Understanding the factors that affect self‐diffusion in isoreticular and multivariate (MTV) MOFs is key to their application in drug delivery, separations, and heterogeneous catalysis. Here, we measure the apparent self‐diffusion of solvents saturated within the pores of large single crystals of MOF‐5, IRMOF‐3 (amino‐functionalized MOF‐5), and 17 MTV‐MOF‐5/IRMOF‐3 materials at various mole fractions. We find that the apparent self‐diffusion coefficient of N,N‐dimethylformamide (DMF) may be tuned linearly between the diffusion coefficients of MOF‐5 and IRMOF‐3 as a function of the linker mole fraction. We compare a series of solvents at saturation in MOF‐5 and IRMOF‐3 to elucidate the mechanism by which the linker amino groups tune molecular diffusion. The ratio of the self‐diffusion coefficients for solvents in MOF‐5 to those in IRMOF‐3 is similar across all solvents tested, regardless of solvent polarity. We conclude that average pore aperture, not solvent‐linker chemical interactions, is the primary factor responsible for the different diffusion dynamics upon introduction of an amino group to the linker.

中文翻译：

---

在等规和多元金属有机骨架中精确控制分子的自我扩散。

了解影响等网状和多元（MTV）MOF中自我扩散的因素是将它们应用于药物递送，分离和非均相催化的关键。在这里，我们测量了在各种条件下MOF-5，IRMOF-3（氨基官能化MOF-5）和17 MTV-MOF-5 / IRMOF-3大单晶的孔隙中饱和溶剂的表观自扩散摩尔分数。我们发现，表观自扩散系数Ñ，N-可以根据连接剂摩尔分数在MOF-5和IRMOF-3的扩散系数之间线性调节二甲基甲酰胺（DMF）。我们比较了MOF-5和IRMOF-3中处于饱和状态的一系列溶剂，以阐明连接基氨基调节分子扩散的机理。在所有测试的溶剂中，无论溶剂极性如何，MOF-5中溶剂与IRMOF-3中溶剂的自扩散系数之比均相似。我们得出的结论是，将氨基引入接头后，平均孔径而不是溶剂-接头化学相互作用是造成不同扩散动力学的主要因素。