The field of mesoporous materials has been expanding rapidly in recent years, and has come to include a wide variety of different types of materials from organic to inorganic, as well as hybrid materials that encompass both worlds. The following account explores one type of mesoporous materials, specifically those consisting of silica with an attached organic group that have come to be known as periodic mesoporous organosilicas (PMOs). Much of the work here involves incorporating new types of organic groups into a mesoporous framework for the purpose of adding a useful functionality, either chemical or physical, to the material. Firstly it is shown that a borazine moiety can be successfully incorporated into a mesoporous material with a very high loading. It was further shown that once incorporated into the material many of the borazine moieties are available for further chemical reactions with acids and transition metals. Next, a new class of materials termed hybrid periodic mesoporous organosilicas (HPMOs) was developed that was able to circumvent many of the problems associated with PMO self-assembly. Now, using very simple techniques, virtually any type of silsesquioxane can be incorporated into a PMO, and the organic group can be specifically at the surface of the pores, thereby maximizing its accessibility. And finally, a PMO is made that incorporates buckyballs, and it is shown that, given the right synthetic conditions, the buckyballs are homogeneously distributed throughout the material.

The main goal of this thesis was to explore the role of H-bonding interactions in ferrocene peptide conjugates at the molecular and supramolecular level. With the help of detailed spectroscopic and crystallographic studies, the intermolecular association of a range of conjugates was studied and described here. It was shown that C-terminal modifications directed the supramolecular assembly. In the case of Fc[CO-Gly-Val-OH]2, the C-terminal carboxylate group directed intermolecular interactions, causing formation of a supramolecular architecture that was characterized by large solvent-filled hydrophobic channels. In the absence of this directional group, as was the case in Fc[CO-Leu-Val-OMe]2 extended β-sheets were formed. Hierarchical self-assembly of disubstituted ferrocene peptide conjugates possessing Gly-Val-Phe and Gly-Val-Phe-Phe peptide substituents gave rise to nano- and micro-sized assemblies. Spontaneous self-assembly of Fc-peptides through intra-and intermolecular hydrogen bonding interactions induced supramolecular building blocks, which further associated to fibers, large fibrous crystals, and twisted ropes. Next, intermolecular H-bonding interactions were studied using a surface-based approach. A fragment of the amyloid-beta (Aβ) peptide was bound to a gold surface through a C-terminal Cys. Various aspects of the peptide film were examined using different electrochemical and surface analytical techniques. The interaction of Congo red and of Lys-Leu-Val-Phe-Phe with the immobilized Aβ fragment was studied using electrochemical methods, showing responses that indicated intermolecular interactions. This surface approach was used to probe the interaction of a series of ferrocene peptides (Fc-CO-Leu-Val-Phe-Phe-OX and Fc-CO-Lys(Boc)-Leu-Val-Phe-Phe-OX with X=H and Me) with the surface-bound Aβ fragment. Biomolecular interactions between Fc-peptides and the Aβ-modified surface were studied by electrochemical methods. The current response of the Fc redox process was modulated by the interaction with the Aβ-modified surface.

Slow photon, or light with reduced group velocity, is a unique phenomenon found in photonic crystals that theoreticians have long suggested to be invaluable for increasing the efficiency of light-driven processes. This thesis demonstrates experimentally the feasibility of using slow photons to optically amplify photochemistry of both organic and inorganic systems. The effect of photonic properties on organic photochemistry was investigated by tracing out the wavelength-dependent rate of photoisomerization of azobenzene anchored on silica opals. The application of slow photons to inorganic photochemical processes was realized by molding nanocrystalline titania into an inverse opal structure and investigating its photodegradation efficiency in relation to the photonic properties. Changes in the photodegradation efficiency were directly linked to modifications of the electronic band gap absorption as a result of the photonic properties. The highest enhancement of twofold was achieved when the energy of the slow photons overlaps with the electronic band gap absorption, such that the loss of light due to photonic stop-band reflection was significantly reduced. In addition, the strength of slow-photon amplification with respect to the macroscopic structural order was studied by introducing controlled disorder via the incorporation of guest spheres into the opal templates. For the first time, a correlation between structural order, photonic properties and a photochemical process was established. The ability to combine slow-photon optical amplification with chemical enhancement was further achieved by incorporating platinum nanoparticles in inverse titania opals where the platinum nanoparticles increased the lifetimes of the higher population of electron-hole pairs arising from slow photon. Overall, various important factors governing the slow photon enhancement were investigated in detail, including the energy of the photonic stop band, angle dependence, thickness of the film, degree of structural order, filling fraction of the dielectric material and diffusion of a second medium if present. Theoretical calculations based on scalar-wave approximation in support of the experimental findings were provided wherever possible. The findings provide a blueprint for achieving optical amplification using slow photons in the broad range of photochemical or photophysical processes.

