Chemistry Commons^™

Data From: Periodic F-Defects On The Mgo Surface As Potential Single-Defect Catalysts With Non-Linear Optical Properties, Alexander I. Boldyrev, Maksim Kulichenko

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In this paper we suggest a new type of a single-atom (or single-defect) catalyst – MgO with periodic defects on the (0 0 1) surface – which possesses noticeable non-linear optical properties. Periodicity of these defects leads to the significant extensive increase in the activity of a catalyst by growth of the concentration of active sites. In this work we showed the presence of diffuse electride-like multi-center bonds inside every periodic F-center. We also discovered that MgO with periodic defects on the surface gains non-linear optical properties due to electride-like polarizable bonds inside every defect. And most importantly, such defective …

Data From: Boron-Made N2: Realization Of A Bb Triple Bond In The B2al3- Cluster, Alexander I. Boldyrev, Nikita Fedik

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Project reports B2Al3- cluster, which mimics triple bond N2 molecule.

Data From: Can Aromaticity Be A Kinetic Trap? Example Of Mechanically Interlocked Aromatic [2-5]Catenanes Built From Cyclo[18]Carbon, Alexander I. Boldyrev, Nikita Fedik

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Project reports the analysis of interlocked C18 rings as building blocks for polycatenanes.

Data From: Two Names Of Stability: Spherical Aromatic Or Superatomic Intermetalloid Cluster [Pd3sn8bi6]4−, Alexander I. Boldyrev, Nikita Fedik

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Project reports the aromaticity in the intermetalloid cluster [Pd3Sn8Bi6]4−.

Data From: A Sandwich-Type Cluster Containing Ge@Pd3 Planar Fragment Flanked By Aromatic Nonagermanide Caps, Alexander I. Boldyrev, Nikolay Tkachenko

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Sandwich-type clusters with the planar fragment containing a heterometallic sheet have remained elusive. In this work, we introduce the [K(2,2,2-crypt)]4{(Ge9)2[η6-Ge(PdPPh3)3]} complex that contains a heterometallic sandwich fragment. The title compound is structurally characterized by means of single-crystal X-ray diffraction, which reveals the presence of an unusual heteroatomic metal planar fragment Ge@Pd3. The planar fragment contains a rare formal zerovalent germanium core and a peculiar bonding mode of sp2-Ge@(PdPPh3)3 trigonal planar structure, whereas the nonagermanide fragments act as capping ligands. The chemical bonding pattern of the planar fragment consists of three 2c-2e Pd-Ge σ-bonds attaching Pd atoms to the core Ge …

Data From: Chemical Bonding Analysis Of Excited States Using The Adaptive Natural Density Partitioning Method, Alexander I. Boldyrev, Nikolay Tkachenko

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A novel approach to chemical bond analysis for excited states has been developed. Using an extended adaptive natural density partitioning method (AdNDP) as implemented in AdNDP 2.0 code, we obtained chemically intuitive bonding patterns for the excited states of H2O, B5+, and C2H4+ molecules. The deformation pathway in the excited states could be easily predicted based on the analysis of the chemical bond pattern. We expect that this new method of chemical bonding analysis would be very helpful for photochemistry, photoelectron spectroscopy, electron spectroscopy and other chemical applications that involved excited states.

Data From: Stability, Electronic, And Optical Properties Of Two-Dimensional Phosphoborane, Alexander I. Boldyrev, Nikolay Tkachenko

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The structure and properties of two-dimensional phosphoborane sheets were computationally investigated using Density Functional Theory calculations. The calculated phonon spectrum and band structure point to dynamic stability and allowed characterization of the predicted two-dimensional material as a direct-gap semiconductor with a band gap of ~1.5 eV. The calculation of the optical properties showed that the two-dimensional material has a relatively small absorptivity coefficient. The parameters of the mechanical properties characterize the two-dimensional phosphoborane as a relatively soft material, similar to the monolayer of MoS2. Assessment of thermal stability by the method of molecular dynamics indicates sufficient stability of the predicted …

Data From: Novel Strongly Correlated Europium Superhydrides, Alexander I. Boldyrev, Nikolay Tkachenko

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We conducted a joint experimental–theoretical investigation of the high-pressure chemistry of europium polyhydrides at pressures of 86–130 GPa. We discovered several novel magnetic Eu superhydrides stabilized by anharmonic effects: cubic EuH9, hexagonal EuH9, and an unexpected cubic (Pm3n) clathrate phase, Eu8H46. Monte Carlo simulations indicate that cubic EuH9 has antiferromagnetic ordering with TN of up to 24 K, whereas hexagonal EuH9 and Pm3n-Eu8H46 possess ferromagnetic ordering with TC = 137 and 336 K, respectively. The electron–phonon interaction is weak in all studied europium hydrides, and their magnetic ordering excludes s-wave superconductivity, except, perhaps, for distorted pseudohexagonal EuH9. The equations of …

