Development of Highly Active and Regioselective Catalysts for the Copolymerization of Epoxides with Cyclic Anhydrides: An Unanticipated Effect of Electronic Variation.

Recent developments in polyester synthesis have established several systems based on zinc, chromium, cobalt, and aluminum catalysts for the ring-opening alternating copolymerization of epoxides with cyclic anhydrides. However, to date, regioselective processes for this copolymerization have remained relatively unexplored. Herein we report the development of a highly active, regioselective system for the copolymerization of a variety of terminal epoxides and cyclic anhydrides.

Intra-molecular triplet energy transfer is a general approach to improve organic fluorophore photostability.

Bright, long-lasting and non-phototoxic organic fluorophores are essential to the continued advancement of biological imaging. Traditional approaches towards achieving photostability, such as the removal of molecular oxygen and the use of small-molecule additives in solution, suffer from potentially toxic side effects, particularly in the context of living cells. The direct conjugation of small-molecule triplet state quenchers, such as cyclooctatetraene (COT), to organic fluorophores has the potential to bypass these issues by restoring reactive fluorophore triplet states to the ground state through intra-molecular triplet energy transfer.

Rapid and efficient redox processes within 2D covalent organic framework thin films.

Two-dimensional covalent organic frameworks (2D COFs) are ideally suited for organizing redox-active subunits into periodic, permanently porous polymer networks of interest for pseudocapacitive energy storage. Here we describe a method for synthesizing crystalline, oriented thin films of a redox-active 2D COF on Au working electrodes. The thickness of the COF film was controlled by varying the initial monomer concentration.

Single layer graphene as an electrochemical platform.

Over the past decade, there has been a great deal of interest in graphene with regards to its electrochemical behavior. Previous studies have focused on understanding fundamental processes such as charge transfer and molecular transport at the graphene-electrolyte interface as well as on applications of graphene in electronic, optical, and mechanical systems. We present illustrative examples of large area, single layer graphene platforms for applications such as optical and sensing devices as well as microfluidic systems.

Increasing the gravimetric energy density of organic based secondary battery cathodes using small radius cations (Li+ and Mg2+).

One of the major challenges in electrochemical energy storage (EES) is increasing the gravimetric capacity and energy density of the cathode material. Here we demonstrate how to increase the gravimetric energy density of electrical energy storage devices based on the use of organic materials through exploitation of the strong ionic coupling between a reduced carbonyl functionality and small cations such as lithium (Li(+)) and magnesium (Mg(2+)). Binding of the cation to the reduced carbonyl results in a positive shift of the formal reduction potential of the carbonyl couple.

Platinum electrodeposition on unsupported carbon nano-onions.

An effort to develop smaller, well-dispersed catalytic materials electrochemically on high-surface-area carbon supports is required for improved fuel cell performance. A high-surface-area carbon material of interest is carbon nano-onions (CNOs), also known as multilayer fullerenes. The most convenient synthesis method for CNOs is annealing nanodiamond particles, thus retaining the size of the precursors and providing the possibility to prepare very small nanocatalysts using electrochemical techniques.

Electrocatalysis of 2,5-dimercapto-1,3,5-thiadiazole by 3,4-ethylenedioxy-substituted conducting polymers.

The electronic properties of electropolymerized films of the 3,4-ethylenedioxy-substituted conducting polymers (CP) poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxypyrrole) (PEDOP) and poly(3,4-ethylenedioxyselenophene) (PEDOS) have been investigated, along with their electrocatalytic activity toward 2,5-dimercapto-1,3,4-thiadiazole (DMcT). For the electropolymerized films, the conductivity onset potential was most negative for PEDOP (-1.50 V), followed by PEDOS (-1.