Extensive research work was carried out in past few decades to synthesize new compounds with extended structures by employing various organic linkers and metals. A large number of potential applications of these coordination polymer materials were explored as it contains both inorganic metals as well as organic molecules. The large open pores of coordination polymer compounds were explored for applications such as absorption, separation, and catalysis etc. whereas the framework part provides a model system to study physical properties such as magnetism, luminescence, ferroelectricity etc. We were mainly interested in designing new magnetic materials with extended structures which is the primary objective of this thesis. To study this a systematic investigations are carried out with azide bridged copper(II) compounds. Azide is a versatile ligand which possesses a large number of bridging modes. On the other hand, the coordination flexibility offered by the copper centres makes it to possess diverse coordination number (4-6) as well as geometry. Copper-azide compounds were synthesized at room temperature and the structure was determined using single-crystal X-ray diffraction studies. Structure and magnetic behavior of the copper-azide compounds were studied and discussed here in this thesis. Further, we have studied selective absorption and separation of aliphatic nitrile compounds by employing a two-dimensional interdigitated coordination polymer. In addition, transformation studies of a Ni5 cluster to a Ni9 cluster have also been carried out. Chapter 1 of this thesis presents a brief overview of azide based compounds and summarizes important copper-azide compounds and their magnetic behavior. In chapter 2, synthesis, structure, and magnetic behavior of two-dimensional copper-azide based compounds have been presented. Field dependent magnetic studies were also carried out for all the compounds. Chapter 3 presents the synthesis, structure, and magnetic behavior of copper-azide compounds where 1,2-diaminopropane was employed as a site blocking agent. In chapter 4, the synthesis, structure, and magnetic behavior of two isostructural three-dimensional copper-azides are presented. In chapter 5, synthesis, structure, and magnetic behavior of the azide based one and two-dimensional compounds are presented. Chapter 6 presents synthesis and structure of a two-dimensional inter-digitated coordination polymer compounds. The selective absorption and separation of aliphatic nitriles were also presented in this chapter. In chapter 7, synthesis, structure, and magnetic behavior of Ni clusters are presented. A transformation study to convert a Ni5 cluster to Ni9 cluster was also carried out and presented in this chapter.

The primary goal of this research concerns the synthesis and characterization of metal-organic frameworks (MOFs) grafted with pendant alkyl substituents to enhance stability and gas sorption properties for use in clean-energy related technologies. Initially, the focus of this work was on the synthesis and comparison of two isostructural MOFs built upon octahedral secondary building blocks; one with no alkyl substituents, and its dimethyl-substituted counterpart. The dimethyl-substituents are observed to enhance the stability of the framework, resulting in high Langmuir surface area (4859 m2 g-1) and hydrogen uptake capacity at 77 K and 1 bar (2.6 wt%). In the second section, the length of pendant alkoxy substituents in semi-flexible MOFs was evaluated through the synthesis and characterization of two isostructural MOFs, one with dimethoxy (PCN-38) and one with diethoxy pendant groups (PCN-39). While PCN-38 exhibited moderate surface area and hydrogen uptake capacities, PCN-39 underwent structural change upon activation leading to a redistribution of pore sizes and selective adsorption of hydrogen over larger gases. This structural transformation is believed to originate from optimal space filling of the pendant groups. In the third section, a series of NbO-type MOFs were synthesized with dimethoxy, diethoxy, dipropoxy, and dihexyloxy substituents and the relationship between chain length and framework stability identified. Increasing chain length was observed to increase moisture stability of the MOFs, resulting in a superhydrophobic material in the case of the dihexyloxy derivative. Thermal stability, however, decreased