Bithiophene and terthiophene derivatives possess interesting antibacterial¡A antifungal¡Aanticancer, and antiviral properties¡CIn order to explore its structure-activity relationships¡Aour laboratory synthesize a series of thiophene derivatives and compounds with en-yne group¡CSynthesis and preliminary anticancer activities will be discussed and described in the thesis¡C

I am interested in the design of DNA binding ligands which are including DNA minor groove binders and G-quadruplex stabilizing agents. Certain natural products, distamycin and belomycin are considered as models for designing new DNA binding agents. A variety of DNA binding ligands were synthesized and accordingly characterized by different bioassays. In the series of azo-pyrrole-polyamide, it showed slight DNA binding affinity but has the properties of DNA photo-cleavage and recognition of mixed sequence. The thiophene series showed strong binding ability for duplex DNA. Bithiophene series showed a remarkable binding affinity to duplex DNA which is compatible to natural products netropsin and distamycin. The pyridodicarboxamide series remain intramolecular hydrogen bonding with poor preferences for duplexes DNA even though they stabilized quadruplex DNA. The bithiophene-bipyrimidine compound binds to specific hexanucleotide sequence 5¡¦-AAGCTT-3¡¦ and acts as an unfused quadruplex stabilization ligand. In the quinoline series, the combination of quinoline and methylpyrrole polyamide proves the attenuation effect for quadruplexes stabilization which provides a novel strategy for development of quadruplex binding logands. In this study, several series of small molecules for DNA binding have been successfully synthesized and proved to interact with DNA secondary structures according to the particular properties of themselves.

Synthetic netropsin analogs of the thiophene and pyridine, induce the netropsin analogs binding DNA from A-T base pair change to G-C base pair. Moreover, dendritic electrostatic groups have bulky conformation, which induce the netropsin analogs binding DNA to major groove.

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Binuclear mixed biscarbene complexes of bithiophene were synthesized via the classical Fischer method of synthesis. The metal carbonyls, Mo(CO)6, Cr(CO)6, W(CO)6 and Mn(MeCp)(CO)3 were reacted with dilithiated bithiophene to afford complexes of the formula, [M(CO)5{C(OEt)C4H2S-C4H2SC(OEt})M'(CO)5] (in case of manganese, M(CO)5 is replaced with MMeCp(CO)2), where [M] and [M'] are the metal carbonyls in different combinations. Quenching was achieved with triethyl oxonium tetrafluoroborate. In all the reactions the products included monocarbene complexes, biscarbene complexes and the decomposition products. C-C coupling reactions produced unexpected biscarbene complexes of Cr, W, and Mo having extended bithiophene spacers. The complexes were of the formula, [M(CO)5{C(OEt)C4H2S-C4H2SC(R)-C(R)C4H2S-C4H2SC(OEt})M'(CO)5] (R = O, OH or OEt). These complexes were characterized with NMR, infrared spectroscopy and some with mass spectrometry. Furthermore, three biscarbene complexes of the metal combinations Mo(CO)6 and Cr(CO)6, W(CO)6 and Cr(CO)6, and Mn(MeCp)(CO)3 and Cr(CO)6 were all reacted with 3-hexyne. The result was the benzannulation or the Dötz products. / Chemistry / M. Sc. (Chemistry)

Binuclear mixed biscarbene complexes of bithiophene were synthesized via the classical Fischer method of synthesis. The metal carbonyls, Mo(CO)6, Cr(CO)6, W(CO)6 and Mn(MeCp)(CO)3 were reacted with dilithiated bithiophene to afford complexes of the formula, [M(CO)5{C(OEt)C4H2S-C4H2SC(OEt})M'(CO)5] (in case of manganese, M(CO)5 is replaced with MMeCp(CO)2), where [M] and [M'] are the metal carbonyls in different combinations. Quenching was achieved with triethyl oxonium tetrafluoroborate. In all the reactions the products included monocarbene complexes, biscarbene complexes and the decomposition products. C-C coupling reactions produced unexpected biscarbene complexes of Cr, W, and Mo having extended bithiophene spacers. The complexes were of the formula, [M(CO)5{C(OEt)C4H2S-C4H2SC(R)-C(R)C4H2S-C4H2SC(OEt})M'(CO)5] (R = O, OH or OEt). These complexes were characterized with NMR, infrared spectroscopy and some with mass spectrometry. Furthermore, three biscarbene complexes of the metal combinations Mo(CO)6 and Cr(CO)6, W(CO)6 and Cr(CO)6, and Mn(MeCp)(CO)3 and Cr(CO)6 were all reacted with 3-hexyne. The result was the benzannulation or the Dötz products. / Chemistry / M. Sc. (Chemistry)

