Physical Sciences and Mathematics Commons^™

Cross Coupling Reactions Catalyzed By (Nhc)Pd(Ii) Complexes, Nevi̇n Gürbüz, Emi̇ne Özge Karaca, İsmai̇l Özdemi̇r, Beki̇r Çeti̇nkaya

Turkish Journal of Chemistry

This review is focused on new developments reported during the last 3 years concerning the catalytic performances of in situ formed or preformed NHC--Pd(II) complexes (NHC: $N$-heterocyclic carbene) for cross-coupling reactions such as Heck--Mizoraki (often shortened to the Heck reaction), Kumada, Negishi, Suzuki--Miyaura (often shortened to the Suzuki reaction), Sonogashira and Hiyama couplings, and the Buchwald--Hartwig aminations, which are extremely powerful in the formation of C--C and C--heteroatom bonds. Due to the great number of publications and limited space here, we made a special attempt to compile the relevant data in tables, which we hope will serve as a guide …

Monodisperse Palladium Nanoparticles Supported On Chemically Derived Graphene: Highly Active And Reusable Nanocatalysts For Suzuki--Miyaura Cross-Coupling Reactions, Feyyaz Durap, Önder Meti̇n

Turkish Journal of Chemistry

Addressed herein is the catalysis of monodisperse palladium nanoparticles (NPs) supported on chemically derived graphene (CDG) for the Suzuki--Miyaura cross-coupling of phenylboronic acid and various aryl halides. Monodisperse Pd NPs were synthesized by the solution phase reduction of palladium(II) acetylacetonate with morpholine borane complex in oleylamine and deposited on CDG via the liquid phase self-assembly method. Colloidal Pd NPs and CDG-Pd catalyst were characterized by TEM, XRD, SEM, and ICP-MS analyses. The CDG-Pd catalyst showed high activity in the Suzuki--Miyaura cross-couplings of different aryl halides including iodides, bromides, and even chlorides with phenylboronic acid under mild conditions. More importantly, the …

Synthesis Of New Thiol-Derivatized Aminophosphines And Their Catalytic Activities In C--C Coupling Reactions, Nermi̇n Bi̇ri̇ci̇k, Nermi̇n Meri̇ç, Cezmi̇ Kayan, Zeynep Özgen, Sevi̇l Şeker Azi̇zoğlu, Bahatti̇n Gümgüm

Turkish Journal of Chemistry

A series of new aminophosphines [Ph$_{2}$PHN-C$_{6}$H$_{4}$-R, where R = $o$-SH (4a), $m$-SH (4b) or $p$-SH (4c)] were readily synthesized from cheap starting materials by the phosphorylation reaction of $o$, $m$, and $p$-aminothiophenols with Ph$_{2}$PCl in the presence of triethyl amine. The new compounds were characterized by NMR and IR spectroscopy and microanalysis. In addition, aminophosphine ligands-palladium systems were investigated as precatalysts in C-C coupling reactions. Compounds 4b and 4c were proved to be excellent catalysts for Suzuki and Heck cross-coupling reactions.

Synthesis, Characterization, And Microwave-Assisted Catalytic Activity In Heck, Suzuki, Sonogashira, And Buchwald-Hartwig Cross-Coupling Reactions Of Novel Benzimidazole Salts Bearing N-Phthalimidoethyl And Benzyl Moieties, Hasan Küçükbay, Ülkü Yilmaz, Kemal Yavuz, Nesri̇n Buğday

Turkish Journal of Chemistry

Five novel benzimidazole salts (1-5) having N-phthalimidoethyl and 4-substituted benzyl were synthesized and identified by $^{1}$H NMR, $^{13}$C NMR, and IR spectroscopic methods and microanalysis. A mixture of the benzimidazole salts (1-5), Pd(OAc)$_{2}$, and K$_{2}$CO$_{3}$ in DMF-H$_{2}$O catalyzed, in high yield, the Suzuki-Miyaura and the Heck-Mizoroki cross-coupling reactions assisted by microwave irradiation in 5 min. The novel benzimidazole salts (1-5), Pd(OAc)$_{2}$, Cs$_{2}$CO$_{3}$, PEG, and Cu nanoparticles catalyzed, in high yield, the Sonogashira coupling reaction promoted by microwave irradiation in 10 min. The same benzimidazole salts (1-5), Pd(OAc)$_{2}$, Cs$_{2}$CO$_{3}$, and TBAB catalyzed, in moderate or low yield, the Buchwald-Hartwig reaction assisted …

