Syntheses, Crystal Structures, and Electronic Structures of Quaternary Group IV-Selenide Semiconductors.

Early transition-metal chalcogenides have garnered recent attention for their optoelectronic properties for solar energy conversion. Herein, the first Zr-/Hf-chalcogenides with a main group cation, BaHfSnSe () and BaZrSnSe(Se) (), have been synthesized. The structure of is formed from isolated SnSe tetrahedra and distorted HfSe octahedra.

Coordination of copper within a crystalline carbon nitride and its catalytic reduction of CO.

Inherently disordered structures of carbon nitrides have hindered an atomic level tunability and understanding of their catalytic reactivity. Starting from a crystalline carbon nitride, poly(triazine imide) or PTI/LiCl, the coordination of copper cations to its intralayer -triazine groups was investigated using molten salt reactions. The reaction of PTI/LiCl within CuCl or eutectic KCl/CuCl molten salt mixtures at 280 to 450 °C could be used to yield three partially disordered and ordered structures, wherein the Cu cations are found to coordinate within the intralayer cavities.

Well-Defined Iron Sites in Crystalline Carbon Nitride.

Carbon nitride materials can be hosts for transition metal sites, but Mössbauer studies on iron complexes in carbon nitrides have always shown a mixture of environments and oxidation states. Here we describe the synthesis and characterization of a crystalline carbon nitride with stoichiometric iron sites that all have the same environment. The material (formula CNHFeLiCl, abbreviated PTI/FeCl) is derived from reacting poly(triazine imide)·LiCl (PTI/LiCl) with a low-melting FeCl/KCl flux, followed by anaerobic rinsing with methanol.