Temperature-dependent luminescence spectra for a series of palladium(II) and platinum(II) complexes with thiocyanate, halide, and dithiocarbamate ligands are presented. All complexes show broad d−d luminescence. Crystal structures are reported for (n-Bu4N)2[Pt(SCN)4] and (n-Bu4N)2[Pd(SCN)4] at 150 and 250 K, for the palladium(II) dimethyldithiocarbamate (MeDTC) complex [Pd(MeDTC)2] at 150 and 300 K, and for its platinum(II) analog at 100 and 300 K. The structures of (n-Bu4N)2[Pt(SCN)4], (n-Bu4N)2[Pd(SCN)4], and [Pt(MeDTC)2] show similar volume increases with temperature. In contrast, the luminescence band maxima of palladium(II) and platinum(II) complexes have opposite shifts with increasing temperature. (n-Bu4N)2[Pd(SCN)4] shows a shift of −2.0 cm−1/K and [Pd(MeDTC)2] a shift of −1.1 cm−1/K, while both platinum(II) complexes have a positive shift of +1.6 cm−1/K. Calculated luminescence spectra with adjustable parameters reproduce the experimental spectra. The variation of their parameters with temperature shows the origin of different trends. Temperature-dependent luminescence spectra of [Pd(SCN)4]2− and [Pt(SCN)4]2− in polymer films of polyvinyl alcohol were measured. No clearcut shifts of maxima were observed for either compound, and their spectra are broader due to the disordered environment.
Tetragonal–Cubic Phase Transition and Low-Field Dielectric Properties of CH3NH3PbI3 Crystals
