Equipping metallo-supramolecular macrocycles with functional groups: assemblies of pyridine-substituted urea ligands
作者:Ralf W. Troff、Rainer Hovorka、Torsten Weilandt、Arne Lützen、Mario Cetina、Martin Nieger、Dieter Lentz、Kari Rissanen、Christoph A. Schalley
DOI:10.1039/c2dt30190c
日期:——
A series of di-(m-pyridyl)-urea ligands were prepared and characterized with respect to their conformations by NOESY experiments and crystallography. Methyl substitution in different positions of the pyridine rings provides control over the position of the pyridine N atoms relative to the urea carbonyl group. The ligands were used to self-assemble metallo-supramolecular M2L2 and M3L3 macrocycles which are generated in a finely balanced equilibrium in DMSO and DMF according to DOSY NMR experiments and ESI FTICR mass spectrometry. Again, crystallography was used to characterize the assemblies. Methyl substitution in positions next to the pyridine nitrogen prevents coordination, while the other ligands form small metallo-supramolecular macrocycles. The incorporated urea carbonyl groups provide hydrogen bonding sites which converge towards the center of the assemblies.
我们制备了一系列二(间位吡啶基)脲配体,并通过 NOESY 实验和晶体学研究确定了它们的构象特征。通过在吡啶环的不同位置进行甲基取代,可以控制吡啶 N 原子相对于脲羰基的位置。这些配体被用于自组装金属超分子 M2L2 和 M3L3 大环,根据 DOSY NMR 实验和 ESI FTICR 质谱分析,这些大环是在 DMSO 和 DMF 中精细平衡生成的。同样,晶体学也被用来表征这些组装体。吡啶氮旁边位置的甲基取代阻止了配位,而其他配体则形成了小的金属超分子大环。加入的脲羰基提供了氢键位点,这些氢键位点向组装体的中心汇聚。