Physical Sciences and Mathematics | Open Access Articles

“Bottled” Spiro-Doubly Aromatic Trinuclear [Pd2ru]+ Complexes, Maksim Kulichenko, Nikita Fedik, Anna Monfredini, Alvaro Muñoz-Castro, Davide Balestri, Alexander I. Boldyrev, Giovanni Maestri

Chemistry and Biochemistry Faculty Publications

Following an ongoing interest in the study of transition metal complexes with exotic bonding networks, we report herein the synthesis of a family of heterobimetallic triangular clusters involving Ru and Pd atoms. These are the first examples of trinuclear complexes combining these nuclei. Structural and bonding analyses revealed both analogies and unexpected differences for these [Pd₂Ru]⁺ complexes compared to their parent [Pd₃]⁺ peers. Noticeably, participation of the Ru atom in the π-aromaticity of the coordinated benzene ring makes the synthesized compound the second reported example of ‘bottled’ double aromaticity. This can also be referred …

Go to article

A Sandwich-Type Cluster Containing Ge@Pd3 Planar Fragment Flanked By Aromatic Nonagermanide Caps, Hong-Lei Xu, Nikolay V. Tkachenko, Zi-Chuan Wang, Wei-Xing Chen, Lei Qiao, Alvaro Muñoz-Castro, Alexander I. Boldyrev, Zhong-Ming Sun

Chemistry and Biochemistry Faculty Publications

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 …

Go to article

Versatility Of The Cyano Group In Intermolecular Interactions, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Several cyano groups are added to an alkane, alkene, and alkyne group so as to construct a Lewis acid molecule with a positive region of electrostatic potential in the area adjoining these substituents. Although each individual cyano group produces only a weak π-hole, when two or more such groups are properly situated, they can pool their π-holes into one much more intense positive region that is located midway between them. A NH₃base is attracted to this site, where it forms a strong noncovalent bond to the Lewis acid, amounting to as much as 13.6 kcal/mol. The precise nature …

Go to article

Effect Of Carbon Hybridization In C—F Bond As An Electron Donor In Triel Bonds, Qingqing Yang, Zongqing Chi, Qingzhong Li, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The ability of the F atom of HC≡CF, H₂C=CHF and H₃CCH₂F to serve as an electron donor to the triel (Tr) atom of TrR₃ in the context of a triel bond is assessed by ab initio calculations. The triel bond formed by C_sp3—F is strongest, as high as 30 kcal/mol, followed by C_sp2—F, and then by C_sp—F whose triel bonds can be as small as 1 kcal/mol. The noncovalent bond strength diminishes in the order Tr = Al > Ga > B, consistent with the intensity of the π-hole …

Go to article

Comparison Of Accelerated Solvent Extraction (Ase) And Energized Dispersive Guided Extraction (Edge) For The Analysis Of Pesticides In Leaves, Ashlie D. Kinross, Kimberly J. Hageman, William J. Doucette, Alexandria L. Foster

Chemistry and Biochemistry Faculty Publications

Various techniques have been evaluated for the extraction and cleanup of pesticides from environmental samples. In this work, a Selective Pressurized Liquid Extraction (SPLE) method for pesticides was developed using a Thermo Fisher Scientific Accelerated Solvent Extraction (ASE) system. This instrument was compared to the newly introduced (2017) extraction instrument, the Energized Dispersive Guided Extraction (EDGE) system, which combines Pressurized Liquid Extraction (PLE) and dispersive Solid Phase Extraction (dSPE). We first optimized the SPLE method using the ASE instrument for pesticide extraction from alfalfa leaves using layers of Florisil and graphitized carbon black (GCB) downstream of the leaf homogenate in …

Go to article

Influence Of Adjuvants On Pesticide Soil-Air Partition Coefficients: Laboratory Measurements And Predicted Effects On Volatilization, Supta Das, Kimberly J. Hageman

Chemistry and Biochemistry Faculty Publications

A solid-phase fugacity meter was used to measure the soil–air partition coefficients of three semivolatile pesticides (chlorpyrifos, pyrimethanil, and trifluralin) in the absence of additional adjuvants (K_{soil–air,AI}), as part of commercial formulations (K_{soil–air,formulation}), and as formulation mixtures with an additional spray adjuvant added (K_{soil–air,formulation+spray adjuvant}). Chlorpyrifos K_{soil–air,formulation} values were also measured over 15–30 °C, allowing for the change in internal energy of the phase transfer reaction (Δ_soil–airU) to be calculated and compared to the Δ_soil–airU for K_{soil–air,AI} from the literature. Measured K_soil–air values …

