Neodymium -diketonate showing slow magnetic relaxation and acting as a ratiometric thermometer based on near-infrared emission

Self-assembly of -diketonate (Htta = thenoyl(trifluoro)acetone) and 4,4-azopyridine (Azo-py) with neodymium( iii ) ions in the presence of methanol resulted in the formation of mononuclear complex [Nd III (TTA) 3 (MeOH) 2 ]0.5Azo-py ( A ) in which two asymmetric units are linked by Azo-py through hydrogen bonding via methanol. A reveals near-infrared emission (NIR) centred at about 895 and 1056 nm, in the 10370 K temperature range, originating from the two emissive transitions on Nd( iii ) from 4 F 3/2 to 4 I 9/2 and 4 I 11/2 levels, respectively. Furthermore, the NIR luminescence intensity of A at room temperature augments two times upon thermal elimination of one coordinated methanol molecule. The thermally activated A exhibits single centre ratiometric thermometer behaviour in a wide temperature range from 10 to 300 K. Moreover, fluorescence properties of A were compared to another mononuclear complex [Nd III (TTA) 3 (4-OHpy)(H 2 O)] ( B ). Assembly A also exhibits field-induced slow magnetic relaxation properties with an energy barrier of E / k B = 19.7(7) K and an attempt time of relaxation, 0 = 3.7(8) 10 7 s for fresh sample A , and E / k B = 27.3 K and 0 = 8.5(0) 10 8 for assembly A after thermal treatment at 370 K. In this work, we investigated thermally-induced Nd-based one centred ratiometric thermometer which also exhibit single molecule magnetic properties.