A C[subscript 2]-symmetric, basic Fe(iii) carboxylate complex derived from a novel triptycene-based chelating carboxylate ligand

Abstract

A triptycene-based bis(benzoxazole) diacid ligand H[subscript 2]L2[superscript Ph4] bearing sterically encumbering groups was synthesized. Treatment of H[subscript 2]L2[superscript Ph4] with Fe(OTf)[subscript 3] afforded a C[subscript 2]-symmetric trinuclear iron(III) complex, [NaFe[subscript 3](L2[superscript Ph4])[subscript 2](μ[subscript 3]-O)(μ-O[subscript 2]CCPh[subscript 3])[subscript 2](H[subscript 2]O)[subscript 3]](OTf)[subscript 2] (8). The triiron core of this complex adopts the well known “basic iron acetate” structure where the heteroleptic carboxylates, comprising two Ph[subscript 3]CCO[− over 2] and two (L2[superscript Ph4])[superscript 2−] ligands, donate the six carboxylate bridges. The (L2[superscript Ph4])[superscript 2−] ligand undergoes only minor conformational changes upon formation of the complex.