Tetranuclear [Mn 2 Co 2 ], [Mn 2 Fe 2 ], and [Mn 2 Mn 2 ] Complexes with Defective Double‐Cubane Cores and Phenoxo and Oxo Bridges: Syntheses, Crystal Structures, and Electronic Properties

Three new tetranuclear complexes [Mn III 2 Co III 2 O 2 (L) 2 ][ClO 4 ] 2 ( 1 ), [Mn III 2 Fe III 2 O 2 (L) 2 ][ClO 4 ] 2 ( 2 ), and [Mn III 2 Mn III 2 O 2 (L) 2 ][Mn II (NCS) 4 ] ( 3 ) have been synthesized through reactions of the mononuclear [Mn III L] precursor with the corresponding metal perchlorate under aerobic conditions [H 3 L = tris(2‐salicylaldimine)amine, a condensation product between tris(2‐aminoethyl)amine and salicylaldehyde in a 1:3 molar ratio]. These compounds have been characterized by spectroscopic and analytical techniques including single‐crystal X‐ray structure analysis, electron paramagnetic resonance (EPR) spectroscopy, Mössbauer spectroscopy, and magnetic measurements. The structure of 1 consists of oxo‐/phenoxo‐bridged Co III and Mn III centers in a defective double‐cubane topology. The molecules of 2 and 3 have similar structures with the Co III centers changed to Fe III centers in 2 and to Mn III centers in 3 . These isostructural complexes have been scrutinized with regard to changes in distortions (distances and angles) of the metal coordination spheres. Magnetic studies indicate that 1 , 2 , and 3 show predominant antiferromagnetic interactions. Changes in the electronic properties concomitant with changes in the distortions in 1 , 2 , and 3 are analyzed in terms of magnetostructural correlations.