Frederick MacDonnell of the University of Texas, Arlington is supported by the Inorganic, Bioinorganic, and Organometallic Chemistry Program, and by the Nanoscience and Engineering Initiative, for a program of research on tertiary and quaternary structures in rigid supramolecular assemblies. Rigid dendrimers (previously prepared by the PI) will be used in synthesis and self-assembly of rigid, spatially well-defined, macromolecular assemblies. Enantiomerically pure complexes of the trisphenanthroline ruthenium(II) type will serve as the the fundamental building blocks for these assemblies. The resulting structures will be spatially well defined, since the components are conformationally inflexible. This project will examine the 'quartenary structure' and behavior of larger aggregations of these macromolecular species -- that is the structure and properties of 'assemblies of assemblies'. Those rigid, spatially well-defined nano-scale composites will be examined as colloidal aggregates in solutions and on surfaces, using several techniques, including microscopy (STM and AFM).
This project involves preparing small molecular complexes containing ruthenium atoms surrounded by organic ligands arranged in a known, regular and rigid structure and linking these units, in a controlled way, into larger aggregates that also have known, rigid, and regular spatial arrangements. These macromolecular assemblies will then be combined to form nano-scale aggregates, in solution, in colloidal suspension and as particles adsorbed on surfaces. This effort will examine how the properties and behavior (both physical and chemical) of the nano-scale aggregates is related to the known characteristics of the component fundamental units that comprise each system. This multilevel approach has high probability of generating understanding and technical experience that will be of considerable benefit to the progress of nanoscience and technology.