Four new metal–organic frameworks with the formulae [Sm₂(phen)₂(NO₃)₂(chdc)₂]·2solv, where solv = N,N-dimethylformamide (DMF; 1), N,N-dimethylacetamide (DMA; 2), N,N-diethylformamide (DEF; 3), N-formylpiperidine (NFP; 4), phen = 1,10-phenanthroline and chdc²⁻ = trans-1,4-cyclohexanedicarboxylate were synthesized and structurally characterized. These compounds are based on similar binuclear samarium(III)-carboxylate blocks, bound by flexible chdc linkers into layered sql-type coordination networks. The amide solvents drive different intralayer block orientations between 1 and 2–4 and different layer-to-layer packings in all the described compounds. A pronounced dependence of the emission color upon the excitation wavelength variation was determined for 1–4, while the relative impacts of Sm³⁺ and phen emission on overall luminescence were found to depend strongly on these packings, and their reasonable correlation to the distances between the closest π–π-stacked phen moieties in the structures was revealed. Phase transitions between compounds 1–4 were studied by means of powder X-ray diffraction. Additionally, bimetallic near-white luminophores were obtained for phases 3 and 4 by doping their synthetic systems with a minor (∼5%) Tb³⁺ additive. In general, this study shows a possibility of tuning the luminescence properties of porous metal–organic frameworks by minor structural differences induced by solvent-driven dynamics with no apparent quenching or other direct impact on the optical properties of the included solvent.

中文翻译：

---

镧系金属-有机框架中的溶晶相变和可调发光发射


四种新型金属有机框架，分子式为 [Sm₂（phen）₂（NO₃）₂（chdc）₂]·2solv，其中溶剂 = N，N-二甲基甲酰胺 （DMF;1）、N，N-二甲基乙酰胺 （DMA;2）、N，N-二乙基甲酰胺 （DEF;3）、N-甲酰哌啶 （NFP;4）、PHen = 1,10-菲咯啉和 CHDC²⁻ = 反式-1,4-环己烷二羧酸盐被合成并进行了结构表征。这些化合物基于类似的双核钐 （III）-羧酸盐嵌段，通过灵活的 chdc 接头结合成分层的 sql 型配位网络。酰胺溶剂驱动 1 和 2-4 之间的不同层内嵌段取向，并在所有描述的化合物中驱动不同的层间堆积。确定了 1-4 的发射颜色对激发波长变化的显着依赖性，而发现 Sm³⁺ 和酚发射对整体发光的相对影响在很大程度上取决于这些堆积，并且它们与结构中最近的 π-π 堆叠酚部分之间的距离有合理的相关性被揭示。通过粉末 X 射线衍射研究化合物 1-4 之间的相变。此外，通过掺杂其合成体系，在第 3 阶段和第 4 阶段获得双金属近白色发光团 （∼5%） Tb³⁺ 添加剂。 一般来说，这项研究表明，通过溶剂驱动动力学引起的微小结构差异，可以调整多孔金属-有机框架的发光特性，而没有明显的猝灭或其他对所含溶剂的光学特性的直接影响。