Cs[H2NB2(C6F5)6] Featuring an Unequivocal 16-Coordinate Cation.

Abstract

Cesium bis(perfluoro-triphenylborane)amide, Cs[H2NB2(C6F5)6] (1), has been prepared by the reaction of sodium salt and CsF in dichloromethane and water. The compound is exceptional for a [H2NB2(C6F5)6](-) salt in that it contains a monatomic solute-free cation. Determination of the molecular structure revealed a novel C2 symmetrical conformation of the weakly coordinating [H2NB2(C6F5)6](-) anion, which gives rise to an unprecedented 16-coordinate (CN 16) Cs(+) cation in a likewise unprecedented tetracosahedral arrangement of F atoms. The poor solubility of 1 allows nearly quantitative separation of Cs(+) from water, which suggests potential applications as an effective (134/137)Cs remover from nuclear waste solutions, administration as an antidote for (134/137)Cs poisoning, and use for (131/137)Cs radiotherapy (brachytherapy). Rb[H2NB2(C6F5)6]·CH2Cl2 (2) has also been characterized, featuring two inequivalent Rb(+) cations having CN 10, one of which involves Rb(+)(η(2)-Cl2CH2)2 coordination.

• Authors: David Pollak, Richard Goddard, Klaus-Richard Pörschke
• Journal: Journal of the American Chemical Society (J Am Chem Soc) Vol. 138 Issue 30 Pg. 9444-51 (08 03 2016) ISSN: 1520-5126 [Electronic] United States
• PMID: 27267866 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)