Zn^II and Pb^II coordination chemistry of 2,6-bis(1,2,3-triazol-4-yl)pyridine (clickate) and the metal ion-dependent emission of ‘clickate’–appended anthracene

Abstract

2012) Zn II and PbII coordination chemistry of 2,6-bis(1,2,3-triazol-4-yl)pyridine (clickate) and the metal ion-dependent emission of 'clickate'-appended anthracene, Supramolecular Chemistry, 24:9, 696-706,The effect of metal coordination of 2-(1-(9-anthryl)methyl-1,2,3-triazol-4-yl)-6-(1-n-octyl-1,2,3-triazol-4-yl)pyridine (2) on the emission of the appended anthryl group was investigated in acetonitrile. The tridentate 2,6-bis(1,2,3-triazol-4-yl)pyridyl ligand included in 2 is referred herein as 'clickate'. Titrating zinc(II) perchlorate or zinc(II) chloride into the solution of fluorescent ligand 2 results in quenching, which is attributed to the formation of a dark 1:1 Zn II complex of 2. Frontier molecular orbital analysis and cyclic voltammetric data support the occurrence of photoinduced electron transfer from the excited state of the anthryl group to the Zn II -bound clickate moiety, which relaxes the excited fluorophore non-radiatively, i.e. quenches fluorescence. Fluorescence quenching of clickate 2 upon forming the Pb II complex was also observed. The Zn II /Pb II -coordination chemistry of clickate was characterised via X-ray crystallography, isothermal titration calorimetry, 1 H NMR spectroscopy and absorption spectroscopy using the symmetrically substituted clickate 2,6-bis(1-n-octyl-1,2,3-triazol-4 yl)pyridine (1).

Tricolor Emission of a Fluorescent Heteroditopic Ligand over a Concentration Gradient of Zinc(II) Ions

“…Similar rhodamine spirolactam systems with different substituents have recently been reported. 35,43,44 The pyridyl and triazolyl groups are in a typical transoid arrangement 45 with a dihedral angle of 13.6° for minimizing the dipole interactions between the two heterocycles.…”

The btp [2,6-bis(1,2,3-triazol-4-yl)pyridine] binding motif: a new versatile terdentate ligand for supramolecular and coordination chemistry

“…It was concluded that magnetic exchange through the hydrogen bonds was the most likely pathway. 114 Both Zhu and Dash briefly mentioned Cu(II) quenching the florescence emission of ligands 5, 26 115 as well as compound 27. 116 However, these systems will be discussed in more detail below in relation to their fluorescence emission enhancement upon interaction with Zn(II).…”

Crystal structure of tris(3-(2-pyridyl)pyrazole)zinc(II)tetrachlorido zincate(II), C24H21Cl4N9Zn2

“…Herein, we report the crystal structure of the title compound. In the title compound, all the bond lengths are within normal ranges [5], similar to its two analogues [6,7]. One Zn(II) is …”