title: Spectroscopic, structural and magnetic investigations of iron(II) complexes based on 1-isopropyl- and 1-isobutyl-substituted tetrazole ligands.
abstract: Two partly new [Fe(intz)6](BF4)2complexes withn= 3 and 4 (i3tz= 1-isopropyl-1H-tetrazole,i4tz= 1-isobutyl-1H-tetrazole) were synthesized and characterised by X-ray powder diffraction, magnetic susceptibility measurements, vibrational, electronic and57Fe-Mößbauer spectroscopy as well as DSC. The [Fe(i3tz)6](BF4)2complex was re-investigated and shows an incomplete spin transition atTc∼ 109 K, while the [Fe(i4tz)6](BF4)2features a complete but rather gradual spin transition withT½= 223 K. In the lack of suitable crystals of [Fe(intz)6](BF4)2withn= 3 and 4, we synthesized crystals of [Ni(intz)6](BF4)2withn= 3 and 4, determined their X-ray crystal structures, and proved them to be homeotypic with the respective Fe-complexes by X-ray powder diffraction. DSC measurements showed an endothermic peak for the [Fe(i3tz)6](BF4)2aroundT= 260 K not corresponding to a spin transition and suggesting a structural phase transition at this temperature. A well-developed peak atTp= 225 K matches the spin-transition temperatureT½= 223 K for [Fe(i4tz)6](BF4)2.
authors.affiliation: Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163-AC, A-1060 Vienna, Austria.
authors.forename: Nader
authors.initials: N
authors.lastname: Hassan
authors.forename: Julia
authors.initials: J
authors.lastname: Stelzl
authors.forename: Peter
authors.initials: P
authors.lastname: Weinberger
authors.forename: Gabor
authors.initials: G
authors.lastname: Molnar
authors.forename: Azzedine
authors.initials: A
authors.lastname: Bousseksou
authors.forename: Frank
authors.initials: F
authors.lastname: Kubel
authors.forename: Kurt
authors.initials: K
authors.lastname: Mereiter
authors.forename: Roman
authors.initials: R
authors.lastname: Boca
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Linert
keywords: 1-Isoalkyl-tetrazole; 57Fe–Mößbauer spectroscopy; Iron(II) spin-crossover; SQUID; Variable temperature IR spectroscopy; Variable temperature UV–Vis–NIR spectroscopy
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