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Chemistry

Series

2021

Marquette University

Articles 1 - 11 of 11

Full-Text Articles in Physical Sciences and Mathematics

Triple Oxygen Isotope Constraints On Atmospheric O2 And Biological Productivity During The Mid-Proterozoic, Peng Liu, Jingjin Liu, Aoshaung Ji, Christopher T. Reinhard, Noah J. Planavsky, Dmitri Babikov, Raymond G. Najjar, James F. Kasting Dec 2021

Triple Oxygen Isotope Constraints On Atmospheric O2 And Biological Productivity During The Mid-Proterozoic, Peng Liu, Jingjin Liu, Aoshaung Ji, Christopher T. Reinhard, Noah J. Planavsky, Dmitri Babikov, Raymond G. Najjar, James F. Kasting

Chemistry Faculty Research and Publications

Reconstructing the history of biological productivity and atmospheric oxygen partial pressure (pO2) is a fundamental goal of geobiology. Recently, the mass-independent fractionation of oxygen isotopes (O-MIF) has been used as a tool for estimating pO2 and productivity during the Proterozoic. O-MIF, reported as Δ′17O, is produced during the formation of ozone and destroyed by isotopic exchange with water by biological and chemical processes. Atmospheric O-MIF can be preserved in the geologic record when pyrite (FeS2) is oxidized during weathering, and the sulfur is redeposited as sulfate. Here, sedimentary sulfates from …

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2d Covalent Organic Frameworks With An Incorporated Manganese Complex For Light Driven Carbon Dioxide Reduction, Denan Wang, Daniel Streater, Yun Peng, Jier Huang Dec 2021

2d Covalent Organic Frameworks With An Incorporated Manganese Complex For Light Driven Carbon Dioxide Reduction, Denan Wang, Daniel Streater, Yun Peng, Jier Huang

Chemistry Faculty Research and Publications

Covalent organic frameworks (COFs) have emerged as a novel class of crystalline porous photocatalytic materials due to their unique properties such as large surface area, tunable porosity, and rigid structure. In this work, we report the direct incorporation of a manganese CO2 molecular catalyst (MC) into COFs (Mn−TTA-COF) and the evaluation of its capability as photocatalyst for visible light driven CO2 reduction to form CO. We found that the photocatalytic activity of Mn−TTA-COF is quite low, which mainly results from the elimination of the CO ligand in the Mn MC upon light illumination, rendering its short duration in …

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Spectrumsdt: A Program For Parallel Calculation Of Coupled Rotational-Vibrational Energies And Lifetimes Of Bound States And Scattering Resonances In Triatomic Systems, Igor Gayday, Alexander Teplukhin, Jonathan Moussa, Dmitri Babikov Oct 2021

Spectrumsdt: A Program For Parallel Calculation Of Coupled Rotational-Vibrational Energies And Lifetimes Of Bound States And Scattering Resonances In Triatomic Systems, Igor Gayday, Alexander Teplukhin, Jonathan Moussa, Dmitri Babikov

Chemistry Faculty Research and Publications

We present SpectrumSDT – a program for calculations of energies and lifetimes of bound rotational-vibrational states below and scattering resonances above the dissociation threshold on a global potential energy surface of a triatomic system, which may include stable molecules, weekly-bound van-der-Waals complexes, and unbound atom + diatom scattering systems. Large-amplitude vibrational motion is treated explicitly using hyper-spherical coordinates. Three options for the rotational-vibrational interaction are supported: uncoupled (symmetric top rotor), partially coupled (to include interaction between several nearest states only) and full-coupled (vibrating asymmetric-top rotor). In addition to energies and lifetimes, SpectrumSDT is able to integrate ro-vibrational wave functions over …

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Dissecting Monomer-Dimer Equilibrium Of An Rnase P Protein Provides Insight Into The Synergistic Flexibility Of 5’ Leader Pre-Trna Recognition, Danyun Zeng, Ainur Abzhanova, Benjamin P. Brown, Nicholas J. Reiter Sep 2021

Dissecting Monomer-Dimer Equilibrium Of An Rnase P Protein Provides Insight Into The Synergistic Flexibility Of 5’ Leader Pre-Trna Recognition, Danyun Zeng, Ainur Abzhanova, Benjamin P. Brown, Nicholas J. Reiter

