| This dissertation pioneers the design, development, and synthesis of supramolecular polyoxometalates (POMs) including POM-containing dendrimers, fabrics, and gels with well-defined structures and functionalities for selective environmentally benign catalysis. This thesis is organized in two parts.; The first portion (Chapters 2 to 5) reports systematic studies of the esterification of [H4P2V3W15O 62]5- with monodentate alcohols, chelating triols, and dendrimeric poly(triol)s. The POM e sterification proceeds with sequential formation of the mono-ester, the di-ester (both anti- and syn-isomers where applicable) and the tri-ester. This chemistry provides a convenient way to modify the surface of the structurally well-defined POMs and to prepare new functional poly(POM) molecules and dendrimers with the desired hydrolytic stability and catalytic activity. New coordination modes of the tris(hydroxymethyl) moiety are identified and the mono-, di- and tri-ester POMs are isolated and characterized. The impact of the steric and electronic properties of the R substituent of the tris moiety, RC(CH2OH) 3, on this POM esterification chemistry is examined. The first examples of catalytic POM-containing dendrimers (dendrimers with POM termini) are reported. A rational synthesis for poly(POM) molecules using structurally well-defined POM building blocks is presented. Representative poly(triol) ligands are designed and synthesized.; The second half of this thesis (Chapter 6) addresses the design and development of catalytically decontaminating molecules and related materials based on bis(tri-ester)hexavanadates. New monomeric complexes [(RC(CH2O) 3)2V6O13]2- (R = NH3+, NH2, n-C 11H23CONH, C6H5, etc.) are prepared and characterized by NMR, and where applicable, by X-ray crystallography (for R = NH3+, NH2, and n-C 11H23CONH). The amine groups of [(NH2C(CH 2O)3)2V6O13]2- , obtained from deprotonation of its corresponding zwitterion [(NH 3C(CH2O)3)2V6O13], react with R'(COCl)n to afford monomeric and polymeric V6-containing molecules and materials. The NH2 group can also function as a ligand in transition metal complexes. For example, it coordinates to Ag+ to give a linear polymeric material Ag[Ag(NH 2C(CH2O)3)2V6O13]. Self-assembly of [H3V10O28]3- with polytriols yields catalytically-active oligomers and cross-linked organic gel materials comprised of multiple V6 units. Several rational synthetic methods are developed for the preparation of supramolecular poly(V 6) and related materials. The monomeric and polymeric V6-containing molecules and related materials are established to have substantial stability with respect to hydrolytic and oxidative degradation and are active catalysts for the aerobic oxidation of thiols under ambient conditions. Polymeric and other forms of such unusually reactive aerobic oxidation catalysts might form the basis of catalytically air purifying materials. |
