Conducting polymers have been extensively investigated in a wide range of applications due to their ability to achieve near metallic conductivity while possessing the flexibility and processability of traditional polymers. However, interchain and solid-state effects have made direct investigation of the polymer systems difficult. A series of systematically varied model compounds have been designed to provide detailed information about through-chain charge transport in well-defined oligothiophenes. Our design incorporates two metal binding pockets at either end of an oligothiophene bridge to investigate the interaction of redox centers and charge transport properties between conducting polymers and bound transition metal centers. Synthesis, characterization, electrochemistry, and detailed EPR investigations of this new series of oligothiophene model compounds and the analogous mononuclear compounds will be discussed herein. Conjugated polymer matrices possess a large number of available oxidation states making them an attractive choice for use as redox-active ligands. This variety of oxidation states offers a means to easily tune the amount of electron density on a metal center and consequently affect the binding of an additional ligand. Our approach utilizes conducting metallopolymers with metal complexes synthetically incorporated directly into the conducting polymer backbone. The redox-dependent properties of this class of materials and their development as small molecule storage and delivery systems have been explored utilizing a variety of novel electropolymerizable transition metal complexes. The design, synthesis, characterization, and redox-affected properties of the monomers, corresponding conducting metallopolymers, and model complexes are discussed. The tub-shaped dibenzo[a,e]cyclooctatetraene molecule undergoes a large change in geometry upon reduction to form the planar aromatic species. Herein, we seek to prepare and investigate a supramolecular assembly utilizing this redox-active molecule. In contrast to electrochemically active frameworks where redox changes occur at the metal centers, incorporation of a functionalized dibenzo[a,e]cyclooctatetraene ligand into an assembly has the potential to result in a redox-active framework. Not only would the redox-activity occur at the organic bridge, but reduction of the system should result in a large geometry change. / text

The design, synthesis, characterization and application of carbene-based metallopolymers are described herein. Metallopolymers have found wide applications in the fields of photovoltaics, energy storage and electrochromic windows. The incorporation of N-heterocyclic carbene (NHC) functionalities into a polymerizable scaffold would allow for many different metals to be attached in a facile and high-yielding manner. Such complexes could be functionalized onto surfaces and utilized as either spectroscopic or antimicrobial devices. Early attempts in our lab focused on utilizing bis(thiophene) diimines (instead of NHCs) as scaffolds for metal chelation and polymerization. This approach was unsuccessful due to the lability of the diimine moiety under electrochemical cycling and the thiophene moieties were not able to undergo polymerization. In order to more fully understand the key transformation in synthesizing the thiophene-substituted diimines, a comprehensive investigation of the aldimine coupling transformation was undertaken. A high concentration of substrate and catalyst was determined to be the most important factor in obtaining high yields of the dimerized products. Green solvents such as acetonitrile and hexanes could be used for the dimerization reaction when the cyanide counteranion was changed from sodium to tetrabutylammonium. The steric limitations were systematically identified and a series of possible substrates have been ruled out as viable candidates for dimerization. Applying the experience gleaned from earlier reports, the first example of an NHC polymer was prepared in which the monomer features an NHC functional group orthogonally connected to its main chain. A polymerizable imidazolylidene-AuCl complex containing pendant bithiophene moieties was prepared by a high yielding, multistep procedure. Oxidative electropolymerization of this monomer afforded the desired polymer (Au[NHC]Cl)n, which was characterized on the basis of electrochemical studies as well as by X-ray crystallography, photoelectron and UV-vis spectroscopy. The methodology described above was expanded to develop a series of analogous poly(N-heterocyclic carbene) complexes with appended entities (M = Ir, Au, Ag, or S)and found to be electrochromic. Most of the polymers exhibit an intense absorbance wave at 700 nm under oxidative conditions which is attributable to the formation of polaron excitations along the polymer main chain. The presence of a transition metal significantly increased the electrochromic character of the polycarbene system. The iridium-containing polymer was found to possess significant near-infrared (NIR) absorbance at 1100 nm in which the metal moiety effectively functions as an electron sink. Electrochemical analysis of the polymer thin films revealed that they exhibit highly reversible electrochromic activities. / text

