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Some years ago, my students and I discovered a new class of molecular clusters termed Metallo-Carbohedrenes or Met-Cars for short. They are comprised of eight early transition metal atoms bound to twelve carbons. In view of their potential use as new electronic and optical materials, as well as predicted value as new catalysts, they have attracted wide interest in the chemistry community. Work is underway in our laboratory to investigate their molecular properties, reactivity, and routes for synthesis in the solid state. Excitation experiments using femtosecond lasers are providing new insights into the coupling of electronic and vibrational modes on the ultra short time scale, and are elucidating their photoinduced behavior.
Along the lines of exploring the physical basis for catalysis, my group is also engaged in a number of studies of the reactivities of transition metal compound clusters of widely varying composition and types, with particular attention to oxygen transfer reactions. Investigations are also under way to learn how the small cluster building blocks lead to different morphologies of growing particles that are of interest in wide-ranging areas from photocatalysis to developing new cluster assembled nanoscale materials.
>Exploring the unknown and finding the unexpected is the challenge and excitement that motivates scientific research. It is especially rewarding when the work offers the promise of new knowledge, as well as potential applications. An area in which one can expect to see major advances in the coming decade is research into the behavior of matter of nanoscale dimensions, clusters and nanoscale materials. The physical and chemical properties of cluster systems at the sub-nano and nano-scale are often found to differ from those of the bulk and display a unique dependence on size, geometry and composition. Most interesting are systems which display properties that vary dramatically with the number of atoms and composition, rather than linearly scale with the size of the system. This realm of cluster science where "one atom makes a difference" is undergoing an explosive growth in activity, and the Castleman group is recognized as a major pioneer in this area in which they have been active for many years. Interest in this field abounds for many reasons, one being the exciting prospects of using clusters as building blocks for tailoring the properties of new materials of nanoscale dimensions. In addition, quantum confinement effects often govern the behavior of matter of this size regime, and studying the dynamics of clusters provides fundamental insights into the interplay of structure, geometry and electronic properties in the chemical behavior that can be manipulated. Clusters are also ideal models for exploring the mechanisms of certain catalytic processes, as well as the role of solvation on a wide variety of reactions including charge/electron and proton transfer, areas in which the Castleman group is also very active. Clusters are an ideal medium for exploring the differences between reactions in the gas and condensed phases, and on surfaces.
Some years ago, my students and I discovered a new class of molecular clusters termed Metallo-Carbohedrenes or Met-Cars for short. They are comprised of eight early transition metal atoms bound to twelve carbons. In view of their potential use as new electronic and optical materials, as well as predicted value as new catalysts, they have attracted wide interest in the chemistry community. Work is underway in our laboratory to investigate their molecular properties, reactivity, and routes for synthesis in the solid state. Excitation experiments using femtosecond lasers are providing new insights into the coupling of electronic and vibrational modes on the ultra short time scale, and are elucidating their photoinduced behavior.
Along the lines of exploring the physical basis for catalysis, my group is also engaged in a number of studies of the reactivities of transition metal compound clusters of widely varying composition and types, with particular attention to oxygen transfer reactions. Investigations are also under way to learn how the small cluster building blocks lead to different morphologies of growing particles that are of interest in wide-ranging areas from photocatalysis to developing new cluster assembled nanoscale materials.