<p> The well-established principles of organic photochemistry, offer chemists the fundamental understanding and tools for studying light induced chemical transformations. Employing visible light for photocatalysis, one can design and develop benign routes for the synthesis of new organic materials. In our present investigation, we have developed novel <i>N-N</i> bond based compounds for visible light mediated phototransformations. We have presented synthesis for targeting achiral/chiral <i>N-N</i> bond based compounds and their study for various light driven applications. To name a few applications, these compounds have shown to react smoothly under visible light, metal-free conditions for classical photoreactions, chloromethylation, asymmetric photocyclization and photopolymerization. A diverse range of compounds has shown to react smoothly to afford products in high yields. </p><p> The scope of this methodology has been evaluated for both intermolecular and intramolecular reactions. Our work benefits from the ability of these compounds to undergo desired phototransformation in both solution and in crystalline media. We have provided photochemical and photophysical details that corroborates our experimental findings and highlights the role of excited state reactivity of the novel N-N bond based compounds. This thesis will be an effort to make chemists familiarize with potential of these compounds in light induced reactions. </p>

<p> Current factories producing plant-based fossil-fuel replacements are neither environmentally friendly nor economically viable because their main product, bio-oil, is burned for heat rather than sold for profit. However, bio-oil is rich in potentially valuable aromatic compounds. In order to valorize bio-oil and improve the economic viability of the factories, we need to understand bio-oil&rsquo;s composition and the effect of processing parameters&mdash;such as plant feedstock and pretreatment method. Unfortunately, bio-oil is a complex lignocellulosic mixture that is difficult to analyze. To fully characterize the hundreds of compounds present, analysis typically requires top-end mass spectrometers and lengthy separations. This cost prohibits many laboratories from pursuing bio-oil research. Then time-consuming separations limit recursive analyses to optimize process parameters. The question takes shape: is it possible to analyze complex lignocellulosic mixtures without lengthy separations or top-end mass spectrometers? To assess the feasibility of rapid, affordable analysis, I set out to develop qualitative and quantitative methods using a quadrupole-time-of-flight (QTOF) mass spectrometer. I hypothesized that (a) ionization dopants could mitigate the need for lengthy separations pre-injection and that (b) tandem mass spectrometry could compensate for the midrange resolving power of the QTOF. To test this hypothesis, I started by analyzing another lignocellulosic biomaterial: autohydrolyzate, the product of hydrothermal pretreatment of biomass feedstocks. I observed that two anionic dopants&mdash;hydroxide and chloride&mdash;worked exceptionally well for selective analysis of the two major components of a lignocellulosic mixture, lignin- and carbohydrate-derivatives. Tandem mass spectrometry confirmed the game-changing selectivity of the dopants. With these favorable results, I applied the ionization dopants to two case studies. Chloride dopant and tandem mass spectrometry were employed to qualitatively analyze the little understood lignin-carbohydrate complexes found in lignocellulosic mixtures. Hydroxide dopant and tandem mass spectrometry were employed to quantitatively analyze the feasibility of valorizing biooil as a performance-enhancing diesel fuel additive. Both projects offered exciting success that redefined the scope of research possible using a QTOF. I demonstrated that by using ionization dopants and tandem mass spectrometry, it is possible for laboratories with limited means to use a cost-effective QTOF for both qualitative and quantitative analysis of complex lignocellulosic mixtures. </p><p>

Studies of the properties of metal cyclopentadienyl compounds were made by infra-red spectroelectrochemistry, electrochemistry, synthesis and $\sp{103}$Rh nuclear magnetic resonance spectrometry. A cell capable of simultaneously recording IR spectra of the region near the electrode surface during electrochemical experiments was developed, and characterized using ferricyanide. The absorbance-time response to potential step and potential sweep experiments was investigated and the experimentally determined response compared to a digital simulation of the response at different distances from the electrode surface. This allowed the distance from the electrode surface to the point of observation to be estimated. The capabilities of the cell were applied to the elucidation of the electrochemical behavior of titanocene dichloride and iron pentacarbonyl. Titanocene dichloride was reduced under an atmosphere of carbon monoxide to titanocene dicarbonyl and ultimately to the anion (CpTi(CO)$\sb4$) $\sp{-}$. No evidence for the formation of a titanium(III) carbonyl species was found. In contrast, reduction of titanocene dichloride in the presence of 2,6-dimethylphenylisocyanide led to the formation of titanium(III) and titanium(II) products, in which one and both of the chloride ligands had been replaced by the isocyanide, respectively. Electrochemical and chemical reduction of fulvalene-dititanium cyclopentadienyl compounds led to the breakage of the carbon-carbon bond linking the two five-membered rings of the fulvalene ligand. The electrochemical properties of a series of ferrocene-containing polyesters in solution was investigated using various stationary and rotating solid electrode techniques. The oxidised form of the polyesters coated the electrode surface in an uneven fashion allowing solution and surface processes to occur simultaneously. Evidence for the nature of this coating was gathered using X-ray photoelectron spectroscopy. The effect of substituents on a series of ring-substituted (h$\sp5$-cyclopentadienyl)dicarbonylrhodium complexes was investigated by means of changes in C-O stretching frequencies as well as $\sp{103}$Rh NMR chemical shifts. The effect of the substituents was found to be neither a purely resonance or inductive phenomenon, but best described by a substituent parameter which took both effects into account.

<p>We have found that calixarenes are good receptors of choline (trimethylammonium group) and they have strong affinity to form host-guest complexes with a variety of molecules carrying this moiety. Furthermore, the ability of lower rim carboxylic acid calix[n]arenes and upper rim phosphonic acid functionalized calix[4]arene to transport choline-conjugated drugs through a liquid membrane was discovered. The results demonstrate that these systems are highly efficient toward transporting choline-conjugated targets, as well as neurotransmitters that possess ionizable amine termini. The breadth of compounds that are transported is significant, facing limitations only when the payloads become extremely lipophilic. These developments reveal new approaches towards attempting synthetic receptor mediated selective small molecule transport in vesicular and cellular systems.