Formation and conversion of six temperature-dependent fluorescent ZnII-complexes containing two in situ formed N-rich heterocyclic ligands
| Autor: | Xia Huang, Li-Ping Si, Mei-Juan Wei, Yue-Peng Cai, Ji-Yuan Zhang, Yan-Jun Ou, Qin Wei |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Schiff base
010405 organic chemistry Stereochemistry Ligand General Chemical Engineering General Chemistry 010402 general chemistry 01 natural sciences Fluorescence 0104 chemical sciences Metal chemistry.chemical_compound Crystallography chemistry Imidazolidine visual_art Pyridine visual_art.visual_art_medium Moiety Reactivity (chemistry) |
| Zdroj: | RSC Advances. 7:6994-7002 |
| ISSN: | 2046-2069 |
| Popis: | Six temperature-dependent Zn(II) complexes 1–6 based on the simple Schiff base L1 from condensation of equivalent 2-pyridine formaldehyde (2-Pfd) and 2-pyridylethylamine (2-Pea) were systematically studied for the first time. These six complexes are: two complexes of ZnL2X2 (1 and 2) involving in situ formed N-rich heterocyclic ligand L2 at 80 °C; two complexes of [Zn2(cis-L3)X4·S] (S = H2O for 3, S = 0 for 5) involving in situ formed azaheterocyclic ligand cis-L3 at 100 °C; and the rest two ones of [[Zn2(trans-L3)X4] (4 and 6) involving in situ formed azaheterocyclic ligand trans-L3 at 120 °C (where X = Cl (1, 3, 4) and N3 (2, 5, 6), L1 = N-(2-pyridylmethyl)-pyridine-2-carbaldimine, L2 = 1-pyridineimidazo-[1,5-a]pyridine, L3 = 1-(1,2-di(pyridin-2-yl)-2-(3-(pyridin-2-yl)H-imidazo-[1,5-a]-pyridin-1-yl)-ethyl)-3-(pyridin-2-yl)H-imidazo-[1,5-a]pyridine). Interestingly, three Cl-based complexes 1, 3, 4 under appropriate conditions can be irreversibly translated into the corresponding N3-based 2, 5, 6, respectively. The possible formation/conversion mechanism shows that the α-H activation in –CHN–CH2– moiety of L1 coordinated to Zn2+ ion should be the original driving force for the intermolecular C–C/C–N coupling and ring formation reactions, meanwhile reaction temperature also plays a very important role during the formation/conversion of 1–6. Moreover, the results indicate that complexes 1–6 have good fluorescence properties as potential fluorescent materials. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|