Multinuclear compounds of s-elements with sterically hindered o-semiquinonates and catecholates

Alkali metals form mutinuclear compounds with redox-active singly and doubly reduced derivatives of sterically of hindered o-benzoquinones. Complexes [Na-6(Cat)(3)(THF)(7)]center dot 4THF, [Na-5(Cat)(2)(SQ)(THF)(5)], [Na-4(SQ)(4)(THF)(4)]center dot THF center dot C6H14, [Na-4(3,5-SQ)(4)(THF)(4)], [K-4(SQ)(4)(THF)(4)]center dot 4THF and [Li-3(SQ)(3)(THF)(3)]center dot THF (Cat is catecholate, SQ is semiquinonate) possessing high sensitivity to atmospheric oxygen were synthesized and their structures were determined. Magnetochemical measurements and quantum chemical calculations revealed that variation of the alkali metal and/or change in the structure of the polymetallic core significantly affect the energy of exchange interaction between the unpaired electrons of the paramagnetic ligands framing the polynuclear metal core formed by s-elements.