Exploiting host-guest chemistry to manipulate magnetic interactions in metallosupramolecular M4L6 tetrahedral cages

DOI: 10.1039/D1SC00647A

Authors: Aaron J Scott (The University of Edinburgh) , Euan K. Brechin (The University of Edinburgh) , Stergios Piligkos (University of Copenhagen) , Gopalan Rajaraman (Indian Institute of Technology Bombay) , Mark Murrie (University of Glasgow) , Simon Coles (University of Southampton) , Wim T. Klooster (University of Southampton) , Gary S. Nichol (The University of Edinburgh) , Paul Lusby (The University of Edinburgh) , Lucy Smythe (University of Glasgow) , Arup Sarkar (Indian Institute of Technology Bombay) , Julia Vallejo (The University of Edinburgh) , Emma Regincos Marti (University of Glasgow)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Chemical Science , VOL 12 , PAGES 5134-5142

State: Published (Approved)
Published: March 2021
Diamond Proposal Number(s): 22240

Abstract: Reaction of Ni(OTf)2 with the bisbidentate quaterpyridine ligand L results in the self-assembly of a tetrahedral, paramagnetic cage [NiII4L6]8+. By selectively exchanging the bound triflate from [OTf⊂NiII4L6](OTf)7 (1), we have been able to prepare a series of host-guest complexes that feauture an encapsulated paramagnetic tetrahalometallate ion inside this paramagnetic host giving [MIIX4⊂NiII4L6](OTf)6, where MIIX42− = MnCl42− (2), CoCl42− (5), CoBr42− (6), NiCl42− (7), CuBr42− (8) or [MIIIX4⊂NiII4L6](OTf)7, where MIIIX4− = FeCl4− (3), FeBr4− (4). Triflate-to-tetrahalometallate exchange occurs in solution and can also be accomplished through single-crystal-to-single-crystal transformations. Host-guest complexes 1-8 all crystallise as homochiral racemates in monoclinic space groups, wherein the four {NiN6} vertex within a single Ni4L6 unit possess the same Δ or Λ stereochemistry. Magnetic susceptibility and magnetisation data show that the magnetic exchange between metal ions in the host [NiII4] complex, and between the host and the MX4n- guest, are of comparable magnitude and antiferromagnetic in nature. Theoretically derived values for the magnetic exchange are in close agreement with experiment, revealing that large spin densities on the electronegative X-atoms of particular {MX4}n− guest molecules leads to stronger host-guest magnetic exchange interactions.

Subject Areas: Chemistry


Instruments: I19-Small Molecule Single Crystal Diffraction

Other Facilities: UK National Crystallography Service

Added On: 02/03/2021 12:24

Documents:
d1sc00647a.pdf

Discipline Tags:

Physical Chemistry Chemistry

Technical Tags:

Diffraction Single Crystal X-ray Diffraction (SXRD)