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The first multivariate ligand MONTs were prepared and characterized and showed statistical copolymerization.

Anthropogenic CO2 emissions, primarily from the combustion of fossil fuels, are driving climate change at an alarming rate. Our current dependence on carbon-based fuels has motivated research interest in the capture and catalytic reduction of carbon dioxide back to liquid fuels. Electrochemical reduction of carbon dioxide has been intensely researched over the past decade. Here, some of the important contributions made to this field over the past decade using the Group VII transition metal bipyridine catalysts are reviewed. Strategies to further our mechanistic understanding of the electrocatalytic reduction of CO2 to CO are described.

Lignin is the largest renewable source of aromatic chemical building blocks on the planet and has great potential for the production of value-added chemicals. Herein, we describe lignin hydrogenolysis/depolymerization of organosolv poplar lignin (OPL) in ethanol/isopropanol solvent in the absence of added catalysts. Different EtOH/i-PrOH ratios as well as various reaction conditions were evaluated. OPL depolymerization was more effective in the mixed media than in ethanol or isopropanol alone. Heating OPL at 270 °C for 4 h in 50:50 (v:v) EtOH/i-PrOH in a closed pressure vessel gave an overall oil yield of 70 wt %, of which about 48% consisted of the monomers (E)-4-propenyl syringol and isoeugenol. Notably, these catalyst-free reactions in ethanol/isopropanol media show monomer yields comparable to those reported for lignin depolymerization using precious metal catalysts and dihydrogen, which suggests unexpectedly favorable H-donor ability of this mixed alcohol medium.

The ever-increasing global fuel demand and environmental consequences of anthropogenic carbon emissions have motivated interest in catalytic disassembly of biomass into liquid fuels and chemicals. Over 1 billion tons of combined residual biomass (i.e., agricultural, forestry, and food waste) are available annually (Langholtz et al., 2016).1 Humankind is dependent on fossil carbon for much of the energy we consume, the medicine we take, and the clothes we wear. Our society will likely remain dependent on fossil carbon so long as they are the primary chemical feedstock for our medicines, polymers, and fuels. The selective upgrading of biomass and biomass derived alcohols may potentially provide “green” alternatives to commonly used fossil carbon derived fuels, solvents, plasticizers, and a multitude of synthetic precursor chemicals. Cu-doped porous metal oxides were identified as highly active catalysts due to their ability to generate hydrogen from alcohols and subsequently catalyze hydrogenolysis of various carbon-oxygen bonds, a crucial component of biomass macromolecules and derivatives. This chapter outlines recent efforts within and without our laboratories for addressing a vital challenge in catalytic biomass disassembly using Cu-doped porous metal oxides (CuPMO) selectivity. Herein we described the innovative strategies used in the context of selective conversion of organosolv poplar lignin, condensation of ethanol, and reaction environment (i.e., temperature, solvent, and substrate) effects on CuPMO structure.

Spironolactone, a potassium-sparing diuretic and aldosterone antagonist, is a mineralocorticoid hormone commonly prescribed to patients suffering from heart failure, hirsutism, dermatological afflictions, and hypertension. Interestingly, relatively little work has been done on the development of vertebrate embryos after exposure to this compound. Here, we treat zebrafish embryos with spironolactone at 10

A gas analyser for acetone based on measurement of the absorption of ultraviolet wavelengths near 285 nm in a compact multipass cell has been demonstrated. The analyser has a robust, compact and low-cost configuration which includes a light emitting diode (LED) light source, silicon photodiode light detection and does not require optical cavity enhancement. The analyser has been tested in various configurations for synthetic gas mixtures and breath samples from several human subjects. The analyser provides a lower limit of detection of 0.7 ppmv acetone, precision of 0.4 ppmv (3σ) and has worst-case residual errors of ±0.2 ppmv (up to 5 ppmv) and ±0.3 ppmv (up to 3.9 ppmv) for synthetic gas mixtures and human breath, respectively. These results indicate that this analyser concept has excellent potential to meet the requirements for making breath acetone measurements for lifestyle monitoring and medical screening applications.

