Isomer-directed structural diversity and its effect on the nanosheet exfoliation and magnetic properties of 2,3-dimethylsuccinate hybrid frameworks

Saines, P.J. and Steinmann, M. and Tan, J.-C. and Yeung, H.H.-M. and Li, W. and Barton, P.T. and Cheetham, A.K. (2012) Isomer-directed structural diversity and its effect on the nanosheet exfoliation and magnetic properties of 2,3-dimethylsuccinate hybrid frameworks. Inorganic Chemistry, 51 (20). pp. 11198-11209. ISSN 0020-1669. (doi:https://doi.org/10.1021/ic302011x) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
http://dx.doi.org/10.1021/ic302011x

Abstract

The structures of seven new transition metal frameworks featuring Mn, Co, or Zn and either the meso or chiral d and l isomers of the 2,3-dimethylsuccinate ligand are reported. Frameworks that exhibit two-dimensional covalently bonded layers with weak interlayer interactions can be made with all three cations by incorporation of the chiral isomers of the 2,3-dimethylsuccinate ligand. The formation of such structures, suitable for the creation of nanosheets via exfoliation, is, however, not as ubiquitous as is the case with the 2,2-dimethylsuccinate frameworks since frameworks that incorporate the meso-2,3-dimethylsuccinate ligand form three-dimensional structures. This clear distinction between the formation of structures with covalent connectivity in two and three dimensions, depending on the choice of 2,3-dimethylsuccinate isomer, is due to the different conformations adopted by the backbone of the ligand. The chiral isomer prefers to adopt an arrangement with its methyl and carboxylate groups gauche to the neighboring functional groups of the same type, while the meso-ligand prefers to adopt trans geometry. A gauche-arrangement of the methyl groups places them on the same side of the ligand, making this geometry ideal for the formation of layered structures; a trans-relationship leads to the methyl groups being further apart, reducing their steric hindrance and making it easier to accommodate them within a three-dimensional structure. The ease of exfoliation of the layered frameworks is examined and compared to those of known transition metal 2,2-dimethylsuccinate frameworks by means of UV-vis spectroscopy. It is suggested that layered frameworks with more corrugated surfaces exfoliate more rapidly. The size, structure, and morphology of the exfoliated nanosheets are also characterized. The magnetic properties of the paramagnetic frameworks reveal that only the three dimensionally covalently bonded phases containing meso-2,3-DMS in trans-arrangements order magnetically. These frameworks are antiferromagnets at low temperatures, although the Co compound undergoes an unusual antiferromagnetic to ferromagnetic transition with increasing applied magnetic field.

Item Type: Article
Subjects: Q Science > QC Physics > QC173.45 Condensed Matter
Q Science > QD Chemistry > QD478 Solid State Chemistry
Divisions: Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Paul Saines
Date Deposited: 06 Oct 2015 15:39 UTC
Last Modified: 07 Oct 2015 09:47 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/50723 (The current URI for this page, for reference purposes)
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