Substituted 2-(2''-Pyridyl)Benzimidazole Palladium(Ii) Complexes As An Efficient Catalytic System For Suzuki--Miyaura Cross-Coupling Reactions, Mahmut Ulusoy, Nurdal Öncel, Emi̇ne Aytar

Turkish Journal of Chemistry

A new series of $N,N$-type 2-(2'-pyridyl)benzimidazole ligands (2A$_{\mathbf{1}}$, 2A$_{\mathbf{2}}$, 3B$_{\mathbf{1}}$, 3B$_{\mathbf{2}}$, 3B$_{\mathbf{3}}$, and 4C$_{\mathbf{1}})$ and their Pd(II) complexes (5A$_{\mathbf{1}}$, 5A$_{\mathbf{2}}$, 6B$_{\mathbf{1}}$, 6B$_{\mathbf{2}}$, 6B$_{\mathbf{3}}$, and 7C$_{\mathbf{1}})$ were prepared and characterized by conventional spectroscopic methods and elemental analyses. The incorporation of $N$-coordinated benzimidazole complexes of palladium gave high catalytic activity in the Suzuki-Miyaura coupling of aryl halides substrates. After determining the best active catalyst as 5A$_{\mathbf{1}}$, bearing the mesityl substituent on the benzimidazole ring with the Pd(II) ion, optimization studies were carried out via changing the substrate, base, time, atmosphere, and the effect of water. The DMF:H$_{2}$O (4/1) and Cs$_{2}$CO$_{3}$ as base …

Combinatorial Potpourri: Permutations, Products, Posets, And Pfaffians, Norman B. Fox

Theses and Dissertations--Mathematics

In this dissertation we first examine the descent set polynomial, which is defined in terms of the descent set statistics of the symmetric group. Algebraic and topological tools are used to explain why large classes of cyclotomic polynomials are factors of the descent set polynomial. Next the diamond product of two Eulerian posets is studied, particularly by examining the effect this product has on their cd-indices. A combinatorial interpretation involving weighted lattice paths is introduced to describe the outcome of applying the diamond product operator to two cd-monomials. Then the cd-index is defined for infinite posets, with …

Weak Values Obtained In Matter-Wave Interferometry, Stephan Sponar, Tobias Denkmayr, Hermann Geppert, Hartmutt Lemmel, Alexandre Matzkin, Jeff Tollaksen, Yuji Hasegawa

Mathematics, Physics, and Computer Science Faculty Articles and Research

Weak values, introduced more than 25 years ago, underwent a metamorphosis from a theoretical curiosity to a powerful resource in photonics for exploring foundations of quantum mechanics, as well as a practical laboratory tool. Due to the tiny coherence volume of particles used in matter-wave optics, a straightforward implementation of weak measurements is not feasible. We have overcome this hurdle by developing a method to weakly measure a massive particle's spin component. A neutron optical approach is realized by utilizing neutron interferometry, where the neutron's spin is coupled weakly to its spatial degree of freedom. Here, we present how one …

An Extension Of Herglotz's Theorem To The Quaternions, Daniel Alpay, Fabrizio Colombo, David P. Kimsey, Irene Sabadini, David P. Kimsey

Mathematics, Physics, and Computer Science Faculty Articles and Research

A classical theorem of Herglotz states that a function n↦r(n) from Z into Cs×s is positive definite if and only there exists a Cs×s-valued positive measure dμ on [0,2π] such that r(n)=∫2π0eintdμ(t)for n∈Z. We prove a quaternionic analogue of this result when the function is allowed to have a number of negative squares. A key tool in the argument is the theory of slice hyperholomorphic functions, and the representation of such functions which have a positive real part in the unit ball of the quaternions. We study in great detail the case of positive definite functions.

Approximation Of Nested Fixpoints, Alexander Kurz

Engineering Faculty Articles and Research

The question addressed in this paper is how to correctly approximate infinite data given by systems of simultaneous corecursive definitions. We devise a categorical framework for reasoning about regular datatypes, that is, datatypes closed under products, coproducts and fixpoints. We argue that the right methodology is on one hand coalgebraic (to deal with possible nontermination and infinite data) and on the other hand 2-categorical (to deal with parameters in a disciplined manner). We prove a coalgebraic version of Bekic lemma that allows us to reduce simultaneous fixpoints to a single fix point. Thus a possibly infinite object of interest is …

Coalgebraic Semantics Of Reflexive Economics (Dagstuhl Seminar 15042), Samson Abramsky, Alexander Kurz, Pierre Lescanne, Viktor Winschel

Engineering Faculty Articles and Research

This report documents the program and the outcomes of Dagstuhl Seminar 15042 “Coalgebraic Semantics of Reflexive Economics”.

