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Abstract Although many monometallic active sites have been installed in metal–organic frameworks (MOFs) for catalytic reactions, there are no effective strategies to generate bimetallic catalysts in MOFs. Here we report the synthesis of a robust, efficient, and reusable MOF catalyst, MOF‐NiH, by adaptively generating and stabilizing dinickel active sites using the bipyridine groups in MOF‐253 with the formula of Al(OH)(2,2′‐bipyridine‐5,5′‐dicarboxylate) forZ‐selective semihydrogenation of alkynes and selective hydrogenation of C=C bonds in α,β‐unsaturated aldehydes and ketones. Spectroscopic studies established the dinickel complex (bpy⋅−)NiII(μ2‐H)2NiII(bpy⋅−) as the active catalyst. MOF‐NiH efficiently catalyzed selective hydrogenation reactions with turnover numbers of up to 192 and could be used in five cycles of hydrogenation reactions without catalyst leaching or significant decrease of catalytic activities. The present work uncovers a synthetic strategy toward solution‐inaccessible Earth‐abundant bimetallic MOF catalysts for sustainable catalysis.
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Haldane topological spin-1 chains in a planar metal-organic framework
Abstract Haldane topological materials contain unique antiferromagnetic chains with symmetry-protected energy gaps. Such materials have potential applications in spintronics and future quantum computers. Haldane topological solids typically consist of spin-1 chains embedded in extended three-dimensional (3D) crystal structures. Here, we demonstrate that [Ni(μ−4,4′-bipyridine)(μ-oxalate)]n(NiBO) instead adopts a two-dimensional (2D) metal-organic framework (MOF) structure of Ni2+spin-1 chains weakly linked by 4,4′-bipyridine. NiBO exhibits Haldane topological properties with a gap between the singlet ground state and the triplet excited state. The latter is split by weak axial and rhombic anisotropies. Several experimental probes, including single-crystal X-ray diffraction, variable-temperature powder neutron diffraction (VT-PND), VT inelastic neutron scattering (VT-INS), DC susceptibility and specific heat measurements, high-field electron spin resonance, and unbiased quantum Monte Carlo simulations, provide a detailed, comprehensive characterization of NiBO. Vibrational (also known as phonon) properties of NiBO have been probed by INS and density-functional theory (DFT) calculations, indicating the absence of phonons near magnetic excitations in NiBO, suppressing spin-phonon coupling. The work here demonstrates that NiBO is indeed a rare 2D-MOF Haldane topological material.
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- Award ID(s):
- 2055499
- PAR ID:
- 10457849
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 14
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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