Synthesis of 4-Hydroxy-2,6-di(pyrazol-1-yl)pyridine, and the Spin State Behaviour of Its Iron(II) Complex Salts

Magnetochemistry

Laurence J. Kershaw Cook²  Malcolm A. Halcrow¹ 

[1] School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK; E-Mail

关键词: iron;    N-donor ligand;    spin-crossover;    crystal structure;    magnetic measurements;    calorimetry;   

DOI  :  10.3390/magnetochemistry1010003

来源: mdpi

【 摘 要 】

Treatment of 4-hydroxy-2,6-dibromopyridine with four equivalent of deprotonated pyrazole in hot diglyme affords 4-hydroxy-2,6-di(pyrazol-1-yl)pyridine (L) in low yield. The three complex salts [FeL₂]X₂ (X⁻ = BF₄⁻, 1; X⁻ = ClO₄⁻, 2; X⁻ = PF₆⁻, 3) have been prepared, and crystallographically characterised as their methanol solvates. The solvate structures contain complexes that are fully high-spin (1 and 3), or in a mixed high:low spin state population at 150 K (2). Bulk samples of 1 and 2 obtained from methanol/diethyl ether contain a second, minor crystal phase that exhibits an abrupt spin-transition near 200 K. Recrystallisation of 1 and 2 from nitromethane/diethyl ether affords powder samples that are highly enriched in this spin-transition phase.

【 授权许可】

CC BY   
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