Calix[4]arene-supported trigonal and square prisms of Mn and Na†

Abstract

The heterometallic tricapped trigonal prism [Mn^III₃Na₆(TBC[4])₃(CO₃)(Cl)(dmso)₇]·5MeCN ([Mn₃Na₆]; 1·5MeCN) and the related heterometallic tetracapped square prism [Mn^III₄Mn^II₂Na₆(bisTBC[4])₂(CO₃)₂(Cl)₂(dmf)₈(MeOH)_1.2(H₂O)_0.8]·6MeCN ([Mn₆Na₆]; 2·6MeCN), are isolated using p-^tBu-calix[4]arene (H₄TBC[4]) and 2,2′-bis-p-^tBu-calix[4]arene (H₈-bisTBC[4]), respectively. In the former the Mn^III ions sit in the TBC[4] polyphenolic pockets, forming three Mn-TBC[4] metalloligands that cap the square faces of the prism, whose vertices contain the six Na ions. Introduction of the bis-calix[4]arene enables expansion of the main building block from three Mn-TBC[4] metalloligands in 1 to four Mn-TBC[4] metalloligands in 2. The result is the formation of a square prism of Na/Mn^II ions, with four of the square faces capped with Mn^III ions. Dc magnetic susceptibility and magnetisation measurements reveal paramagnetism in 1 and weak antiferromagnetic exchange interactions in 2.