Synthesis and Characterization of Acetonitrile‐Ligated Transition‐Metal Complexes with Tetrakis(pentafluorophenyl)borate as Counteranions

Complexes with the general formula [M II (NCCH 3 ) 6 ][TPFB] 2 [M = Cr, Fe, Co, Ni, Cu, Zn, (TPFB) – = tetrakis(pentafluorophenyl)borate] were synthesized and characterized both in the solid state and in solution. According to the spectroscopic data, [TPFB] can be considered as a truly noncoordinating anion. The NCCH 3 ligands are lost if the samples are kept at room temperature for extended periods of time. Thermolysis leads to the loss of the NCCH 3 ligands and decomposition of the anion above 100 °C with the formation of MF 2 . It has to be noted that distortion of the geometries of the Cu II , Zn II and Cr II complexes occurs, as evidenced by infrared spectroscopy. The complexes can be easily prepared and obtained in high yields and are moderately sensitive to air. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)