Paramagnetism at Ambient Temperature, Diamagnetism at Low Temperature in a Ru26+ Core: Structural Evidence for Zero-Field Splitting

摘要: Variable temperature magnetic studies of the Ru(2)(6+) guanidinate compounds Ru(2)(hpp)(4)Cl(2) (1) and Ru(2)(hpp)(4)(CF(3)SO(3))(2) (2) show that they are paramagnetic with two unpaired electrons at room appear essentially diamagnetic 2 K. In neither compound do Ru-Ru distances vary by more than 0.008(1) A from 27 to 296 This argues strongly ground state electronic configuration remains constant over this range decrease in magnetism as is lowered must be attributable zero-field splitting (3)A(2g) arising sigma(2)pi(4)delta(2)pi(2). The distance 1 about 0.04-0.05 longer which indicates Ru(2)(hpp)(4)(2+) core quite sensitive nature axial ligands. spectra three absorption bands for each compound.