with increasing chain length, as evidenced from in situ synchrotron powder X-ray diffraction measurements (PXRD). This is in contrast to data obtained from thermogravimetric analysis and shows that the standard use of thermogravimetric analysis, which measures combustion temperatures, may not always provide an accurate description of the thermal stability of MOFs. The role of pendant groups in gas adsorption processes was evaluated through identification of side chains and guest species in the pores of MOFs through in situ synchrotron PXRD measurements. In summary, three separate isostructural series of MOFs with various pendant groups have been discussed in this dissertation, with the roles of those pendant groups toward crystal structure, stability, and gas sorption properties analyzed.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents a study related to the synthesis and structural analysis of coordination polymers and molecular compounds derived from Hg(TeAr)2. Was used as starting reagents some Hg(TeAr)2, considered basic building blocks for synthesis inorganic, and dithioligands of the type carbamate and phosphate, since they are extremely versatile in complexation to transition elements. The compounds obtained were: [Hg(TePh)(S2CNEt2)]n (1), [Hg(TePh){S2P(OEt)2}]n (2), [Hg(TePh)(S2CNC4H8)]n (3), [Hg2(Tedmb)2(S2CNC4H8)2]n (4), [Hg(dmb)(S2CNC4H8)] (5), [Hg(Temes)(S2CNC4H8)]n (6) e [Hg(mes)(S2CNC4H8)] (7), being can perform a structural study all these compounds, using as the main tool method the X-ray diffraction in sigle crystal, in addition to infrared spectroscopy and elementar analysis. Based on the structural analysis of these compounds can be concluded that the organization of crystal packing and the formation of supramolecular structures depends largely on the choice of appropriate ligands, being can thus control over the coupling between the minimum units generated, making possible to obtain systems really polymeric or molecular. / Este trabalho apresenta o estudo relacionado à síntese e a caracterização estrutural de novos polímeros de coordenação e compostos moleculares derivados de Hg(TeAr)2. Utilizou-se como reagentes de partida alguns Hg(TeAr)2, considerados blocos de montagem básicos para síntese inorgânica, e ditioligantes do tipo carbamato e fosfato, uma vez que estes são de extrema versatilidade na complexação a elementos de transição. Os compostos obtidos foram: [Hg(TePh)(S2CNEt2)]n (1), [Hg(TePh){S2P(OEt)2}]n (2), [Hg(TePh)(S2CNC4H8)]n (3), [Hg2(Tedmb)2(S2CNC4H8)2]n (4), [Hg(dmb)(S2CNC4H8)] (5), [Hg(Temes)(S2CNC4H8)]n (6) e [Hg(mes)(S2CNC4H8)] (7), sendo possível efetuar um estudo estrutural de todos esses compostos, utilizando como ferramenta principal o método de difração de raios X em monocristal, além da espectroscopia de infravermelho e análise elementar. A partir da análise estrutural desses compostos pode-se concluir que a organização do empacotamento cristalino e a formação de estruturas supramoleculares depende imensamente da escolha de ligantes adequados, sendo possível desta forma um controle sobre o acoplamento entre as unidades mínimas geradas, possibilitando a obtenção de sistemas realmente poliméricos ou moleculares.

La thèse commence le 1er octobre 2012. IL s'agit pour cette première année de thèse de synthétiser différents complexes de coordination a base du Ruthénium, Fer, Manganèse et de Cobalt à ligands polypyridinique. Ces complexes seront ensuite assemblés par lien covalent. Nous proposons d'utiliser entre autre les techniques d'electrochimie pour induire ces couplages. On cherchera aussi a immobiliser les assemblages sur surface. La principale difficulté attendue dans cette etape du travail concerne la fonctionalisation dissymétrique des ligands pour l'obtention de triade. / This thesis deals with the synthesis and characterization of inorganic triads for photoinduced charge separation. A range of photosensitizers will be studied, and the effect of the donor and acceptor will be assesed as well. These systems will be studied in solution and immobalized on surfaces. Cette thèse traite de la synthèse et la caractérisation des triades inorganiques pour la séparation de charge photoinduite. Une gamme de photosensibilisateurs seront étudiées, et l'effet du donneur et accepteur sera ainsi étudié. Ces systèmes seront étudiés en solution et immobalizes sur les surfaces.