LAUSR

The reaction of [Na][C2B8H11] with anhydrous FeCl2 in THF affords a mixture of DD/LL and MESO isomers of anionic paramagnetic commo-ferracarborane [Ph3PR][commo-1,1′-Fe(closo-2,4-C2B8H10)2] (MESO, R = Me: 1a; MESO, Et: 1b; DD/LL, R = Me: 2a; DD/LL, R = Et: 2b) with unusual closo geometry. Both: DD/LL and MESO isomers were successfully isolated and their structures were determined using X-Ray diffraction studies. Paramagnetic properties were confirmed with EPR-spectra as well as oxidative-reductive properties were investigated using cyclic voltammetry. It was shown that facile DD/LL → MESO and MESO → DD/LL transformation leading to equilibrium in CH2Cl2 solution occurs. Quantum chemical calculations of the isomer-to-isomer transformations were performed. Ferra-copper zwitterionic complexes [3,3′,6,7′-exo-{Ph3PCu}-3,3′,6,7′-(µ-H)4-commo-1,1′-Fe(2,4-C2B8H8)2] and [3,3′,6,6′-exo-{Ph3PCu}-3,3′,6,6′-(µ-H)4-commo-1,1′-Fe(2,4-C2B8H8)2] were synthesized and their structures were determined by X-Ray diffraction studies.