Kumar Kunal, Abe Daisuke, Komori-Orisaku Keiko, Stefańczyk Olaf, Nakabayashi Koji, Shakirova Julia R, Tunik Sergey P, Ohkoshi Shin-Ichi
Department of Chemistry, School of Science, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
Institute of Chemistry, St.-Petersburg State University 26 Universitetskiy Pr., Petergof St.-Petersburg Russia.
RSC Adv. 2019 Jul 29;9(41):23444-23449. doi: 10.1039/c9ra03276b.
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(TTA)(MeOH)]·0.5Azo-py (A) in which two asymmetric units are linked by Azo-py through hydrogen bonding 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 F to I and I 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(TTA)(4-OHpy)(HO)] (B). Assembly A also exhibits field-induced slow magnetic relaxation properties with an energy barrier of Δ/ = 19.7(7) K and an attempt time of relaxation, = 3.7(8) × 10 s for fresh sample A, and Δ/ = 27.3 K and = 8.5(0) × 10 for assembly A after thermal treatment at 370 K.
在甲醇存在的情况下，β-二酮（Htta = 噻吩甲酰三氟丙酮）和4,4'-偶氮吡啶（Azo-py）与钕（iii）离子自组装，形成单核配合物[Nd(TTA)(MeOH)]·0.5Azo-py（A），其中两个不对称单元通过Azo-py与甲醇形成氢键相连。A在10 - 370 K温度范围内呈现以约895和1056 nm为中心的近红外发射（NIR），分别源自Nd（iii）上从F到I和I能级的两个发射跃迁。此外，在室温下，热消除一个配位甲醇分子后，A的近红外发光强度增加两倍。热激活的A在10至300 K的宽温度范围内表现出单中心比率温度计行为。此外，将A的荧光性质与另一种单核配合物[Nd(TTA)(4-OHpy)(HO)]（B）进行了比较。组装体A还表现出场诱导的慢磁弛豫性质，新鲜样品A的能垒为Δ/ = 19.7(7) K，弛豫尝试时间为 = 3.7(8) × 10 s，在370 K热处理后的组装体A的能垒为Δ/ = 27.3 K， = 8.5(0) × 10 。
