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Articles 1 - 9 of 9
Full-Text Articles in Physical Sciences and Mathematics
Theoretical Studies Of Ir And Nmr Spectral Changes Induced By Sigma-Hole Hydrogen, Halogen, Chalcogen, Pnicogen, And Tetrel Bonds In A Model Protein Environment, Mariusz Michalczyk, Wiktor Zierkiewicz, Rafał Wysokiński, Steve Scheiner
Theoretical Studies Of Ir And Nmr Spectral Changes Induced By Sigma-Hole Hydrogen, Halogen, Chalcogen, Pnicogen, And Tetrel Bonds In A Model Protein Environment, Mariusz Michalczyk, Wiktor Zierkiewicz, Rafał Wysokiński, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Various types of σ-hole bond complexes were formed with FX, HFY, H2FZ, and H3FT (X = Cl, Br, I; Y = S, Se, Te; Z = P, As, Sb; T = Si, Ge, Sn) as Lewis acid. In order to examine their interactions with a protein, N-methylacetamide (NMA), a model of the peptide linkage was used as the base. These noncovalent bonds were compared by computational means with H-bonds formed by NMA with XH molecules (X = F, Cl, Br, I). In all cases, the A–F bond, which lies opposite the base and is responsible for …
Effects Of Halogen, Chalcogen, Pnicogen, And Tetrel Bonds On Ir And Nmr Spectra, Jia Lu, Steve Scheiner
Effects Of Halogen, Chalcogen, Pnicogen, And Tetrel Bonds On Ir And Nmr Spectra, Jia Lu, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Complexes were formed pairing FX, FHY, FH2Z, and FH3T (X = Cl, Br, I; Y = S, Se, Te; Z = P, As, Sb; T = Si, Ge, Sn) with NH3 in order to form an A⋯N noncovalent bond, where A refers to the central atom. Geometries, energetics, atomic charges, and spectroscopic characteristics of these complexes were evaluated via DFT calculations. In all cases, the A–F bond, which is located opposite the base and is responsible for the σ-hole on the A atom, elongates and its stretching frequency undergoes a shift to the red. This …
Violation Of Electrostatic Rules: Shifting Balance Between Pnicogen Bond And Lone Pair−Π Interaction Tuned By Substituents, Zongqing Chi, Tong Yan, Qing-Zhong Li, Steve Scheiner
Violation Of Electrostatic Rules: Shifting Balance Between Pnicogen Bond And Lone Pair−Π Interaction Tuned By Substituents, Zongqing Chi, Tong Yan, Qing-Zhong Li, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Complexes were formed pairing ZCl3 (Z=P, As, Sb) with C2R4 (R= H, F, CN). The first interaction present is a pnicogen bond between the Z atom and the C=C π-bond. This bond weakens as the H atoms of ethylene are replaced by electron-withdrawing F and CN and the potential above the alkene switches from negative to positive. In the latter two cases, another set of noncovalent bonds is formed between the Cl lone pairs of ZCl3 and the π*(C=C) antibonding orbital, as well as with the F or CN substituents. The growing strength of these interactions, coupled with a large …
Comparison Between Hydrogen And Halogen Bonds In Complexes Of 6-Ox-Fulvene With Pnicogen And Chalcogen Electron Donors, Mingchang Hou, Qing-Zhong Li, Steve Scheiner
Comparison Between Hydrogen And Halogen Bonds In Complexes Of 6-Ox-Fulvene With Pnicogen And Chalcogen Electron Donors, Mingchang Hou, Qing-Zhong Li, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Quantum chemical calculations are applied to complexes of 6‐OX‐fulvene (X=H, Cl, Br, I) with ZH3/H2Y (Z=N, P, As, Sb; Y=O, S, Se, Te) to study the competition between the hydrogen bond and the halogen bond. The H‐bond weakens as the base atom grows in size and the associated negative electrostatic potential on the Lewis base atom diminishes. The pattern for the halogen bonds is more complicated. In most cases, the halogen bond is stronger for the heavier halogen atom, and pnicogen electron donors are more strongly bound than chalcogen. Halogen bonds to chalcogen atoms strengthen in the order O
On The Ability Of Pnicogen Atoms To Engage In Both Σ And Π-Hole Complexes. Heterodimers Of Zf2C6H5 (Z = P, As, Sb, Bi) And Nh3, Wiktor Zierkiewicz, Mariusz Michalczyk, Rafał Wysokiński, Steve Scheiner
On The Ability Of Pnicogen Atoms To Engage In Both Σ And Π-Hole Complexes. Heterodimers Of Zf2C6H5 (Z = P, As, Sb, Bi) And Nh3, Wiktor Zierkiewicz, Mariusz Michalczyk, Rafał Wysokiński, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
