Conformational flexibility of 2,6-bis(pyrazol-1-ylmethyl)pyridine (L5) in [(L5)CoII(H2O)3]Cl2 and [(L5)NiII(H2O)2Cl]Cl·H2O. Molecular structures and non-covalent interactions

2011 ◽  
Vol 372 (1) ◽  
pp. 327-332 ◽  
Author(s):  
Anuj Kumar Sharma ◽  
Anindita De ◽  
V. Balamurugan ◽  
Rabindranath Mukherjee
Keyword(s):  
Conformational Flexibility ◽  
Molecular Structures ◽  
Non Covalent Interactions ◽  
Covalent Interactions

scholarly journals 1,3,5-Triaza-7-Phosphaadamantane (PTA) as a 31P NMR Probe for Organometallic Transition Metal Complexes in Solution

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1390 ◽  
Author(s):  
Ilya G. Shenderovich
Keyword(s):  
Chemical Shift ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Density Functional ◽  
Molecular Structures ◽  
Basis Sets ◽  
Functional Theory ◽  
Non Covalent Interactions ◽  
Covalent Interactions

Due to the rigid structure of 1,3,5-triaza-7-phosphaadamantane (PTA), its 31P chemical shift solely depends on non-covalent interactions in which the molecule is involved. The maximum range of change caused by the most common of these, hydrogen bonding, is only 6 ppm, because the active site is one of the PTA nitrogen atoms. In contrast, when the PTA phosphorus atom is coordinated to a metal, the range of change exceeds 100 ppm. This feature can be used to support or reject specific structural models of organometallic transition metal complexes in solution by comparing the experimental and Density Functional Theory (DFT) calculated values of this 31P chemical shift. This approach has been tested on a variety of the metals of groups 8–12 and molecular structures. General recommendations for appropriate basis sets are reported.

scholarly journals Dynamic chiral self-recognition in aromatic dimers of styrene oxide revealed by rotational spectroscopy

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Sérgio R. Domingos ◽  
Cristóbal Pérez ◽  
Nora M. Kreienborg ◽  
Christian Merten ◽  
Melanie Schnell
Keyword(s):  
Styrene Oxide ◽  
Intermolecular Forces ◽  
Molecular Structures ◽  
Conformational Space ◽  
Rotational Spectroscopy ◽  
Self Recognition ◽  
Quantum Chemistry Calculations ◽  
Conformational Landscape ◽  
Non Covalent Interactions ◽  
Covalent Interactions

AbstractChiral molecular recognition is a pivotal phenomenon in biomolecular science, governed by subtle balances of intermolecular forces that are difficult to quantify. Non-covalent interactions involving aromatic moieties are particularly important in this realm, as recurring motifs in biomolecular aggregation. In this work, we use high-resolution broadband rotational spectroscopy to probe the dynamic conformational landscape enclosing the self-pairing topologies of styrene oxide, a chiral aromatic system. We reach a definite assignment of four homochiral and two heterochiral dimers using auxiliary quantum chemistry calculations as well as structure-solving methods based on experimental isotopic information. A complete picture of the dimer conformational space is obtained, and plausible routes for conformational relaxation are derived. Molecular structures are discussed in terms of conformational flexibility, the concerted effort of weak intermolecular interactions, and their role in the expression of the molecular fit.

Interaction of Platinum-based Drugs with Proteins: An Overview of Representative Crystallographic Studies

2020 ◽  
Vol 20 ◽  
Author(s):  
Giarita Ferraro ◽  
Domenico Loreto ◽  
Antonello Merlino
Keyword(s):  
Molecular Mechanisms ◽  
Protein Structures ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Metal Compounds ◽  
X Ray ◽  
Metal Ligands ◽  
Protein Adduct ◽  
Non Covalent Interactions ◽  
Covalent Interactions

