Spin Crossover in New Iron(II) Coordination Compounds with Tris(pyrazol-1-yl)Methane

We review here new advances in the synthesis and investigation of iron(II) coordination compounds with tris(pyrazol-1-yl)methane and its derivatives as ligands. The complexes demonstrate thermally induced spin crossover accompanied by thermochromism. Factors that influence the nature and temperature of the spin crossover are discussed.

Synthesis and reactivity at the Ir-MeTpm platform: from κ1-N coordination to κ3-N-based organometallic chemistry

Reaction of [Ir(μ-Cl)(COE)2]2 (COE = cis-cyclooctene) with tris(3,5-dimethylpyrazol-1-yl)methane (MeTpm) affords [IrCl(κ1-N-MeTpm)(COD)] (1) (COD = 1,5-cyclooctadiene). The formation of 1 implies the transfer dehydrogenation of a COE ligand to give COD and COA (cyclooctane). A mechanistic proposal based on DFT calculations that explains this iridium promoted process has been disclosed. Additionally, reactivity studies have allowed the preparation and characterization, including determination of the molecular structures of a number of iridium complexes with the MeTpm ligand in κ1, κ2 or κ3-N coordination modes. Moreover, the first example of an Ir-cyclooctyl complex featuring hydride and carbonyl ligands, whose solid state structure has been determined by X-ray diffraction methods, is reported.

Accessing spin-crossover behaviour in iron(ii) complexes of N-confused scorpionate ligands

Scorpionates with a dislocated pyrazolyl have been prepared on a large scale to allow new variations in iron(ii) spin-crossover materials.