Kulmaczewski, R, Shepherd, HJ, Cespedes, O et al. (1 more author) (2014) A homologous series of [Fe(H₂Bpz₂)₂(L)] spin-crossover complexes with annelated bipyridyl co-ligands. Inorganic Chemistry: including bioinorganic chemistry, 53 (18). 9809 - 9817. ISSN 0020-1669
Abstract
Four new iron(II) complexes [Fe(H2Bpz2)2(L)] were prepared (pz = pyrazolyl), where L is dipyrido[3,2-f:2',3'-h]quinoxaline (dpq), dipyrido[3,2-a:2'3'-c]phenazine (dppz), dipyrido[3,2-a:2'3'-c]benzo[i]-phenazine (dppn), and dipyrido[3,2-a:2',3'-c](6,7,8,9-tetrahydro)phenazine (dppc). Crystal structures of [Fe(H2Bpz2)2(dpq)], [Fe(H2Bpz2)2(dppz)], and [Fe(H2Bpz2)2(dppn)] all reveal stacks of complex molecules formed through π-π stacking between interdigitated bipyridyl chelate ligands, often with additional intercalated toluene or uncoordinated bipyridyl ligand (dpq). Molecules of [Fe(H2Bpz2)2(dppc)] form a different stacking motif in the crystal, with weaker contacts between individual molecules. Many of the structures also contain channels of disordered solvent, running between the molecular stacks. Despite their different stacking motifs, all these compounds exhibit very gradual thermal spin-crossover (SCO) on cooling, which occur over different temperature ranges but are otherwise quite similar in form. Weak thermal hysteresis in one of these spin equilibria can be attributed to the effects of a change in bipyridyl ligand conformation in the molecular stacks around 150 K, which was observed crystallographically. These results demonstrate that strong mechanical coupling between molecules in a crystal is not sufficient to engineer cooperative SCO switching, if other regions of the lattice are less densely packed.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry copyright © American Chemical Society 2014 after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/ic501402q |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 12 Feb 2015 09:39 |
Last Modified: | 30 Jun 2020 14:49 |
Published Version: | http://dx.doi.org/10.1021/ic501402q |
Status: | Published |
Publisher: | American Chemical Society |
Identification Number: | 10.1021/ic501402q |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:83002 |