Spin crossover in mixed ligand iron(iii) complexes. (23rd October 2017)

• Record Type: Journal Article
• Authors: Phonsri, Wasinee; Harding, Phimphaka; Murray, Keith S.; Moubaraki, Boujemaa; Harding, David J.
• Is Part Of: New journal of chemistry. Volume 41:Number 22(2017)
• Page Start: 13747
• Page End: 13753
• Publication Date: 2017-10-23
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c7nj03676k
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : The use of two subtly different ligands is used to explore their impact on spin crossover characteristics. Abstract : Mixed ligand complexes [Fe(qsal-Cl)(qsal-Br)]Y·sol (Y = NCS, sol = MeOH1 ; PF6 2 ; BPh4, sol = 2CH2 Cl2 3 ; OTf, sol = 0.5MeOH4 ) have been synthesized. X-ray crystallographic studies of1, 2 and4 at 123 K reveal that the Fe(iii ) centres are low spin in all cases. In2 there are two independent Fe(iii ) centres in the asymmetric unit cell. The structure of3 has been determined at 100, 123 and 269 K with the Fe centre low spin, mixed spin and mostly high spin, respectively. Packing in the complexes is dominated by π–π interactions which form a 1D chain. C–H⋯π, C–H⋯Cl/Br and C–Cl/Br⋯π interactions link the chains to form highly cooperative supramolecular 3D networks mirroring the homoleptic complexes. SQUID magnetometric studies show almost complete, 50% complete and stepped spin crossover for1, 2 and3 respectively. [Fe(qsal-Cl)(qsal-Br)]OTf·0.5MeOH4 is low spin up to 350 K. Compared to the homoleptic complexes spin crossover behaviour is mostly intermediate between the [Fe(qsal-Cl)2 ] + and [Fe(qsal-Br)2 ] + systems except for3 where spin crossover characteristics are improved compared to the homoleptic complexes.