Multifunctional Heterometallic Oxide and Oxyfluoride Hybrid Solids

Abstract

Heterometallic-oxide and oxyfluoride/organics are hybrids containing both organic ligands and inorganic metal-oxide/oxyfluoride components. These interesting types of materials are beginning to receive widespread attention because of their potential to express, within the same material, both the robustness and physical properties of inorganic components in conjunction with the versatility and chemical flexibility of organic ligands. My research efforts within this area have focused on the synthesis and design of new heterometallic hybrids which possess varied novel structures, and new investigations of their optical and phtocatalystic properties.

Metal oxide systems were selected that contain an early transition-metal (i.e. V, Nb, Mo, W, Re) with a d0 electron configuration and a late transition-metal (i.e. Ag, Cu) with a d10 electron configuration. Organic ligands used in the reactions were chosen to possess different charges and sizes, and that would preferentially coordinate to the late transition metals that form part of the metal-oxide. The target of my work has been to investigate the hydrothermal syntheses of novel heterometallic hybrids and to explore the use of organic ligands in modifying and controlling the formation of resultant structures of metal oxides. The first section covers a new series of Ag/Cu-containing heterometallic-oxides/organics, with 0-1D, 2D layer, 3D pillar-layered or multi-fold interpenetrating structures through molecular-level interactions, and that have led to new insights regarding the range of optical bandgap absorption in compounds with d0/d10 transition metals. The latter aspect is analyzed with regard to its use in designing future photocatalytic materials. The syntheses, properties, and potential applications of these new materials are presented and analyzed herein, and especially, for the first known series of photocatalytically active silver-vanadate hybrids evaluated. The second section is focused on the synthesis and probing of the structures of new heterometallic-oxyfluoride/organics containing symmetric and/or asymmetric early transition metal (V, Nb, Mo, W) oxyfluorides anions. Their optical properties were studied as a function of small molecule absorptions. An understanding of the structure-properties relationships is used for further design and synthesis new visible-light photocatalytic materials.