scholarly journals Gallic Acid Dimer As a Double π–Hole Donor: Evidence from X-ray, Theoretical Calculations, and Generalization from the Cambridge Structural Database

2019 ◽  
Vol 19 (7) ◽  
pp. 3989-3997 ◽  
Author(s):  
Rafel Prohens ◽  
Dafne de Sande ◽  
Mercè Font-Bardia ◽  
Antonio Franconetti ◽  
José F. González ◽  
...  
Keyword(s):  
Gallic Acid ◽  
Theoretical Calculations ◽  
Cambridge Structural Database ◽  
X Ray ◽  
Structural Database

Spacer conformation in biologically active molecules

2004 ◽  
Vol 76 (5) ◽  
pp. 959-964 ◽  
Author(s):  
J. Karolak-Wojciechowska ◽  
A. Fruzinski
Keyword(s):  
Statistical Data ◽  
Population Analysis ◽  
Cambridge Structural Database ◽  
Biologically Active ◽  
Aliphatic Chain ◽  
X Ray ◽  
Flexible Spacer ◽  
Conformational Preferences ◽  
Structural Database ◽  
The One

Based on our contemporary studies on the structures of biologically active molecules, we focus our attention on the aliphatic chain and its conformation. That flexible spacer definitely influenced the balanced position of all pharmacophoric points in molecules of biological ligands. The one atomic linker and two or three atomic spacers with one heteroatom X =O, S, CH2, NH have been taken into account. The conformational preferences clearly depend on the heteroatom X. In the discussion, we utilize our own X-ray data, computation chemistry methods, population analysis, and statistical data from the Cambridge Structural Database (CSD).

scholarly journals SYNTHESIS AND STRUCTURE OF 3,5-DIAMINO-1,2,4-TRIAZOLIUM TETRACHLORO-GALLATE

2019 ◽  
Vol 62 (4) ◽  
pp. 121-127
Author(s):  
Tatyana V. Kudayarova ◽  
Elena A. Danilova ◽  
Yuliya A. Piteva ◽  
Kristina E. Mochalina ◽  
Maxim V. Dmitriev
Keyword(s):  
Complex Compound ◽  
Crystal Packing ◽  
Intermolecular Hydrogen Bond ◽  
Cambridge Structural Database ◽  
X Ray Diffraction ◽  
Centrosymmetric Dimer ◽  
X Ray ◽  
Preferential Localization ◽  
Structural Database ◽  
Almost All

This paper discusses the synthesis and structure of a complex compound based on 3,5-diamino-1H-1,2,4-triazole (guanazole) with gallium ions, formed by the interaction of anhydrous gallium (III) chloride and guanazole in dried methanol. After distilling off the solvent under vacuum, the resulting product was washed with hexane, acetone. The target compound was extracted with acetonitrile, and slow evaporation of the latter at room temperature for three days resulted in beige-colored crystals, which were characterized by IR spectroscopy, elemental analysis, mass-spectrometry and X-ray diffraction analysis. The complex composition of gallate, C2H6N5+∙[GaCl4], exists as two crystallographically independent cations and two anions. The complex compound crystallizes in the centrosymmetric space group of the monoclinic syngony. The tetrachlorogallate anion is a slightly distorted tetrahedron, which is typical of structures of this type. 1,2,4-triazolium cations are selectively protonated on the N4 and N4A atoms, however, the site of the preferential localization of the positive charge is the N2 and N2A atoms. In addition to the electrostatic interaction of oppositely charged ions, a developed system of hydrogen bonds plays an important role in the stabilization of the crystal packing: almost all hydrogen and chlorine atoms are involved in its formation. Each of the crystallographically independent cations forms a centrosymmetric dimer due to the intermolecular hydrogen bond N2 – H2···N3 and N2A – H2A···N3A.  A full set of X-ray data is deposited into the Cambridge Structural Database of Compounds - the Cambridge Structural Database (Contributor CCDC 1894815) and it can be gotten from the site www.ccdc.cam.ac.uk/data_request/cif.