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-05-22T15:47:02Z No. of bitstreams: 1 felipemagestescaldini.pdf: 2661212 bytes, checksum: 68339e788685f873502440bba4b26794 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-22T17:40:25Z (GMT) No. of bitstreams: 1 felipemagestescaldini.pdf: 2661212 bytes, checksum: 68339e788685f873502440bba4b26794 (MD5) / Made available in DSpace on 2017-05-22T17:40:25Z (GMT). No. of bitstreams: 1 felipemagestescaldini.pdf: 2661212 bytes, checksum: 68339e788685f873502440bba4b26794 (MD5) Previous issue date: 2013-02-25 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho descreve a síntese e caracterização de oito compostos de coordenação, [Zn(PYA)2(H2O)2]n (1), [Mn(PYA)2(H2O)2]n (2), {[Co(2,5PDC)(H2O)2] .H2O}n (3), [Mn(2,5HPDC)2(H2O)2] (4), [Ni(2,3HPDC)2(H2O)2] (5), {[Cu(3,4HPDC)2(H2O)2] .DMSO}n (6), {[Co(3,4HPDC)2(H2O)2](H2O)(DMSO)}n (7) e {[Cu2(3,4HPDC)2(H2O)5]}n (8) contendo ligantes da família dos ácidos piridinodicarboxílicos, que são N-, O- doadores e podem proporcionar modos de coordenação interessantes frente aos íons metálicos da 1º série de transição selecionados para o trabalho (Mn2+, Co2+, Ni2+, Cu2+ e Zn2+). Os ligantes utilizados foram os ácidos 2,3 piridinodicarboxílico (2,3H2PDC), 2,5 piridinodicarboxílico (2,5H2PDC), 3,4 piridinodicarboxílico (3,4H2PDC), trans-3-(piridil)-acrílico (HPYA) e 3-(2-tienil)acrílico (HTA). Dos oito compostos descritos neste trabalho, apenas três são inéditos. Os compostos inéditos, (6), (7) e (8) foram caracterizados por análise elementar, análise térmica (TG e DTA), espectroscopia vibracional na região do infravermelho, e difração de raios X por monocristal. Nesses três compostos, em acordo com os dados espectroscópicos, a difração de raios X por monocristal mostrou que os ligantes se apresentam na forma parcialmente desprotonada e além disso, observou-se a formação de redes poliméricas. Em todos os casos, os arranjos supramoleculares são formados por ligações de hidrogênio. Todos os compostos apresentam o metal central em geometria octaédrica, com excessão do composto (8) que mostra dois centros de Cu(II), sendo um em geometria octaédrica e outro como pirâmide de base quadrada. Foi feita também a descrição topológica das redes poliméricas formadas, com auxilio do programa TOPOS. Dentre os compostos apresentados neste trabalho, apenas os compostos (4) e (5) não formam cadeias ou redes poliméricas. O teste de capacidade de adsorção de gás para o composto polimérico (6) foi feito através das isotermas de N2, utilizando o método BET. / This work describes the synthesis and characterization of eight coordination compounds, [Zn(PYA)2(H2O)2]n (1), [Mn(PYA)2(H2O)2]n (2), {[Co(2,5PDC)(H2O)2] .H2O}n (3), [Mn(2,5HPDC)2(H2O)2] (4), [Ni(2,3HPDC)2(H2O)2] (5), {[Cu(3,4HPDC)2(H2O)2] .DMSO}n (6), {[Co(3,4HPDC)2(H2O)2](H2O)(DMSO)}n (7) and {[Cu2(3,4HPDC)2(H2O)5]}n (8) containing N-,O-donor ligands from pyridinedicarboxylic acids family that can provide interesting coordination modes toward the first row transition metal ions (Mn2+, Co2+, Ni2+, Cu2+ e Zn2+). 2,3 pyridinedicarboxylic (2,3H2PDC), 2,5 pyridinedicarboxylic (2,5H2PDC), 3,4 pyridinedicarboxylic (3,4H2PDC), trans-3-(pyridyl)-acrylic (HPYA) and 3-(2-thienyl)acrylic acid (HTA) were used as ligands. Among the eight compounds described in this work, only three are unpublished. The novel compounds, (6), (7) and (8) were characterized by elemental analysis, thermal analysis (TG and DTA), infrared vibrational spectroscopy, and single crystal X-ray diffraction analysis. In these three compounds, in accordance with the spectroscopic data, single crystal X-ray diffraction analysis showed that the ligands are present in partially deprotonated form and furthermore, the formation of polymeric networks was observed. In all cases, supramolecular arrangements are formed by hydrogen bonds. All compounds show the metal center in octahedral geometry, except compound (8) that has two Cu (II) centers; one in octahedral geometry and other in a square pyramidal geometry. A topological description was also made for the polymeric networks formed, supported by the software TOPOS. Among all compounds presented in this work, only compounds (4) and (5) do not form polymeric chains or networks. The gas adsorption capacity test was realized for the polymeric compound (6), through N2 isothermal, using BET method.