This thesis explores 4,5-diazafluorenyl derivatives as binucleating ligands for the syntheses of heterobimetallic complexes. The 4,5-diazafluorenide (L-) ligand contains two coordination sites: a Cp moiety and two N-donors. L- was used to construct PtII-CuI and PtII-RuII heterobimetallic complexes. Various modifications have been made to the L- framework to alter the regioselectivity. A pendent phosphine was arm attached to the methylene linker to form 9-(2-(diphenylphosphino)ethyl)-4,5-diazafluorenide (Lp-) and provides a P,C-chelate to anchor metals to the C-donor on the L- backbone. Lp- was used to synthesize PtII-CuI complexes and dinuclear RuII complexes. Bulky mesityl groups were installed ortho- to the N-donors to form 3,6-dimesityl-4,5-diazafluorenide (LMes-). The LMes- derivative provides steric protection that prevents bulky metal fragments from binding to the N-donors. LMes- was used to construct a series of RuII-M complexes (M = FeII, CoII, PtII, CuI) where the metals span from group 8 to 11.

Stoichiometric and catalytic small molecule activation reactions are vital for the synthesis of new materials. The activation of phosphorus-hydrogen or phosphorus-phosphorus bonds allows for the facile synthesis of new phosphorus-containing molecules for a wide variety of applications.1 An investigation of the P-H dehydrocoupling reaction was undertaken utilizing two rhodium(I) based catalysts. Over the course of this investigation it was found that the Rh(I) systems were also active catalysts for the reverse reaction: phosphorus-phosphorus bond hydrogenation (and hydrosilylation). This reaction was exploited for the synthesis of novel phosphines from P-P bound species. Molecules with P-P bonds were reacted in a stoichiometric fashion with the catalyst precursor, producing a variety of novel species with interesting bonding features which shed some light on the reaction mechanism. Following the discovery in 2006 that a linked phosphine-borane system could reversibly activate hydrogen2 a tremendous effort has been put forth to understand and expand this unprecedented reactivity.3,4 This new archetype for metal-free small molecule activation, containing a bulky Lewis acid and Lewis base which are unable to bond directly due to steric repulsion, has been termed a “frustrated Lewis pair” (FLP).3,4 The FLP concept is expanded to include bulky P-P bound species, pyridines and P-O bound Lewis bases as partners for B(C6F5)3. In some cases small molecule activation produced ion pairs or zwitterions related to those found for reactions with tertiary phosphines,3,4 but in others novel reaction pathways were discovered including phosphorus-phosphorus bond cleavage, catalytic hydrogenations and the formation of novel intramolecular FLPs. An unexpected situation was observed for the pair of 2,6-lutidine with B(C6F5)3, where adduct formation was observed along with free Lewis acid and base, but H2 activation by the FLP proceeded smoothly. Covalently bound phosphinoboranes of the general formula R2PB(C6F5)2 are synthesized. While systems with small R groups dimerized, monomers existed for cases with bulkier R groups. These monomers were found to exhibit extraordinarily short phosphorus-boron bonds yet were still capable of H2 activation analogous to bimolecular phosphine-borane systems. These systems also showed unique reactivity with Lewis acids and Lewis bases. This work further demonstrates the broad and general utility of the FLP concept in the synthesis of new materials and in catalytic transformations.

