L. J. K. Cook, Rufeida Mohammed, G. Sherborne
Apr 15, 2015
Citations
1
Influential Citations
151
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Quality indicators
Journal
Coordination Chemistry Reviews
Abstract
Abstract The isomeric complexes [Fe(1-bpp)2]2+ and [Fe(3-bpp)2]2+ (1-bpp = 2,6-di[pyrazol-1-yl]pyridine; 3-bpp = 2,6-di[1H-pyrazol-3-yl]pyridine) and their derivatives are some of the most widely investigated complexes in spin-crossover research. This article addresses two unique aspects of their spin-state chemistry. First, is an unusual structural distortion in the high-spin form that can inhibit spin-crossover in the solid state. A new analysis of these structures using continuous shape measures has explained this distortion in terms of its effect on the metal coordination geometry, and has shown that the most highly distorted structures are a consequence of crystal packing effects. Second, solution studies have quantified the influence of second-sphere hydrogen bonding on spin-crossover in [Fe(3-bpp)2]2+, which responds to the presence of different anions and solvents (especially water). Previously unpublished data from the unsymmetric isomer [Fe(1,3-bpp)2]2+ (1,3-bpp = 2-[pyrazol-1-yl]-6-[1H-pyrazol-3-yl]pyridine) are presented for comparison. Modifications to the structure of [Fe(3-bpp)2]2+, intended to augment these supramolecular effects, are also described.