Ces travaux portent sur la conception et l’étude des propriétés photophysiques de polymères de coordination et organométalliques. Dans un premier temps, nous nous sommes intéressés aux adduits formés à partir d’halogénure de cuivre(I) (CuxXyLz ; X= I, Br, Cl). Cette famille de composés possède une grande richesse structurelle de part les conditions de synthèse (choix du ligand, stoechiométrie, choix du solvant, température…) et des propriétés de luminescence variées. Nous nous sommes concentrés sur la synthèse, la caractérisation physique et photophysique d’adduits de CuX à ligands de types monothioéther (RSR) et dithioéther (RS(CH2)nSR). Nous avons ensuite étendu notre étude aux adduits CuX coordinés à des ligands P-chirogéniques (i.e chiralité portée par l’atome de phosphore) puis à des adduits CuX coordinés à la fois par des ligands phosphorés (PPh3 ou dppm) et par des ligands mono- ou dithioéthers. Dans un second temps, nous avons voulu connaître l’impact de l’incorporation de ligands P-chirogéniques (P(C17H35)(Ph)(i-Pr)) sur les propriétés photophysiques de polymères organométalliques conjugués 1D à base de platine(II) et de ligands arylbiséthynyles (-C≡C(Ar)C≡C-). Ce type de polymère basé sur le platine(II) est souvent utilisé comme modèle dans la compréhension des transferts d’énergie dans les états excités. Ces polymères, une fois caractérisés, ont été comparés aux analogues achiraux contenant le fragment trans-Pt(P(PBu)3)2 et plusieurs différences ont été notées. Les observations et conclusions sur la relation structure-propriété sont utiles pour la conception future de matériaux photoniques portant des groupements chiraux. / This work focuses on the design and study of photophysical properties of coordination and organometallics polymers. Initially, we focused on adducts formed from copper(I) halides (CuxXyLz; X = I, Br, Cl). Indeed, these compounds have great structural diversity depending on the synthesis conditions (nature of ligand, stoichiometry, choice of solvent, temperature...) and various luminescence properties. We focused on the synthesis, physical and photophysical characterization of copper(I) halide adducts based on monothioether (RSR) and dithioether (RS(CH2)nSR) ligands. Then, we extended our study to the adducts of copper(I) halide coordinated by phosphorus P-chirogenics ligands (ie chirality carried by the phosphorus atom) and then to CuX adducts coordinated by both phosphorus ligands (PPh3 or dppm)) and mono- or dithioether ligands. Secondly, the impact of the incorporation of P-chirogenics ligands (P(C17H35)(Ph)(i-Pr)) on the photophysical properties of organometallic conjugated polymers 1D based on platinum(II) and arylbisethynyles ligands (-C≡C(Ar)C≡C-) was investigated. This type of polymer based on platinum(II) is often used as a model for the understanding of excited states energy transfers. These polymers, once characterized, were compared to the achiral analogues containing the fragment of trans-Pt(P(PBu)3)2 and several differences were noted. The findings and conclusions on the structure-property relationship are useful in the future design of photonic materials bearing chiral groups.

Nous avons mis en place un dispositif de microscopie par génération de somme de fréquences optiques pour étudier les milieux isotropes chiraux. Ce dispositif a tout d'abord été validé en utilisant la molécule chirale de bi-2-naphtol en solution liquide et en milieu sol-gel. Nous avons établi les conditions expérimentales permettant de limiter les phénomènes de blanchiment par absorption biphotonique du chromophore. Nous avons ensuite entrepris une étude des polymères de coordination chiraux élaborés à partir de l'auto-assemblage de ligands organiques chiraux et d'ions métalliques en solution. Nous avons mesuré un signal SFG chiral apparaissant lors du séchage de films de polymères et de complexes de coordination chiraux. Nous démontrons ainsi que la technique de microscopie SFG spécifique des milieux isotropes chiraux permet de détecter le processus de coordination des polymères de coordination chiraux en phase condensée et de suivre l'établissement de la phase solide. / We have built a set-up to perform sum frequency generation (SFG) microscopy in order to study isotropic chiral media. This set-up was first validated with molecules of bi-2-naphthol in liquid solution and sol-gel matrices. We have established the experimental conditions to limit the bleaching phenomena of the chromophore by two-photon absorption. Next, we have conducted a study of chiral coordination polymers produced through the self-assembly of chiral organic ligands and metal ions in solutions. We have measured a chiral SFG signal developing while films of chiral coordination polymers and complexes are drying. Thus we show that SFG microscopy specific to isotropic chiral media makes it possible to detect the coordination process of chiral coordination polymers in the condensed phase and monitor the establishment of the solid phase.

