Keiko Komori-Orisaku

Self-assembly of β-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 10–370 K temperature range, originating from the two emissive transitions on Nd(III) from ⁴F_3/2 to ⁴I_9/2 and ⁴I_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)(H₂O)] (B). Assembly A also exhibits field-induced slow magnetic relaxation properties with an energy barrier of ΔE/k_B = 19.7(7) K and an attempt time of relaxation, τ₀ = 3.7(8) × 10⁻⁷ s for fresh sample A, and ΔE/k_B = 27.3 K and τ₀ = 8.5(0) × 10⁻⁸ for assembly A after thermal treatment at 370 K.

The self‐assembly of cobalt(II) with purine and octacyanidotungstate(V) results in the formation of the three‐dimensional Co₃[W(CN)₈]₂(purine)₂⋅8.5H₂O (1) coordination polymer. This compound exhibits humidity‐induced variation of the number of water molecules of crystallisation leading to a reversible structural phase transition and the alternation of the long‐range ferromagnetic ordering temperature from T_C=29 K for the pristine assembly (1) to T_C=49 K for the sample stored in a low‐humidity atmosphere (1‐deh). This phenomenon can be attributed to a reversible change in the hydrogen‐bonding network resulting in the modification of the local geometries of cobalt(II) as well as the cyanido bridges.

Nanosecond-scale pulsed laser irradiation of cis,cis-1,3-cyclooctadiene via an Nd:YAG laser at 266 nm induced highly selective cyclization of the 1,3-diene moiety to afford cis-bicyclo[4.2.0]oct-7-ene in high yield. The pulsed Nd:YAG laser light is highly monochromatic thereby allowing efficient control of the photoreaction selectivity by controlling the photostationary state.

The rationale behind the stereospecific synthesis of a facial isomer of tris(quinolin-8-olate)aluminum (Alq ₃ ) is studied by density functional theory (DFT) calculations, which predict the favourable influence of an H ₃ O ⁺ ion on the distribution ratio between a meridional and a thermodynamically unstable facial isomer.

The 3rd harmonic generation in a Nd:YAG pulsed laser induces the high throughput [2 + 2] cycloaddition of 1,2-bis(4-pyridyl)ethylene that assemble itself tightly into a face-to-face manner around the Yb³⁺ octaaqua complex via hydrogen bonds, without damaging the cyclobutyl ring-containing products.

The structure of the reactive cobalt complex catalyst for the enantioselective borohydride reduction of ketones was completely determined by ESI-MS, NMR, and X-ray analyses. It was confirmed that as an axial ligand, 1-chlorovinyl group derived from 1,1,1-trichloroethane was attached. Based on the X-ray analysis, two rotamers on cobalt–carbon bond were found in one unit. The obtained 1-chlorovinylcobalt(III) complex was examined for the enantioselective reduction to afford the reduced product in high yield with a high enantioselectivity.