Three new isostructural chiral silver–lanthanide heterometal–organic frameworks [Ag₃Ln₇(μ₃-OH)₈(bpdc)₆(NO₃)₃(H₂O)₆](NO₃)·2H₂O [Ln = Eu (1), Tb (2, Sm (3); H₂bpdc = 2,2′-bipyridine-3,3′-dicarboxylic acid] based on heptanuclear lanthanide clusters [Ln₇(μ₃-OH)₈]¹³⁺ comprised of one-dimensional triple right-handed helical chains were hydrothermally synthesized. Various means such as UV–vis spectroscopy, IR spectroscopy, elemental analysis, powder X-ray diffraction, and thermogravimetric/differential thermal analysis were used to characterize the compounds, wherein compound 3 was crystallographically characterized. In the structure of compound 3, eight μ₃-OH^– groups link seven Sm³⁺ ions, forming a heptanuclear cluster, [Sm₇(μ₃-OH)₈]¹³⁺, and the adjacent [Sm₇(μ₃-OH)₈]¹³⁺ clusters are linked by the carboxylic groups of bpdc^2– ligands, leading to the formation of a one-dimensional triple right-handed helical chain. The adjacent triple right-handed helical chains are further joined together by coordinating the pyridyl N atoms of the bpdc^2– ligands with Ag⁺, resulting in a chiral three-dimensional silver(I)–lanthanide(III) heterometal–organic framework with one-dimensional channels wherein NO₃^– anions and crystal lattice H₂O molecules are trapped. The compounds were studied systematically with respect to their photoluminescence properties and energy-transfer mechanism, and it was found that H₂bpdc (the energy level for the triplet states of the ligand H₂bpdc is 21505 cm^–1) can sensitize Eu³⁺ luminescence more effectively than Tb³⁺ and Sm³⁺ luminescence because of effective energy transfer from bpdc^2– to Eu³⁺ under excitation in compound 1.

中文翻译：

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的基于[LN一维三右手螺旋链手性银-镧系元素金属有机骨架由₇（μ ₃ -OH）₈ ] ¹³⁺集群

三个新的同构的手性银-镧系元素heterometal有机骨架将[Ag ₃ LN ₇（μ ₃ -OH）₈（BPDC）₆（NO ₃）₃（H ₂ O）₆ ]（NO ₃）·2H ₂ -O [Ln为铕（1），TB（2，SM（3）; H ₂ BPDC = 2,2'-联吡啶-3,3'-二羧酸]根据heptanuclear镧系簇[LN ₇（μ ₃ -OH）₈ ] ^{13 +}由一维三重右旋螺旋链组成的水热合成。各种方法，例如紫外-可见光谱，红外光谱，元素分析，粉末X射线衍射和热重/差热分析均用于表征化合物，其中化合物3在晶体学上进行了表征。在化合物的结构3，八μ ₃ -OH ^-基团连结7根的Sm ³⁺离子，形成了heptanuclear簇，[钐₇（μ ₃ -OH）₈ ] ¹³⁺，并且相邻[钐₇（μ ₃ - OH）₈ ] ¹³⁺簇通过bpdc ^2–配体的羧基连接，导致形成一维三重右旋螺旋链。相邻的三重右旋螺旋链通过将bpdc ^2–配体的吡啶N原子与Ag ⁺配位而进一步连接在一起，从而形成具有一个单价的手性三维银（I）-镧系元素（III）杂金属-有机骨架维信道，其中，NO ₃ ^-的阴离子和晶格ħ ₂水分子被捕获。对这些化合物的光致发光性质和能量转移机理进行了系统研究，结果发现H ₂bpdc（配体H ₂ bpdc的三重态的能级为21505 cm ^–1）比Tb ³⁺和Sm ³⁺发光更能敏化Eu ³⁺发光，因为有效的能量从bpdc ^2–传递到Eu ^{3 +}在化合物1的激发下。