Chemistry Faculty Research and Publications

Ribonuclease P (RNase P) is a universal RNA-protein endonuclease that catalyzes 5’ precursor-tRNA (ptRNA) processing. The RNase P RNA plays the catalytic role in ptRNA processing; however, the RNase P protein is required for catalysis in vivo and interacts with the 5’ leader sequence. A single P RNA and a P protein form the functional RNase P holoenzyme yet dimeric forms of bacterial RNase P can interact with non-tRNA substrates and influence bacterial cell growth. Oligomeric forms of the P protein can also occur in vitro and occlude the 5’ leader ptRNA binding interface, presenting a challenge in accurately defining …

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Electronic Structures And Spectroscopic Signatures Of Diiron Intermediates Generated By O2 Activation Of Nonheme Iron(Ii)–Thiolate Complexes, Danushka M. Ekanayake, Dao Pham, Andrew L. Probst, Joshua R. Miller, Cordina V. Popescu, Adam T. Fiedler Sep 2021

Electronic Structures And Spectroscopic Signatures Of Diiron Intermediates Generated By O2 Activation Of Nonheme Iron(Ii)–Thiolate Complexes, Danushka M. Ekanayake, Dao Pham, Andrew L. Probst, Joshua R. Miller, Cordina V. Popescu, Adam T. Fiedler

Chemistry Faculty Research and Publications

The activation of O2 at thiolate–ligated iron(II) sites is essential to the function of numerous metalloenzymes and synthetic catalysts. Iron–thiolate bonds in the active sites of nonheme iron enzymes arise from either coordination of an endogenous cysteinate residue or binding of a deprotonated thiol-containing substrate. Examples of the latter include sulfoxide synthases, such as EgtB and OvoA, that utilize O2 to catalyze tandem S–C bond formation and S-oxygenation steps in thiohistidine biosyntheses. We recently reported the preparation of two mononuclear nonheme iron–thiolate complexes (1 and 2) that serve as structural active-site models of substrate-bound EgtB …

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Covalent Immobilization Of Molecular Complexes On Metal-Organic Frameworks Towards Robust And Highly Efficient Heterogeneous Water Oxidation Catalysts, Xiangming Liang, Sizhou Yang, Junyi Yang, Wanjun Sun, Xiangyang Li, Baochun Ma, Jier Huang, Jiangwei Zhang, Lele Duan, Yong Ding Aug 2021

Covalent Immobilization Of Molecular Complexes On Metal-Organic Frameworks Towards Robust And Highly Efficient Heterogeneous Water Oxidation Catalysts, Xiangming Liang, Sizhou Yang, Junyi Yang, Wanjun Sun, Xiangyang Li, Baochun Ma, Jier Huang, Jiangwei Zhang, Lele Duan, Yong Ding

Chemistry Faculty Research and Publications

The major challenges to practical implementation of efficient noble metal based molecular water oxidation catalysts are their stability and recycle ability. Herein, noble metal Ru based molecular water oxidation catalysts were covalently anchored in MOFs through “amide bond” as bridges, which leads to the formation of high-efficiency and robust heterogeneous catalysts for water oxidation reaction. We show that the efficiency for CeIV-driven water oxidation was significantly enhanced by 120 times when the Ru molecules were immobilized on the frameworks of MIL-101(Cr). The relationship between recycle stability and the structure of the Ru complexes covalently anchored in MOFs was …

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Catalytic Transfer Deuteration And Hydrodeuteration: Emerging Techniques To Selectively Transform Alkenes And Alkynes To Deuterated Alkanes, Zoua Pa Vang, Samuel J. Hintzsche, Joseph R. Clark Jul 2021

Catalytic Transfer Deuteration And Hydrodeuteration: Emerging Techniques To Selectively Transform Alkenes And Alkynes To Deuterated Alkanes, Zoua Pa Vang, Samuel J. Hintzsche, Joseph R. Clark

Chemistry Faculty Research and Publications

Increasing demand for deuterium-labeled organic molecules has spurred a renewed interest in selective methods for deuterium installation. Catalytic transfer deuteration and transfer hydrodeuteration are emerging as powerful techniques for the selective incorporation of deuterium into small molecules. These reactions not only obviate the use of D2 gas and pressurized reaction setups but provide new opportunities for selectively installing deuterium into small molecules. Commercial or readily synthesized deuterium donors are typically employed as easy-to-handle reagents for transfer deuteration and hydrodeuteration reactions. In this minireview, recent advances in the catalytic transfer deuteration and hydrodeuteration of alkenes and alkynes for the selective …

