Self-Assembled Structures from Solid Cd(II) Acetate in Thiol/Ethanol Solutions: a Novel Type of Organic Chemical Garden

Cd(II) acetate in tablet form, immersed in ethanol solutions with a high concentration of heptanethiol (30-80 mM) was able to develop self-assembled sail-shaped structures. The solution in which the self-assembled structure is formed is totally organic (both solute and solvent), thus representing a unique case among organic Chemical Gardens. The constituting material for this new Chemical Garden (CG) is made of a single phase, namely a cadmium heptanethiolate with a microcrystalline structure consisting of a central cluster [CdnSn]. The morphological and structural features were studied using different techniques (SEM-EDS, elemental analysis, FT-IR, 113Cd MAS NMR, XRPD). A crystalline cell for the Cd(II) heptanethiolate cluster was obtained that completely differs from that of the solid phase precipitated by mixing an ethanol solution of Cd(II) acetate with heptanethiol. It follows that the conditions under which the formation of Cd(II) thiolate occurs (slowly from solid, quickly from solution) play a critical role in determining the nature and structure of the precipitating phase.