In recent years, application of fluorescent conjugated polymers to sense chemical and biological analytes has received much attention owing to its technological significance. Water soluble conjugated polymers are interesting towards the developing sensors for biomolecules. In this present contribution, we describe the syntheses and characterization of a series of water soluble conjugated polymers with sulfonic acid groups in the side chain. Such anionic conjugated polymers are designed to interact with biomolecules such as cytochrome-C. All polymers are water soluble and showed strong blue emission. Significant quenching of the fluorescence from our functionalized PPP was observed upon addition of viologen derivatives or cytochrome -C. / Singapore-MIT Alliance (SMA)

The syntheses of new classes of conjugated polymers are presented. The synthesis of novel alkyne bridged trispyrazolylmethane ligands, their coordination behavior and their crystallographic properties are studied. A series of functionalized poly(paraphenyleneethynylene)s, PPEs, are produced by click chemistry with post and pre-polymerization. Unpredictable solid-state polymerizations of defect free conjugated polythiophenes are investigated. Finally, by click chemistry aromatic diazides and aromatic diynes are coupled to produce a library of 1,2,3-triazoles and new conjugated polymers, poly(arylenetriazoline)s.

Conjugated polymers and oligomers have been widely studied based on their wide range of useful properties and applications. Given the importance of self-assembly and charge transfer in the development of conjugated materials for use in electronic applications, it is crucial to: (i) prepare functional materials by molecular design, (ii) evaluate the structure-property relationships of new materials, and (iii) develop fundamental understanding of electronic structure and charge transport behavior. The use of conjugated polymeric materials in electronic applications relies on control of the assembly and orientation of the polymer chains in the solid state. Conjugated polymers with liquid crystalline behavior could be used to implement an additional level of control over orientation and resultant properties. Substitution of the conjugated polythiophene backbone with semifluoroalkyl side chains (i.e., the diblock -(CH2)m(CF2)nF) has afforded materials with unusual properties. The mutual immiscibility of the aromatic backbone, the alkyl side-chain segments, and the fluoroalkyl side-chain termini provides control over supramolecular packing. A series of eight polymers has been synthesized, in which the lengths of the alkyl (m) and fluoroalkyl (n) segments are varied. One regiorandom analogue and two poly(3-alkylthiophene)s were also synthesized for comparative purposes. The structure, molecular weight, and regioregularity of the polymers were evaluated using a variety of techniques. The semifluoroalkyl-substituted polymers have been systematically studied to determine the effect of side chain length and m:n block ratios on their solution state, liquid crystalline, and solid state properties. The effect of side chains on conjugation was determined, where solubility allowed, by solution-state UV-visible and fluorescence spectroscopy. The thermal and liquid crystalline properties of the homopolymers were evaluated by DSC, variable-temperature X-ray diffraction, and polarized optical microscopy. Several semifluoroalkyl-substituted polythiophene homologues show liquid crystalline behavior. Molecular packing and charge transport are key factors governing the use of conjugated materials in electronic applications. A wide variety of oligomers have been studied as models for charge migration in conjugated polymers. One-dimensional models do not adequately represent two-dimensional charge transport; thus, a variety of two-dimensional, covalently-linked models have been developed. Previous work by our group, and others, led to the proposal of bis(oligothienyl) compounds as models to study the interaction of the ð-conjugated chains. Previous reports by other researchers described the synthesis and characterization of hydrogen-terminated analogues of 1,8-bis(oligothienyl)naphthalenes. However, these materials proved to be unsuitable for use as charge transport models, as they were subject to irreversible polymerization upon oxidation. Installation of methyl groups at the terminal a-positions of 1,8-bis(oligothienyl)naphthalenes allowed us to create a series of models in which conjugated chains are held in close proximity. This provides access to multiple redox states, and future systems based on these molecules may be used as models for charge transport or as functional materials for incorporation into devices.