Mon travail de thèse a consisté à poursuivre le développement et l’application des matrices bithiophéniques spécifique aux alcaloïdes. Après l’optimisation d’un protocole efficace d’analyse, adapté à l’objectif de l’étude, la mise au point d’une méthode de dosage des alcaloïdes par MALDI dans des extraits végétaux et sans prétraitement préalable a été étudiée. Cette méthode a pu être validée en étudiant des alcaloïdes existant dans différents extraits des plantes toxiques. Ensuite, la synthèse et l’évaluation de nouveaux composés bithiophéniques ont été présentés de manière à évaluer les facteurs favorisant l’interaction avec les alcaloïdes. Ultérieurement, cinq nouvelles matrices intéressantes furent l’objet d’une étude plus détaillée. Sur la base des résultats obtenus, le dérivé fluoré F T3 s’avère le plus efficace. ll présente une meilleure sélectivité que la matrice courante CHCA vis-à-vis des alcaloïdes et plus performant pour analyser les alcaloïdes dans différents mélanges complexes tels que des extraits bruts de plantes, des insectes, et des solutions bio-actives commerciales (médicament et répulsif). À la fin, ces sont regroupés les résultats de l’étude des paramètres thermodynamiques de la matrice MT3P, ce qui permettra de proposer des hypothèses expliquant la sélectivité de la matrice bithiophéniques fonctionnalisée pour les alcaloïdes. / My thesis work consisted of pursuing the development and application of bithiophenic maldi matrices specific for alkaloids. After optimization of an efficient analysis protocol adapted to the objective of the study, a method for the determination of alkaloids in vegetable extracts by MALDI was developed. This method was validated by studying many alkaloids existing in extracts of different toxic plants. Subsequently, synthesis and evaluation of novel bithiophenic compounds were presented in order to evaluate the factors favoring the interaction with alkaloids. Then, five matrices among the molecules tested and having produced interesting results are chosen and were the subject of a more detailed study. On the basis of the results obtained, the fluorinated derivative PFPT3P proves to be the most effective molecules. It has a better selectivity with respect to alkaloids than the current matrix HCCA and performs better to analyze these metabolites in different complex mixtures such as crude extracts of plants,insects and commercial bioactive solutions (drug and repellent). At the end, the results of the study of the thermodynamic parameters of MT3P matrix are grouped. This will make possible to propose hypotheses explaining the selectivity of the functionalized bithiophene matrices for alkaloids.

Luminescent boron containing materials find numerous applications in modern technologies such as display/lighting, bio-imaging and sensing. Thus, investigations of structure-property relationships in organic luminescent compounds to understand their molecular and bulk properties are of fundamental importance. The main thrust of this thesis is the development of facile synthetic routes for boron containing novel polyads and study their structure-property correlations and to utilize this information to design functional materials with desired properties such as multiple emission, bio imaging, anion sensing and organic photo voltaic characteristics. This thesis contains seven chapters and the contents of each chapter are described below. Chapter 1 This chapter is a concise overview of the recent developments in the chemistry of boron based molecular systems such as triarylborane and BODIPYs. This chapter also highlights the basic nature of broad emissive materials. In addition, an advance in the frontier areas such as bio imaging is discussed in brief. Chapter 2 This chapter describes the structure and optical properties of a new triad (Borane-Bithiophene-BODIPY) 1. Triad 1 exhibits unprecedented tricolour emission when excited at borane centred high energy absorption band and also acts as a selective fluorescent and colorimetric sensor for fluoride ion with ratiometric response. The experimental results are supported by computational studies. Chapter 3 Two fluorescent compounds with similar absorption profiles and complementarily emissive properties can be regarded as the ideal couple for the generation of white-light. Two structurally close and complementarily fluorescent boron based molecular siblings 2 and 3 were prepared. The luminescence properties of individual triads were modulated to an extent to complement each other by controlling the intramolecular energy transfer in triads by fine-tuning the dihedral angle between fluorophores in 2 and 3. A binary mixture of 2 and 3 emitted white-light. Chapter 4 This chapter deals with a straight forward strategy for the generation of white-light emission in aqueous media. Using a blue-emissive AIE-active (aggregation-induced emission) 1, 8-naphthalimide- based sensitizer and a boron-dipyrromethene based red emitter as a dopant, water dispersible nanostructures with tunable emission features are produced. The white-light emissive (WL) nano-aggregates are stable at neutral pH and have been elegantly utilized for four-colour cell imaging (including near- infrared imaging). Chapter 5 This chapter describes the design and development of a NIR emitting triarylborane decorated styryl-BODIPY (4) via a facile synthetic route. Incorporation of TAB entities results in a significantly red shifted broad emission in 4 (compared to compound M3 which is devoid of TAB unit). The near coplanar orientation of Ar3B planes and BODIPY core results in a highly efficient (TAB to BODIPY) EET process in 4. Conjugate 4 acts as a highly selective and sensitive fluoride sensor with naked eye visual response as well as ratiometric fluorescent response. The dual emission in fluoride bound 4 possibly results from the restricted partial TAB to BODIPY energy transfer. Chapter 6 This chapter describes how the energy of transitions of the broad emissive molecular triads can be fine-tuned by judiciously changing the spacer oligothiophene length. A series of triarylborane and BODIPY conjugates (TAB-π-BODIPY) has been designed, and synthesized by a combined strategy of changing the connection mode between the two units, extending the conjugation size by introducing terthiophene, quaterthiophene, and pentathiophene units. The electrochemical and photophysical behavior of these conjugates were investigated. The experimental findings were rationalized by density functional theory calculations. Chapter 7 This chapter describes design and development of boron based novel electron acceptor BDY for the bulk-heterojunction solar cell. The electron mobility values of BDY was found to be of the order of standard PCBM. Bulk-heterojunction was fabricated using BDY as the electron acceptor layer. The power conversion efficiency of the newly developed solar cells with BDY as electron acceptor is much higher than the value obtained for standard cells with PCBM as the electron acceptor.

