Iron(III) Azadiphenolate Compounds in a New Family of Spin Crossover Iron(II)–Iron(III) Mixed-Valent Complexes

Content Provider	Directory of Open Access Journals (DOAJ)
Author	Wasinee Phonsri David S. Macedo Barnaby A. I. Lewis Declan F. Wain Keith S. Murray
Abstract	A new family of mixed valent, double salt spin crossover compounds containing anionic $Fe^{III}$ and cationic $Fe^{II}$ compounds i.e., [Fe^{II}{(pz)_{3}CH}_{2}][Fe^{III}$(azp)_{2}]_{2}·2H_{2}$O (4), [Fe^{II}(TPPZ)_{2}][Fe^{III}$(azp)_{2}]_{2}]·H_{2}$O (5) and [Fe^{II}(TPPZ)_{2}][Fe^{III}$(azp)_{2}]_{2}]·H_{2}$O·3MeCN (6) (where $(pz)_{3}$CH = tris-pyrazolylmethane, TPPZ = 2,3,5,6, tetrapyridylpyrazine and $azp^{2−}$ = azadiphenolato) has been synthesized and characterised. This is the first time that the rare anionic spin crossover species, [Fe^{III}(azp)_{2}$]^{−}$, has been used as an anionic component in double salts complexes. Single crystal structures and magnetic studies showed that compound 6 exhibits a spin transition relating to one of the $Fe^{III}$ centres of the constituent $Fe^{II}$ and $Fe^{III}$ sites. Crystal structures of the anionic and cationic precursor complexes were also analysed and compared to the double salt products thus providing a clearer picture for future crystal design in double spin crossover materials. We discuss the effects that the solvent and counterion had on the crystal packing and spin crossover properties.
Related Links	https://www.mdpi.com/2312-7481/5/2/37
e-ISSN	23127481
DOI	10.3390/magnetochemistry5020037
Journal	Magnetochemistry
Issue Number	2
Volume Number	5
Language	English
Publisher	MDPI AG
Publisher Place	Switzerland
Access Restriction	Open
Subject Keyword	Chemistry Spin Crossover Mixed Valent Double Salts Mixed $fe^{ii}–fe^{iii}$ Magnetic Properties Crystal Structures
Content Type	Text
Resource Type	Article