Light-induced spin-state switching in Fe(II) spin-crossover complexes with thiazole-based chelating ligands.

Homoleptic complexes [Fe(4bt)](ClO) (1), [Fe(2bt)](ClO) (2), and [Fe(3tpH)](ClO) (3) were obtained by a reaction between the Fe(II) precursor salt and the corresponding thiazole-based bidentate ligand (L = 4bt = 4,4'-bithiazole, 2bt = 2,2'-bithiazole, 3tpH = 3-(thiazol-2-yl)pyrazole). X-ray crystal structure determination revealed crystallization of solvent-free complex 1, a solvate 2·MeOH, and a co-crystal 3·2(3tpH). The crystal packing of all these complexes is dominated by one-dimensional interactions between the [Fe(L)] cations.

Abrupt Spin Transition in a Heteroleptic Fe(II) Complex with Pendant Naphthalene Functionality.

A heteroleptic spin-crossover (SCO) complex, [Fe(tpma)(xnap-bim)](ClO) (; tpma = tris(2-pyridylmethyl)amine, xnap-bim = 8,15-dihydrodiimidazo[1,2-:2',1'-]naphtho[2,3-][1,4]diazocine), has been obtained by reacting a Fe(II) precursor salt with tetradentate tpma and bidentate xnap-bim ligands. Depending on crystallization conditions, two different solvates have been obtained, ·2.25py·0.

Heteroleptic Fe(II) Complexes with NS Coordination as a Platform for Designing Spin-Crossover Materials.

Heteroleptic complexes [Fe(bpte)(bim)]X and [Fe(bpte)(xbim)]X (bpte = S,S'-bis(2-pyridylmethyl)-1,2-thioethane, bim = 2,2'-biimidazole, xbim = 1,1'-(α,α'-o-xylyl)-2,2'-biimidazole, X = ClO, BF, OTf) were prepared by reacting the corresponding Fe(II) salts with a 1:1 mixture of the ligands. All mononuclear complexes exhibit temperature-induced spin crossover (SCO) with the onset above room temperature. The SCO is rather gradual, due to low cooperativity of interactions between the cationic complexes, as revealed by crystal structure analyses.