Improvement of processes that utilize renewable feedstocks to produce chemicals ordinarily derived from fossil carbon feedstocks is paramount to creating environmentally sustainable chemical and fu...

The ever-increasing global fuel demand and environmental consequences of anthropogenic carbon emissions have motivated interest in catalytic reduction of carbon dioxide to liquid fuels. Over the past 45 years substantial research progress has been made in homogeneous electrocatalytic systems for the reduction of carbon dioxide. This chapter will present much of the significant research in this field, in the context of innovative strategies for controlling carbon dioxide electrocatalysis.

Multiphoton excitation allows one to access high energy excited states and perform valuable tasks in biological systems using tissue penetrating near-infrared (NIR) light. Here, we describe new photoactive manganese tricarbonyl complexes incorporating the ligand 4'-p-N,N-bis(2-hydroxyethyl)amino-benzyl-2,2':6',2″-terpyridine (TPYOH), which can serve as an antenna for two photon NIR excitation. Solutions of Mn(CO)3(TPYOH)X (X = Br- or CF3SO3-) complexes are very photoactive toward CO release under visible light excitation (405 nm, 451 nm). The same responses were also triggered by multiphoton excitation at 750 and 800 nm. In this context, we discuss the potential applications of these complexes as visible/NIR light photoactivated carbon monoxide releasing moieties (photoCORMs). We also report the isolation and crystal structures of the TPYOH complexes Mn(TPYOH)Cl2 and [Mn(TPYOH)2](CF3SO3)2, to illustrate a possible photolysis product(s).

The selective conversion of lignin into aromatic compounds has the potential to serve as a “green” alternative to the production of petrochemical aromatics. Herein, we evaluate the addition of dimethyl carbonate (DMC) to a biomass conversion system that uses a Cu-doped porous metal oxide (Cu20PMO) catalyst in supercritical methanol (sc-MeOH) to disassemble lignin with little to no char formation. While Cu20PMO catalyzes C–O hydrogenolysis of aryl–ether bonds linking lignin monomers, it also catalyzes arene methylation and hydrogenation, leading to product proliferation. The MeOH/DMC co-solvent system significantly suppresses arene hydrogenation of the phenolic intermediates responsible for much of the undesirable product diversity via O-methylation of phenolic −OH groups to form more stable aryl-OCH3 species. Consequently, product proliferation was greatly reduced and aromatic yields greatly enhanced with lignin models, 2-methoxy-4-propylphenol, benzyl phenyl ether, and 2-phenoxy-1-phenylethan-1-ol. In ad...

Iron–iron hydrogenase model compounds have potential as hydrogen producing catalysts that are inexpensive and environmentally friendly. Many of these model compounds are dependent on light for activity but little is know about the photochemical intermediates or products that are formed and catalytically important. The photochemistry of μ-pdt-[Fe(CO) 2 CN] 2 2− ( 2 ) is explored in acetonitrile and spectral changes in the IR support lost of CN−. UV–Vis spectroscopy was used to determine quantum yields for the disappearance of 2 , which was found to be 0.38 ± 0.04 in acetonitrile when irradiated with 365 nm light under nitrogen.

The organometallic complex Fe2(μ-S2)(CO)6 has interesting biological implications. The concepts of bio-organometallic chemistry are rarely discussed at the undergraduate level, but this experiment can start such a conversation and, in addition, teach valuable synthetic techniques. The lab experiment takes a total of five, 3-h lab periods and includes synthesis, purification, and characterization of the title molecule. The synthesis is done using standard Schlenk line techniques, but the product is air stable, which allows for standard benchtop purification. The compound is characterized using UV–vis spectroscopy, Fourier transform infrared spectroscopy, 13C NMR spectroscopy, and mass spectrometry.