Self-assembly of b-diketonate (Htta ¼ thenoyl(trifluoro)acetone) and 4,4 0 -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 10-370 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 DE/k B ¼ 19.7(7) K and an attempt time of relaxation, s 0 ¼ 3.7(8) Â 10 À7 s for fresh sample A, and DE/k B ¼ 27.3 K and s 0 ¼ 8.5(0) Â 10 À8 for assembly A after thermal treatment at 370 K.

We report a mixed-valence cobalt(II/III)–octacyanidotungstate(IV/V) magnet, [CoII(H2O)]2[CoIII{μ-(R)-1-(4-pyridyl)ethanol}2][WIV(CN)8][WV(CN)8]·5H2O. Synchrotron-radiation X-ray single crystal structural analysis, infrared spectrum, and density-functional theory (DFT) calculation indicate that this compound has a chiral structure with the P21 space group and both CoII(S = 3/2)–NC–WV(S = 1/2) and CoIII(S = 0)–NC–WIV(S = 0) moieties, which are structurally distinguishable in the crystal structure. Magnetic measurements reveal that this compound exhibits ferromagnetism with a Curie temperature of 11 K and a coercive field of 1500 Oe, which is caused by the coexistence of the superexchange interaction in the CoII–WV chain and double exchange interaction between the chains.

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The self-assembly of cobalt(II) with purine and octacyanidotungstate(V) resultsi nt he formation of the threedimensional Co 3 [W(CN) 8 ] 2 (purine) 2 ·8.5H 2 O( 1)c oordination polymer.T his compound exhibits humidity-inducedv ariation of the number of water molecules of crystallisation leading to ar eversible structuralp hase transition and the alternation of the long-range ferromagnetic ordering temperature from T C = 29 Kf or the pristine assembly (1)t oT C = 49 Kf or the sample stored in al ow-humidity atmosphere (1-deh). This phenomenon can be attributed to ar eversible change in the hydrogen-bonding network resulting in the modification of the local geometrieso fc obalt(II) as well as the cyanido bridges.