Go to article

N3-Ligated Nickel(Ii) Diketonate Complexes: Synthesis, Characterization And Evaluation Of O2 Reactivity, Josiah G. D. Elsberg, Austin Peterson, Amy L. Fuller, Lisa M. Berreau

Chemistry and Biochemistry Faculty Publications

Interest in O₂-dependent aliphatic carbon–carbon (C–C) bond cleavage reactions of first row divalent metal diketonate complexes stems from the desire to further understand the reaction pathways of enzymes such as DKE1 and to extract information to develop applications in organic synthesis. A recent report of O₂-dependent aliphatic C–C bond cleavage at ambient temperature in Ni(II) diketonate complexes supported by a tridentate nitrogen donor ligand [(MBBP)Ni(PhC(O)CHC(O)Ph)]Cl (7-Cl; MBBP = 2,6-bis(1-methylbenzimidazol-2-yl)pyridine) in the presence of NEt₃ spurred our interest in further examining the chemistry of such complexes. A series of new TERPY-ligated Ni(II) diketonate complexes of the …

Go to article

Co Sense And Release Flavonols: Progress Toward The Development Of An Analyte Replacement Photocorm For Use In Living Cells, Marina Popova, Tatiana Soboleva, Abby D. Benninghoff, Lisa M. Berreau

Chemistry and Biochemistry Faculty Publications

Carbon monoxide (CO) is a signaling molecule in humans. Prior research suggests that therapeutic levels of CO can have beneficial effects in treating a variety of physiological and pathological conditions. To facilitate understanding of the role of CO in biology, molecules that enable fluorescence detection of CO in living systems have emerged as an important class of chemical tools. A key unmet challenge in this field is the development of fluorescent analyte replacement probes that replenish the CO that is consumed during detection. Herein, we report the first examples of CO sense and release molecules that involve combining a common …

Go to article

Modeling The Alkaline Hydrolysis Of Diaryl Sulfate Diesters: A Mechanistic Study, Klaudia Szeler, Nicholas H. Williams, Alvan C. Hengge, Shina C. Kamerlin

Chemistry and Biochemistry Faculty Publications

Phosphate and sulfate esters have important roles in regulating cellular processes. However, while there has been substantial experimental and computational investigation of the mechanisms and the transition states involved in phosphate ester hydrolysis, there is far less work on sulfate ester hydrolysis. Here, we report a detailed computational study of the alkaline hydrolysis of diaryl sulfate diesters, using different DFT functionals as well as mixed implicit/explicit solvation with varying numbers of explicit water molecules. We consider the impact of the computational model on computed linear free-energy relationships (LFER) and the nature of the transition states (TS) involved. We obtain good …

Go to article

Boron-Made N2: Realization Of A B≡B Triple Bond In The B2al3− Cluster, Nikita Fedik, Chaonan Mu, Ivan A. Popov, Wei Wang, Jie Wang, Haopeng Wang, Kit H. Bowen, Alexander I. Boldyrev, Xinxing Zhang

Chemistry and Biochemistry Faculty Publications

Until now, all B≡B triple bonds have been achieved by adopting two ligands in the L→B≡B←L manner. Herein, we report an alternative route of designing the B≡B bonds based on the assumption that by acquiring two extra electrons, an element with the atomic number Z can have properties similar to those of the element with the atomic number Z+2. Specifically, we show that due to the electron donation from Al to B, the negatively charged B≡B kernel in the B2Al3− cluster mimics a triple N≡N bond. Comprehensive computational searches reveal that the global minimum structure of B2Al3− exhibits a …

Go to article

Competition Between Intra And Intermolecular Triel Bonds. Complexes Between Naphthalene Derivatives And Neutral Or Anionic Lewis Bases, Wiktor Zierkiewicz, Mariusz Michalczyk, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

A TrF₂ group (Tr = B, Al, Ga, In, Tl) is placed on one of the α positions of naphthalene, and its ability to engage in a triel bond (TrB) with a weak (NCH) and strong (NC⁻) nucleophile is assessed by ab initio calculations. As a competitor, an NH₂ group is placed on the neighboring C^α, from which point it forms an intramolecular TrB with the TrF₂ group. The latter internal TrB reduces the intensity of the π-hole on the Tr atom, decreasing its ability to engage in a second external TrB. The …

Go to article

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

Chemistry and Biochemistry Faculty Publications

The unusual stability of cyclo[18]carbon arising from its aromaticity might be used to provide the kinetic trapping needed in the design of interlocked systems. The kinetic barrier separating the interlocked rings and the chemically bonded complex is about 30 kcal mol−1. In addition, the rings can slide freely, which is a promising property for the design of molecular gears and motors.