Stoichiometric and catalytic small molecule activation reactions are vital for the synthesis of new materials. The activation of phosphorus-hydrogen or phosphorus-phosphorus bonds allows for the facile synthesis of new phosphorus-containing molecules for a wide variety of applications.1 An investigation of the P-H dehydrocoupling reaction was undertaken utilizing two rhodium(I) based catalysts. Over the course of this investigation it was found that the Rh(I) systems were also active catalysts for the reverse reaction: phosphorus-phosphorus bond hydrogenation (and hydrosilylation). This reaction was exploited for the synthesis of novel phosphines from P-P bound species. Molecules with P-P bonds were reacted in a stoichiometric fashion with the catalyst precursor, producing a variety of novel species with interesting bonding features which shed some light on the reaction mechanism. Following the discovery in 2006 that a linked phosphine-borane system could reversibly activate hydrogen2 a tremendous effort has been put forth to understand and expand this unprecedented reactivity.3,4 This new archetype for metal-free small molecule activation, containing a bulky Lewis acid and Lewis base which are unable to bond directly due to steric repulsion, has been termed a “frustrated Lewis pair” (FLP).3,4 The FLP concept is expanded to include bulky P-P bound species, pyridines and P-O bound Lewis bases as partners for B(C6F5)3. In some cases small molecule activation produced ion pairs or zwitterions related to those found for reactions with tertiary phosphines,3,4 but in others novel reaction pathways were discovered including phosphorus-phosphorus bond cleavage, catalytic hydrogenations and the formation of novel intramolecular FLPs. An unexpected situation was observed for the pair of 2,6-lutidine with B(C6F5)3, where adduct formation was observed along with free Lewis acid and base, but H2 activation by the FLP proceeded smoothly. Covalently bound phosphinoboranes of the general formula R2PB(C6F5)2 are synthesized. While systems with small R groups dimerized, monomers existed for cases with bulkier R groups. These monomers were found to exhibit extraordinarily short phosphorus-boron bonds yet were still capable of H2 activation analogous to bimolecular phosphine-borane systems. These systems also showed unique reactivity with Lewis acids and Lewis bases. This work further demonstrates the broad and general utility of the FLP concept in the synthesis of new materials and in catalytic transformations.

Combinations of sterically encumbered Lewis acids and Lewis bases are precluded from dative bond formation, failing to yield classical Lewis acid-base adducts. These unique systems are referred to as frustrated Lewis pairs (FLPs) and demonstrate a plethora of unique small molecule activations.Herein, the syntheses of phosphonium alkoxy- and aryloxyborate salts in addition to phosphonium thioborate salts are detailed. The scope of Lewis acid and base, alcohol and thiol, that are effective in this chemistry, is also detailed. The syntheses of novel borate and boronate esters of the form B(OR)3 and (C6R4O2)B(C6F5) are detailed and applied in metal-free heterolytic dihydrogen activation with phosphines. The further study of a variety of perfluoroboranes in the activation of H2 with tertiary phosphines is also detailed. Derivatization of triarylboranes, boronate esters, borinic esters and chloroboranes by reaction with one or two equivalents of alky- or aryldiazomethane is achieved yielding the corresponding RR’C insertion products. The solid-state structures of the free boranes, in addition to Lewis base adducts of a sampling of these species, are detailed. Reactivity of the resulting sterically encumbered boranes in imine hydrogenations, H2 and XeF2 activation are also detailed. Combinations of intermolecular frustrated Lewis pairs are found to react collaboratively to activate greenhouse gases such as carbon dioxide (CO2) and nitrous oxide (N2O), yielding the corresponding zwitterionic compounds R3P(CO2)BR2R’ and R3P(N2O)BR’3. Atom connectivity has been established via X-ray crystallographic studies and molecular structures and parameters are discussed. Subsequent exchange chemistry of both CO2 and N2O species with transition metal and other d-block Lewis acids are investigated and yield zwitterionic compounds and ion pairs which are otherwise unobtainable employing more conventional methods. Transition metal containing Lewis acids are employed in conjunction with tri(tert-butyl)phosphine for the FLP-mediated direct activation of N2O.

