Vlasta BonaÄić-Koutecký
Humboldt University of Berlin, Germany
Title: Tuning optical and catalytic properties of ligated noble metal clusters by synergistic role of metallic and organic subunits
Biography
Biography: Vlasta BonaÄić-Koutecký
Abstract
Theoretical investigation of the linear and nonlinear optical properties of thiolate-protected low nuclearity noble metal clusters will be first presented. In this context theoretical approaches for reliable description of two-photon absorption spectra will be addressed. Goal is to design species exhibiting strong one-photon and/or two-photon absorption and emission in the UV-VIS spectral range. We will show that the optical properties can be tuned by creating the appropriate interplay between electronic excitations within the cluster core and selected prototype of ligands. Comparison with available experimental results will be discussed. We conclude that such low nuclearity protected noble metal clusters are promising for bio-labelling and imaging as alternatives to the standard fluorescent probes such as quantum dots or organic dyes. Second, we present our study of small coinage metal hydride ligated nanoclusters showing their capability to release the hydrogen. We propose the concept of synergistic role of ligand and substrate in catalysis on example of formic acid. This new catalyst neatly fits into a zeolite which does not perturb reactivity, thus providing a unique example on how “heterogenization” of a homogenous catalyst for the selective catalyzed extrusion of carbon dioxide from formic acid can be achieved, with important application in hydrogen storage and in situ generation of H2. The above results motivated us to investigate the selective decomposition of formic acid driven by highly porous aluminum based metal-organic framework in order to design new materials for the heterogenous catalysis. Thus, we illustrated that unique optical and reactivity properties of ligated noble metal clusters which can be tuned by appropriate interplay between metallic and organic subunits have significant potential for different applications.
Figure 1: Two-photon absorption of ligand-protected Ag15 nanoclusters. Towards a new class of nonlinear optics nanomaterials.