Photogenerated O-Azaxylylenes: Mechanistic Studies And Synthetic Applications, William Cole Cronk

Electronic Theses and Dissertations

This research sets out to build upon excited state o-azaxylylene cycloaddition. The mechanism behind the excitation and cycloaddition process of photogenerated o-azaxylylenes was determined experimentally. Time-correlated single-photon counting, steady-state spectroscopy, triplet quenching experiments, and quantum yield studies provided evidence suggesting that excited state intramolecular proton transfer is followed by intersystem crossing and stepwise addition to the tethered unsaturated pendant.

In keeping with the principles of diversity oriented synthesis, a modular approach was taken to gain access to a diverse array of N,O,S-Polyheterocycles which were modified postphotochemically via Suzuki coupling to yield fused biaryls. Cycloaddition products, outfitted with halogens …

Riemannian Geometry (Abstract), Chikako Mese

Kenneth C. Schraut Memorial Lectures

Riemannian Geometry studies the geometry of curved spaces. It originated with the ideas of the Bernhard Riemann in the 19th century extending Gaussian geometry, or the study of geometry of curves and surfaces contained in 3 dimensional Euclidean space.

Sixteenth Kenneth C. Schraut Memorial Lecture (Poster), University Of Dayton. Department Of Mathematics

Kenneth C. Schraut Memorial Lectures

No abstract provided.

Tigra Scientifica Volume Ii, Issue 1

Tigra scientifica

It is our pleasure to welcome readers to the Fall 2015 issue of Tigra scientifica Science News Magazine. This is the 10th issue in this series of exemplary writings by students enrolled in Clemson University’s Creative Inquiry (CI) course, Popular Science Journalism. Science and technology have an enormous impact on society. Thus, science journalists shoulder the responsibility of transmitting accurate, comprehensible, and timely information to bridge the gap between scientists and the general public. A talented group of Clemson University undergraduate students has embraced this responsibility to produce this magazine.

Linkages Between Water Challenges And Land Use Planning In Megacities, Enjie Li, Joanna Endter-Wada, Shujuan Li

Joanna Endter-Wada

No abstract provided.

A Systems-Based Approach To Address Unintended Consequences Of Demand-Driven Transportation Planning In National Parks And Public Lands, Steven Lawson, Peter Newman, Christopher Monz

Christopher Monz

No abstract provided.

Voigt, Reuss, Hill, And Self-Consistent Techniques For Modeling Ultrasonic Scattering, Christopher M. Kube, Joseph A. Turner

Department of Mechanical and Materials Engineering: Faculty Publications

An elastic wave propagating in a metal loses a portion of its energy from scattering caused by acoustic impedance differences existing at the boundaries of anisotropic grains. Theoretical scattering models capture this phenomena by assuming the incoming wave is described by an average elastic moduli tensorC_0ijkl (x) that is perturbed by a grain with elasticityC_ijkl (x ') where the scattering event occurs when x = x’. Previous models have assumed that C_0ijkl (x) is the Voigt average of the singlecrystal elastic moduli tensor. However, this assumption …

Acoustic Nonlinearity Parameters For Transversely Isotropic Polycrystalline Materials, Christopher M. Kube, Joseph A. Turner

Department of Mechanical and Materials Engineering: Faculty Publications

This article considers polycrystalline materials with macroscopic elastic anisotropy and the effect of the anisotropy on the quadratic nonlinearity parameter used to describe second harmonic generation in solids. The polycrystal is assumed to have transversely isotropic elastic symmetry, which leads to a directional dependence of the nonlinearity parameters. Additionally, the anisotropy leads to second harmonic generation from an input shear wave. Estimates of the longitudinal and shear wave nonlinearity parameters are given as a function of single-crystal elastic constants, macroscopic anisotropy constants, and propagation direction. An inverse model is presented that relates measured nonlinearity parameters to the macroscopic anisotropy constants. …

Acoustic Attenuation Coefficients For Polycrystalline Materials Containing Crystallites Of Any Symmetry Class, Christopher M. Kube, Joesph A. Turner

Department of Mechanical and Materials Engineering: Faculty Publications

This letter provides a theoretical extension to the elastic properties of polycrystals in order to describe elastic wave scattering from grain boundaries. The extension allows the longitudinal and shear attenuation coefficients for scattering to be derived and is valid for polycrystals containing crystallites of any symmetry class. Attenuation curves are given for polycrystalline SiO₂, ZrO₂, and SnF₂, which contain monoclinic crystallites. This work will allow ultrasonic techniques to be applied to new classes of materials containing nontrivial microstructures.

