scholarly journals Tuning PCP–Ir complexes: the impact of an N-heterocyclic olefin

2015 ◽  
Vol 51 (62) ◽  
pp. 12431-12434 ◽  
Author(s):  
Manuel Iglesias ◽  
Amaia Iturmendi ◽  
Pablo J. Sanz Miguel ◽  
Victor Polo ◽  
Jesús J. Pérez-Torrente ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Rare Case ◽  
Dual Nature ◽  
X Ray ◽  
Coordination Modes ◽  
X Ray Crystallography ◽  
The Impact

A flexible N-heterocyclic olefin (NHO) allows the adoption of facial coordination modes in Ir(i) or meridional in Ir(iii) complexes due to the dual nature (ylide–olefin) of the NHO scaffold. This results in a rare case of olefin “slippage” that is supported by X-ray crystallography and DFT calculations.

The Structure and Internal Dynamics of R6-p-C6H4-R6 Biradical: EPR, X-ray Crystallography and DFT Calculations

2018 ◽  
Vol 50 (1-3) ◽  
pp. 425-439 ◽  
Author(s):  
A. I. Kokorin ◽  
O. I. Gromov ◽  
P. V. Dorovatovskii ◽  
V. A. Lazarenko ◽  
V. N. Khrustalev ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Internal Dynamics ◽  
X Ray ◽  
X Ray Crystallography

Structures of Nonheme Oxoiron(IV) Complexes from X-ray Crystallography, NMR Spectroscopy, and DFT Calculations

2005 ◽  
Vol 44 (24) ◽  
pp. 3690-3694 ◽  
Author(s):  
Eric J. Klinker ◽  
József Kaizer ◽  
William W. Brennessel ◽  
Nathaniel L. Woodrum ◽  
Christopher J. Cramer ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
X Ray ◽  
X Ray Crystallography

Substituent position effect on the crystal structures of N-phenyl-2-phthalimidoethanesulfonamide derivatives

2018 ◽  
Vol 74 (1) ◽  
pp. 31-36
Author(s):  
Resul Sevinçek ◽  
Duygu Barut Celepci ◽  
Serap Köktaş Koca ◽  
Özlem Akgül ◽  
Muittin Aygün
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Packing ◽  
Biological Activities ◽  
Position Effect ◽  
Intermolecular Hydrogen Bond ◽  
X Ray ◽  
Space Groups ◽  
X Ray Crystallography ◽  
Hydrogen Bond Interactions ◽  
The Impact

In order to determine the impact of different substituents and their positions on intermolecular interactions and ultimately on the crystal packing, unsubstituted N-phenyl-2-phthalimidoethanesulfonamide, C16H14N2O4S, (I), and the N-(4-nitrophenyl)-, C16H13N3O6S, (II), N-(4-methoxyphenyl)-, C16H16N3O6S, (III), and N-(2-ethylphenyl)-, as the monohydrate, C18H18N2O4S·H2O, (IV), derivatives have been characterized by single-crystal X-ray crystallography. Sulfonamides (I) and (II) have triclinic crystal systems, while (III) and (IV) are monoclinic. Although the molecules differ from each other only with respect to small substituents and their positions, they crystallized in different space groups as a result of differing intra- and intermolecular hydrogen-bond interactions. The structures of (I), (II) and (III) are stabilized by intermolecular N—H...O and C—H...O hydrogen bonds, while that of (IV) is stabilized by intermolecular O—H...O and C—H...O hydrogen bonds. All four structures are of interest with respect to their biological activities and have been studied as part of a program to develop anticonvulsant drugs for the treatment of epilepsy.

scholarly journals The critical role of QM/MM X-ray refinement and accurate tautomer/protomer determination in structure-based drug design

2020 ◽  
Author(s):  
Oleg Y. Borbulevych ◽  
Roger I. Martin ◽  
Lance M. Westerhoff
Keyword(s):  
Drug Design ◽  
Critical Role ◽  
Pharmaceutical Research ◽  
Energy Functional ◽  
Structural Refinement ◽  
Structure Based Drug Design ◽  
X Ray ◽  
X Ray Crystallography ◽  
Refinement Method ◽  
The Impact

Abstract Conventional protein:ligand crystallographic refinement uses stereochemistry restraints coupled with a rudimentary energy functional to ensure the correct geometry of the model of the macromolecule—along with any bound ligand(s)—within the context of the experimental, X-ray density. These methods generally lack explicit terms for electrostatics, polarization, dispersion, hydrogen bonds, and other key interactions, and instead they use pre-determined parameters (e.g. bond lengths, angles, and torsions) to drive structural refinement. In order to address this deficiency and obtain a more complete and ultimately more accurate structure, we have developed an automated approach for macromolecular refinement based on a two layer, QM/MM (ONIOM) scheme as implemented within our DivCon Discovery Suite and "plugged in" to two mainstream crystallographic packages: PHENIX and BUSTER. This implementation is able to use one or more region layer(s), which is(are) characterized using linear-scaling, semi-empirical quantum mechanics, followed by a system layer which includes the balance of the model and which is described using a molecular mechanics functional. In this work, we applied our Phenix/DivCon refinement method—coupled with our XModeScore method for experimental tautomer/protomer state determination—to the characterization of structure sets relevant to structure-based drug design (SBDD). We then use these newly refined structures to show the impact of QM/MM X-ray refined structure on our understanding of function by exploring the influence of these improved structures on protein:ligand binding affinity prediction (and we likewise show how we use post-refinement scoring outliers to inform subsequent X-ray crystallographic efforts). Through this endeavor, we demonstrate a computational chemistry ↔ structural biology (X-ray crystallography) "feedback loop" which has utility in industrial and academic pharmaceutical research as well as other allied fields.

Study of the Structure of 1-Hydroxymethylindazole and 1-Hydroxymethylbenzotriazole by X-Ray Crystallography, Multinuclear NMR in Solution and DFT Calculations.

ChemInform ◽  
2004 ◽  
Vol 35 (34) ◽  
Author(s):  
Ibon Alkorta ◽  
Jose Elguero ◽  
Nadine Jagerovic ◽  
Alain Fruchier ◽  
Glenn P. A. Yap
Keyword(s):  
Dft Calculations ◽  
X Ray ◽  
Multinuclear Nmr ◽  
X Ray Crystallography

Dynamic stereoisomerization in inherently chiral bimetallic [2]catenanes

2015 ◽  
Vol 51 (27) ◽  
pp. 5840-5843 ◽  
Author(s):  
Thirumurugan Prakasam ◽  
Matteo Lusi ◽  
Elisa Nauha ◽  
John-Carl Olsen ◽  
Mohamadou Sy ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Variable Temperature ◽  
Redox Processes ◽  
Metal Translocation ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Inherently Chiral

Stereoisomerization and the unprecedented phenomenon of metal translocation in the absence of redox processes were probed in two inherently chiral bimetallic [2]catenanes by using a combination of variable-temperature 1H NMR and CD spectroscopies, X-ray crystallography, and DFT calculations.

Spectroscopic and dynamic NMR study, X-ray crystallography and DFT calculations of two phosphoramidates: (C4H3O2)P(O)(Cl)C6H14N and (C4H3O2)P(O)(C6H11NH)2

2013 ◽  
Vol 1046 ◽  
pp. 64-73 ◽  
Author(s):  
F.M. Oliveira ◽  
L.C.A. Barbosa ◽  
A.J. Demuner ◽  
C.R.A. Maltha ◽  
S.A. Fernandes ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Dynamic Nmr ◽  
X Ray ◽  
X Ray Crystallography ◽  
Nmr Study
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