Metal-organic frameworks (MOFs) have been intensely researched over the past 20 years. In this dissertation, metal-inorganic frameworks (MIFs), a new class of porous and nonporous materials using inorganic complexes as linkers, in lieu of traditional organic linkers in MOFs is reported. Besides novel MIF regimes, the previously described fluorous MOF "FMOF-1", is re-categorized herein as "F-MIF1". F-MIF-1 is comprised of [Ag4Tz6]2- (Tz = 3,5-bis-trifluoromethyl-1,2,4-triazolate) inorganic clusters connected by 3-coordinate Ag+ metal centers. Chapter 2 describes isosteric heat of adsorption studies of F-MIF1 for CO2 at near ambient temperatures, suggesting promise for carbon capture and storage. We then successfully exchanged some of these Ag(I) centers with Au(I) to form an isostructural Au/F-MIF1. Other, nonporous MIFs have been synthesized using Ag2Tz2 clusters with bridging diamine linkers 4,4'-bipyridine, pyrazine, and a Pt(II) complex containing two oppositely-situated non-coordinating pyridines. This strategy attained luminescent products better-positioned for photonic devices than porous materials due to greater exciton density. Chapter 3 overviews work using an entirely inorganic luminescent complex, [Pt2(P2O5)4]4- (a.k.a. "PtPOP") to form new carbon-free MIFs. PtPOP is highly luminescent in solution, but as a solid shows poor quantum yield (QY ~0.02) and poor stability under ambient conditions. By complexing PtPOP to various metals, we have shown a dramatic enhancement in its solid-state luminescence (by an order of magnitude) and stability (from day to year scale). One embodiment (MIF-1) demonstrates microporous character. Chapter 4 overviews the design and application of new MIF linkers. Pt complexes based upon (pyridyl)azolates, functionalized with carboxylic acid groups, have been synthesized. These complexes, and their esterized precursors, show strong luminescence on their own. They have been used to generate new luminescent MIFs. Such new MIFs may be useful toward future inorganic (LEDs) or organic (OLEDs) light-emitting diodes, respectively. The electronic communication along their infinite coordination structures is desirable for color tuning and enhanced conductivity functions, compared to the small molecules used in such technologies, which rely on intermolecular interactions for these functions.

The present thesis provides a systematic investigation of coordination polymers of 3d, rare-earth (4f) and main group element (Bi) using both rigid aromatic, flexible aliphatic linkers. Luminescent sensing behavior towards nitro aromatics, metal ions and ferroelectric behavior have been investigated using some of the prepared compounds. The possible usefulness of lone pair on the structure has been investigated using bismuth based coordination polymers. The thermal and optical behavior of lanthanide coordination polymers (Ce, Pr and Nd) have also been studied. Chapter 1 An Overview of Coordination Polymer (CP) Compounds This chapter presents a brief introduction to coordination polymer (CP) compounds. Starting from the brief historical background on coordination compounds, this chapter shed light on some earlier developments in this family of compounds by Yaghi, Robson and others. The usefulness of carboxylate and imidazolates in construction of some important coordination polymer compounds like MOF-5, HKUST-1, ZIFs, MIL-53, UiO-66, CD-MOF-1 etc has been described in detail along with its properties. The coordination polymers exhibit many important properties and some of the properties like sorption, separation, ionic conductivity, catalysis and ferroelectricity have been discussed briefly and summerized. Chapter 1 also provides the general synthetic and characterization approaches that have been employed during the present studies. Chapter 2 Part A: Adenine Based Coordination Polymers with Cyclohexane dicarboxylic acids This chapter presents the synthesis, structure and properties of four new coordination polymers [Zn4(C8H10O4)2.5(C5H4N5)3.2H2O].7H2O.2DMA (I), [Cd3(C8H10O4)2(C5H4N5)2.H2O] (II), [Cd(C8H11O4)2(C5H5N5)2.2H2O] (III), [Cd(C8H10O4)(C7H8N5O).H2O]. 