Article
Chemistry, Inorganic & Nuclear
Mengyuan Wu, Yuhao He, Li Zhang, Rui Wei, Dongmin Wang, Jingjing Liu, Liu Leo Liu, Gengwen Tan
Summary: The synthesis and characterization of an acyclic silylone supported by a mesoionic carbene were reported. The study discovered that the silicon center of the compound is highly electron-rich and has lone-pair electrons. Reactivity tests showed that the compound can coordinate with CuCl molecules.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2022)
Article
Nuclear Science & Technology
Masashi Kaneko, Yuji Sasaki, Masahiko Matsumiya, Masahiko Nakase, Kenji Takeshita
Summary: Density-functional theory calculations were used to model the molecular structure and complex formation reactions of metal ion complexes with DTPA and DTPABA chelates, revealing that Am3+ forms more stable complexes with both chelates than Eu3+. The higher selectivity of Am3+ over Eu3+ is attributed to the larger bond overlap between the Am3+ 5 f-orbital and N 2s, 2p-orbital, leading to differences in complex formation stabilities. This study may help in understanding the origin of metal ion selectivity and in exploring novel ligands.
JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY
(2021)
Article
Chemistry, Inorganic & Nuclear
Ravi Srivastava, Martin Jakoobi, Chloe Thieuleux, Elsje Alessandra Quadrelli, Clement Camp
Summary: The rhodium complex Rh(HL)(COD)Cl, featuring a functionalized N-heterocyclic carbene ligand with an oxygen-containing pendant arm, has been used to synthesize a series of neutral and cationic Rh(i) O,C chelates. Analysis shows that the strength of the Rh-O bond is greatly affected by the nature of the O-donor, resulting in significant differences in catalytic activity. The most active catalyst, [Rh(L)(COD)]2, demonstrates good catalytic performance under mild conditions for hydrosilylation and selective remote functionalization of internal olefins.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Multidisciplinary
Cameron F. Baker, John A. Seed, Ralph W. Adams, Daniel Lee, Stephen T. Liddle
Summary: This study presents an experimental and computational assessment of two cerium(IV)-diphosphonioalkylidene complexes, confirming the presence of Ce-C double bonds. The research provides quantified benchmarks for understanding diphosphonioalkylidene bonding and reveals the contributions of Ce 4f orbitals and the variance in 4f spin-orbit contributions to the Ce-C bonding.
Article
Chemistry, Multidisciplinary
Cheng Xu, Zhen Ye, Li Xiang, Shuhan Yang, Qian Peng, Xuebing Leng, Yaofeng Chen
Summary: The synthesis of silacycle compounds, including the insertion of metal-substituted silylene fragments into the aromatic ring of naphthalene, is of both fundamental and application importance. This insertion is followed by interesting rearrangements to yield silaspiro-benzocycloheptenyl and cyclobutenosilaindan derivatives, with mechanistic aspects revealed through DFT investigations. Additionally, formed cyclobutenosilaindan potassium can readily react with various compounds to afford substituted cyclobutenosilaindans in high yields.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Paul Schmid, Felipe Fantuzzi, Jonas Klopf, Niklas B. Schroeder, Rian D. Dewhurst, Holger Braunschweig, Volker Engel, Bernd Engels
Summary: This issue features the research work of Bernd Engels, Holger Braunschweig, Volker Engel and their coworkers at University of Wurzburg on bridged boron compounds, highlighting the fascinating relationships between their composition, geometrical structures, and electronic structures.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Physical
Min Zhang, Yang Wang, Shi-Jun Li, Xinghua Wang, Qianqian Shi, Xue Li, Ling-Bo Qu, Donghui Wei, Yu Lan
Summary: This study proposes an NHC and NHC center dot H+ cooperative catalytic model for inert C-C bond activations, and uses density functional theory calculations to discover two ways in which the organocatalyst functions in [4 + 2] annulation reactions. It also introduces an atomic electronegativity index to predict the site of stereoselective C-C bond formation accurately.
