoqi
• Format: Article
• Language: English
• Subjects: 2,2′:6′,2″-Terpyridine; Crystal structure; Fluoresence; Pyrazoline; π-Stacking
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2017.07.057

Introducing pyrazoline derivatives into the classical 2,2′:6′,2″-terpyridine (2,2′:6′,2″-tpy) backbone leads to the synthesis of a new class of compounds, 4′-pyrazolinyl-2,2′:6′,2″-tpys. Six such derivatives bearing differently substituted pyrazolines have been synthesized with a facile two-step procedure using simple chalcone compounds and 4′-hydrazino-2,2′:6′,2″-tpy as starting materials, and they were fully characterized by IR, NMR, MS and elemental analysis. Two representative crystal structures have been determined by single crystal X-ray diffraction analysis. The solid state structures reveal the presence of two enantiomers as a racemate in each of these compounds and the arrangement between aromatic rings in both tpy and pyrazoline domains can be affected by the substituents. The intermolecular packing is mainly driven by the π-stacking interactions between aromatic regions. The solution electronic absorption and emission behaviors of the new compounds were also investigated. [Display omitted] •A series of 4′-pyrazolinyl-2,2′:6′,2″-terpyridine derivatives were synthesized.•The condensation of 4′-hydrazino-2,2′:6′,2″-terpyridine with chalcones was studied.•The X-ray structural analysis of two representative target compounds was conducted.•The compounds were fully characterized by spectroscopic and photophysical methods.