Aryl and Heteroaryl N1-Tetrazoles through Ligand-Free Suzuki-Reaction under Aerobic, Aqueous Conditions

Bifunctional Fe(II) spin crossover-complexes based on ω-(1H-tetrazol-1-yl) carboxylic acids

To increase the supramolecular cooperativity in Fe(ii) spin crossover materials based on N1-substituted tetrazoles, a series of ω-(1H-tetrazol-1-yl) carboxylic acids with chain-lengths of C2-C4 were synthesized. Structural characterization confirmed the formation of a strong hydrogen-bond network, responsible for enhanced cooperativity in the materials and thus largely complete spin-state transitions for the ligands with chain lenghts of C2 and C4. To complement the structural and magnetic investigation, electronic spectroscopy was used to investigate the spin-state transition. An initial attempt to utilize the bifunctional coordination ability of the ω-(1H-tetrazol-1-yl) carboxylic acids for preparation of mixed-metallic 3d-4f coordination polymers resulted in a novel one-dimensional gadolinium-oxo chain system with the ω-(1H-tetrazol-1-yl) carboxylic acid acting as μ2-η2:η1 chelating-bridging ligand.

Halogenated Alkyltetrazoles for the Rational Design of FeII Spin-Crossover Materials: Fine-Tuning of the Ligand Size

1-(3-Halopropyl)-1H-tetrazoles and their corresponding Fe^II spin-crossover complexes have been investigated in a combined experimental and theoretical study. Halogen substitution was found to positively influence the spin transition, shifting the transition temperature about 70 K towards room temperature. Halogens located at the ω position were found to be too far away from the coordinating tetrazole moiety to have an electronic impact on the spin transition. The subtle variation of the steric demand of the ligand in a highly comparable series was found to have a comparatively large impact on the spin-transition behavior, which highlights the sensitivity of the effect to subtle structural changes.