Interfacial Electronic Structure At The Ch3nh3pbi3/Moox Interface, Peng Liu, Xiaoliang Liu, Lu Lyu, Haipeng Xie, Hong Zhang, Dongmei Niu, Han Huang, Cheng Bi, Zhengguo Xiao, Jinsong Huang, Yongli Gao

Department of Mechanical and Materials Engineering: Faculty Publications

Interfacial electronic properties of the CH₃NH₃PbI₃ (MAPbI₃)/M_oOx interface are investigated using ultraviolet photoemission spectroscopy and X-ray photoemission spectroscopy. It is found that the pristine MAPbI₃ film coated onto the substrate of poly (3,4-ethylenedioxythiophene) poly(styrenesulfonate)/indium tin oxide by two-step method behaves as an n-type semiconductor, with a band gap of ~1.7 eV and a valence band edge of 1.40 eV below the Fermi energy (EF). With the MoOx deposition of 64A ° upon MAPbI3, the energy levels of MAPbI3 shift toward higher binding energy by 0.25 eV due to electron transfer …

Erratum: “The Operation Mechanism Of Poly (9,9-Dioctylfluorenyl-2,7-Diyl) Dots In High Efficiency Polymer Solar Cells” [Appl. Phys. Lett. 106, 193904 (2015)], Chunyu Liu, Yeyuan He, Xinyuan Zhang, Zhiqi Li, Jinfeng Li, Liang Shen, Zhihui Zhang, Wenbin Guo, Shengping Ruan

Department of Mechanical and Materials Engineering: Faculty Publications

We have noticed an error in Fig. 7 of the original article. Figs. 7(a) and 7(b) should be exchanged and the revised figure is shown below. We apologize for this error.¹

The Operation Mechanism Of Poly(9,9-Dioctylfluorenyl-2,7-Diyl) Dots In High Efficiency Polymer Solar Cells, Chunyu Liu, Yeyuan He, Xinyuan Zhang, Zhiqi Li, Liang Shen, Zhihui Zhang, Wenbin Guo, Shengping Ruan

Department of Mechanical and Materials Engineering: Faculty Publications

The highly efficient polymer solar cells were realized by doping poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) dots into active layer. The dependence of doping amount on devices performance was investigated and a high efficiency of 7.15% was obtained at an optimal concentration, accounting for a 22.4% enhancement. The incorporation of PFO dots (Pdots) is conducted to the improvement of Jsc and fill factor mainly due to the enhancement of light absorption and charge transport property. Pdots blended in active layer provides an interface for charge transfer and enables the formation of percolation pathways for electron transport. The introduction of Pdots was proven an effective …

Surface Analytical Investigation On Organometal Triiodide Perovskite, Chengong Wang, Xiaoliang Liu, Congcong Wang, Zhengguo Xiao, Cheng Bi, Yuchuan Shao, Jinsong Huang, Yongli Gao

Department of Mechanical and Materials Engineering: Faculty Publications

In a little over a year, there has been an unexpected breakthrough and rapid evolution of highly efficient solid-state hybrid solar cells based on organometal trihalide perovskite materials. This technology has the potential to produce solar cells with the very highest efficiencies while retaining the very lowest cost. The authors have measured the electronic density of states of CH₃NH₃PbI₃ using ultraviolet photoemission spectroscopy (UPS), inverse photoemission spectroscopy (IPES), and x-ray photoemission spectroscopy (XPS). The valence band maximum and conduction band minimum positions are obtained from the UPS and IPES spectra, respectively, by linear extrapolation of …

Phase Transformation And Magnetic Properties Of Rapidly Solidified Mn-Al-C Alloys Modified With Zr, Yunlong Geng, Micheal J. Lucis, Pamela Rasmussen, Jeffrey E. Shield

