Spin Crossover in a 3, 5‐Bis(2‐pyridyl)‐1, 2, 4‐triazolate‐Bridged Dinuclear Iron(II) Complex [{Fe(NCBH3)(py)}2(μ‐L1)2] – Powder versus Single Crystal Study. Issue 5 (10th December 2012)

• Record Type: Journal Article
• Authors: Schneider, Caspar J.; Cashion, John D.; Chilton, Nicholas F.; Etrillard, Céline; Fuentealba, Mauricio; Howard, Judith A. K.; Létard, Jean‐François; Milsmann, Carsten; Moubaraki, Boujemaa; Sparkes, Hazel A.; Batten, Stuart R.; Murray, Keith S.
• Other Names: Murray Keith S. sponsoringEditor.; Oshio Hiroki sponsoringEditor.; Real Jose Antonio sponsoringEditor.
• Is Part Of: European journal of inorganic chemistry. Issue 5/6(2013)
• Page Start: 850
• Page End: 864
• Publication Date: 2012-12-10
• Subjects: Spin crossover -- Polymorphism -- Iron -- N ligands -- Density functional calculations -- LIESST; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201201075
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: The structural characteristics and physical properties of the 3, 5‐bis(2‐pyridyl)‐1, 2, 4‐triazolate (L 1 ) bridged dinuclear iron(II) spin‐crossover complex [{Fe(NCBH3 )(py)}2 (μ‐L 1 )2 ] (1 ) in both powder (1p ) and single crystal (1c ) forms have been investigated. Both forms of [{Fe(NCBH3 )(py)}2 (μ‐L 1 )2 ] display a thermally induced spin transition; however, the transitions have different T 1/2 values and different degrees of spin conversion. Both forms display the photomagnetic light‐induced excited spin‐state trapping (LIESST) effect as well as reverse LIESST and have been compared by Raman spectral and powder X‐ray diffraction methods, which indicate that they are polymorphs. The single crystal form1c shows a "half" spin transition and has been further characterised at temperatures above and below the spin transition by low temperature crystallographic methods including single crystal LIESST experiments (at 40 K) and by Mössbauer spectroscopy; thus, the nature of the [HS‐LS] form and the different spin isomers were revealed. To complement the experimental results, compound1 and several other related Fe II dinuclear spin‐crossover compounds have been evaluated by quantum‐chemical DFT calculations. Additionally, the susceptibilities for the powder form1p, which displays a complete two‐step spin‐crossover, were also fitted to a phenomenological model for dinuclear spin‐crossover complexes. Abstract : A detailed synthetic, crystallographic, magnetic, light‐induced excited spin‐state trapping (LIESST), Mössbauer effect and theoretical investigation of spin‐crossover transitions is described for two polymorphs (crystalline and powder forms) of a triazolate‐bridged dinuclear iron(II) complex.