Two-dimensional, conductive niobium and molybdenum metal-organic frameworks

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The incorporation of second-row transition metals into metal-organic frameworks could greatly improve the performance of these materials across a wide variety of applications due to the enhanced covalency, redox activity, and spin-orbit coupling of late-row metals relative to their first-row analogues. Thus far, however, the synthesis of such materials has been limited to a small number of metals and structural motifs. Here, we report the syntheses of the two-dimensional metal-organic framework materials (H2NMe2)2Nb2(Cl2dhbq)3 and Mo2(Cl2dhbq)3 (H2Cl2dhbq = 3,6-dichloro-2,5-dihydroxybenzoquinone), which feature mononuclear niobium or molybdenum metal nodes and are formed through reactions driven by metal-to-ligand electron transfer. Characterization of these materials via X-ray absorption spectroscopy suggests a local trigonal prismatic coordination geometry for both niobium and molybdenum, consistent with their increased covalency relative to related first-row transition metal compounds. A combination of vibrational spectroscopy, magnetic susceptibility, and electronic conductivity measurements reveal that these two frameworks possess distinct electronic structures. In particular, while the niobium compound displays evidence for redox-trapping and strong magnetic interactions, the molybdenum phase is valence-delocalized with evidence of large polaron formation. Weak interlayer interactions in the neutral molybdenum phase enable solvent-assisted exfoliation to yield few-layer hexagonal nanosheets. Together, these results represent the first syntheses of metal-organic frameworks containing mononuclear niobium and molybdenum nodes, establishing a route to frameworks incorporating a more diverse range of second- and third-row transition metals with increased covalency and the potential for improved charge transport and stronger magnetic coupling.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:11

Enthalten in:

Chemical science - 11(2020), 26 vom: 14. Juli, Seite 6690-6700

Sprache:

Englisch

Beteiligte Personen:

Ziebel, Michael E [VerfasserIn]
Ondry, Justin C [VerfasserIn]
Long, Jeffrey R [VerfasserIn]

Links:

Volltext

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Journal Article

Anmerkungen:

Date Revised 29.03.2024

published: Electronic-eCollection

Citation Status PubMed-not-MEDLINE

doi:

10.1039/d0sc02515a

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM315243716