CONICET | Buscador de Institutos y Recursos Humanos

Tetrazole-saccharinates have emerged as coordination ligands, useful in fields such as catalysis, supramolecular chemistry and molecular magnetism. Understanding the relevance of different tautomeric forms and possible conformations then appears of fundamental importance to explore their applications. We devised synthetic routes to a small library of these conjugates, where the two heterocycles are connected through a nitrogen bridge.1,2 It has been shown that the preferred tautomeric species of these compounds is very much determined by the chemical environment.1,2 As shown by X-ray diffraction,2 crystalline 2-methyltetrazole-saccharinate 1 exists as the amino-bridged tautomer. Investigation of a cryogenic matrix prepared after sublimation of 1 and deposition of the sublimate with argon, revealed that in the gas phase it exists as the theoretically predicted most stable imino-bridged form 2.3 The experimental IR spectrum of the matrix-isolated compound was fully assigned, based on the B3LYP/6-311++G(3df,3pd) calculated spectra for the relevant forms 2a,b. A mechanism for the tautomeric conversion upon sublimation is proposed.