Synthetic Factors Determining the Curvature and Nuclearity of the Giant Mn 70 and Mn 84 Clusters with a Torus Structure of ∼4 nm Diameter

• Published in: Inorganic chemistry 2023-04, Vol.62 (15), p.6020-6031
• Main Authors: Hale, Ashlyn R, Abboud, Khalil A, Christou, George
• Format: Article
• Language: English
• Subjects: Chemistry
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.2c04520

New members of the Mn and Mn torus-like cluster family have been prepared from a hybrid comproportionation-alcoholysis reaction of [Mn O (O CR) (H O) ] in alcohol in the presence of R'CO H with N BuMnO or Mn salts as initiators. Reactions using MeCO H in PrOH or BuOH gave [Mn O (O CMe) (O Pr) ( PrOH) (H O) ] ( ) and [Mn O (O CMe) (OH) (O Bu) ( BuOH) (H O) ] ( ), respectively, whereas EtCO H in PrOH gave [Mn O (O CEt) (O Pr) ( PrOH) (H O) ] ( ). They consist of alternating near-linear [Mn (μ -O) ] and distorted-cubane [Mn (μ -O) (μ -OR) ] units bridged by syn,syn-μ-RCO and μ -O groups and overall are [Mn ] and [Mn ] oligomers, the repeating unit containing two Mn and two Mn units. / / possess external diameters (including organic ligands) of 4.0/4.1/4.6 nm, respectively, and crystallize as supramolecular nanotubes but with different packing arrangements. Considering all Mn /Mn tori now available, we conclude that the Mn vs Mn nuclearity is determined by the relative bulk of the carboxylates vs the alkoxides, their increasing bulk favoring Mn and Mn , respectively, with carboxylates larger than acetate giving Mn . Alternating current (ac) magnetic susceptibility studies revealed frequency-dependent χ signals below ∼2.4 K, indicating to be new members of the giant [Mn ] torus family of giant single-molecule magnets (SMMs), in which Mn and Mn are the largest homometallic Mn/O clusters and SMMs to date.