Color-Tunable and White-Light Luminescence in Lanthanide–Dicyanoaurate Coordination Polymers

The new lanthanide–dicyanoaurate coordination polymers [^<i>n</i>Bu₄N]₂­[Ln­(NO₃)₄­Au­(CN)₂] (Ln = Sm, Dy) and Sm­[Au­(CN)₂]₃·3H₂O were prepared and structurally characterized and their luminescence spectra described. The emissions of solid-solutions of [^<i>n</i>Bu₄N]₂­[Ln­(NO₃)₄­Au­(CN)₂] (Ln = Ce, Sm, Eu, Tb, and Dy) were explored with an emphasis on their capacity for luminescent color tuning and white-light emission via the selection of composition, excitation wavelength, and temperature. Specifically, the binary solid-solutions [^<i>n</i>Bu₄N]₂­[Ce_0.4Dy_0.6(NO₃)₄­Au­(CN)₂] and [^<i>n</i>Bu₄N]₂­[Sm_0.75Tb_0.25(NO₃)₄­Au­(CN)₂], and the ternary solid-solutions [^<i>n</i>Bu₄N]₂­[Ce_0.2Sm_0.6­Tb_0.2(NO₃)₄­Au­(CN)₂] and [^<i>n</i>Bu₄N]₂­[Ce_0.33Eu_0.17­Tb_0.5(NO₃)₄­Au­(CN)₂], were prepared and examined in terms of suitability for color-tuning capacity. These results showcase that the emission from the [^<i>n</i>Bu₄N]₂­[Ln­(NO₃)₄­Au­(CN)₂] framework has the capacity to be tuned to extremes corresponding to deep reds (CIE coordinates 0.65, 0.35), greens (0.28, 0.63), and deep blue/violet (0.16, 0.06) as well as white (0.31, 0.33). Conversely, the emission of the Sm­[Au­(CN)₂]₃·3H₂O framework, when doped with the green phosphor Tb­(III), changes only slightly because of the predominantly Au­(I)-based emission and Sm­(III) → Au­(I) energy transfer

Interpreting Effects of Structure Variations Induced by Temperature and Pressure on Luminescence Spectra of Platinum(II) Bis(dithiocarbamate) Compounds

Luminescence spectra of two square-planar dithiocarbamate complexes of platinum­(II) with different steric bulk, platinum­(II) bis­(dimethyldithiocarbamate) (Pt­(MeDTC)₂) and platinum­(II) bis­(di­(<i>o</i>-pyridyl)­dithiocarbamate) (Pt­(dopDTC)₂), are presented at variable temperature and pressure. The spectra show broad d–d luminescence transitions with maxima at approximately 13500 cm^–1 (740 nm). Variations of the solid-state spectra with temperature and pressure reveal intrinsic differences due to subtle variations of molecular and crystal structures, reported at 100 and 296 K for Pt­(dopDTC)₂. Luminescence maxima of Pt­(MeDTC)₂ shift to higher energy as temperature increases by +320 cm^–1 for an increase by 200 K, mainly caused by a bandwidth increase from 3065 to 4000 cm^–1 on the high-energy side of the band over the same temperature range. Luminescence maxima of Pt­(dopDTC)₂ shift in the opposite direction by −460 cm^–1 for a temperature increase by 200 K. The bandwidth of approximately 2900 cm^–1 does not vary with temperature. Both ground and emitting-state properties and subtle structural differences between the two compounds lead to this different behavior. Luminescence maxima measured at variable pressure show shifts to higher energy by +47 ± 3 and +11 ± 1 cm^–1/kbar, for Pt­(MeDTC)₂ and Pt­(dopDTC)₂, respectively, a surprising difference by a factor of 4. The crystal structures indicate that decreasing intermolecular interactions with increasing pressure are likely to contribute to the exceptionally high shift for Pt­(MeDTC)₂

Interpreting Effects of Structure Variations Induced by Temperature and Pressure on Luminescence Spectra of Platinum(II) Bis(dithiocarbamate) Compounds

Luminescence spectra of two square-planar dithiocarbamate complexes of platinum­(II) with different steric bulk, platinum­(II) bis­(dimethyldithiocarbamate) (Pt­(MeDTC)₂) and platinum­(II) bis­(di­(<i>o</i>-pyridyl)­dithiocarbamate) (Pt­(dopDTC)₂), are presented at variable temperature and pressure. The spectra show broad d–d luminescence transitions with maxima at approximately 13500 cm^–1 (740 nm). Variations of the solid-state spectra with temperature and pressure reveal intrinsic differences due to subtle variations of molecular and crystal structures, reported at 100 and 296 K for Pt­(dopDTC)₂. Luminescence maxima of Pt­(MeDTC)₂ shift to higher energy as temperature increases by +320 cm^–1 for an increase by 200 K, mainly caused by a bandwidth increase from 3065 to 4000 cm^–1 on the high-energy side of the band over the same temperature range. Luminescence maxima of Pt­(dopDTC)₂ shift in the opposite direction by −460 cm^–1 for a temperature increase by 200 K. The bandwidth of approximately 2900 cm^–1 does not vary with temperature. Both ground and emitting-state properties and subtle structural differences between the two compounds lead to this different behavior. Luminescence maxima measured at variable pressure show shifts to higher energy by +47 ± 3 and +11 ± 1 cm^–1/kbar, for Pt­(MeDTC)₂ and Pt­(dopDTC)₂, respectively, a surprising difference by a factor of 4. The crystal structures indicate that decreasing intermolecular interactions with increasing pressure are likely to contribute to the exceptionally high shift for Pt­(MeDTC)₂