Volume 85, Issue 3

The 14th International Conference on Polymers and Organic Chemistry (POC 2012) was held 6-9 January 2012 in Doha, capital of the State of Qatar. This conference followed the 13th edition of this series, which was held in Montreal, Canada in 2009, and is a biannual meeting that travels from one continent to another since its inception in 1982 in Lyon, France to discuss recent results in the fields of polymer and organic chemistry in order to promote their importance in our everyday lives. This was the first IUPAC-sponsored meeting ever in the State of Qatar and the first time this meeting (POC) took place in the Arab world since it was established. POC 2012 was a very successful event, attended by approximately 300 chemists from over 15 countries. The conference featured Dr. Robert H. Grubbs, Victor and Elizabeth Atkins Professor of Chemistry at the California Institute of Technology and 2005 Nobel Laureate in Chemistry, as keynote speaker. His lecture was titled “The synthesis of large and small molecules using olefin metathesis catalysts”. The conference consisted of eight oral sessions, which focused on: - Polyolefins (Chair: Dr. Abbas Razavi, Total Petrochemicals Research Feluy) - Responsive and smart polymers (Chair: Dr. David E. Bergbreiter, Texas A&M University) - Polymers in energy (Chair: Dr. Hiroyuki Nishide, Waseda University) - Polymers as therapeutics (Chair: Dr. Karen L. Wooley, Texas A&M University) - Advances in polymer synthesis (Chair: Prof. Brigitte Voit, Leibniz-Institut für Polymerforschung Dresden) - Orthogonal chemistry: organic and polymer synthesis (Chair: Dr. Craig Hawker, University of California Santa Barbara) - Macromolecular engineering with biomolecules (Chair: Dr. Hanadi F. Sleiman, McGill University) - Polymers from renewable resources (Chair: Dr. Joe Kurian, Dupont Company). In addition to the keynote lecture, the conference featured an impressive 43 invited lectures by prominent chemists from all over the globe. The oral sessions featured an additional 29 contributed talks. The poster session showcased the latest results presented by 71 faculty and students attendees. The organizers of the POC 2012 would like to thank the sponsors who generously supported this event. Qatar Petrochemical Company (QAPCO) was the premier sponsor. The organizers are also grateful to the following sponsors: Qatar Fertiliser Company (QAFCO), Qatar University, Qatar Foundation, Texas A&M University at Qatar, and Qatar Airways. I would like finally to acknowledge all the members of the POC 2012 Organizing Committee and International Advisory Committee for their immense contributions. Special thanks are extended in particular to Hala El-Dakak and G. Benjamin Cieslinski for their outstanding efforts. Hassan S. Bazzi Conference Chair

Organocatalysts have been extensively studied for the past few decades as alternatives to transition-metal catalysts. Immobilizing organocatalysts on polymer supports allows easy recovery and simple product purification after a reaction. Select examples of recent reports that describe the potential advantages of using soluble polymers to prepare soluble polymer-supported organocatalysts useful in organic synthesis are reviewed.

1,4:3,6-Dianhydrohexitols (DAHs) are nontoxic and sustainable diols that have been extensively applied as monomers for the preparation of polymer materials by step-growth polymerization processes. The presence of two reactive alcohol groups was exploited to design a library of symmetric and asymmetric stereocontrolled alkyne- and/or azide-functionalized AA/BB and AB monomers suitable for thermal or copper(I)-catalyzed azide-alkyne cycloaddition (TAAC and CuAAC). Step-growth polymerization of these monomers yielded a series of linear polytriazoles as well as partially biosourced networks using a combination of AB + A 2 B 2 derivatives. Characterization of the resulting materials allowed for the establishment of a thorough structure–property relationship emphasizing the impact of monomer stereochemistry and cycloaddition regioselectivity on materials properties.

In this research, switchgrass (SG) fiber-reinforced poly(trimethylene terephthalate) (PTT) biocomposites were prepared by extrusion followed by injection molding machine. The methylene-diphenyl-diisocyanate-polybutadiene (MDIPB) prepolymer was used to enhance the impact strength of the biocomposites. In addition, the polymeric methylene-diphenyl-diisocyanate (PMDI) compatibilizer was used to enhance the mechanical properties of the composites. The effect of compatibilizer on mechanical, crystallization melting, thermomechanical, melt flow index (MFI), morphological, and thermal stability properties of the composites was studied. Thermomechanical properties of the biocomposites were studied by dynamic mechanical analysis (DMA). Scanning electron microscopy (SEM) was used to observe the interfacial adhesion between the fiber and matrix. The results showed that MDIPB and PMDI have a significant effect on the mechanical properties of the composites. The impact strength of MDIPB- and PMDI-compatibilized composites was increased by 87 % when compared to the uncompatibilized composite.

