was found that on reducing the initial pH of a TPA-SnS-3 (where TPA denotes the tetrapropylammonium cation) reaction mixture from 13±14 to 10 by addition of HCl solution to the aforementioned reaction mixture, one observed the formation of the dense packed berndtite, SnS 2 , layer phase (Fig. 6). In contrast, on changing the initial pH to only 11±12, a new layered material with an interlamellar spacing of 10.24 was produced with some unreacted tin. It is clear from the above results that the pH of the reaction mixture plays a crucial role in the assembly of the (Sn 2 S 6 ) 4± building blocks and the formation of the R-SnS-n materials.
To conclude, the ªvery soft chemistryº paradigm of the templated and acid-induced condensation±polymerization of tin(IV) sulfide molecular dimers (Sn 2 S 6 ) 4± leads to the formation of the structurally characterized microporous layered tin(IV) sulfide, (DABCOH) 2 Sn 3 S 7 . This suggests that many new and interesting families of low-dimensional and open-framework metal chalcogenide materials wait to be discovered by simply experimenting with different organic and inorganic templates, modular metal chalcogenide building blocks, aqueous and non-aqueous solvents, and pH. It is clearly worthwhile exploring the self-assembly of a diverse range of molecular metal sulfides in the acidic domain under ambient conditions as a viable alternative to the commonly used basic hydrothermal, solvothermal, and molten-flux methodologies. Work along these lines is under way in our laboratory. Futhermore, this approach could greatly simplify aspects of scale-up and combinatorial chemistry design principles for self-assembled open-framework materials.