b S Supporting Information
' INTRODUCTIONTemplated metal oxides have attracted sustained interest for many years, owing to their remarkably high degrees of compositional and structural diversity 1 and for technologically desirable physical properties. 2 However, increasing demand for new materials with enhanced properties has highlighted the lack of design and predictability in the syntheses of such compounds. The greatest limitation lies in our poor understanding of the mechanisms by which these compounds form. 3 While mechanisms have been postulated, 4À8 true design remains elusive. Significant progress has been made in the identification of reaction parameters that most strongly influence the formation of these materials.The primary influence over the structure of the inorganic component is reagent composition. Differences in reactant concentrations are known to directly affect the identity and availability of the primary building units from which the inorganic components are constructed. 9À14 Reactant concentrations are clearly affected by a range of experimental parameters, ranging from the dependence of metal speciation on both pH and temperature to differences associated with source materials and reaction times. The manner in which the inorganic reactants oligomerize and polymerize in the systems described above is thought to be controlled by charge density matching 4,5 between the organic cations and the anionic inorganic synthons. This secondary influence allows for crystallization only after the charge densities of the cationic and anionic components match. The importance of charge density matching has been demonstrated in a range of systems, including silicates, 15À17 oxovanadium phosphates, 18 gallium phosphates, 4,5 molybdates, 19 and vanadium tellurites. 20 Despite the utility of the charge density matching approach, differences in reactant concentrations and amine pK a alone do not wholly dictate the connectivities and structures of the resulting inorganic architectures. Charge density matching cannot differentiate between markedly different inorganic structures that have nearly identical charge densities. For example, we have reported the formation of both [Mo 3 O 10 ] n 2nÀ and [Mo 8 O 26 ] n 4nÀ chains from reactions in which the respective amines had similar pK a 's and were used in nearly identical concentrations. 19 We have also observed both [V 2 Te 2 O 10 ] n 2nÀ chains and [V 2 TeO 8 ] n 2nÀ layers in reactions containing either 1,4-diaminobutane or 1,3-diaminopropane, respectively. 20 In each system, the differences in charge densities of the inorganic components are small. As such, a series of tertiary influences has been proposed, including amine symmetry and hydrogen-bonding preferences. 19À21 This report contains an elucidation and observation of tertiary influences in the formation of new organically templated vanadium tellurites. The NaVO 3 /Na 2 TeO 3 /2,5-dimethylpiperazine and NaVO 3 /Na 2 TeO 3 /2-methylpiperazine systems were explored using composition space analysis, result...