A variety of modified Phillips catalysts were synthesized by employing three kinds of chemical modifiers for silica support: (1) organic modification with silane coupling agents, (2) Lewis acidic modification with typical metal alkyl or alkoxide, and (3) modification with transition-metal alkoxide. The activity and branching ability of these catalysts were investigated for ethylene polymerization. It was revealed that the chemical modification of silica support was a good methodology for controlling the catalyst activity as well as the branching level in resultant polyethylene.

A series of polystyrenes bearing multiple different functional groups has been synthesized, and these materials have been used as catalysts and reagents in a variety of organic reactions. Polymers functionalized with various combinations of amine, phenol, phosphine, and thiourea groups have been prepared in both non-cross-linked (soluble) and cross-linked (insoluble) formats. Reactions catalyzed by these polymers include Morita–Baylis–Hillman (MBH), alkyne to 1,3-diene isomerization, and decarboxylative Doebner–Knoevenagel reactions. Furthermore, Wittig and tandem Wittig/reduction reactions have been performed using heterogeneous polymeric reagents possessing a combination of amine and phosphine groups.

The combination of controlled radical polymerization (CRP) reactions and click chemistry offers high potential for the preparation of multifunctional polymers and significantly broadens the application scope of functional soft matter materials. In order to demonstrate the strategies as well as the potential of this methodology combination, examples for end-group and side-chain modification of polymers produced by CRP methods and the use of the resulting materials in functional polymer films are given.

Catalyst-transfer condensation polymerization, in which the catalyst activates the polymer end-group, followed by reaction with the monomer and transfer of the catalyst to the elongated polymer end-group, has made it feasible to control the molecular weight, polydispersity, and end-groups of π-conjugated polymers. In this paper, our recent progress of Kumada–Tamao Ni catalyst-transfer coupling polymerization and Suzuki–Miyaura Pd catalyst-transfer coupling polymerization is described. In the former polymerization method, the polymerization of Grignard pyridine monomers was investigated for the synthesis of well-defined n-type π-conjugated polymers. Para -type pyridine monomer, 3-alkoxy-2-bromo-5-chloromagnesiopyridine, afforded poly(pyridine-2,5-diyl) with low solubility in the reaction solvent, whereas meta -type pyridine monomer, 2-alkoxy-5-bromo-3-chloromagnesio-pyridine, yielded soluble poly(pyridine-3,5-diyl) with controlled molecular weight and low polydispersity. In Suzuki–Miyaura catalyst-transfer coupling polymerization, t -Bu 3 PPd(Ph)Br was an effective catalyst, and well-defined poly( p -phenylene) and poly(3-hexylthiophene) (P3HT) were obtained by concomitant use of CsF/18-crown-6 as a base in tetrahydrofuran (THF) and a small amount of water.

After recalling the basic relations relevant to both steady-state and time-resolved fluorescence polarization, it is shown how the values of steady-state polarized intensities recorded experimentally usually need to be corrected for systematic effects and errors, caused by instrumentation and sample properties. A list of selected reference values of steady-state fluorescence anisotropy and polarization is given. Attention is also paid to analysis of time-resolved fluorescence anisotropy data obtained by pulse fluorometry or phase and modulation fluorometry techniques. Recommendations for checking the accuracy of measurements are provided together with a list of selected time-resolved fluorescence anisotropy data as reported in the literature.

Solid state electroanalytical chemistry (SSEAC) deals with studies of the processes, materials, and methods specifically aimed to obtain analytical information (quantitative elemental composition, phase composition, structure information, and reactivity) on solid materials by means of electrochemical methods. The electrochemical characterization of solids is not only crucial for electrochemical applications of materials (e.g., in batteries, fuel cells, corrosion protection, electrochemical machining, etc.) but it lends itself also for providing analytical information on the structure and chemical and mineralogical composition of solid materials of all kinds such as metals and alloys, various films, conducting polymers, and materials used in nanotechnology. The present report concerns the relationships between molecular electrochemistry (i.e., solution electrochemistry) and solid state electrochemistry as applied to analysis. Special attention is focused on a critical evaluation of the different types of analytical information that are accessible by SSEAC.