Go to article

Dominant Negative Effects By Inactive Spa47 Mutants Inhibit T3ss Function And Shigella Virulence, Jamie L. Burgess, Heather B. Case, R. Alan Burgess, Nicholas E. Dickenson

Chemistry and Biochemistry Faculty Publications

Type three secretion systems (T3SS) are complex nano-machines that evolved to inject bacterial effector proteins directly into the cytoplasm of eukaryotic cells. Many high-priority human pathogens rely on one or more T3SSs to cause disease and evade host immune responses, underscoring the need to better understand the mechanisms through which T3SSs function and their role(s) in supporting pathogen virulence. We recently identified the Shigella protein Spa47 as an oligomerization-activated T3SS ATPase that fuels the T3SS and supports overall Shigella virulence. Here, we provide both in vitro and in vivo characterization of Spa47 oligomerization and activation in the presence and absence …

Go to article

Physical Sciences and Mathematics Commons^™

Full-Text Articles in Physical Sciences and Mathematics

“Bottled” Spiro-Doubly Aromatic Trinuclear [Pd2ru]+ Complexes, Maksim Kulichenko, Nikita Fedik, Anna Monfredini, Alvaro Muñoz-Castro, Davide Balestri, Alexander I. Boldyrev, Giovanni Maestri

Chemistry and Biochemistry Faculty Publications

A Sandwich-Type Cluster Containing Ge@Pd3 Planar Fragment Flanked By Aromatic Nonagermanide Caps, Hong-Lei Xu, Nikolay V. Tkachenko, Zi-Chuan Wang, Wei-Xing Chen, Lei Qiao, Alvaro Muñoz-Castro, Alexander I. Boldyrev, Zhong-Ming Sun

Chemistry and Biochemistry Faculty Publications

Versatility Of The Cyano Group In Intermolecular Interactions, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Effect Of Carbon Hybridization In C—F Bond As An Electron Donor In Triel Bonds, Qingqing Yang, Zongqing Chi, Qingzhong Li, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Comparison Of Accelerated Solvent Extraction (Ase) And Energized Dispersive Guided Extraction (Edge) For The Analysis Of Pesticides In Leaves, Ashlie D. Kinross, Kimberly J. Hageman, William J. Doucette, Alexandria L. Foster

Chemistry and Biochemistry Faculty Publications

Influence Of Adjuvants On Pesticide Soil-Air Partition Coefficients: Laboratory Measurements And Predicted Effects On Volatilization, Supta Das, Kimberly J. Hageman

Chemistry and Biochemistry Faculty Publications

N3-Ligated Nickel(Ii) Diketonate Complexes: Synthesis, Characterization And Evaluation Of O2 Reactivity, Josiah G. D. Elsberg, Austin Peterson, Amy L. Fuller, Lisa M. Berreau

Chemistry and Biochemistry Faculty Publications

Co Sense And Release Flavonols: Progress Toward The Development Of An Analyte Replacement Photocorm For Use In Living Cells, Marina Popova, Tatiana Soboleva, Abby D. Benninghoff, Lisa M. Berreau

Chemistry and Biochemistry Faculty Publications

Modeling The Alkaline Hydrolysis Of Diaryl Sulfate Diesters: A Mechanistic Study, Klaudia Szeler, Nicholas H. Williams, Alvan C. Hengge, Shina C. Kamerlin

Chemistry and Biochemistry Faculty Publications

Boron-Made N2: Realization Of A B≡B Triple Bond In The B2al3− Cluster, Nikita Fedik, Chaonan Mu, Ivan A. Popov, Wei Wang, Jie Wang, Haopeng Wang, Kit H. Bowen, Alexander I. Boldyrev, Xinxing Zhang

Chemistry and Biochemistry Faculty Publications

Competition Between Intra And Intermolecular Triel Bonds. Complexes Between Naphthalene Derivatives And Neutral Or Anionic Lewis Bases, Wiktor Zierkiewicz, Mariusz Michalczyk, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

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

Chemistry and Biochemistry Faculty Publications

Dominant Negative Effects By Inactive Spa47 Mutants Inhibit T3ss Function And Shigella Virulence, Jamie L. Burgess, Heather B. Case, R. Alan Burgess, Nicholas E. Dickenson

Chemistry and Biochemistry Faculty Publications