4H2O (IV), (CHDA = cyclohexane dicarboxylic acid, ad = adenine, DMA = dimethylacetamide, 9-HEA = 9-hydroxyethyl adenine). The compound I and II forms three-dimensional structure having distinct arrangements of 1,4-CHDA and adenine units with Zn and Cd metals respectively. The molecular complex unit is observed in compound III with 1,2-CHDA and adenine. Compound IV forms two-dimensional structure with 9-HEA and 1,2-CHDA. The observation of base-pairing interactions in the above compounds is noteworthy. In compounds I, II and IV amino groups are appears to be free and utilized for the detection of nitro aromatic explosives through fluorescence quenching. The results revealed that the emission behavior of the present compounds is greatly influenced by the hydroxyl nitroaromatic analyses like indophenol, dinitrophenyl and trinitrophenols with very low detection limits. The compound I also exhibits considerable sensitivity towards metal ion detection, especially Fe2+/Fe3+, Cr3+, Ag+ and Hg2+ ions in solution. The presence of free nitrogen sites in compound II has been explored for the base catalyzed Knoevenagel condensation reaction, the quantitative yields are observed with various aldehyde substrates. Part B: Adenine Based Coordination Polymer with Oxydiacetic acid: [Cd2(C4H4O5)2(C5H5N5)].H2O.DMA The synthesis, structure and properties of a Cd based coordination polymer with oxydiacetic acid and adenine, [Cd2(C4H4O5)2(C5H5N5)].H2O. DMA is described. The compound has a two-dimensional structure formed by the connectivity involving Cd and oxydiacetic acid. The adenine ligand binds with the Cd metal center through the pyrimidine nitrogen and hangs in the inter layer spaces. The layers are stacked in a ABAB.... fashion and the inter layer spaces occupied by the dimethyl amine and water molecules. The water molecules are very labile and its removal can be accomplished by heating the sample at 100°C, which is also confirmed by the single crystal XRD, PXRD and IR studies. The availability of free amino groups of adenine molecule has been utilized for the detection of nitroaromatics, especially nitrophenols with good sensitivity. The amino group was also found to be useful in catalyzing Knoevenagel condensation reactions. Chapter 3: Rare-Earth Metal Carboxylates: Ln2(µ3-OH)(C4H4O5)2(C4H2O4)].2H2O [Ln=Ce, Pr and Nd] This chapter describes synthesis, structure and properties of series of rare-earth based compounds, [Ln2(µ3-OH)(C4H4O5)2(C4H2O4)].2H2O (Ln = Ce, Pr and Nd). The malic acid and fumaric acid form part of the structure. The lanthanide centers are connected by the malate units to form a two dimensional layers, which are pillared by fumarate units forming the three-dimensional structure. Overall, structure can be described as I2O1 type inorganic in two-dimension (Ln-O-Ln layers) and organic in one dimension. The extra framework water molecules form a dimer and occupy the channels. The robustness of the framework was reflected in terms of facile removal and reinsertion of the water molecules, which is also confirmed by single crystal XRD, variable temperature IR and cyclic TGA study. The presence of water dimers and weakly interacting water chain suggested the possibility of proton migration in these compounds. Proton conductivity studies reveal the conductivity values of ~2.85 x 10-6 Ω-1cm-1 at 98% relative humidity. The optical studies revealed an up-conversion behavior involving more than one photon for the neodymium compound. Chapter 4: Bismuth Carboxylates with Brucite and Fluorite Related Structures The synthesis, structure and properties of three new bismuth based coordination polymers have been described in this chapter. The compounds [C4N2H10][Bi(C7H4NO4)(C7H3NO4)].H2O (I), [Bi(C5H3N2O4) (C5H2N2O4)] (II) and [Bi(µ2-OH)(C7H3NO4)] (III) were isolated employing hydrothermal condition with three different heterocyclicdicarboxylic acids, 3,6-pyridinedicarboxylic acid, 4,5-imidazoledicarboxylic acid and 3,4-pyridinedicarboxylic acid respectively. The structures of all the compounds have linkages between Bi2O2 and the corresponding dicarboxylate forming a simple molecular unit in I, a bilayer arrangement in II and a three-dimensional extended structure in III. The topological arrangement of the nodal building units in the structures resembles brucite related layers in II