Abstract
Since its discovery, the olefin metathesis (OM)
reaction has found numerous applications in total synthesis, industrial
processes, pharmaceutical, and material chemistry. Ruthenium (Ru), Molybdenum (Mo),
and Tungsten (W)-based homogeneous catalysts are the most prominent due to
their high activity and functional group stability. However, the transition to
more abundant first-row metals, such as Vanadium (V), is desirable due to the
low cost, decreased environmental footprint, and reduced toxicity. V alkylidenes are a promising class of compounds that have
shown reactivity in OM, especially in ring-opening metathesis polymerization
(ROMP) of cyclic olefins. However, those complexes found limited application in
reactions with terminal olefins due to instability toward ethylene.FIU
researchers have developed a method that enables the synthesis of a new class
of V catalysts. This synthesis method produced the first catalytically active V
oxo alkylidene, VO(CHSiMe3)(PEt3)2Cl,
which exhibits high productivity with various terminal olefins in ring-closing
metathesis (RCM) reactions. Additionally, the highly polarized V=C bond of this
complex enables the regioselective formation of metallacyclobutane, resulting
in reversible =CH2 transfer between terminal olefins without the
formation of cross-products and ethylene, making this complex an ideal catalyst
for carbon isotope exchange (CIE) performed directly on target molecules.
Additional complexes
are being synthesized and tested.Benefit
Olefin Metathesis:Cheaper: Vanadium is substantially less expensive than the rare metals that are currently used for OM.Decreased environmental footprint and reduced toxicity: purification, isolation, and recycling of currently used metals consume energy and generate a significant amount of waste.Superior performance compared to currently used catalysts.Carbon isotope exchange:Eliminates tedious, time-consuming, and costly practices where the development of new multi-step synthetic strategies for each specific target molecule is required.Market Application
Olefin Metathesis:Propylene production from ethylene and 2-butenes (Olefins Conversion Technology).Production of plasticizers and detergents precursors (Shell Higher Olefin Process).Synthesis of polymers, petrochemicals, agrochemicals, and conversion of low-molecular-weight alkanes to diesel fuel via “alkane metathesis”.Eco-friendly conversion of renewable seed oil feedstock into biofuel and linear alpha-olefins, that are utilized to produce cosmetics, soaps, detergents, polymer additives and coatings. Carbon isotope exchange: Incorporation of carbon isotopes directly into target compounds for metabolic and pharmacokinetic studies.Integration of carbon-11 into pharmaceuticals for positron emission tomography.Publications
Synthesis of
Vanadium Oxo Alkylidene Complex and Its Reactivity in Ring-Closing Olefin
Metathesis Reactions. Dmitry S. Belov, Didac A. Fenoll, Indranil Chakraborty,
Xavier Solans-Monfort, and Konstantin V. Bukhryakov. Organometallics
2021 40 (17), 2939-2944.Synthesis
and Activity of Vanadium Oxo NHC Alkylidenes. Remarkable Preference for
Degenerate Metathesis and Application for Carbon Isotope Exchange. Dmitry S.
Belov, Carlos M. Acosta, Miquel Garcia-Molina, Kelly L. Rue, Xavier
Solans-Monfort, and Konstantin V. Bukhryakov. Organometallics 2022 41
(21), 2897-2902.
Abstract
Florida International University (FIU) is pursuing business partners interested in commercializing Electronically Activated C-MEMS Electrodes for On-chip Micro Super-capacitors as a very promising method for fabricating electrochemical micro-capacitors. Carbon micro-electrode arrays for use in micro-capacitors are fabricated using the carbon microelectromechanical system (C-MEMS) technique. This technique employs electrochemical activation in order to improve the capacitive behavior of carbon micro-electrode arrays. Cyclic voltammetry (CV) and galvanostatic charge-discharge results indicated that electrochemical activation effectively increases the capacitance of micro-electrode arrays by as many as three orders of magnitudes. Specific geometric capacitance reaching as high as 7mFcm-2 at a scan rate of 5mVs-1 has been observed with just 30 minutes of electrochemical activation. In addition after 1000 CV cycles the capacitance loss is less than 13 percent. This indicates that electrochemically activated C-MEMS micro-electrode arrays are promising candidates for on chip electrochemical micro-capacitors. FIU inventors have successfully demonstrated that C-MEMS fabricated micro-electrodes are potentially capable of delivering energy storage solutions for micro-devices. In addition fabrication of higher aspect ratio micro-electrodes could increase the device’s surface area while maintaining a desirable in the limited footprint. Other future developments include fabrication of high aspect ratio 3D electrodes, which would increase adhesion of carbon current collectors to the substrate, and optimizing the conditions of electrochemical activation.Benefit
For the first time C-MEMS electrodes have been successfully activated using electrochemical activationActivated C-MEMS electrodes provide a higher specific capacitance compared to non-activated C-MEMSThree dimensional C-MEMS electrodes provide more efficient surface area compared to conventional thin film electrodesAdditionally, the C-MEMS technique is compatible with other microfabrication techniquesMarket Application
Can be used as three dimensional electrodes for on-chip electrochemical micro-supercapacitorsThe technology has specific applications in the fields of micro-power sources and energy storage
Engineering