Conducting metallopolymers are a new and fascinating class of materials that incorporate metals into conducting polymer systems. These new materials combine the processing advantages of polymers with the electronic, optical and catalytic properties provided by the presence of metal centers. A large number of conducting metallopolymers have been synthesized and studied and have found applications in areas such as sensors, memory and light-emitting devices, solar cells, and catalysis. Among the various applications, conducting metallopolymers as emitting layers in high-efficiency polymer light-emitting diodes (PLEDs) attract great research interest. In order to get PLEDs with long lifetime, high quantum efficiency, and excellent color purity, we have developed an approach to synthesize well-defined conducting metallopolymers that incorporate lanthanide complexes in an inner sphere fashion. As such, we aim to take full advantage of the properties of both organic and inorganic components with high efficiency due to the direct electronic interface this configuration creates. Lanthanide complexes with polymerizable groups have been synthesized, characterized and utilized as precursors for conducting metallopolymers. These lanthanide monomers and corresponding metallopolymers display visible and near-infrared luminescence at room temperature that is consistent with efficient energy transfer from the organic polymer matrix to the lanthanide metal ion followed by lanthanide luminescence. As a second but closely related area, electrogenerated chemiluminescence (ECL) of polymers is attractive for light-emitting devices. Up to now, there are limited studies dealing with ECL from pure active materials deposited as solid films on electrodes. The operation theory and degradation mechanism are still under investigation. To advance the development of ECL of conducting metallopolymers, we prepared cyclometalated Pt(II) complexes with polythiophene system. Conducting metallopolymer films are prepared through controlled electropolymerization. ECL of the Pt(II) containing conducting polymers are observed for the first time. Finally, a preliminary study of magnetism and conductivity of conducting metallopolymers has been done. We incorporate Fe(II)/Fe(III) into our newly designed ligand systems with polymerizable thiophene derivatives. Three complexes show spin crossover (SCO) phenomena with the highest transition temperature at 265 K, which are further verified by variable temperature electron paramagnetic resonance spectra. / text

The work herein consists of two projects in which nanoparticle-metallopolymer hybrid bulk-heterojunction (BHJ) systems are modified for improved performance in photovoltaic and electronic applications. The first project describes the process for growing two distinct nanoparticle compositions within the same active layer of a conducting metallopolymer composed of two metal-complexes, which are based on the N,N’-((2,2’-dimethyl)propyl)bis(5-(2,2’-bithiophene-5-yl)salcylidenimine ligand. The second project describes the synthesis of an alternative electropolymerizable ligand N,N’-((2,2’-dimethyl)propyl)bis(5-(thieno[3,2-b]thiophen-5-yl) salicylidenimine. The purpose of exchanging of bithiophene moieties for fused-ring thieno[3,2-b]thiophene units was to produce a stabilizing effect in the resulting polymer, as evidenced by a slight delay in the rate of photo-bleaching. / text

No description available.

Conducting metallopolymers have been investigated for a variety of applications due to their ability to take advantage of both the mechanical processability of the polymer material, as well as the optical and electronic properties of the metal. Our project goal is to design, synthesize and characterize novel iridium(III)-containing conducting metallopolymers for use as the active layer in polymer light-emitting diodes. We have utilized thiophene functionalized ligands that can be readily electropolymerized into conducting polymer thin films and can be easily incorporated into a device structure. Iridium(III) was chosen as the metal center due to its promising photophysical properties, as similar complexes have demonstrated high luminescent quantum yields and short phosphorescent lifetimes. The coordination environment around the metal can be altered synthetically to tune the emission wavelength across the visible spectrum. The synthetic control over the polymer backbone, as well as the iridium(III) ligand environment, allowed us to independently vary each component, which has provided a variety of materials. The materials are characterized through 1H and 13C NMR, mass spectrometry, elemental analysis, electrochemistry, X-Ray diffraction and X-Ray Photoelectron Spectroscopy. The photophysical properties of the materials are studied through UVvii Visible absorption spectroscopy, UV-Vis-NIR spectroelectrochemistry and steadystate/ time-resolved emission spectroscopy. / text

Described herein are two projects focusing on developing and investigating two types of nanoparticles (NPs) grown by the seeded growth method from a conducting metallopolymer for photovoltaic (PV) applications. Core/shell CdS/ZnS NPs are proven to resist the photo-oxidation of PV devices, while CuInxGa(1-x)Se2 (CIGS) NPs are expected to optimize the efficiency of PV devices. / text