Structured phospholipids with functional ingredients like conjugated linoleic acid (CLA) and plant sterols to deliver their physiological effects in different food formulations were synthesized. The lipase and phospholipase A2 catalyzed enzymatic acidolysis reaction between phospholipids (PLs) and CLA was used for fatty acid modification, while the phospholipase D catalyzed transphosphatidylation reaction between PLs and sterol was used for head group modification. Enzymatic processes were an effective way to produce structured phospholipids. Screening of four lipases and immobilized phospholipase A2 and combination of lipase and phospholipase showed that only Lipozyme RM IM and Lipozyme TL IM were effective in incorporation of CLA into PLs. The maximum incorporation achieved by the latter enzyme was 16% with soy PLs in 72 h. The class of phospholipids had a significant effect on the rate of incorporation of CLA compare to source of PLs. A method capable of predicting the rate of incorporation of CLA into phospholipids was developed using response surface methodology. A three-level four-factor Central Composite Rotatable Design (CCRD) was used. The four factors selected were lipase dosage (Ed, wt.% of substrate), substrate ratio (Sr,mol%), reaction time (ti, h) and reaction temperature (Te,oC). The enzyme load and substrate ratio had a greater effect on the rate of incorporation than did reaction time and temperature. A polynomial regression equation was developed to predict the reaction rate. The new phosphatidyl derivative, phosphatidyl-sitosterol, was found to be synthesized by the transfer reaction of phosphatidyl residue from phosphatidylcholine to β-sitosterol by phospholipase D from Streptomyces sp. in biphasic medium. The novel phosphatidyl .sitosterol derivative was identified by MALDI-TOF mass spectrometry. Plant sterols were modified to a more polar lipid class by synthesizing phospholipid derivatives of them. When these structured phospholipids were added to a whey protein based oil-in-water emulsion, the CLA incorporated structured phospholipids (CLA-PL) had higher heat stability and oxidative stability compared to the controls.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 143-162).

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Research conducted for this dissertation had three goals; 1) determine if CLA can induce milk fat depression immediately postpartum, 2) determine if CLA can alter energy availability, 3) determine the mechanism behind the mammary gland's decreased sensitivity to CLA immediately postpartum. The first study provides strong evidence indicating CLA can decrease milk fat synthesis immediately postpartum, but the dose required is approximately 3x greater than in established lactation. This trial also provided evidence that CLA can alter energy status, as CLA decreased days to EBAL nadir by nearly 5 days. This is relevant as recovery of EBAL from its lowest point provides an important signal for initiating ovarian activity and days to nadir is highly correlated with days to first ovulation. Study two was designed to determine if CLA induced milk fat depression could improve energy status during heat stress. Rumen-inert CLA reduced milk fat synthesis, and was able to improve energy availability, but did not increase milk yield or yield of other milk components. Although production was unchanged in this study, the study did provide further evidence that rumen-inert CLA can alter energy availability. Study three utilized intravenous infusion of CLA in cows in mid and early lactation to determine the mechanism for the mammary gland's decreased sensitivity in early lactation. It is postulated that increased fatty acid oxidation and subsequent enhanced levels of circulating NEFA present during the transition period competitively prevent adequate CLA uptake by the mammary gland. In the current study, trans-10, cis-12 CLA concentration in milk was not different between early and established lactation, while milk fat yield was drastically reduced on d 4 and 5 of trans-10, cis-12 CLA infusion in mid lactation cows, but unaltered in early lactation. Further, NEFA levels were nearly 3 fold higher in early lactation than in mid lactation, providing further evidence that increased circulating NEFAs in early lactation are unlikely to be the source of the mammary gland's decreased sensitivity during this time. Do to the variation in gene expression observed in this trial, we were unable to make any definitive conclusions as to the sensitivity of the expression of genes involved in milk lipid synthesis to CLA in early vs. mid lactation.

