Architectures in Copper Metal–Organic Frameworks from 4‐Substituted Anionic 1,2,4‐Triazoles

Abstract

Three new metal‐organic frameworks, [Cu3(L1)2(OH)4]n (1), [Cu(L1)(Cl)]n (2), and [Cu(H2O)(L2)(Cl)]n (3), were synthesized under hydrothermal conditions by reaction of 4‐substituted 1,2,4‐triazole derivative ligands (L1 = 4‐(1,2,4‐triazol‐4‐yl)ethanesulfonate; L2 = 4‐(1,2,4‐triazol‐4‐yl)benzenesulfonate) with Cu2+ salts. The different geometry and chemical features of the ligands have yielded unique crystal structures with different dimensionalities. The magnetic properties of the three compounds have been analyzed, all of which show antiferromagnetic interactions: J1 = –130 cm–1 and J2 = –370 cm–1 (1), J = –12.3 (2), and –216 cm–1 (3) (convention used H = –J). The nature and the magnitude of the antiferromagnetic super exchange are correlated with the crystal structure and the distinct bridging modes between spin carriers in the solid state.

Solid-State Ring-Opening Structural Transformation in Triazolyl Ethanesulfonate Based Silver Complexes

“…Flexible bis­(triazole) ligands such as 1,2-bis­(1,2,4-triazole-1-yl)­ethane can adopt gauche (angular) or anti (linear) conformations on the basis of relative orientation of CH 2 groups. , In contrast to bis­(triazole) ligands, triazoles in combination with highly polar functional groups such as sulfonic acid have scarcely been explored so far. With the sulfonate-functionalized triazole ligand (2-(4 H -1,2,4-triazol-4-yl)­ethanesulfonate), coordination polymers with divalent metal ions, i.e., Zn 2+ , Cu 2+ , Ni 2+ , Co 2+ , Fe 2+ , and Cd 2+ , have been reported regarding their structural and physical properties including magnetism and photoluminescence. − Most of these examples exhibit linear trinuclear triazole-bridged metal complexes, whereas, in contrast, herein we represent the first report on silver complexes that exhibit planar nine-membered cyclic arrangements with three triazole rings coordinating three Ag + ions in a linear fashion each. This special cyclic structural arrangement with Ag + ions and sulfonate-functionalized triazole ligands leads to a new type of solid-state structure transformation, to the best of our knowledge not reported so far in the literature.…”