NMR thermosensing properties on binuclear triple-decker complexes of terbium(III) and dysprosium(III) with 15-crown-5-phthalocyanine

[Display omitted] •Trisphthalocyaninates of lanthanides as temperature sensors (303–323 K).•Analysis of the lanthanide-induced chemical shifts and relaxation data.•Terbium complex has the highest sensitivity among the published in organic media.•NMR determination of local temperature in aqueous media. In this paper, we have firstly demonstrated the thermosensing properties of binuclear triple-decker terbium(III) and dysprosium(III) complexes with 15-crown-5-phthalocyanine Tb2[(15C5)4Pc]3 (I) and Dy2[(15C5)4Pc]3 (II) in the physiological temperature range (303–323 K). Measuring the LIS values for I and II in CDCl3 has revealed high temperature sensitivity for the signals of the aromatic protons of the inner deck of the complexes: ∂δ/∂T = 1.1 and 0.55 ppm/K for I and II, respectively. Terbium-containing complex I has the highest sensitivity of the LIS among the published complexes of 4f and d elements with polydentate ligands in organic media. A significant impact of the Curie-spin contribution to the paramagnetic spin–spin relaxation rate enhancement has been found, which has a pronounced temperature dependence. The results obtained for kinetically and thermodynamically stable Ln2[(15C5)4Pc]3 complexes allow one to consider them pronounced NMR thermosensors in nonpolar solutions. The possibility of the solubilization of complex I in aqueous media due to the presence of crown ether moieties has been also demonstrated.