Paramagnetic hexaborate clusters with mixed halide, halide/alkyl or halide/hydride substitution were prepared from oxidizable dianionic precursors and were characterized by cyclic voltammetry, EPR, vibrational and UV-VIS spectroscopy. The EPR studies reveal increasing g anisotropv and EPR linewidths on replacing Cl by Br and especially by I substituents; on the other hand, the replacement of one
... [Show full abstract] halide by one alkyl (CH3 or CH2CN) or hydride substituent in [B(6)Hal(5)R](.-) causes decreasing radical persistence and g anisotropy. Three results indicate a fairly uniform participation of the cluster core and the substituent sphere in the spin distribution as a major factor for the stability of these non-pi radicals.