Orientadores: André Luiz Barboza Formiga, Maria Isabel Felisberti / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-20T16:07:14Z (GMT). No. of bitstreams: 1 Jannuzzi_SergioAugustoVenturinelli_M.pdf: 35610656 bytes, checksum: f2dffeb8cf285399ac0996a04b2601a7 (MD5) Previous issue date: 2011 / Resumo: O presente trabalho ocupa-se da síntese, caracterização e aplicação de um material híbrido orgânico-inorgânico em que o bloco orgânico é o polímero poli(4-vinilpiridina) e o bloco inorgânico é o pentacianoferrato(II) de sódio. A primeira parte trata da influência do polímero nas propriedades do complexo, e vice-versa. A segunda parte ilustra a aplicação do metalopolímero na produção de estruturas análogas ao azul da Prússia (AP) pela reação de Fe com as unidades pentacianoferrato. A banda de transferência de carga metal-ligante do pentacianoferrato do metalopolímero em solução desloca-se para energias menores na medida em que aumenta a fração de meros livres da cadeia polimérica, indicando que a fração do bloco orgânico modula a polaridade do ambiente químico do complexo. Por outro lado, a crescente quantidade de complexo ligado às cadeias poliméricas aumenta viscosidade das soluções de metalopolímeros, evidenciando que o pentacianoferrato expande o novelo macromolecular. Estruturas tipo azul da Prússia sintetizadas a partir do metalopolímero exibem elevada estabilidade coloidal quando comparadas aos compostos isentos de polímero e apresentam banda de intervalência em menores energias do que o frequentemente reportado para esse tipo de estrutura, provavelmente em virtude do envolvimento das partículas de AP pelo polímero / Abstract: This work comprises the synthesis, characterization and application of a hybrid organic-inorganic metallopolymer, in which the organic block is the polymer poly(4-vinylpyridine) and the inorganic block is the complex sodium pentacyanoferrate(II). The first part presents the influence of the polymer on the properties of the complex and vice-versa. The second part illustrates an application of the metallopolymer on the production of Prussian blue (AP) analogs based on the reaction of Fe with the pentacyanoferrate moieties. The metal-to-ligand charge transfer band of the polymer-bound pentacyanoferrate in solution shifts towards lower energies whereas the free monomers fraction arises. It indicates that the organic block fraction tunes the polarity of the pentacyanoferrate chemical environment. On the other side, the increasing fraction of complex bound to the polymer chain increases the metallopolymer solution viscosities. This is an evidence that the pentacyanoferrate expands the macromolecular coil. Prussian blue-type structures synthesized from metallopolymers exhibit enhanced colloidal stability when compared to the polymer-free compounds. They also present intervalence bands at lower energies than those frequentlly reported for this type of inorganic structure. The reason is probably the polymer wrapping of the particles / Mestrado / Quimica Inorganica / Mestre em Química

No description available.

Poly-N-isopropylacrylamide (PNIPAM) gels grafted to redox-active metal monomers undergo sudden expansion-contraction activity in response to change in environmental conditions, such as temperature, pH, ion concentration, and oxidation states of the metal. The relevance of these conditions to biological systems has garnered attention for PNIPAM-based polymer as potential biomedical materials. Candidate transition metal monomers containing ruthenium and nickel cores were designed and synthesized for copolymerization with NIPAM and cross-linker methylene-bis-acrylamide in order to attain metallopolymer microspheres with a high percentage of metal incorporation. Synthesis of 4-vinyl-4'-methyl-2,2'-bipyridine (vmbpy) was optimized from literature procedures for usage in the metal-containing monomers. Metal-containing monomers were then synthesized, purified, and characterized using electrospray ionization mass spectrometry (ESI-MS), proton nuclear magnetic resonance ( 1 H-NMR), X-ray diffraction, Ultraviolet-Visible light (UV-Vis) spectroscopy, and spectrofluorometry. While the Ru complex was pure and exhibited interesting photochemical properties, lability of the ligands on the Ni monomers resulted in complication of their synthesis. Polymer microspheres of poly(NIPAM-co-vmbpy), the cross-linked copolymer constructed from NIPAM and vmbpy monomers, were synthesized from modified emulsion polymerization procedures. Experimental setup parameters and conditions—such as the methods of injection of initiator and stirring, the time duration for incubating the emulsion, and the initiation temperature—were varied to assess their influences on the material properties of the final product. The polymers were tested for size and morphological uniformity by dynamic light scattering (DLS) and scanning electron microscopy (SEM). While varying the method of initiator injection had no measurable effect on the product, strong mechanical stirring and incubation of the polymer emulsion for 15-25 minutes at 71 °C procured similar polymer products. Consistent properties ensured the polymers' suitability for further material development. Preliminary morphological and spectroscopic characterization was conducted of metallopolymers made from Ru and Ni grafted to PNIPAM. Metallopolymers containing polypyridyl Ru cores exhibited desirable spectroscopic properties and spherical morphology.