Crystalline-Amorphous-Crystalline Transformation in a Highly Brilliant Luminescent System with Trigonal-Planar Gold(I) Centers
نویسندگان
چکیده
Photoluminescent compounds showing emission color changes in response to external stimuli have received considerable attention because of their wide range of applications. Here, we report the unique photoluminescence behavior of a digold(I) coordination system with trigonal-planar Au(I) centers, [Au2(dppm)3](2+) (dppm = bis(diphenylphosphino)methane). This system shows an extremely intense phosphorescence, with a quantum yield of >95% in the solid state. Both the emission color and thermal stability vary due to changing counter ions (Cl(-) vs. OTf(-)). Of particular note is the thermal crystalline-amorphous-crystalline transformation for the chloride salt, which is accompanied by drastic emission color changes. Single-crystal and powder X-ray diffractions demonstrate that the two-step transformation is induced by the loss of water molecules of crystallization with the subsequent removal of a dppm ligand to form [Au2(dppm)2](2+), which is mechanically reverted back to [Au2(dppm)3](2+).
منابع مشابه
Magnetic and Electerical Resistivity Behavior of Amorphous Ni Co P Films
Magnetic and Electrical Resistivity Study of Electroless Amorphous Ternary System (Ni-Co-P) show a qualitative dependence of crystalline phases formed during transformation on the annealing temperature and composition. Electrical Resistivity values increases with increase in cobalt content and samples with higher resistivity show lower temperature coefficients. The Initial increase in magnetiza...
متن کاملMechanochemical synthesis of crystalline and amorphous digold(I) helicates exhibiting anion- and phase-switchable luminescence properties.
For the first time, mechanochemical synthesis has been used for the preparation of crystalline and amorphous dinuclear gold(i) helicates, [Au2L2](X)2 (L = xantphos; X = CF3SO3, SCN, BF4 and PF6), that show anion- and phase-switchable luminescence properties. This solid-state approach provides strategies for developing switchable luminescent materials.
متن کاملFormation of oriented particles in an amorphous host: ZnS nanocrystals in silicon
Processes for incorporating randomly oriented crystalline precipitates in an amorphous host can be traced back to the 17th century when Cassius produced ‘‘gold ruby’’ glass. In this glass, octahedral colloidal precipitates of gold scatter light by the Mie process to produce a deep red color. In contrast to gold ruby glass, we describe a type of material in which the crystalline precipitates are...
متن کاملCalcium Carbonate Storage in Amorphous Form and Its Template-Induced Crystallization
Calcium carbonate crystallization in organisms often occurs through the transformation from the amorphous precursor. It is believed that the amorphous phase could be temporarily stabilized and stored, until its templated transition to the crystalline form is induced. Here we develop a bioinspired crystallization strategy that is based on the above mechanism. Amorphous calcium carbonate (ACC) sp...
متن کاملStructure and diffusion of boron in amorphous silica: Role of oxygen vacancy related defects
Based on first-principles density-functional calculations, we present the structure and diffusion of boron in amorphous silica, as well as in crystalline silica for comparison purpose. We find that incorporation of a boron atom into the amorphous silica matrix results in various minimum-energy configurations with and without oxygen deficient centers, and also the B-related defects can undergo i...
متن کامل