Spin crossover (SCO) iron(II) coordination polymer chain: Synthesis, structural and magnetic characterizations of [Fe(abpt)2(μ-M(CN)4)] (M=PtII and NiII)

• DOI: 10.1016/j.poly.2013.06.008
• Publication Date: 2013-06-19T16:18:13Z
• Authors: Fatima Setifi; Catherine Charles; Sylvie Houille; Franck Thétiot; Smail Triki; Carlos J. Gómez-G...; Sébastien Pillet
• Keywords: Spin Crossover; Isostructural; Moiety; Bridging ligand; Powder Diffraction

Abstract New iron(II) coordination polymeric neutral chain of formula [Fe(abpt) 2 (μ-M(CN) 4 )], with M = Pt II ( 1 ), Ni II ( 2 ) and abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole, have been synthesized and characterized by infrared spectroscopy, X-ray diffraction and magnetic measurements. The two compounds are isostructural as deduced from a Rietveld analysis of X-ray powder diffraction data of 2 simulated from the single crystal structure of 1 . The crystal packing of 1 is formed by regular chains running along the crystallographic [−1 0 1] direction where the planar [Pt(CN) 4 ] 2− anion acts as a μ 2 -bridging ligand via two nitrogen atoms of two different trans cyano groups, while the two abpt molecules act as chelating ligands. Along the neutral chains, the Fe⋯Pt distances are imposed by the cyano groups of the [Pt(CN) 4 ] 2− moiety (5.027 and 5.022 A at 294 and 150 K, respectively), leading to Fe⋯Fe intrachain distances of 10.055 and 10.045 A at 294 and 150 K, respectively. The thermal dependence of the product of the molar magnetic susceptibility times the temperature ( χ m T ) for compound 1 shows a constant value close to 0.2 emu K mol −1 in the temperature range 10–300 K in the cooling and warming scans. Above 300 K, compound 1 shows a SCO transition from the LS to the HS configuration although the transition is not fully achieved at 400 K.