An "S"-shaped pentanuclear CuII cluster derived from the metal-assisted hydrolysis of pyCOpyCOpy: structural, magnetic and spectroscopic studies.

Reaction of [Cu2(O2CMe)4(H2O)2] with 2,6-di-(2-pyridylcarbonyl)-pyridine (pyCOpyCOpy or dpcp) in MeCN-H2O 10:1, led to the pentanuclear copper(II) complex [Cu5(O2CMe)6{pyC(O)(OH)pyC(O)(OH)py}2] () which crystallizes in the triclinic P1 space group. The copper(II) atoms are arranged in an "S"-shaped configuration, and are bridged by the doubly deprotonated bis(gem-diol) form of the ligand, pyC(O)(OH)pyC(O)(OH)py2-. Magnetic susceptibility data indicate the interplay of both ferro- and antiferromagnetic intramolecular interactions stabilizing an S=3/2 ground state.

Properties of a triazolopyridine system as a molecular chemosensor for metal ions, anions, and amino acids.

The characteristics as a chemosensor of the compound 3-methyl-6,8-di(2-pyridyl)-[1,2,3]triazolo[5',1':6,1]pyrido[2,3-]pyrimidine (1) have been analyzed. Interaction with Cu(2+) produces a quenching of the fluorescence, while interaction with Zn(2+) leads to a quenching of the fluorescence followed by a bathochromic shift. The crystal structure of the Zn(1)(H(2)O)(3)(ClO(4))(2) x H(2)O complex shows the coordination of Zn(2+) through the terpyridine moiety.

3-(2-Pyridyl)-[1,2,3]triazolo[1,5-a]pyridines. An experimental and theoretical (DFT) study of the ring-chain isomerization.

An experimental ((1)H NMR) and theoretical (DFT) study of the ring-chain-ring isomerization of 3-(2-pyridyl)-[1,2,3]triazolo[1,5-a]pyrid-7-yl derivatives (A) into 6-{[1,2,3]triazolo[1,5-a]pyrid-3-yl}-2-pyridyl derivatives (B) has been carried out. Based on the calculations, a mechanism of several steps will be proposed. The experimental results as well as the calculations lead to the conclusion that the A-B ratio depends on the electronic properties of the substituents.