Data From: Computational Prediction Of The Low-Temperature Ferromagnetic Semiconducting 2d Sin Monolayer, Alexander I. Boldyrev, Nikolay Tkachenko

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Since the discovery of graphene, 2D materials have captured the minds of scientists because of their attractive and unique electronic properties. In particular, magnetic 2D materials have become a subject of extensive discussions today. Using density functional theory calculations, it is shown that 2D SiN sheet (built out of nonmetallic main group atoms) is a ferromagnetic semiconducting material with a magnetic moment 1 μB per unit cell and an indirect bandgap of 1.55 eV. Calculated phonon spectrum and conducted ab initio molecular dynamics simulation reveal thermal and dynamical stability of the designed material. It is shown that the ferromagnetic state …

Data For: Record Low Ionization Potentials Of Alkali Metal Complexes With Crown Ethers And Cryptands, Alexander I. Boldyrev, Nikolay Tkachenko

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Electronic properties of series of alkali metals complexes with crown ethers and cryptands were studied via DFT hybrid functionals. For [M([2.2.2]crypt)] (M=Li, Na, K) extremely low (1.70–1.52 eV) adiabatic ionization potentials were found. Such low values of ionization energies are significantly lower than those of alkali metal atoms. Thus, the investigated complexes can be defined as superalkalis. As a result, our investigation opens up new directions in the designing of chemical species with record low ionization potentials and extends the explanation of the ability of the cryptates and alkali crown ether complexes to stabilize multiple charged Zintl ions.

Dataset For: Multiple Local Σ-Aromaticity Of Nonagermanide Clusters, Alexander I. Boldyrev, Nikolay Tkachenko

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Nonagermanide clusters are widely used in inorganic synthesis and are actively studied by experimentalists and theoreticians. However, chemical bonding of such versatile species is still not completely understood. In our work we deciphered a bonding pattern for various experimentally obtained nonagermanide species. We localized the electron density via the AdNDP algorithm for the model structures ([Ge9]4−, [Ge9{P(NH2)2}3]−, Cu[Ge9{P(NH2)2}3] and Cu(NHC)[Ge9{P(NH2)2}3]) and obtained a simple and chemically intuitive bonding pattern which can explain the variety of active sites and the existence of both D3h and C4v geometries for such clusters. Moreover, the [Ge9]4− core is found to be a unique example …

Data From: Dibridged, Monobridged, Vinylidene-Like, And Linear Structures For The Alkaline Earth Dihydrides Be2h2, Mg2h2, Ca2h2, Sr2h2, And Ba2h2. Proposals For Observations, Alexander I. Boldyrev, Nikolay Tkachenko

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This research reports a search for peculiar monobridged structures of the E2H2 molecules (E = Be, Mg, Ca, Sr, Ba). For Be2H2 and Mg2H2, the monobridged geometry is not an equilibrium but rather a transition state between the vinylidene-like structure and the global minimum HE–EH linear geometry. However, for Ca2H2, Sr2H2, and Ba2H2, this situation changes significantly; the linear structure is no longer the global minimum but lies higher in energy than two other equilibria, the dibridged and monobridged structures. The planar dibridged structures of both Sr2H2 and Ba2H2 should be observable via IR spectroscopy. Although the remarkable monobridged structures …

Data From: Structure And Bonding In [Sb@In8sb12]3− And [Sb@In8sb12]5−, Alexander I. Boldyrev, Nikolay Tkachenko

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We report the characterization of the compound [K([2.2.2]crypt)]4[In8Sb13], which proves to contain a 1:1 mixture of [Sb@In8Sb12]3− and [Sb@In8Sb12]5−. The tri-anion displays perfect Th symmetry, the first completely inorganic molecule to do so, and contains eight equivalent In3+ centers in a cube. The gas-phase potential energy surface of the penta-anion has eight equivalent minima where the extra pair of electrons is localized on one In+ center, and these minima are linked by low-lying transition states where the electron pair is delocalized over two adjacent centers. The best fit to the electron density is obtained from a model where the structure …

Data From: Σ-Aromaticity-Induced Stabilization Of Heterometallic Supertetrahedral Clusters [Zn6ge16]4− And [Cd6ge16]4−, Alexander I. Boldyrev, Nikolay Tkachenko

