Synthesis, structures and properties of ironIII complexes with (o-carboranyl)bis-(2-hydroxymethyl)pyridine: Racemic versus meso

The reaction of iron(II) chloride with anti- or syn-1,2-bis{(pyridin-2'-yl) methanol}-1,2-dicarba-closododecaborane (anti- or syn-oCB-L1) afforded two new complexes, [Fe2Cl2(anti-oCB-L1(2))(2)] (1) or Fe2Cl3(syn-oCB-L1(2))(EtO)(H2O) (2), respectively. Both complexes were unambiguously characterized by means of X-ray structure analysis. Their solid state structures give evidence for the different coordination modes of the ligands. Both compounds are dinuclear FeIII complexes, however, whereas in complex 1 there are two anti-oCB-L1(2) ligands per molecular unit, in complex 2 only one syn-oCB-L1(2) is found. In complex 1, anti-oCB-L1(2) acts as a tetradentate N2O2-ligand affording a homochiral complex as a partial racemic mixture of Delta,Delta-[Fe2Cl2((RR)anti-oCB-L1(2))(2)] and Lambda,Lambda-[Fe2Cl2((SS)anti-oCB-L1(2))(2)]. In complex 2, syn-oCB-L1(2) behaves as a bis-bidentate NO ligand. Only complex 1 could be synthesized in good yield and as a pure phase and it has been therefore fully characterized by spectroscopic methods and the magnetic properties studied. (c) 2016 Elsevier B.V. All rights reserved.