Department of Mechanical and Materials Engineering: Faculty Publications

Mn_54-xAl₄₃C₃Zr_x (x=1, 3) alloys were prepared by rapid solidification followed by heat treatment to produce the ferromagnetic s phase. The substitution of Zr for Mn in the structure resulted in an increase of the saturation magnetization (Ms) compared to that of Mn_54-xAl₄₃C₃. While the highest Ms (12861 emu/g) was obtained in Mn_54-xAl₄₃C₃Zr₁, the coercivity was also improved to 1.62 kOe, compared to 1.25 kOe for Mn_54-xAl₄₃C₃. To further improve the coercivity through grain …

Virtue Ethics: Examining Influences On The Ethical Commitment Of Information System Workers In Trusted Positions, John Max Gray

CCE Theses and Dissertations

Despite an abundance of research on the problem of insider threats, only limited success has been achieved in preventing trusted insiders from committing security violations. Virtue ethics may be an approach that can be utilized to address this issue. Human factors such as moral considerations impact Information System (IS) design, use, and security; consequently they affect the security posture and culture of an organization. Virtue ethics based concepts have the potential to influence and align the moral values and behavior of information systems workers with those of an organization in order to provide increased protection of IS assets. An individual’s …

Incremental Sparse-Pca Feature Extraction For Data Streams, Jean-Pierre Nziga

CCE Theses and Dissertations

Intruders attempt to penetrate commercial systems daily and cause considerable financial losses for individuals and organizations. Intrusion detection systems monitor network events to detect computer security threats. An extensive amount of network data is devoted to detecting malicious activities.

Storing, processing, and analyzing the massive volume of data is costly and indicate the need to find efficient methods to perform network data reduction that does not require the data to be first captured and stored. A better approach allows the extraction of useful variables from data streams in real time and in a single pass. The removal of irrelevant attributes …

A Predictive Modeling System: Early Identification Of Students At-Risk Enrolled In Online Learning Programs, Mary L. Fonti

CCE Theses and Dissertations

Predictive statistical modeling shows promise in accurately predicting academic performance for students enrolled in online programs. This approach has proven effective in accurately identifying students who are at-risk enabling instructors to provide instructional intervention. While the potential benefits of statistical modeling is significant, implementations have proven to be complex, costly, and difficult to maintain. To address these issues, the purpose of this study is to develop a fully integrated, automated predictive modeling system (PMS) that is flexible, easy to use, and portable to identify students who are potentially at-risk for not succeeding in a course they are currently enrolled in. …

Police Opinions Of Digital Evidence Response Handling In The State Of Georgia: An Examination From The Viewpoint Of Local Agencies’ Patrol Officers, Tanya Macneil

CCE Theses and Dissertations

This research examined opinions of local law enforcement agencies’ patrol officers in the State of Georgia regarding preparedness and expectations for handling of digital evidence. The increased criminal use of technology requires that patrol officers be prepared to handle digital evidence in many different situations. The researcher’s goal was to gain insight into how patrol officers view their preparedness to handle digital evidence as well as their opinions on management expectations regarding patrol officers’ abilities to handle digital evidence. The research focused on identifying whether a gap existed between patrol officers’ opinions of digital evidence and the patrol officers’ views …

Use Of Entropy For Feature Selection With Intrusion Detection System Parameters, Frank Acker

CCE Theses and Dissertations

The metric of entropy provides a measure about the randomness of data and a measure of information gained by comparing different attributes. Intrusion detection systems can collect very large amounts of data, which are not necessarily manageable by manual means. Collected intrusion detection data often contains redundant, duplicate, and irrelevant entries, which makes analysis computationally intensive likely leading to unreliable results. Reducing the data to what is relevant and pertinent to the analysis requires the use of data mining techniques and statistics. Identifying patterns in the data is part of analysis for intrusion detections in which the patterns are categorized …

Designing An Effective Information Security Policy For Exceptional Situations In An Organization: An Experimental Study, George S. Antoniou

CCE Theses and Dissertations

An increasing number of researchers are recognizing the importance of the role played by employees in maintaining the effectiveness of an information security policy. Currently, little research exists to validate the relationship between the actions (behaviors) taken by employees in response to exceptional situations (antecedents) regarding an organization’s information security policy, the impact (consequences) those actions have on an organization, and the motives that prompt those actions. When these exceptional situations occur, employees may feel compelled to engage in behaviors that violate the terms of an information security policy because strict compliance with the policy could cause the organization to …