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In this work, the largest heterometallic supertetrahedral clusters, [Zn6Ge16]4− and [Cd6Ge16]4−, were directly self-assembled through highly-charged [Ge4]4− units and transition metal cations, in which 3-center–2-electron σ bonding in Ge2Zn or Ge2Cd triangles plays a vital role in the stabilization of the whole structure. The cluster structures have an open framework with a large central cavity of diameter 4.6 Å for Zn and 5.0 Å for Cd, respectively. Time-dependent HRESI-MS spectra show that the larger clusters grow from smaller components with a single [Ge4]4− and ZnMes2 units. Calculations performed at the DFT level indicate a very large HOMO–LUMO energy gap in …

Data From: All-Metal Σ-Antiaromaticity In Dimeric Cluster Anion {[Cuge9mes]2}4−, Alexander I. Boldyrev, Nikolay Tkachenko

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In this work, we report a dimeric cluster anion, {[CuGe9Mes]2}4−, which was isolated as the [K(2,2,2-crypt)]+ salt and characterized by using single-crystal X-ray diffraction and ESI mass spectroscopy. The title cluster represents the first locally σ-antiaromatic compound in the solid state, as well as the first heteroatomic antiaromatic compound.

Air Quality Measurements In Ephraim, Ut, Alex Allred

Utah Space Grant Consortium

Standard Air Quality indicators: NO, NOx, SO2, CO, O3 and PM2.5 were measured in Ephraim, Sanpete county, Utah from Dec 16, 2020 -Mar 6, 2021. The Air quailty monitoring station was installed in December 2020 and is currently operating. Ephraim is located in a high mountain valley at 5541 feet elevation. Events of interest were evaluated using back trajectories and wind rose analysis.

Evaluating Gallium As A Catalyst For Silicon Nanodot Synthesis, Rylan Woods

Utah Space Grant Consortium

Silicon nanostructures, such as silicon nanowires and silicon nanodots, exhibit notably different thermoelectric, electric, and optical properties from bulk silicon. These nanostructures are ideal for utilization in a variety of electronic and optical devices ranging from batteries to solar panels. While various synthesis methods and catalysts exist for making silicon nanowires, gallium exhibits unique nanowire shapes compared to other catalyst metals such as gold or silver. This experiment uses gallium as a catalyst to form silicon nanostructures onoriented silicon substrate at temperatures of 0, 850, and 900ºC. Analyzing dosed samples via SEM resulted in several samples showing possible evidence of …

Developing Advanced Electrodes And Electrolytes For Energy Storage Beyond Li Ion Batteries, Kevin V. Nielson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Electric vehicles, smart phones, and portable computers are all powered by lithium-ion batteries. This is because Li-ion batteries can store more energy in less space than other battery technologies. Also, they are rechargeable and last for a long time. The most recent 2019 Nobel prize in chemistry was awarded to John Goodenough, M. Stanley Whittingham and Akira Yoshino “for the development of lithium-ion batteries”. Through their work, they have made possible cars that do not burn fossil fuels and phones that are wireless and portable. Not only can Li-ion power your phone, it is an incredibly efficient way to store …

Renewable Energy Conversion: Organic Redox Flow Batteries And Electrocatalytic Carbon Dioxide Reduction, Camden R. Debruler

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Steadily increasing global energy demands have pushed the industry to investigate renewable energy sources like solar and wind to help alleviate the strain on fossil fuel based non-renewable energy sources while also reducing carbon emissions. However, the energy producing power of these renewable technologies is limited by factors such as weather and the day-night cycle. Additional energy storage technologies are needed which are capable of storing excess energy during periods of high productivity, and delivering it when production rates fluctuate.

Batteries represent one possible energy storage device to meet this need. Specifically, redox flow batteries (RFBs) offer advantages in terms …

Anion–Anion Interactions In Aerogen-Bonded Complexes. Influence Of Solvent Environment, Anna Grabarz, Mariusz Michalczyk, Wiktor Zierkiewicz, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Ab initio calculations are applied to the question as to whether a AeX₅− anion (Ae = Kr, Xe) can engage in a stable complex with another anion: F−, Cl−, or CN−. The latter approaches the central Ae atom from above the molecular plane, along its C₅ axis. While the electrostatic repulsion between the two anions prevents their association in the gas phase, immersion of the system in a polar medium allows dimerization to proceed. The aerogen bond is a weak one, with binding energies less than 2 kcal/mol, even in highly polar aqueous solvent. The complexes are …

