Despite the fact that new dimensionally reduced hybrid organic− inorganic compounds have attracted considerable interest because of their unique optical and electronic properties, the rational synthesis of these new materials remains elusive. Here we systematically studied the relative influence of the major synthetic parameters, including temperature, ligand structure, and ligand-to-metal stoichiometry, on the preparation of dimensionally reduced TiS 2 . One-dimensional TiS 2 phases tend to form at high ligand-to-metal ratios and relatively lower temperatures, while the two-dimensional parent lattices are preferred at higher temperatures. The organic ligand structure dictates the temperature window in which a dimensionally reduced phase can be accessed. Although a small change in ligand structure, such as changing ethylenediamine to propylenediamine, for example, will significantly influence the stability of these phases, it will only subtly change the electronic structure. Via the development of a systematic understanding of the effects of various factors during the synthesis, this work provides a pathway to rationally create new dimensionally reduced materials. ■ INTRODUCTIONSimilar to how carbon can be sculpted into low-dimensional allotropes such as fullerenes, 1 nanotubes, 2 graphene, 3 and graphene nanoribbons, 4 there is an emerging body of work suggesting that the framework connectivity of atoms for any crystalline solid can be ligand-terminated along specific axes to create stable, crystalline van der Waals solids comprised of single-or few-atom thick fragments. 5−8 Indeed, dimensionally reduced solids have been discovered from the perovskite lattice, 9,10 zinc blende/wurtzite lattice, 11 two-dimensional (2D) metal chalcogenide lattice, 12,13 and layered iron selenide lattice. 14 These dimensionally reduced phases are thermodynamically stable because, for a set of metal cations and anions with specific oxidation states, there is some inherent stability for a specific type of polyhedral shape and connectivity. 8 For example, in ZnS and numerous dimensionally reduced ZnS derivatives, Zn exhibits tetrahedral coordination and cornersharing connectivity partly because the Zn 2+ and S 2− oxidation states, radius ratio, and electronegativity difference remain unchanged. 11 Dimensionally reduced systems have optical, electronic, and magnetic behavior different from those of the parent lattice, 12,14 which makes them potentially interesting in phosphors and battery electrodes. 15,16 These properties can be further tuned by changing the dimensionality, changing the coordinating ligand, and intercalating metals into the van der Waals gap.In contrast to the solution-phase growth of colloidal semiconducting nanocrystals, which has experienced more than 30 years of scientific exploration, 17−22 the synthesis of dimensionally reduced solids is still in its infancy. While one can envision the existence of different ligand-terminated, dimensionally reduced structures from a given lattice framework, 8 there are very few ...

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