*Communication* **A Brucite-Like Mixed-Valent Cluster Capped by [MnIII***p***-tBu-calix[4]arene]**<sup>−</sup> **Moieties**

### **Marco Coletta 1, Maria A. Palacios 1,**†**, Euan K. Brechin 1,\* and Scott J. Dalgarno 2,\***


Received: 30 March 2020; Accepted: 8 April 2020; Published: 9 April 2020

**Abstract:** *<sup>p</sup>*-tBu-calix[4]arene (H4TBC[4]) has proven to be an incredibly versatile ligand for the synthesis of 3*d*- and 3*d*/4*f*- clusters, in particular those containing mixed-valent Mn ions. These are of interest to the magnetochemist for the diversity of magnetic behaviours that can be shown, along with a huge variety of nuclearities and topologies accessible, which allow one to outline magneto-structural correlations and a quantitative understanding of their properties. This contribution reports the synthesis, analysis and magnetic properties of a Brucite-like Mn-oxo/hydroxo octanuclear fragment encapsulated within/capped by four [MnIII-TBC[4]]− moieties. A diol coligand in the reaction mixture plays a seemingly important role in determining the outcome, though it is not incorporated in the final structure.

**Keywords:** calixarenes; coordination clusters; manganese; molecular magnetism
