Tuning the electron transfer events in a series of cyanide-bridged [FeCo] squares according to different electron donors
It has been recognized that both the ligand fields and intermolecular interactions may greatly impact the electron-transfer-coupled spin transition (ETCST) events in switchable magnetic materials; however, the engineering of these factors within a given system is still challenging. In this article,...
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Veröffentlicht in: | Dalton transactions : an international journal of inorganic chemistry 2022-10, Vol.51 (41), p.15669-15674 |
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Zusammenfassung: | It has been recognized that both the ligand fields and intermolecular interactions may greatly impact the electron-transfer-coupled spin transition (ETCST) events in switchable magnetic materials; however, the engineering of these factors within a given system is still challenging. In this article, we chose the 4,4′-substituent 2,2′-bipyridine derivatives as chelating ligands according to their increasing electron-donating strength and incremental potential for forming hydrogen bonds (bpy
CHO,CH
3
(L1) < bpy
CH
2
OH,CH
3
(L2) < bpy
CH
2
OH,CH
2
OH
(L3)), and prepared three new [Fe
2
Co
2
] complexes, {[(Tp*)Fe(CN)
3
Co(L)
2
]
2
[ClO
4
]
2
}·Sol (
1
, L = L1, Sol = 4MeCN·2H
2
O;
2
, L = L2, Sol = 3MeCN;
3
, L = L3, Sol = 4MeOH; Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate). X-ray crystallography studies revealed that all the complexes share similar cyanide-bridged [Fe
2
Co
2
] square compositions except for the different substituted groups of L ligands, which led to the clearly evidenced intercluster hydrogen bonds between the neighbouring hydroxyl groups in
2
and
3
. As a result,
1
remained in the paramagnetic [Fe
III,LS
2
Co
II,HS
2
] state over the whole temperature range, while
2
and
3
showed complete ETCST behaviour with the transition temperatures (
T
1/2
) being 221 and 294 K, respectively.
Combined substituent effects and hydrogen-bonding interactions modulate the electron transfer in cyanide bridged [Fe
2
Co
2
] squares: ferrimagnetism without ETCST for
1
, while complete ETCST with
T
1/2
being 221 and 294 K for
2
and
3
, respectively. |
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ISSN: | 1477-9226 1477-9234 |
DOI: | 10.1039/d2dt02416k |