Two-dimensional square-grid iron() coordination polymers showing anion-dependent spin crossover behavior
Two Fe( ii )-based coordination polymers [Fe(tpmd) 2 (NCS) 2 ]·5.5H 2 O ( 1 ) and [Fe(tpmd) 2 (NCSe) 2 ]·7H 2 O ( 2 ) with the framework of square-grid type have been assembled from FeSO 4 ·7H 2 O, N , N , N ′, N ′-tetrakis(pyridin-4-yl)methanediamine (tpmd), and KNCS/KNCSe in methanol and character...
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Published in | RSC advances Vol. 1; no. 9; pp. 54 - 549 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Royal Society of Chemistry
31.01.2020
The Royal Society of Chemistry |
Subjects | |
Online Access | Get full text |
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Summary: | Two Fe(
ii
)-based coordination polymers [Fe(tpmd)
2
(NCS)
2
]·5.5H
2
O (
1
) and [Fe(tpmd)
2
(NCSe)
2
]·7H
2
O (
2
) with the framework of square-grid type have been assembled from FeSO
4
·7H
2
O,
N
,
N
,
N
′,
N
′-tetrakis(pyridin-4-yl)methanediamine (tpmd), and KNCS/KNCSe in methanol and characterized. By utilizing two pyridine groups of a tpmd ligand,
1
and
2
are formed in two-dimensional layered structures through coordination of octahedral iron(
ii
) ions with the tpmd to NCS
−
/NCSe
−
ligands in which they have a supramolecular isomorphous conformation.
1
shows a paramagnetic behavior between 2 and 300 K, while
2
exhibits two-step spin crossover (
ca.
145 and 50 K) in the temperature range due to the coordination of NCSe
−
ligands. At 300 K
2
is fully high-spin state. However, at 100 K
2
becomes
ca.
50% high spin and 50% low spin iron(
ii
) ions, which is verified by magnetic moments. In the structural analysis of
2
at 100 K, two different layers are observed with different bond distances around iron(
ii
) ions in which the layers are stacked alternately.
Two-dimensional Fe-based coordination polymers with square-grid shapes were prepared by self-assembly and exhibited an interesting spin crossover behavior depending on the coordinated counter ions. |
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Bibliography: | Electronic supplementary information (ESI) available. CCDC 1946253-1946255 10.1039/c9ra09782a For ESI and crystallographic data in CIF or other electronic format see DOI ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2046-2069 2046-2069 |
DOI: | 10.1039/c9ra09782a |