The primary goal of this study is to develop novel metal catalyzed multicomponent reaction methods to generate imidazoles and their derivatives. This is directed towards the assembly of poly-substituted imidazoles, imidazolones and imidazole-containing pi-conjugated polymers. These products are generated in one-pot from such basic components as imines, acid chlorides, carbon monoxide, and/or organostannanes, via the use of palladium catalysis. / In Chapter 2, the design of a new palladium catalyzed synthesis of highly substituted imidazoles from imines and acid chlorides is described. This reaction involves the palladium catalyzed generation of 1, 3-oxazolium-5-oxides (Munchnones); which are trapped with N-tosyl substituted imines via a 1, 3 dipolar cycloaddition reaction to form the final products. Overall, this provides a one step method to assemble imidazoles from imines and acid chlorides with excellent regiochemical control. The versatility of this process is demonstrated by the assembly of diversely substituted imidazoles, including those with aryl, alkyl, heterocyclic and vinyl substituents. / Chapter 3 describes a new, palladium catalyzed, five component coupling of imines, chloroformates, organotin reagents, carbon monoxide and ammonium acetate to form imidazolones. The key step in this process is the efficient formation of ketocarbamates via the carbonylative cross coupling type reaction of imines, chloroformates and organostannanes. These products can be easily converted into imidazolones via a cyclocondensation with ammonium acetate. / The synthesis of pi-conjugated imidazole-containing polymers is described in Chapter 4. This process is designed based upon our previous studies on palladium catalyzed multicomponent synthesis of imidazoles, developed in Chapter 2. It is shown that bifunctional monomers such as di-imines, di-acid chlorides and di-N-tosylimines can be coupled together to assemble pi-conjugated imidazole-containing oligomers and polymers utilizing this same palladium catalyzed reaction. This approach was used to create a novel library of conjugated imidazole polymers. By modifying the substituents on the polymer structures, the UV-vis absorbance and fluorescence excitation/emission spectra of these compounds are varied over a range of 150 nm. / In Chapter 5, the palladium catalyzed multicomponent polymerization is discussed in more detail. This includes the analysis of the end groups on the polymer backbone, as well as mechanistic studies into how the polymerization is terminated. These results suggest that the sulfinate anion liberated upon N-tosylimine cycloaddition may be non-innocent in this polymerization, and its presence could lead to termination of the growing polymer chain.

Diabetic cardiomyopathy is defined as changes in the structure and function of the myocardium that occur in diabetic patients in the absence of other cardiovascular risk factors. Our laboratory has shown that conjugated linoleic acid (CLA - a naturally-occurring polyunsaturated fatty acid with multiple health benefits) prevents endothelin-1-induced myocyte hypertrophy in vitro, as well as cardiac hypertrophy in vivo using a rodent model of spontaneously hypertensive heart failure. These cardioprotective effects of CLA were mediated through activation of peroxisome proliferator activated receptors (PPAR isomers α and γ) and stimulation of diacylglycerol kinase ζ (DGKζ). Thus, the aims of this study were to (i) determine the effect of CLA on hyperglycemia-induced structural and functional abnormalities of cardiomyocytes, and (ii) assess the role of PPAR-γ and DGK. High glucose treatment induced hypertrophy of primary adult cardiomyocytes, as indicated by augmented cell size and protein synthesis compared to untreated cardiomyocytes. The hyperglycemia-induced hypertrophy was attenuated by pretreatment with CLA (30 µM). The ability of CLA to prevent hyperglycemia-induced hypertrophy was suppressed by GW9662 (1 µM) and R59022 (10 μM), pharmacological inhibitors of PPAR-γ and DGK, respectively. In addition to structural abnormalities, high glucose impaired contractile function of adult cardiomyocytes as measured by maximal velocity of shortening, maximal velocity of relengthening, and peak shortening. Hyperglycemia-induced contractile dysfunction was likewise prevented by pretreatment with CLA (30 µM). Collectively, these findings support the idea that hyperglycemia is an independent risk factor for the development of diabetic cardiomyopathy. Hypertrophy and contractile dysfunction elicited by high glucose were prevented by CLA. The antihypertrophic actions of CLA are mediated, at least in part, by activation of PPAR-γ and DGK.