Luminescent properties of complexes of tellurium (iv) halides with pyridine (C$_{5}$H$_{5}$NH)$_{2}$TeHaI$_{6}$ (HaI = Cl, Br)

The spectral-luminescent properties of complex compounds of tellurium(III) halides with pyridine of the composition (C$_{5}$H$_{5}$NH)$_{2}$TeHaI$_{6}$ (HaI = Cl, Br) are studied. In the case of a distorted island octahedral coordination of the Тe(IV) ion, only the (C$_{5}$H$_{5}$NH)$_{2}$TeСl$_{6}$ chloride complex exhibits luminescence at 77 K. Comparative analysis of the influence of the tellurium(IV) coordination polyhedron geometry and the A band position (transition $^{3}P_{1}\to{}^{1}S_{0}$) in the luminescence spectra on the luminescence properties of tellurium (IV) complexes with pyridine and alkali metals (Cs, Rb) showed that the existence of distortions of the tellurium(IV) coordination polyhedron and the bathochromic shift of the $A$ band facilitate efficient dissipation of electronic excitation energy in the complexes.