and fluorite related arrangement in compound III. By utilizing the secondary interactions, the structure of III can be correlated to a Kagome related net. The observation of such classical inorganic related structures in the bismuth carboxylates is noteworthy. Heterogeneous catalytic studies indicate Lewis acidic nature in the bismuth center in all three compounds. Chapter 5: Solvent dependent Delamination, Restacking and Ferroelectric studies in a Two-Dimensional Compound [NH4][Ag3(C9H5NO4S)2(C13H14N2)2].8H2O This chapter describes synthesis, structure, water dependent delamination/restacking and ferroelectric behavior in a layered coordination polymer compound, [NH4][Ag3(C9H5NO4S)2(C13H14N2)2].8H2O. The compound has a two-dimensional structure with the water molecules occupying the inter-lamellar spaces. The lattice water molecules can be fully removed and reinserted, which accompany the crystalline-amorphous-crystalline transformation. This transformation resembles the collapse/delamination and re-stacking of the layers. This transformation has also been investigated by in-situ IR and PXRD studies. The presence of a natural dipole (anionic framework and cationic ammonium ions) along with the non-centrosymmetric space group gives rise to a room-temperature ferroelectric behavior to the compound with saturation polarization (Ps) of 1.95 μC/cm2 and remnant polarization of 0.63 μC/cm2. The temperature dependent dielectric measurements indicate that the ferroelectric-paraelectric transformation occurs at 320 K. The ferroelectric-paraelectric transformation also follows the crystalline-amorphous-crystalline transitions.

Small molecule Zn(II) complexes containing N- and S- donor environments may serve as appropriate models for mimicking Zn protein sites, and thus, their reactions with heavy metal ions such as Pt(II) and W(0) may provide insight into possible adduct formation and zinc displacement. To study such possible interactions between zinc finger proteins and platinum-bound DNA, the ZnN2S2 dimeric complex, N,N?-bis(2- mercaptoethyl)-1,4-diazacycloheptane zinc (II), [Zn-1?]2, has been examined for Znbound thiolate reactivity in the presence of Pt(II) nitrogen ? rich compounds. The reactions yielded Zn/Pt di- and tri- nuclear thiolate-bridged adducts and metalexchanged products, which were initially observed via ESI-mass spectrometry (ESI-MS) analysis of reaction solutions, and ultimately verified by comparison to the ESI-MS analysis, 195Pt NMR spectroscopy, and X-ray crystallography of directly synthesized complexes. The isolation of Zn-(?-SR)-Pt-bridged [(Zn(bme-dach)Cl)(Pt(dien))]Cl adduct from these studies is, to our knowledge, the first Zn-Pt bimetallic thiolatebridged model demonstrating the interaction between Zn-bound thiolates and Pt(II). Additional derivatives involving Pd(II) and Au(III) have been explored to parallel the experiments executed with Pt(II). The [Zn-1?]2 was then modified by cleavage with Na+[ICH2CO2]- to produce (N- (3-Thiabutyl)-N?-(3-thiapentaneoate)-1,4-diazacycloheptane) zinc(II), Zn-1?-Ac or ZnN2SS?O, and 1,4-diazacycloheptane-1,4-diylbis(3-thiapentanoato) zinc(II), Zn-1?-Ac2 or ZnN2S?2O2, monomeric complexes (where S = thiolate, S? = thioether). The [Zn-1?]2 di- and Zn-1?-Ac mono-thiolato complexes demonstrated reactivity towards labile-ligand tungsten carbonyl species, (THF)W(CO)5 and (pip)2W(CO)4, to yield, respectively, the [(Zn-1?-Cl)W(CO)4]- complex and the [(Zn-1?-Ac)W(CO)5]x coordination polymer. With the aid of CO ligands for IR spectral monitoring, the products were isolated and characterized spectroscopically, as well as by X-ray diffraction and elemental analysis. To examine the potential for zinc complexes (or zinc-templated ligands) to possibly serve as a toxic metal remediation agents, Zn-1?-Ac and Zn-1?-Ac2 were reacted with Ni(BF4)2. The formation of Zn/Ni exchanged products confirmed the capability of ?free? Ni(II) to displace Zn(II) within the N-, S-, and O- chelate environment. The Zn/Ni exchanged complexes were analyzed by ESI-MS, UV-visible spectroscopy, IR spectroscopy of the acetate regions, and X-ray crystallography. They serve as foundation molecules for more noxious metal exchange / zinc displacement products.