Combinations of sterically encumbered Lewis acids and Lewis bases are precluded from dative bond formation, failing to yield classical Lewis acid-base adducts. These unique systems are referred to as frustrated Lewis pairs (FLPs) and demonstrate a plethora of unique small molecule activations.Herein, the syntheses of phosphonium alkoxy- and aryloxyborate salts in addition to phosphonium thioborate salts are detailed. The scope of Lewis acid and base, alcohol and thiol, that are effective in this chemistry, is also detailed. The syntheses of novel borate and boronate esters of the form B(OR)3 and (C6R4O2)B(C6F5) are detailed and applied in metal-free heterolytic dihydrogen activation with phosphines. The further study of a variety of perfluoroboranes in the activation of H2 with tertiary phosphines is also detailed. Derivatization of triarylboranes, boronate esters, borinic esters and chloroboranes by reaction with one or two equivalents of alky- or aryldiazomethane is achieved yielding the corresponding RR’C insertion products. The solid-state structures of the free boranes, in addition to Lewis base adducts of a sampling of these species, are detailed. Reactivity of the resulting sterically encumbered boranes in imine hydrogenations, H2 and XeF2 activation are also detailed. Combinations of intermolecular frustrated Lewis pairs are found to react collaboratively to activate greenhouse gases such as carbon dioxide (CO2) and nitrous oxide (N2O), yielding the corresponding zwitterionic compounds R3P(CO2)BR2R’ and R3P(N2O)BR’3. Atom connectivity has been established via X-ray crystallographic studies and molecular structures and parameters are discussed. Subsequent exchange chemistry of both CO2 and N2O species with transition metal and other d-block Lewis acids are investigated and yield zwitterionic compounds and ion pairs which are otherwise unobtainable employing more conventional methods. Transition metal containing Lewis acids are employed in conjunction with tri(tert-butyl)phosphine for the FLP-mediated direct activation of N2O.

This thesis explores 4,5-diazafluorenyl derivatives as binucleating ligands for the syntheses of heterobimetallic complexes. The 4,5-diazafluorenide (L-) ligand contains two coordination sites: a Cp moiety and two N-donors. L- was used to construct PtII-CuI and PtII-RuII heterobimetallic complexes. Various modifications have been made to the L- framework to alter the regioselectivity. A pendent phosphine was arm attached to the methylene linker to form 9-(2-(diphenylphosphino)ethyl)-4,5-diazafluorenide (Lp-) and provides a P,C-chelate to anchor metals to the C-donor on the L- backbone. Lp- was used to synthesize PtII-CuI complexes and dinuclear RuII complexes. Bulky mesityl groups were installed ortho- to the N-donors to form 3,6-dimesityl-4,5-diazafluorenide (LMes-). The LMes- derivative provides steric protection that prevents bulky metal fragments from binding to the N-donors. LMes- was used to construct a series of RuII-M complexes (M = FeII, CoII, PtII, CuI) where the metals span from group 8 to 11.

Slow photon, or light with reduced group velocity, is a unique phenomenon found in photonic crystals that theoreticians have long suggested to be invaluable for increasing the efficiency of light-driven processes. This thesis demonstrates experimentally the feasibility of using slow photons to optically amplify photochemistry of both organic and inorganic systems. The effect of photonic properties on organic photochemistry was investigated by tracing out the wavelength-dependent rate of photoisomerization of azobenzene anchored on silica opals. The application of slow photons to inorganic photochemical processes was realized by molding nanocrystalline titania into an inverse opal structure and investigating its photodegradation efficiency in relation to the photonic properties. Changes in the photodegradation efficiency were directly linked to modifications of the electronic band gap absorption as a result of the photonic properties. The highest enhancement of twofold was achieved when the energy of the slow photons overlaps with the electronic band gap absorption, such that the loss of light due to photonic stop-band reflection was significantly reduced. In addition, the strength of slow-photon amplification with respect to the macroscopic structural order was studied by introducing controlled disorder via the incorporation of guest spheres into the opal templates. For the first time, a correlation between structural order, photonic properties and a photochemical process was established. The ability to combine slow-photon optical amplification with chemical enhancement was further achieved by incorporating platinum nanoparticles in inverse titania opals where the platinum nanoparticles increased the lifetimes of the higher population of electron-hole pairs arising from slow photon. Overall, various important factors governing the slow photon enhancement were investigated in detail, including the energy of the photonic stop band, angle dependence, thickness of the film, degree of structural order, filling fraction of the dielectric material and diffusion of a second medium if present. Theoretical calculations based on scalar-wave approximation in support of the experimental findings were provided wherever possible. The findings provide a blueprint for achieving optical amplification using slow photons in the broad range of photochemical or photophysical processes.