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Spin‐Crossover Studies on a Series of 1D Chain and Dinuclear Iron(II) Triazine‐Dipyridylamine Compounds
Author(s) -
Neville Suzanne M.,
Leita Ben A.,
Offermann Daniel A.,
Duriska Martin B.,
Moubaraki Boujemaa,
Chapman Karena W.,
Halder Gregory J.,
Murray Keith S.
Publication year - 2007
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200601034
Subject(s) - spin crossover , chemistry , isostructural , crystallography , spin transition , ligand (biochemistry) , triazine , chalcogenide , stereochemistry , crystal structure , polymer chemistry , organic chemistry , biochemistry , receptor
Four isostructural one‐dimensional polymeric iron(II) spin crossover materials containing the ligand 2‐chloro‐4,6‐bis(dipyrid‐2‐ylamino)‐1,3,5‐triazine (cddt) have been synthesised and magnetically and structurally characterised. The polymeric material Fe(NCS) 2 (cddt) · n (guest) ( 1 ), self assembles into three crystallographically distinct phases; the compounds 1b and 1c , [Fe(NCS) 2 (cddt)] · 2(CH 3 OH), are polymorphs, however, 1a , [Fe(NCS) 2 (cddt)] · 1/2(CHCl 3 ) · (H 2 O) contains a different solvent system. Each phase shows very different magnetic behaviour; phases 1a and 1b remain high spin over all temperatures, whilst phase 1c undergoes a “half” spin crossover between 225 and 125 K. The structural consequences of the spin transition in 1c have been followed using variable temperature synchrotron powder X‐ray diffraction techniques. Variation of the chalcogenide ligand in the complex [Fe(NCSe) 2 (cddt)] · 2(CH 3 OH), 2 , leads to a full one‐step spin crossover with a T 1/2 of 200 K. Structural analysis of 1c below the transition temperature reveals alternating, crystallographically distinct, HS and LS iron(II) centres (HS: high spin, LS: low spin) along the chain, and structural analysis of 2 below the transition temperature reveals all LS iron(II) centres. Also reported are the structural characterisations of two dinuclear materials, containing the ligand 2,4,6‐tris(dipyridin‐2‐ylamino)‐1,3,5‐triazine (tdt), of the formula [Fe(tdt)(X) 2 ] 2 · (ClO 4 ) · (solvent) (X = H 2 O, Cl – for 3a , 3b ) which are analogous to those recently reported by Gamez et al. In addition, the structural characterisations are described for dinuclear materials, containing the ligand cddt, of the formula [Fe(cddt)(Cl)(X)] 2 · (Y) 2 · n (solvent) (X: H 2 O or NCCH 3 , Y: ClO 4 – , BF 4 – 4a , 4b and 4d ) and for a cobalt(II) analogue, [Co(cddt)(Cl)(H 2 O)] 2 · (BF 4 ) 2 · n (solvent) ( 4c ).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)