When bound to a pair of F atoms and a phenyl ring, a pyramidal pnicogen (Z) atom can form a pnicogen bond wherein an NH3 base lies opposite one F atom. In addition to this σ-hole complex, the ZF2C6H5 molecule can distort in such a way that the NH3 approaches on the opposite side to the lone pair on Z, where there is a so-called π-hole. The interaction energies of these π-hole dimers are roughly 30 kcal/mol, much larger than the equivalent quantities for the σ-hole complexes, which are only 4–13 kcal/mol. On …
Structures Of Clusters Surrounding Ions Stabilized By Hydrogen, Halogen, Chalcogen, And Pnicogen Bonds, Steve Scheiner, Mariusz Michalczyk, Wiktor Zierkiewicz
Structures Of Clusters Surrounding Ions Stabilized By Hydrogen, Halogen, Chalcogen, And Pnicogen Bonds, Steve Scheiner, Mariusz Michalczyk, Wiktor Zierkiewicz
Chemistry and Biochemistry Faculty Publications
Four H-binding HCl and HF molecules position themselves at the vertices of a tetrahedron when surrounding a central Cl-. Halogen bonding BrF and ClF form a slightly distorted tetrahedron, a tendency that is amplified for ClCN which forms a trigonal pyramid. Chalcogen bonding SF2, SeF2, SeFMe, and SeCSe occupy one hemisphere of the central ion, leaving the other hemisphere empty. This pattern is repeated for pnicogen bonding PF3, SeF3 and AsCF. The clustering of solvent molecules on one side of the Cl- is attributed to weak attractive interactions between them, including chalcogen, pnicogen, halogen, and hydrogen bonds. Binding energies of …
Hexacoordinated Tetrel-Bonded Complexes Between Tf4 (T = Si, Ge, Sn, Pb) And Nch. Competition Between Σ- And Π-Holes, Mariusz Michalczyk, Wiktor Zierkiewicz, Rafal Wysokiński, Steve Scheiner
Hexacoordinated Tetrel-Bonded Complexes Between Tf4 (T = Si, Ge, Sn, Pb) And Nch. Competition Between Σ- And Π-Holes, Mariusz Michalczyk, Wiktor Zierkiewicz, Rafal Wysokiński, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
In order to accommodate the approach of two NCH bases, a tetrahedral TF4 molecule (T=Si,Ge,Sn,Pb) distorts into an octahedral structure in which the two bases can be situated either cis or trans to one another. The square planar geometry of TF4, associated with the trans arrangement of the bases, is higher in energy than its see-saw structure which corresponds to the cis trimer. On the other hand, the square geometry offers an unobstructed path of the bases to the π-holes above and below the tetrel atom so enjoys a higher interaction energy than is the case for the σ-holes approached …
Comparison Of Σ-Hole And Π-Hole Tetrel Bonds In Complexes Of Borazine With Th3f And F2to/H2to (T=C,Si,Ge), Jingru Zhang, Qingze Hu, Qing-Zhong Li, Steve Scheiner, Shufeng Liu
Comparison Of Σ-Hole And Π-Hole Tetrel Bonds In Complexes Of Borazine With Th3f And F2to/H2to (T=C,Si,Ge), Jingru Zhang, Qingze Hu, Qing-Zhong Li, Steve Scheiner, Shufeng Liu
Chemistry and Biochemistry Faculty Publications
The complexes between borazine and TH3F/F2TO/H2TO (T=C, Si, Ge) are investigated with high-level quantum chemical calculations. Borazine has three sites of negative electrostatic potential: the N atom, the ring center, and the H atom of the B-H bond, while TH3F and F2TO/H2TO provide the σ-hole and π-hole, respectively, for the tetrel bond. The N atom of borazine is the favored site for both the σ and π-hole tetrel bonds. Less stable dimers include a σ-tetrel bond to the borazine ring center and to the BH proton. The π-hole tetrel-bonded complexes are more strongly bound than aretheirσ-hole counterparts. Due to the …
Dual Geometry Schemes In Tetrel Bonds: Complexes Between Tf4(T = Si, Ge, Sn) And Pyridine Derivatives, Wiktor Zierkiewicz, Mariusz Michalczyk, Rafał Wysokiński, Steve Scheiner
Dual Geometry Schemes In Tetrel Bonds: Complexes Between Tf4(T = Si, Ge, Sn) And Pyridine Derivatives, Wiktor Zierkiewicz, Mariusz Michalczyk, Rafał Wysokiński, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
When an N-base approaches the tetrel atom of TF4(T = Si, Ge, Sn) the latter moleculedeforms from a tetrahedral structure in the monomer to a trigonal bipyramid. The base can situateitself at either an axial or equatorial position, leading to two different equilibrium geometries.The interaction energies are considerably larger for the equatorial structures, up around 50 kcal/mol,which also have a shorter R(T··N) separation. On the other hand, the energy needed to deform thetetrahedral monomer into the equatorial structure is much higher than the equivalent deformationenergy in the axial dimer. When these two opposite trends are combined, it is the axial …