Donor-acceptor conjugated polymers opened a new era for conjugated polymer research due to the abundant selection and combination of different conjugated units. This class of polymers function as semiconductor materials with potential application in plastic consumer electronics. The frontier molecular orbital energies of the polymers are generally determined by the selection of donor and acceptor units in the backbone structure, and their substituents. The side chains attached to the backbone not only affect the solubility of the materials, but also their self-assembly and morphological characteristics, which indirectly govern optoelectronic properties. It is important therefore to consider backbone architectures and the side chains together, to control (opto)-electronic properties for specific applications, while also maintaining solution processability without disrupting solid-state packing. The research presented in this dissertation focuses largely on the side chains: how the bulk and position of side chains affect the (opto)-electronic properties of select donor-acceptor (D-A) conjugated polymers. More precisely the intent is to vary the size and position of branches in the alkyl side chains of donor-acceptor polymers, in the attempt to solubilize poorly soluble polymers, without disrupting self-assembly of the polymer backbones into close p-stacks. After an introductory chapter 1, chapter 2 mainly focuses on the synthesis and structure-property study of polymers with 2,3,5,6-tetrafluorobenzene (TFB) as the acceptor motif and benzo[1,2-b:4,5-b′]dithiophene (BDT) as donor units carrying solubilizing substituents. TFB units were chosen based on previous observations that this acceptor unit imparts particularly poor solubility to various donor-acceptor copolymers. The current study indicates that bulky branches placed close to the polymer backbone could solubilize the PBDTTFB copolymers without altering the absorption profile and oxidation potentials. Optical, wide-angle x-ray diffraction (WAXD) and solubility studies shows that solubility is closely related to branching size and position. As the branch size in increased, the solubility of these polymers undergoes a step-change. The third chapter mainly focuses on the structure-property study of D-A polymers with thienopyrroledione (TPD) as acceptor. Unlike TFB, this acceptor can carry additional side chains that can compete with the space-filling demands of the donor unit side chains. As donor, the rigid BDT unit was compared with 3,3’-dialkoxy-2,2’bithiophene (RO2T2) units which have a similar size, but contain a “swiveling” central σ-bond. Bulkiness of side chains attached to the T2 units should be expected to have a more severe impact, possibly causing the two thiophene units of the T2 units to twist out of plane. It was demonstrated that alkoxy side chains with bulky branches in close proximity to the polymer backbones does not disrupt conjugation in these polymers. The UV-Vis absorption spectra of RO2T2-TPD polymers were red-shifted (more than 120 nm) in comparison to PBDTTPD polymers due to the smaller Eg (energy gap), which might be attributed to the expected higher energy HOMO imparted by the donor unit. The π-π stacking of polymers with BDT units was little affected by the bulky side chains. However, the π-π stacking of polymers with RO2T2 units was much more sensitive to side-chain bulk, with high degree of order and close π-π stacking only if proper local free spacing exists for side-chain interdigitation. Chapter 4 reports efforts to study polymers from the same set of RO2T2 monomers studied in Chapter 3, but without acceptor units that might otherwise drive self-assembly. RO2T2 homopolymers were synthesized via the Grignard metathesis (GRIM) method. Further, copolymers were prepared with RO2T2 units alternating with thiophene, thieno[3,2-b]thiophene or bithiophene. The spectroscopic studies suggest these polymers with bulky side chains exhibit some varying level of backbone conjugation. Somewhat surprisingly, despite an expected decrease in the strength of intermolecular donor-acceptor interactions, the solubilities were in some cases low, but varied with volume fraction of side chains. Further, even for polymers that appear to easily dissolve, aggregation in solution is so extensive as to give ensembles “too large” for characterization by GPC and or solution NMR. Oxidation potentials seem essentially insensitive to any of the structural variables (governed mostly by the backbone RO2T2 units).