The nature of the C–Br⋯Br–C intermolecular interactions found in molecular crystals: a general theoretical-database study

CrystEngComm ◽  
2015 ◽  
Vol 17 (17) ◽  
pp. 3354-3365 ◽  
Author(s):  
Marçal Capdevila-Cortada ◽  
Juan J. Novoa
Keyword(s):  
Intermolecular Interactions ◽  
Theoretical Calculations ◽  
Molecular Crystals ◽  
Cambridge Structural Database ◽  
Database Study ◽  
Structural Database

The properties of C–Br⋯Br–C interactions have been determined by doing MP2 theoretical calculations on model dimers and on dimers taken from the Cambridge Structural Database (presenting Br⋯Br distances within the 3.0 to 4.5 Å range).

scholarly journals A Computational Study of Metallacycles Formed by Pyrazolate Ligands and the Coinage Metals M = Cu(I), Ag(I) and Au(I): (pzM)n for n = 2, 3, 4, 5 and 6. Comparison with Structures Reported in the Cambridge Crystallographic Data Center (CCDC)

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5108
Author(s):  
José Elguero ◽  
Ibon Alkorta
Keyword(s):  
Data Center ◽  
Computational Study ◽  
Crystallographic Data ◽  
Cambridge Structural Database ◽  
X Ray ◽  
Cambridge Crystallographic Data Center ◽  
Coinage Metals ◽  
Structural Database

The structures reported in the Cambridge Structural Database (CSD) for neutral metallacycles formed by coinage metals in their valence (I) (cations) and pyrazolate anions were examined. Depending on the metal, dimers and trimers are the most common but some larger rings have also been reported, although some of the larger structures are not devoid of ambiguity. M06-2x calculations were carried out on simplified structures (without C-substituents on the pyrazolate rings) in order to facilitate a comparison with the reported X-ray structures (geometries and energies). The problems of stability of the different ring sizes were also analyzed.

Radical⋯radical chalcogen bonds: CSD analysis and DFT calculations

2020 ◽  
Vol 22 (22) ◽  
pp. 12757-12765
Author(s):  
Bartomeu Galmés ◽  
Jaume Adrover ◽  
Giancarlo Terraneo ◽  
Antonio Frontera ◽  
Giuseppe Resnati
Keyword(s):  
Dft Calculations ◽  
Theoretical Calculations ◽  
Substituent Effects ◽  
Cambridge Structural Database ◽  
Structural Database

A search in the Cambridge Structural Database and theoretical calculations (UPBE0-D3/def2-TZVP level of theory) show the existence and relevance of substituent effects on the strength of radical⋯radical chalcogen bonding interactions.

On the preferences of five-membered chelate rings in coordination chemistry: insights from the Cambridge Structural Database and theoretical calculations

2019 ◽  
Vol 48 (17) ◽  
pp. 5476-5490 ◽  
Author(s):  
Maryam Bazargan ◽  
Masoud Mirzaei ◽  
Antonio Franconetti ◽  
Antonio Frontera
Keyword(s):  
Coordination Chemistry ◽  
Metal Ions ◽  
Chelate Ring ◽  
Theoretical Calculations ◽  
Cambridge Structural Database ◽  
Membered Chelate Ring ◽  
Structural Database ◽  
Theoretical Results ◽  
Chelate Rings

We illustrate, combining experimental and theoretical results, that the five-membered chelate ring is able to adapt itself to a great variety of metal ions.

Non-aromatic endocyclic angle at the ring fusion with the aromatic ring in benzocyclopentene and -hexene, revisited

2004 ◽  
Vol 60 (3) ◽  
pp. 293-299
Author(s):  
Dirk J. A. De Ridder ◽  
Hans-Beat Bürgi
Keyword(s):  
Bond Length ◽  
Aromatic Ring ◽  
Cambridge Structural Database ◽  
Mirror Plane ◽  
Ring Size ◽  
Acta Cryst ◽  
Ring Fusion ◽  
X Ray ◽  
Fused Ring ◽  
Structural Database

X-ray geometries of monocycloalkenobenzenes with a fused-ring size of r = 5, 6 were obtained by the use of the Cambridge Structural Database. In contrast to Allen's study [Acta Cryst. (1981), B37, 900–906], the data were not averaged over exact or imposed m ad symmetry (m ad is the mirror plane going through the midpoint of the aromatic ring fusion bond and the aromatic bond parallel to it). The distribution of the non-aromatic endocyclic angle ∊ at the ring fusion clearly shows two and three, respectively, distinct curves for r = 5 and r = 6. The respective ranges are 104.3–112.6 and 104.4–123.2°. If one of the C atoms directly attached to the aromatic ring is sp 2 hybridized, the bond length e between the aromatic ring and this atom is shortened by some 0.044 (15) and 0.027 (12) Å for r = 5 and r = 6, respectively. However, for r = 5, e is only shortened by 0.030 (17) Å when both C atoms directly attached to the aromatic ring are sp 2 hybridized. For r = 5, the endocyclic angle ∊ is 1.2 (13)° smaller at the side involving the sp 2 hybridized C atom.

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