Impact of dehydration and mechanical amorphization on the magnetic properties of Ni(ii)-MOF-74

Muratović, Senada; Karadeniz, Bahar; Stolar, Tomislav; Lukin, Stipe; Halasz, Ivan; Herak, Mirta; Mali, Gregor; Krupskaya, Yulia; Kataev, Vladislav; Žilić, Dijana; Užarević, Krunoslav (2020) Impact of dehydration and mechanical amorphization on the magnetic properties of Ni(ii)-MOF-74. Journal of Materials Chemistry C, 8 . pp. 7132-7142. ISSN 2050-7526

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Official URL: https://pubs.rsc.org/en/content/articlelanding/202...

Abstract

Mechanically responsive metal–organic frameworks (MOFs) came very recently into the spotlight of material science for their unique properties and potential new fields of application. We present here a clarification of the magnetic properties of prototypical magnetic MOF-74 material, Ni(II)-MOF-74, using magnetization measurements, X-band electron spin resonance (ESR), multi-frequency high-field ESR (HF-ESR), and theoretical model. It was established that the guests populating the honeycomb channels have little influence on the magnetism of Ni-MOF-74, whereas magnetic properties change significantly upon mechanical amorphization. Amorphous material (am-Ni-MOF-74), which can be readily prepared by the mechanochemical treatment of dehydrated Ni-MOF-74 (deh-Ni-MOF-74), as shown by in situ monitoring methods, displays significantly lower bulk magnetization compared to Ni-MOF-74 and deh-Ni-MOF-74. This decline in magnetization is established to be a consequence of the spin-crossover from high-spin to a low-spin state of nickel(II) ions. The observed spin-crossover was rationalized by an insight into the changes of the nickel coordination sphere during the amorphization, which was provided by solid-state nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. Additionally, it was found that am-Ni-MOF-74 behaves differently than its zinc analogue when exposed to vapors or liquid-additives in the milling process, indicating that the nature of the metal node plays a substantial role in the mechanical properties of this modular family of MOF materials.

Item Type:

Article

Uncontrolled Keywords:

MOF-74 ; Ni(II) ; mechanically responsive MOF ; magnetic MOF ; amorphization ; dehydration ; magnetism ; ESR/EPR ; high and low spin Ni(II) ; spin-crossover

Subjects:

NATURAL SCIENCES > Physics
NATURAL SCIENCES > Chemistry

Divisions:

Division of Physical Chemistry

Projects:

Project title	Project leader	Project code	Project type
Studija važnosti spinskih međudjelovanja kao osnova za nove pristupe u istraživanju materijala-SPES	Marina Ilakovac Kveder	IP-2018-01-3168	HRZZ
Mehaniokemijska reaktivnost pod kontroliranim uvjetima temperature i atmosfere za čišću sintezu funkcionalnih materijala-MECHANOCONTROL	Krunoslav Užarević	UIP-2014-09-4744	HRZZ
UNSPECIFIED	UNSPECIFIED	PZS-2019-02-4129	UNSPECIFIED
Magneto-structural correlations in molecular magnetic complexes studied by electron spin resonance spectroscopy	UNSPECIFIED	German (DAAD)-Croatian (MZO) bilateral project	UNSPECIFIED
UNSPECIFIED	UNSPECIFIED	Slovenian Research Agency No. P1-0021 and No. N1-0079	UNSPECIFIED