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)center dot 1/2py (V center dot 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)center dot 5H(2)O (C2) and {OC6H10(NH)(2)}Pt(C2O4) (C3). In the crystal, C1 forms a planar 2D network by N-H center dot center dot center dot Cl and N-H center dot center dot center dot 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.