Photoluminescent and vapochromic properties of the Mn(II)-doped (C6H11NH3)2PbBr4 layered organic–inorganic hybrid perovskite

Mechanical and Thermal ON-OFF Switching of the Vapochromic Behavior of a Luminescent Polymorphic Pt(II) Complex

Vapochromic materials that exhibit color/luminescence changes induced by vapor exposure have attracted considerable attention. Herein, we report the grinding- and heating-induced ON-OFF switching of the vapochromic behavior of [Pt(ppyCl₂)(Clacac)] (1; ppyCl₂ = 2-(3-chlorophenyl)-4-chloropyridinato, Clacac = 3-chloroacetylacetonato). 1 formed yellow and orange polymorphs (1-Y and 1-O), and 1-Y could be converted to 1-Og, which showed a very similar crystal structure but with a broadened X-ray diffraction pattern compared with that of 1-O. Moreover, 1-Og can be reversibly transformed into 1-O via heating and grinding. Notably, 1-Og underwent a N,N-dimethylacetamide vapor-induced transformation to 1-Y, whereas 1-O did not undergo such a transformation. These results indicate the ON-OFF switching of vapochromic behavior induced via grinding and heating. This finding will be beneficial for developing intelligent molecular devices.

Cyclohexylammonium Hexaisothiocyanatonickelate(II) Dihydrate as a Single-Source Precursor for High Surface Area Nickel Oxide and Sulfide Nanocrystals

Cyclohexylammonium hexaisothiocyanatonickelate(II) dihydrate, (C6H11NH3)4[Ni(NCS)6]·2H2O, was synthesized, for the first time, by a four-step method in a yield of 95%. The compound was fully characterized by elemental microanalysis, Fourier transform infrared (FTIR), ultraviolet-visible-near infrared (UV-Vis-NIR), and nuclear magnetic resonance (NMR) spectroscopy and thermogravimetry. A single crystal X-ray diffraction (SXRD) gave the monoclinic space group P21/c with a = 15.8179 (5) Å, b = 10.6222 (3) Å, c = 13.8751 (4) Å, β = 109.362 (1)°, V = 2199.45 (11) Å3, Z = 2 (T = 293 K) for this novel hybrid organic–inorganic compound. The title compound was employed as a single-source precursor for the synthesis of mesoporous, high surface area nickel oxide (53 Å; 452 m2/g) and nickel sulfide (46 Å; 220 m2/g) via pyrolysis under air at 550 °C or helium atmosphere at 500 °C, respectively. X-ray powder diffraction (XRPD) demonstrated the nanocrystalline nature of both NiO and NiS with an average crystallite size of 16 and 54 nm, respectively. Scanning electron microscope (SEM) indicated the formation of agglomerated, quasi-spherical particles of nickel oxide and agglomerated flake-like structures of nickel sulfide. The high surface area, porosity, and nanocrystallinity of both NiO and NiS, obtained via this approach, are promising for a wide spectrum of applications.