Article
Chemistry, Physical
Mali Zhou, Jianjian Liu, Rui Deng, Qingyun Wang, Shuquan Wu, Pengcheng Zheng, Yonggui Robin Chi
Summary: A catalytic strategy for asymmetric synthesis of chiral tetrasubstituted silicon-stereogenic silanes is disclosed. By using a covalently symmetric silane as the substrate and a N-heterocyclic carbene catalyst, the substrate can be selectively activated and undergo desymmetrization reaction to afford optically enriched products.
Article
Chemistry, Multidisciplinary
Kevin Breitwieser, Hilke Bahmann, Robert Weiss, Dominik Munz
Summary: Stabilizing free radicals using C-donor ligands has been investigated by analyzing the pi-donation and pi-acceptance effects. This study provides a new understanding of NHC chemistry and allows for predicting the thermodynamic stability of covalent radicals and quantifying redox non-innocence.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Marcos A. S. Francisco, Felipe Fantuzzi, Thiago M. Cardozo, Pierre M. Esteves, Bernd Engels, Ricardo R. Oliveira
Summary: This study discusses the design principles and computational investigation of new organometallic platforms containing stable manganese-manganese bonds. The analysis focuses on the metal-carbene interaction and auxiliary coordination to generate short metal-metal bonds, closed-shell singlet multiplicities, and positive singlet-triplet energy gaps. The research identifies two classes of viable synthetic targets with thoroughly investigated electrostructural properties.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Physical
Timo Glaser, Jannick Meinecke, Christian Laenger, Jan-Niclas Luy, Ralf Tonner, Ulrich Koert, Michael Duerr
Summary: The reaction of methyl enol ether functionalized cyclooctyne on the silicon (001) surface was studied using both X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT). Three different groups of final states were identified, all binding to Si(001) via the strained triple bond of cyclooctyne but differing in the configuration of the methyl enol ether group. The majority of molecules adsorbed without further reaction of the enol ether group, with other configurations involving ether cleavage or transformation into a carbonyl group on the silicon surface.
Article
Chemistry, Physical
Janis Musso, Roman Schowner, Laura Falivene, Wolfgang Frey, Luigi Cavallo, Michael R. Buchmeiser
Summary: A series of cationic tungsten oxo alkylidene N-heterocyclic carbene (NHC) complexes were synthesized and characterized by single crystal X-ray diffraction. The correlation between the C-13 NMR chemical shifts of alkylidene C atoms and the DFT calculated chemical shifts was studied, revealing a good correlation and strong correlation with the rate of ring-closing metathesis. Analysis of catalyst geometries and magnetic shielding tensors allowed for assigning different structures to different levels of shielded alkylidene C atoms and corresponding reaction rates.
Article
Nanoscience & Nanotechnology
Caifa You, Xue-Qi Wang, Xiuwen Zhou, Yi Yuan, Liang-Sheng Liao, Yu-Chan Liao, Pi-Tai Chou, Yun Chi
Summary: In this study, two series of deep-blue-emitting homoleptic iridium(III) phosphors were synthesized using a different strategy to achieve high yields. The phosphors were examined through various spectroscopic and structural analysis methods, revealing their potential as deep-blue emitters for OLEDs. OLED devices based on these phosphors showed promising external quantum efficiencies and emission characteristics.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Inorganic & Nuclear
Yong-Sok Lee, Zhongyu Mou, Ana Christina L. Opina, Olga Vasalatiy
Summary: The study investigated the geometries, energetics, and electrostatic potentials of Lu complexes with various DOTA-based chelates to understand the origin of isomer stability. It was found that electrostatic and steric repulsions play key roles in destabilizing certain isomers, and potential energy barriers for inter-conversion via arm rotation were also calculated. The possibility of designing better chelates for Ln(3+) ions for molecular medicine was discussed.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
San Hua Lim, Chee Kok Poh
Summary: This study demonstrates that SiC monolayers are promising substrates for the development of highly stable single atom catalysts, with enhanced diffusion barrier energy and stability. These catalysts also show a significant reduction in activation barrier energy for CO oxidation.
