Adam P. Smith

Fabrication of Highly-Ordered TiO2 Nanotube Arrays and Their Use in Dye-Sensitized Solar Cells

Highly ordered TiO(2) nanotubes were successfully fabricated using a nanoporous alumina templating method. A modified sol-gel route was used to infiltrate the alumina pores with Ti(OC(3)H(7))(4) which was subsequently converted into TiO(2) nanotubes. The average external diameter, tube lengths, and wall thickness achieved were 295 nm, 6-15 microm, and 21-42 nm, respectively. Diffraction data reveals that the nanotubes consist solely of the anatase phase. Dye-sensitized solar cells using TiO(2) nanotube arrays as the working electrode yielded power conversion efficiencies as high as 3.5% with a maximum incident photon-to-current conversion efficiency of 20% at 520 nm.

Metal complexes with polymeric ligands: Chelation and metalloinitiation approaches to metal tris(bipyridine)-containing materials

Synthetic approaches to metal complexes with polymeric ligands are described. The development of efficient methods for preparing simple bipyridine (bpy) derivatives and their corresponding metal complexes has facilitated their use as initiators and coupling agents in polymer syntheses. Ligand reagents were utilized as initiators in controlled polymerization reactions to form poly(2-R-2-oxazolines) (R = methyl, ethyl, phenyl, undecyl), polystyrenes, poly(methyl methacrylates) (PMMA)s, poly(e-caprolactone)s, and poly(lactic acid)s with bipyridine chelates at the end or centers of the chains. Poly(ethylene glycol) macroligands were formed by a chain-coupling method. Detailed studies of reaction kinetics were performed to determine the scope and limitations of each reaction type with different catalysts and reaction conditions. These results are illustrated for bpyPMMA n (n = 1 or 2), which was prepared by atom transfer radical polymerization with a CuBr/1,4,4,7,7,10-hexamethyltriethylenetetraamine catalyst system. Results of the kinetics investigations performed with other ligands and metalloinitiators are summarized. Macroligands thus prepared were coordinated to a labile metal ion, Fe(II), with standard protocols. Ultraviolet-visible spectral data for selected Fe-centered polymers are provided that confirm the production of the targeted polymeric iron complex products. An inert metal, Ru(II), was used as a template for generating architectural diversity; polymeric complexes with one to six chains emanating from the central core, as well as different heteroarm star products, were prepared.

An improved synthesis of hydroxymethyl bipyridines

Abstract This account describes quick and efficient syntheses of 4,4′-bis(hydroxymethyl)-2,2′-bipyridine and 4-hydroxymethyl-2,2′-bipyridine from 4,4′-dimethyl-2,2′-bipyridine and 4-methyl-2,2′-bipyridine, respectively, via (trimethylsilyl)methyl-, bromomethyl-, and acetoxymethyl- intermediates.

Metal complexes with polymeric ligands: modular synthesis of multifunctional materials for applications in biomedicine and nanotechnology

Polymeric metal complexes exhibiting useful properties were prepared by chelating macroligands to labile and inert metal ions. The specific structures elucidated through this method, as well as potential applications for these complexes are described. By carefully selecting the appropriate metal ion and polymer, these materials can be tuned for a host of applications in fields ranging from biomedicine to nanotechnology.