Biological composites bear complex designs and hierarchical structures that are key to their specific function and exceptional properties. However, the structural and functional complexities of natural materials are difficult to integrate into synthetic composites, as the control of materials across multiple length scales is a major scientific challenge. We work on the preparation, assembly, and multi-length scale structuring of Metal-Organic Frameworks (MOFs) and other colloidal materials and composite systems for optical and ion conduction applications, using an interdisciplinary approach. Most MOFs possess non-cubic lattices and anisotropic functionality dependent upon crystallographic direction and are generally synthesized in bulk as loose as microcrystalline powders. As such, for practical purposes, general methods to manipulate and orient free-standing MOF crystals would be useful to harness their anisotropic functionality. This talk will focus on our exploitation of physicochemical interactions at air/liquid/solid interfaces, as well as top-down processing methods and external fields to manipulate MOF materials, ranging from tuning MOF crystal size and shapes to the dynamic alignment of NU-1000 MOF microrods as well as E-field assisted liquid crystalline assembly of MOF particle superstructures and the applications of oriented MOF materials.

In the quest to develop highly stable nanoparticles, N-heterocyclic carbenes (NHC) have emerged as an alternative to thiol-based ligands for stabilizing metal nanoparticles (NPs), as the metal-NHC bond is usually much stronger than the corresponding metal-thiol bond. This should result in more stable NPs which are less susceptible to ligand exchange reactions. Over the last decade an increasing number of NHC-stabilized NPs have been reported and significant effort was made in utilizing these compounds, such as for bioimaging, sensing and also heterogeneous catalysis. We will give an account on our efforts to develop carbene-stabilized gold nanoparticles. Firstly, we will discuss NHC-stabilized AuNPs where the NHC is derived from the natural chiral pool. For this, L and D- histidine were converted into their imidazolium salt using methyl iodine. Subsequently, the imidazolium salt is converted to its corresponding organometallic gold chloride complex, which can be reduced to histidine-2-ylidene stabilized AuNPs. Due to the chiral nature of histidine, dichroic effects can be detected in circular dichroism spectroscopy. Further water-soluble and pH-responsive histidine-2-ylidene stabilized AuNPs can be obtained through a free unprotected C-terminus of the employed histidine. Subsequently we will also report on the synthesis of hyper-crosslinked polymers containing benzimidazolium as NHC precursors to stabilize AuNPs and their application if flow catalysis. The translation of this chemistry to copper based NPs will also be discussed, and finally this talk will also touch on the first examples of protic acyclic diamino carbene stabilized AuNPs (ADCAuNPs).