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[H(OEt2)2]+ and [Ph3C]+ Salts of the Borate Anions [B(CF3)4]-, [(CF3)3BCN]-, and [B(CN)4]-

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journal contribution
posted on 10.10.2005, 00:00 authored by Maik Finze, Eduard Bernhardt, Michael Berkei, Helge Willner, Joyce Hung, Robert M. Waymouth
The reaction of gaseous HCl with K[B(CF3)4] in diethyl ether gave the oxonium acid [H(OEt2)2][B(CF3)4] as a stable salt at room temperature. Syntheses of [Ph3C][B(CF3)4] and [Ph3C][(CF3)3BCN] were accomplished from the corresponding potassium salts and Ph3CCl. The metathesis reaction of Ag[B(CN)4] with trityl bromide resulted in formation of [Ph3C][B(CN)4]. Treatment of Cp2ZrMe2 with [H(OEt2)2][B(CF3)4], [Ph3C][B(CF3)4], [Ph3C][(CF3)3BCN], and [Ph3C][B(CN)4], monitored by NMR spectroscopy, showed the formation of [Cp2ZrMe(OEt2)]+, [(Cp2ZrMe)2-μ-Me]+, [Cp2ZrMe]+, Cp2ZrMe{NCB(CF3)3}, and Cp2Zr{NCB(CN)3}2, respectively. Attempted polymerizations of propene with catalysts generated in situ from rac-Et(1-Ind)2ZrMe2 and [H(OEt2)2][B(CF3)4], [Ph3C][B(CF3)4], or [Ph3C][B(CN)4] yielded only little to no polymer, possibly due to the low solubility of the catalysts in the reaction medium.