Article
Chemistry, Multidisciplinary
Lucas de Azevedo Santos, Teodorico C. Ramalho, Trevor A. Hamlin, F. Matthias Bickelhaupt
Summary: Quantum chemical methods were used to analyze the nature and origin of directionality in pnictogen, chalcogen, and halogen bonds in F(m)Z·F- complexes. The results show that covalent interactions, in addition to electrostatic attraction, contribute significantly to the bond energy. Interestingly, despite electrostatic interactions favoring bending, all these bonds exhibit directionality, which contradicts the sigma-hole model. These findings are applicable to various complexes, including ClI·NH3, HClTe·NH3, and H2ClSb·NH3.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Andre Nicolai Petelski, Celia Fonseca Guerra
Summary: Hydrogen-bonded supramolecular systems can obtain extra stabilization through complexation with ions. The presence of ions weakens the hydrogen bonds but strengthens the cooperativity by pulling the monomers closer together. This results in larger steric repulsion but enhanced donor-acceptor interactions, leading to more charge donation and enhanced electrostatic attraction.
CHEMISTRY-AN ASIAN JOURNAL
(2022)
Article
Chemistry, Inorganic & Nuclear
Daniel E. Trujillo-Gonzalez, Gerardo Gonzalez-Garcia, Trevor A. Hamlin, F. Matthias Bickelhaupt, Holger Braunschweig, J. Oscar C. Jimenez-Halla, Miquel Sola
Summary: Boron-boron multiple bonds, such as diborenes and diborynes, are stabilized by sigma-donor ligands that provide electron density to these electron-deficient species. These compounds play a significant role in the study of chemical bonding and can activate small molecules like transition metals. Our density functional calculations showed that ligands with high or medium Lewis basicity effectively stabilize diborynes, while beryllium-based ligands show promise in stabilizing diborynes without affecting the triple bond character.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Bryan Phuti Moloto, Pascal Vermeeren, Marco Dalla Tiezza, Tessel Bouwens, Catharine Esterhuysen, Trevor A. Hamlin, F. Matthias Bickelhaupt
Summary: In this study, the activation of H(n)A-AH(n) bonds (AH(n) = CH3, NH2, OH, F) by PdLn catalysts with different ligands (L-n = no ligand, PH3, (PH3)(2)) was investigated using relativistic density functional theory. The results show that the activation energy for oxidative addition decreases from H3C-CH3 to H2N-NH2 to HO-OH, and the activation of the F-F bond is barrierless. The enhanced reactivity along this series of substrates is attributed to the combination of reduced activation strain, decreased Pauli repulsion, and enhanced backbonding interaction between the palladium catalyst and the substrate.
PURE AND APPLIED CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Celine Nieuwland, Siebe Lekanne Deprez, Claris de Vries, Celia Fonseca Guerra
Summary: Our quantum chemical analyses revealed that replacing O with the larger chalcogens S and Se in benzene-1,3,5-tricarboxamides (OBTAs) enhances intermolecular interactions and increases the stability of hydrogen-bonded supramolecular polymers due to improved geometry for self-assembly and enhanced covalent interactions. Additionally, the cooperativity in benzene-1,3,5-triamide (BTA) self-assembly is attributed to charge separation in the sigma-electronic system following the covalency in the hydrogen bonds.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Thomas Hansen, Pascal Vermeeren, Kim W. J. Zijderveld, F. Matthias Bickelhaupt, Trevor A. A. Hamlin
Summary: The influence of ring strain on the competition between the S(N)2 and E2 pathways has been studied using quantum chemical methods. It was found that increasing ring strain decreases the activation energy of the S(N)2 pathway but generally increases the activation energy of the E2 pathway. This results in a mechanistic switch in the preferred reaction pathway for strong Lewis bases, favoring S(N)2 for small cyclic substrates and E2 for large cyclic substrates.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Jie Jian, Roel Hammink, Paul Tinnemans, F. Matthias Bickelhaupt, Jordi Poater, Jasmin Mecinovic
Summary: In this study, the noncovalent interactions between the tetrazole ring and neighboring aromatic ring substituents were investigated through synthetic, spectroscopic, structural, and quantum chemical analyses. The results showed that through-space NH-π interactions and π-π interactions contribute to the trends of pKa values and proton affinities of 2-arylphenyl-1H-tetrazoles. These findings are important for the rational design of tetrazole-based drugs and materials.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Physical
Humberto A. Rodriguez, F. Matthias Bickelhaupt, Israel Fernandez
Summary: The Burgi-Dunitz (BD) angle is essential in organic chemistry for understanding nucleophilic addition to carbonyl groups. However, the origin of the obtuse trajectory of the nucleophile is still not fully understood. This study quantifies the importance of physical factors quantum chemically to explain the obtuse BD angle. The obtuse angle is a result of reduced Pauli repulsion, a more stabilizing HOMO-π*-LUMO(C=O) interaction, and a favorable electrostatic attraction.
