Induced chirality of phenylene-based conjugated polymers complexed with polysaccharides
Prakash Manandhar, Tereza Vokata, and Joong Ho Moon
Department of Chemistry & Biochemistry, Biomolecular Sciences Institute, Florida International University, 11200 SW 8th St., Miami, Florida 33199, United States
Understanding the structure-function relationship of conjugated polymers (CPs) interacting with various biologically active materials is pivotal for designing functional materials for biological sensing, labeling, and delivery. The physical and biophysical properties of functional materials are closely related to the functional groups of CPs and natures of self-assembly in an aqueous environment. In this presentation, we report substantial self-assembly differences of a set of four CPs containing the same positively charged side chains, which only different in the backbone chemical structure and connectivity, upon complexation with linear polyanion, glycosaminoglycan (GAG). Electronic spectroscopic data including induced circular dichroism (ICD) reveal that CP/GAG form unique helixes depending on the nature of backbone and the type of GAG. The structure-property relationships can be useful for fabrication of highly ordered macromolecular materials for broad electronic or biological applications.
EXAMINING THE GAS ADSORPTION PROPERTIES IN MOLECULAR POROUS MATERIALS BASED UPON COPPER–ADENINE PADDLEWHEEL COMPLEXES
Tony Pham,1 Katherine A. Forrest,1 Patrick S. Nugent,1 Michael J. Zaworotko,2 and Brian Space1
1.) Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE205, Tampa, FL 33620-5250, United States
2.) Department of Chemical & Environmental Sciences, University of Limerick, Limerick, Republic of Ireland
Experimental and theoretical gas adsorption studies were performed in MPM-1-Cl and MPM-1-TIFSIX, two robust molecular porous materials (MPMs) with the empirical formula [Cu2(adenine)4Cl2]Cl2 and [Cu2(adenine)4(TiF6)2], respectively. Both MPMs consist of a hydrogen-bonding network that is self-assembled by dinuclear copper–adenine paddlewheel complexes. The difference between the two structures is simply the axial ligand. Experimental measurements revealed that MPM-1-TIFSIX displays higher CO2 uptake, isosteric heat of adsorption (Qst), and selectivity than MPM-1-Cl. These findings have been verified through molecular simulations. The zero-loading Qst for CO2 in MPM-1-TIFSIX is actually comparable to that for the top-performing metal–organic frameworks (MOFs). MPM-1-TIFSIX was also shown to exhibit high H2 uptake and Qst for H2 through experimental studies, which were subsequently supported by simulation. Modeling studies have also yielded insights into the adsorption sites in both MPMs.
Growth of Fluorescent Noble Metal Nanoclusters Protected with Dithiolate Ligands
Dinesh Mishra, Fadi Aldeek, Goutam Palui, and Hedi Mattoussi
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA.
We describe the use of Lipoic Acid modified with poly(ethyleneglycol) and zwitterion group in the aqueous growth of fluorescent gold and silver nanoclusters. The conventional growth method, i.e., borohydride reduction of metal precursors in the presence of thiol ligand produces red/NIR emitting clusters with PL efficiency up to 14%. These clusters exhibit long term stability in buffer and other biologically relevant conditions. To attain tunable emission, we rely on the photochemical reducing property of thiolates. Lipoic acid has a strained ring with a disulfide bond, which is cleaved by UV radiation to generate thiols and other byproducts. When this mixture of photochemically generated compounds and gold(III) compounds is refluxed in basic condition, luminescent gold clusters are formed. By varying the cluster growth conditions, we could tune the optical emission of gold clusters from blue to red. Growth of bimetallic nanoclusters made of gold and silver is also presented. We followed two different approaches: a) growth by co-reduction of the mixture of gold and silver precursors and (b) reaction of silver(I)-thiolate complexes with pre-synthesized Au11clusters, which results in the formation of luminescent Au/Ag nanoclusters with unique optical properties. The characterization of these materials using various techniques is also described.
SYNTHESIS, STRUCTURE, AND PROPERTIES OF BISMUTH CONTAINING MIXED METAL OXIDES
Michael Lufaso1, Daniel Chica1, Jessica Wilson1, Eric Hearn1, Jeffrey Auletta1
1 Department of Chemistry, University of North Florida, Jacksonville, FL 32224, USA
Solid-state chemistry is aligned with emerging and potential technologies, which require materials with improved properties to meet the desired and stringent requirements for many applications. Advances in the physical sciences benefit from synthesis of new materials and their characterization, and also an understanding of the extent of chemical substitutions to alter their physical properties. Exploratory and targeted methods each have unique advantages in the synthesis of new materials. These methods were used to prepare well-characterized bismuth containing mixed-metal oxides, which exhibit structural variety and diverse physical properties. The phase compositions and crystal structures were determined using diffraction techniques. The influence of synthesis temperature and limits of chemical substitution on the crystal structure and unit cell volume were explored. To pursue structure-property relationships, variable temperature electrical and dielectric property measurements were performed and indicate tunable activation energies of conduction, tunable dielectric properties, and promising responses for gas sensing.
Oxidation of Glycerol With Electroless CuNiMoP/Al2O3 Catalyst by Statistically Designed Experiments
Joel Sankar, Dr. Egwu Eric E Kalu and Dr. Edith Onyeozili
Florida A&M University
Task-Specific Design and Functionalization of Advanced Porous Organic Polymers
University of South Florida
Porous organic polymers (POPs) represent an emerging class of nanoporous materials, and they feature robust covalent framework structures with high water and chemical stability. This, together with their high surface areas and tunable pore sizes, makes them hold promise for a variety of applications. We will demonstrate how POPs can be task-specific designed and functionalized via either de novel synthesis or stepwise post-synthetic modification for applications in environmental remediation such as oil spill cleanup, heavy metal removal, ion exchange, nuclear waste treatment.