Rational Design of Polynuclear Organometallic Assemblies from a Simple Heteromultifunctional Ligand

In
modern coordination chemistry, supramolecular coordination complexes
take advantage of ligand design to control the shapes and sizes of
such architectures. Here we describe how to utilize starting building
blocks and a multifunctional ligand to rationally design and synthesize
different types of discrete assemblies. Using a hydroxamate ligand
featuring two pair of chelating sites together with half-sandwich
iridium and rhodium fragments, we were able to construct a series
multinuclear organometallic macrocycles and cages through stepwise
coordination-driven self-assembly. Experimental observations, supported
by computational work, show that selective coordination modes were
ascribed to the significant electronic density differences of the
two chelating sites, (O,O′)
and (N,N′). The results underline
the advantages of the discrimination between soft and hard binding
sites, and suggest that hydroxamic acids can be used as a versatile
class of facile multifunctional scaffold for the construction of novel
two-dimensional and three-dimensional architectures.

在现代配位化学领域，超分子配位复合物通过配体设计手段，实现对这类架构的形状与尺寸的精准调控。本描述旨在阐述如何运用起始构建模块与多功能配体，进行有理化的设计与合成，以构建不同类型的离散组装结构。本研究采用一种具有两对螯合位点的羟肟酸配体，结合半夹心结构的铱和钌片段，通过逐步的配位驱动自组装，成功构建了一系列多核有机金属大环和笼状结构。实验观察结果，经计算工作验证，表明选择性配位模式归因于两个螯合位点（O,O' 和 N,N'）间显著的电子密度差异。研究结果凸显了区分软硬结合位点的优势，并暗示羟肟酸可作为一类灵活的多功能支架，广泛用于构建新颖的二维和三维架构。