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Efficient Method For An Approximate Treatment Of The Coriolis Effect In Calculations Of Quantum Dynamics And Spectroscopy, With Application To Scattering Resonances In Ozone, Igor Gayday, Dmitri Babikov Jul 2021

Efficient Method For An Approximate Treatment Of The Coriolis Effect In Calculations Of Quantum Dynamics And Spectroscopy, With Application To Scattering Resonances In Ozone, Igor Gayday, Dmitri Babikov

Chemistry Faculty Research and Publications

A numerical approach is developed to capture the effect of rotation–vibration coupling in a practically affordable way. In this approach only a limited number of adjacent rotational components are considered to be coupled, while the couplings to other rotational components are neglected. This partially coupled (PC) approach permits to reduce the size of Hamiltonian matrix significantly, which enables the calculations of ro-vibrational states above dissociation threshold (scattering resonances) for large values of total angular momentum. This method is employed here to reveal the role of the Coriolis effect in the ozone formation reaction at room temperature, dominated by large values …

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In Situ Activated Co3–XNiXO4 As A Highly Active And Ultrastable Electrocatalyst For Hydrogen Generation, Kailu Guo, Yantao Wang, Junfeng Huang, Min Lu, Hua Li, Yong Peng, Pinxian Xi, Haoli Zhang, Jier Huang, Siyu Lu, Cailing Xu Jul 2021

In Situ Activated Co3–XNiXO4 As A Highly Active And Ultrastable Electrocatalyst For Hydrogen Generation, Kailu Guo, Yantao Wang, Junfeng Huang, Min Lu, Hua Li, Yong Peng, Pinxian Xi, Haoli Zhang, Jier Huang, Siyu Lu, Cailing Xu

Chemistry Faculty Research and Publications

The spinel Co3O4 has emerged as a promising alternative to noble-metal-based electrocatalysts for electrochemical water electrolysis in alkaline medium. However, pure Co3O4, despite having high activity in anodic water oxidation, remains inactive toward the hydrogen evolution reaction (HER). Here, a Ni-doped Co3O4(Co3–xNixO4) prepared by a simple method exhibits favorable HER activity and stability (>300 h, whether in 1 M KOH or the realistic 30 wt % KOH solution) after in situ electrochemical activation, outperforming almost all of the oxide-based electrocatalysts. More …

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Four Isotope-Labeled Recombination Pathways Of Ozone Formation, Dmitri Babikov, Elizaveta Grushnikova, Igor Gayday, Alexander Teplukhin Feb 2021

Four Isotope-Labeled Recombination Pathways Of Ozone Formation, Dmitri Babikov, Elizaveta Grushnikova, Igor Gayday, Alexander Teplukhin

Chemistry Faculty Research and Publications

A theoretical approach is developed for the description of all possible recombination pathways in the ozone forming reaction, without neglecting any process a priori, and without decoupling the individual pathways one from another. These pathways become physically distinct when a rare isotope of oxygen is introduced, such as 18O, which represents a sensitive probe of the ozone forming reaction. Each isotopologue of O3 contains two types of physically distinct entrance channels and two types of physically distinct product wells, creating four recombination pathways. Calculations are done for singly and doubly substituted isotopologues of ozone, eight rate coefficients …

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Unraveling A Trifecta Of Weak Non-Covalent Interactions: The Dissociation Energy Of The Anisole-Ammonia 1:1 Complex, John L. Loman, James T. Makuvaza, Damian L. Kokkin, Scott A. Reid Jan 2021

Unraveling A Trifecta Of Weak Non-Covalent Interactions: The Dissociation Energy Of The Anisole-Ammonia 1:1 Complex, John L. Loman, James T. Makuvaza, Damian L. Kokkin, Scott A. Reid

Chemistry Faculty Research and Publications

The anisole-ammonia 1:1 complex is a challenge for both experiment and theory. Early studies supported a non-planar structure, involving a trifecta of weak non-covalent interactions: N-H/O, N-H/π, and C-H/N. The calculated structure and binding energy of the complex proved remarkably sensitive to the level of theory employed. Here, we report the first experimental measurement of the ground state dissociation energy of the complex, and derive an excited (S1) state dissociation energy that is in excellent agreement with the cutoff observed in the experimental excitation spectrum. Results are compared with previous predictions and new calculations based on benchmarked Density …

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