RESUMO
The electrochemical synthesis of metal-organic frameworks (MOFs) has been widely explored but has involved indirect routes, including anodic dissolution of solid metal electrodes or the use of interfacial redox chemistry to generate base equivalents and drive MOF assembly. These methods are limited in scope, as the former relies on the use of an anode consisting of the metal ion to be incorporated into the MOF, and the latter relies on the compatibility of the metal/ligand solution with the probase that is subsequently oxidized or reduced. We report the facile, direct electrochemical syntheses of four iron-based MOFs via controlled potential oxidation of dissolved metal cations. Oxidation of Fe(II) at +0.75 V (vs Ag/Ag+) in a solution containing 2,6-lutidine and terephthalic acid affords highly crystalline Fe-MIL-101. Controlled potential electrolysis with carboxy-functionalized ITO affords Fe-MIL-101 grown directly on the surface of modified electrodes. The methods we report herein represent the first general routes that employ interfacial electrochemistry to alter the oxidation state of metal ions dissolved in solution to directly trigger MOF formation. The reported method is functional group tolerant and will be broadly applicable to the bulk synthesis or surface growth of a range of MOFs based on metal ions with accessible oxidation states.
RESUMO
Glutathione is an important biological molecule which can be an indicator of numerous diseases. A method for self-powered detection of glutathione levels in solution has been developed using an enzymatic biofuel cell. The device consists of a glucose oxidase anode and a bilirubin oxidase cathode. For the detection of glutathione, the inhibition of bilirubin oxidase leads to a measurable decrease in current and power output. The reported method has a detection limit of 0.043 mM and a linear range up to 1.7 mM. Being able to detect a range of concentrations can be useful in evaluating a patient's health. This method has the potential to be implemented as a quick, low-cost alternative to previously reported methods.
