The literature synthesis of 9-oxabispidine [OC6H10(NH)2, C] has been revisited and optimized, which includes determination of the crystal structures of C, the secondary component trans-(PhSO2)NC4H6O(CH2I)2 (trans-III), and the unexpected solute intermediate OC6H10(NSO2Ph)2·(1)/2py (V·(1)/2py). The reaction of (1,5-hexadiene)platinum dichloride with C yields {OC6H10(NH)2}PtCl2 (C1), which is converted to {OC6H10(NH)2}Pt(cbdca)·5H2O (C2) and {OC6H10(NH)2}Pt(C2O4) (C3). In the crystal, C1 forms a planar 2D network by N-H··Cl and N-H··O hydrogen bonding. In the crystal structure of C2, which is isomorphous to the parent bispidine compound (A2), all complex molecules are encapsulated by a water shell. While complexes C1 and C3 are virtually insoluble in water, C2 dissolves quite well. The low cytotoxicity of compounds C1-C3 is explained by an increased polarity of the bonds in the C skeleton as a consequence of the electronegative O atom.

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.