Noncovalent Bonds Through Sigma And Pi-Hole Located On The Same Molecule. Guiding Principles And Comparisons, Wiktor Ziekiewicz, Mariusz Michalczyk, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Over the last years, scientific interest in noncovalent interactions based on the presence of electron-depleted regions called σ-holes or π-holes has markedly accelerated. Their high directionality and strength, comparable to hydrogen bonds, has been documented in many fields of modern chemistry. The current review gathers and digests recent results concerning these bonds, with a focus on those systems where both σ and π-holes are present on the same molecule. The underlying principles guiding the bonding in both sorts of interactions are discussed, and the trends that emerge from recent work offer a guide as to how one might design systems …

Collaborative Research: Development Of A Better Understanding Of Ambient Rm Chemistry, Reactions Forming, And Methods For Measurement, Seth Lyman

Funded Research Records

No abstract provided.

Career: Time-Resolved Studies Of Charge Transfer And Chemical Reactivity At Photoelectrode-Electrolyte Interfaces, Yi Rao

Funded Research Records

No abstract provided.

Data From: Realization Of Lewis Basic Sodium Anion In The Nabh3- Cluster, Alexander I. Boldyrev, Nikita Fedik

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Project reports the first example of dative bond formed by Na- (anion) in a cluster NaBH3-.

Eager Sentinels: The Pcr-Free Biosensor For A Fast, Simple, And Sensitive Detection Of Rna, Artavazd Badalyan

Funded Research Records

No abstract provided.

Comparison Of Bifurcated Halogen With Hydrogen Bonds, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Bifurcated halogen bonds are constructed with FBr and FI as Lewis acids, paired with NH₃ and NCH bases. The first type considered places two bases together with a single acid, while the reverse case of two acids sharing a single base constitutes the second type. These bifurcated systems are compared with the analogous H-bonds wherein FH serves as the acid. In most cases, a bifurcated system is energetically inferior to a single linear bond. There is a larger energetic cost to forcing the single σ-hole of an acid to interact with a pair of bases, than the other way …

Development Of An Understanding Of Reactive Mercury In Ambient Air: A Review, Mae Sexauer Gustin, Sarrah M. Dunham-Cheatham, Jiaoyan Huang, Steve Lindberg, Seth N. Lyman

Chemistry and Biochemistry Faculty Publications

This review focuses on providing the history of measurement efforts to quantify and characterize the compounds of reactive mercury (RM), and the current status of measurement methods and knowledge. RM collectively represents gaseous oxidized mercury (GOM) and that bound to particles. The presence of RM was first recognized through measurement of coal-fired power plant emissions. Once discovered, researchers focused on developing methods for measuring RM in ambient air. First, tubular KCl-coated denuders were used for stack gas measurements, followed by mist chambers and annular denuders for ambient air measurements. For ~15 years, thermal desorption of an annular KCl denuder in …

The Impact Of Biological Components On A Dog's Personality, Kinsley Batson

Fall Student Research Symposium 2020

We interact with dogs every day, and they are often referred to as "man's best friend." But what makes a dog the happy-go-lucky, cuddly fur ball of happiness that so many love? Similar to humans, there is a nature vs. nurture debate on what shapes a dog's personality. While it is likely a mixture of both, I've researched a variety of biological components that help to make a dog a dog. Some of these include face shape, how their brain responds to audio stimuli, and a specific gene, also found in children with Williams syndrome, that is thought to make …

Why Dogs Are Feared, Hannah Ericson

Fall Student Research Symposium 2020

From German Shepherds to Pit bulls, a specific breed of dog is often singled out as being more dangerous than the others. There are stories and myths behind the behavior of such breeds, as well as simply looking scary. In this presentation, I will discuss why certain traits in dogs promote fear (such as dark coloring) and why certain breeds promote fear - such as a modern day prejudice that is quite similar to racism in the human society.

Cloning Type Iv-B Crispr System Into A Plasmid, Olivia Gornichec, Kailey Welch

Fall Student Research Symposium 2020

Bacterial CRISPR-Cas systems have recently been repurposed as RNA-guided genome editors in research labs across the world. Yet CRISPR-Cas adaptive immune systems are very diverse and many systems remain uncharacterized. Discovering the structure and function of newly discovered and uncharacterized systems may further advance existing genome editing technologies, or lead to new ones. To better understand the function of the little-researched Type IV-B system we cloned the genes of a Type IV-B system from Mycobacterium J623 into a plasmid containing a target sequence of a Type IV-A and Type V system. The Type IV-B system was placed on the target …