: Pt-based drugs are widely used in clinics for the treatment of cancer. The mechanism of action of these molecules rely on their interaction with DNA. However, the recognition of these metal compounds by proteins plays an important role in defining pharmacokinetics, side effects and their overall pharmacological profiles. Single crystal X-ray diffraction studies provided important information on the molecular mechanisms at the basis of this process. Here, the molecular structures of representative adducts obtained upon reaction with proteins of selected Pt-based drugs, including cisplatin, carboplatin and oxaliplatin, were briefly described and comparatively examined. Data indicate that metal ligands play a significant role in driving the reaction of Pt compounds with proteins; non-covalent interactions that are formed in the early steps of Pt compound/protein recognition process play a crucial role in defining the structure of the final Pt-protein adduct. In the metalated protein structures, Pt centers coordinate few protein side chains, such as His, Met, Cys, Asp, Glu and Lys residues upon releasing of labile ligands.

NON COVALENT INTERACTIONS IN LARGE DIAMONDOID DIMERS IN THE GAS PHASE - A MICROWAVE STUDY

2017 ◽  
Author(s):  
Cristobal Perez ◽  
Melanie Schnell ◽  
Peter Schreiner ◽  
Norbert Mitzel ◽  
Yury Vishnevskiy ◽  
...  
Keyword(s):  
Gas Phase ◽  
Non Covalent Interactions ◽  
Covalent Interactions

Vapour Pressure Isotope Effect on Evaporation from Pure Organic Phases - a PIMD Approach

2020 ◽  
Author(s):  
Luis Vasquez ◽  
Agnieszka Dybala-Defratyka
Keyword(s):  
Path Integral ◽  
Vapour Pressure ◽  
Density Functional ◽  
Isotope Effects ◽  
Tight Binding ◽  
Decomposition Analysis ◽  
Energy Decomposition Analysis ◽  
Special Importance ◽  
Non Covalent Interactions ◽  
Covalent Interactions

<p></p><p>Very often in order to understand physical and chemical processes taking place among several phases fractionation of naturally abundant isotopes is monitored. Its measurement can be accompanied by theoretical determination to provide a more insightful interpretation of observed phenomena. Predictions are challenging due to the complexity of the effects involved in fractionation such as solvent effects and non-covalent interactions governing the behavior of the system which results in the necessity of using large models of those systems. This is sometimes a bottleneck and limits the theoretical description to only a few methods.<br> In this work vapour pressure isotope effects on evaporation from various organic solvents (ethanol, bromobenzene, dibromomethane, and trichloromethane) in the pure phase are estimated by combining force field or self-consistent charge density-functional tight-binding (SCC-DFTB) atomistic simulations with path integral principle. Furthermore, the recently developed Suzuki-Chin path integral is tested. In general, isotope effects are predicted qualitatively for most of the cases, however, the distinction between position-specific isotope effects observed for ethanol was only reproduced by SCC-DFTB, which indicates the importance of using non-harmonic bond approximations.<br> Energy decomposition analysis performed using the symmetry-adapted perturbation theory (SAPT) revealed sometimes quite substantial differences in interaction energy depending on whether the studied system was treated classically or quantum mechanically. Those observed differences might be the source of different magnitudes of isotope effects predicted using these two different levels of theory which is of special importance for the systems governed by non-covalent interactions.</p><br><p></p>

scholarly journals Heterogenisation of polyoxometalates and other metal-based complexes in metal–organic frameworks: from synthesis to characterisation and applications in catalysis

2021 ◽  
Author(s):  
P. Mialane ◽  
C. Mellot-Draznieks ◽  
P. Gairola ◽  
M. Duguet ◽  
Y. Benseghir ◽  
...  
Keyword(s):  
Metal Organic Frameworks ◽  
Coordination Complexes ◽  
Metal Organic ◽  
Non Covalent Interactions ◽  
Molecular Catalysts ◽  
Covalent Interactions

This review provides a thorough overview of composites with molecular catalysts (polyoxometalates, or organometallic or coordination complexes) immobilised into MOFs via non-covalent interactions.

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