Elucidating the Growth of Metal–Organic Nanotubes Combining Isoreticular Synthesis with Liquid-Cell Transmisson Electron Microscopy

Metal–organic
nanotubes (MONTs) are tunable porous 1D materials
that are envisioned to be complementary to carbon nanotubes for anisotropic
applications. To date, characterization of MONTs relies on single
crystal X-ray diffraction (SCXRD) to determine structure and composition.
This requires crystals on the micrometer regime, effectively rendering
bulk 3D materials. By tracking the growth of a MONT as a function
of time with liquid-cell transmisson electron microscopy (LCTEM),
TEM, and SCXRD, it was possible to ascertain that the material in
the bulk phase matches the nanomaterial in terms of molecular structure.
This result allowed for the first measurements of finite bundles of
MONTs on the nanometer scale. By employing in situ LCTEM, a time course of the formation of small bundles of MONTs
could be acquired which provided mechanistic information on MONT formation
which is of utility in reaction optimization and applications development.

金属有机纳米管（Metal–organic nanotubes, MONTs）是一类可调控的多孔一维材料，被视为碳纳米管在各向异性应用中的互补材料。迄今为止，MONTs的表征仍需依托单晶X射线衍射（Single Crystal X-ray Diffraction, SCXRD）确定其结构与组成，但该方法要求样品晶体尺寸达到微米级，实际上仅能表征块状三维材料。通过液体池透射电子显微镜（Liquid-Cell Transmission Electron Microscopy, LCTEM）、透射电子显微镜（Transmission Electron Microscopy, TEM）与SCXRD实时追踪MONT的生长随时间的变化过程，研究人员得以确认：块体相材料的分子结构与纳米级MONTs完全一致。这一成果首次实现了纳米尺度下有限尺寸MONT管束的定量表征。通过原位LCTEM技术，研究人员可获取MONTs小束形成的时间进程数据，进而得到MONTs形成过程的机理信息，该信息可用于反应优化与应用开发。