Article
Chemistry, Organic
Daniela Rodrigues Silva, Lucas A. Zeoly, Pascal Vermeeren, Rodrigo A. Cormanich, Trevor A. Hamlin, Celia Fonseca Guerra, Matheus P. Freitas
Summary: We investigated the stereoselectivity and reactivity of sodium borohydride reduction of 2-X-cyclohexanones (X=H, Cl, Br) using a combined approach of competitive experiments and density functional theory calculations. The results showed that the hydride addition proceeded via a late transition state and the reaction barrier decreased as the halogen substitution decreased, in line with relative reactivities observed in the competitive experiments. Moreover, including implicit solvation in combination with an explicit solvent molecule was crucial to accurately reproduce the experimentally observed stereoselective formation of the cis product.
JOURNAL OF PHYSICAL ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Lucas de Azevedo Santos, Storm van Der Voort, Shiri R. Burema, Celia Fonseca Guerra, F. Matthias Bickelhaupt
Summary: The atypical blueshift in hydrogen-bonded complexes X•••H3C-Y compared to Cl•••H3N and Cl•••H3C-H is found to originate from a direct X•••C interaction, rather than H-C bond contraction. This blueshift acts as a diagnostic for tetrel bonding, with redshift more commonly found in systems involving direct X•••H hydrogen bonds.
Article
Chemistry, Multidisciplinary
Celine Nieuwland, Pascal Vermeeren, F. Matthias Bickelhaupt, Celia Fonseca Guerra
Summary: The symmetry-decomposed Voronoi deformation density (VDD) charge analysis is a useful computational tool in chemistry that allows the quantification of atomic charge flow and the understanding of chemical bonding. It can decompose the charge flow into different types of orbital interactions and different irreducible representations of point-group symmetry. This method is now also applicable to interacting open-shell molecular fragments, providing detailed insights into chemical bonding beyond what is accessible from energy decomposition analysis (EDA).
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2023)
Editorial Material
Multidisciplinary Sciences
Jordi Poater, Pascal Vermeeren, Trevor A. A. Hamlin, F. Matthias Bickelhaupt, Miquel Sola
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Celine Nieuwland, David Almacellas, Mac M. Veldhuizen, Lucas de Azevedo Santos, Jordi Poater, Celia Fonseca Guerra
Summary: Non-frontier atom exchanges in hydrogen-bonded aromatic dimers can cause significant changes in interaction energy, which are related to charge accumulation in the monomers.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Organic
David Almacellas, Celia Fonseca Guerra, Jordi Poater
Summary: This study designs a new hydrogen-bonded rosette structure to enhance the stability of supramolecular systems through increased cooperative effects. Relativistic dispersion-corrected density functional theory calculations show that this rosette structure has shorter bond lengths, stronger donor-acceptor interactions, and more attractive electrostatic interactions.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)