Fascinating structures of a mixed valence [MnIII]•[MnIIMnIII] co‒crystal and a MnIIINaI complex: slow magnetic relaxation and theoretical investigations

ABSTRACT: Herein, a co‒crystal, incorporating mixed valence manganese ions, namely [MnIII]•[MnIIMnIII] formulated as [{MnIII(Vaan)2}•{MnIIMnIII(Vaan)2(H2O)3}•14H2O] (1) and a MnIIINaI compound {MnIIINaI(Vaan)2(H2O)2}•H2O] (2), are synthesized utilizing MnII precursor salts and a rarely used ligand, 2−[(2−Hydroxy−3−methoxy−benzylidene)−amino]−benzoic acid (H2Vaan). Structure analyses illustrate that 1 contains a cationic dinuclear unit (MnIIMnIII) and an anionic mononuclear unit MnIII to generate the co–crystal whereas a different recipe produces compound 2. Detailed descriptions of the prevailing supramolecular interactions within the systems have been provided. Interestingly, as far our knowledge goes, 1 is the first example of a co–crystal involving mixed valence MnII/MnIII species. Notably, dc and ac susceptibility measurements indicate the existence of slow relaxation of magnetization in both complexes. Furthermore, we have analyzed the nature of the magnetic interactions present using Density Functio...