【作者】 杨小平； 苏成勇； 郑康成； 刘汉钦；

【Author】 Yang Xiaoping~(**) Su Chengyong Zheng Kangcheng Liu Hanqin (Institute of Physical Chemistry.School of Chemistry and Chemical Engineering,Zhongshan UniversityGuangzhou 510275)

【机构】 中山大学化学与化工学院物化所；

【摘要】 <正>由于稀土的光致发光配合物在荧光探针、超分子器件及核磁造影剂等方面的广泛用途,对稀土配位化学的研究日益重要。近年来,含氮三角架配体由于其多配位点、半刚性及易合成等特点,引起了人们的广泛兴趣。本文报道了稀土离子与三角架配体 N,N-二 （2-苯并咪唑亚甲基）-N-（2-吡啶亚甲基）胺（L,图1）和安替吡啉（L＇）形成的二元固体配合物[LnL（NO₃）₃]·C₂H₅OH（Ln=La、Tb 和 Tm）及三元固体配合物[LaL（L＇）₃]（ClO₄）₃的制备,研究了它们在 CD₃CN 和 DMSO-d₆中的¹H NMR,结合配合物的晶体结构、IR 及 EHMO 计算,探讨了配体在溶液中的配位形式。在 CD₃CN 中,抗磁性二元配合物 [LaL（NO₃）₃]·C₂H₅OH 中的配体 L 由于参与了配位,与自由配体相比,其芳环质子的化学位移向低场移动。而在三元配合物[LaL（L＇）₃]（ClO₄）₃中,由于受到配体 L＇苯环产生的抗磁性屏蔽作用,配体 L 芳环质子的化学位移明显向高场移动。在 CD₃CN 中,配体 L 以四齿配位 （N_a、N_b、N_c 和 N_d）,L＇用羰基氧配位,稀土离子在二元与三元配合物中的配位数分别为 10和7。三元配合物中,由于三个 L＇的空间位阻作用,将对稀土离子发光有淬灭作用的溶剂分子排斥出稀土离子的配位层。在 DMSO-d₆中,二元及三元配合物中的配体 L 表现出与自由配体一致的¹H NMR 谱,这表明由于强极性的溶剂分子参与 Ln³⁺的配位竞争,配合物发生了解离。更多还原

【Abstract】 The coordination chemistry,of lanthanides has become of increasing significance due to the wide use of lanthanide complexes in luminescent probes,supramolecular devices or MRI contrast agents. In the last few years,the tripodal ligands bearing nitrogen atoms have drown much attention because of their polydentate,flexility and ease to synthesize.The preparation for binary and ternary solid complexes of lanthanide ions with tripodal ligand N,N-bis（2-benzimidazolylmethyl）- N-（2-pyridylmethyl）amine（L）and antipyrine（L’）.[LnL（NO₃）₃]·C₂H₅OH（Ln=La.Tb and Tm） and[LaL（L’）₃]（ClO₄）₃,were reported in this article.Their H NMR spectra were studied in CD₃CN and DMSO-d₆,and the coordinate forms of the two ligands were discussed with crystal structure. IR and EHMO calctdation.In CD₃CN.due to coordination,the signals for three aromatic rings in the diamagnetic binary complex[LaL（NO₃）₃]·C₂H₅OH are shifted to lower field as compared to those of the free ligand L.However.because of the dimagnetic shield caused by three benzene rings of the ligand L’.they are shifted to higher field in the ternary complex[LaL（L’）₃]（ClO₄）₃.In CD₃CN.L is a tetradentate ligand（N_a,N_b,N_cand N_d）.and L’coordinates to the lanthanide ion with its carbonyl oxygen.The coordination numbers are 10 and 7 in binary,and ternary complexes respectively.In the ternary complexes,solvent molecules are excluded from the coordination sphere,due to the steric effect of the three big ligands L’,even though the solvent molecules can efficiently quench the lanthanide luminescence.In the DMSO-d₆,because of the competition between strongly polar solvent molecules and ligands for the lanthanide ion.the complexes decompose and show identical ¹H NMR spectra as of the free ligand.更多还原