New salicylaldoximato-borate ligands resulting from anion hydrolysis and their respective copper and iron complexes

Dalton Trans. 2019 Aug 21;48(31):11872-11881. doi: 10.1039/c9dt01968e. Epub 2019 Jul 16.

Abstract

Anion hydrolysis reactions between salicylaldoximato ligands (L'-L''') and copper and iron BF4- metal salts, have resulted in the formation of new salicylaldoximato borate containing transition metal complexes: [Fe2(L' + 2H)2](BF4)2(MeOH)4 (C1), [Fe3(L'' + 4H)(OH)2(Py)2](BF4)2(H2O)2(Py)2 (C2), and [Cu2(L''' + H)2Cl2] (C3). Each of the complexes have been structurally characterised, revealing the indirect role boron plays in the formation of these complexes. For complexes C1 and C2, Mössbauer spectroscopy confirmed the existence of Fe(iii) oxidation states. SQUID magnetometry measurements were performed on complexes C2 and C3, revealing the presence of two competing exchange pathways between the three Fe(iii) centres in C2, with antiferromagnetic exchange dominating. For C3 weak antiferromagnetic exchange dominated between the two Cu(ii) centres.