Understanding the electron density reorganization upon stacking vs. H-bonding interaction in methyl gallate–caffeine complexes

RSC Advances ◽  
2014 ◽  
Vol 4 (48) ◽  
pp. 25018-25027 ◽  
Author(s):  
Laura Estévez ◽  
Marta Sánchez-Lozano ◽  
Ricardo A. Mosquera

QTAIM analysis of selected subcomplexes contained in methyl gallate-caffeine crystal indicate: a) significant differences between electron density reorganization involved in H-bonds and stacking interactions; b) cooperative effects are only significant when bond paths associated to homomonomeric hydrogen bonds are found.

2014 ◽  
Vol 70 (2) ◽  
pp. m35-m35
Author(s):  
Jing-Wei Dai ◽  
Zhao-Yang Li ◽  
Osamu Sato

In the title complex, [Fe(NCS)2(C18H18N4)], the FeIIcation is chelated by a tris(2-pyridylmethyl)amine ligand and coordinated by two thiocyanate anions in a distorted N6octahedral geometry. In the crystal, weak C—H...S hydrogen bonds and π–π stacking interactions between parallel pyridine rings of adjacent molecules [centroid–centroid distance = 3.653 (3) Å] link the molecules into a two-dimensional supramolecular architecture. The structure contains voids of 124 (9) Å3, which are free of solvent molecules.


2014 ◽  
Vol 70 (10) ◽  
pp. o1130-o1130 ◽  
Author(s):  
Wataru Furukawa ◽  
Munenori Takehara ◽  
Yoshinori Inoue ◽  
Chitoshi Kitamura

In an attempt to brominate 1,4-dipropoxy-9,10-anthraquinone, a mixture of products, including the title compound, C14H7BrO4, was obtained. The molecule is essentially planar (r.m.s. deviation = 0.029 Å) and two intramolecular O—H...O hydrogen bonds occur. In the crystal, the molecules are linked by weak C—H...O hydrogen bonds, Br...O contacts [3.240 (5) Å], and π–π stacking interactions [shortest centroid–centroid separation = 3.562 (4) Å], generating a three-dimensional network.


2013 ◽  
Vol 69 (2) ◽  
pp. m73-m74 ◽  
Author(s):  
Sigurd Øien ◽  
David Stephen Wragg ◽  
Karl Petter Lillerud ◽  
Mats Tilset

In the title compound, [Cu2Cl4(C12H8N2O4)2]·4C3H7NO, which contains a chloride-bridged centrosymmetric CuIIdimer, the CuIIatom is in a distorted square-pyramidal 4 + 1 coordination geometry defined by the N atoms of the chelating 2,2′-bipyridine ligand, a terminal chloride and two bridging chloride ligands. Of the two independent dimethylformamide molecules, one is hydrogen bonded to a single –COOH group, while one links two adjacent –COOH groupsviaa strong accepted O—H...O and a weak donated C(O)—H...O hydrogen bond. Two of these last molecules and the two –COOH groups form a centrosymmetric hydrogen-bonded ring in which the CH=O and the –COOH groups by disorder adopt two alternate orientations in a 0.44:0.56 ratio. These hydrogen bonds link the CuIIcomplex molecules and the dimethylformamide solvent molecules into infinite chains along [-111]. Slipped π–π stacking interactions between two centrosymmetric pyridine rings (centroid–centroid distance = 3.63 Å) contribute to the coherence of the structure along [0-11].


2001 ◽  
Vol 58 (1) ◽  
pp. 94-108 ◽  
Author(s):  
Craig J. Kelly ◽  
Janet M. S. Skakle ◽  
James L. Wardell ◽  
Solange M. S. V. Wardell ◽  
John N. Low ◽  
...  

Molecules of N-(4′-iodophenylsulfonyl)-4-nitroaniline, 4-O2NC6H4NHSO2C6H4I-4′ (1), are linked by three-centre I...O2N interactions into chains and these chains are linked into a three-dimensional framework by C—H...O hydrogen bonds. In the isomeric N-(4′-nitrophenylsulfonyl)-4-iodoaniline, 4-IC6H4NHSO2C6H4NO2-4′ (2), the chains generated by the I...O2N interactions are again linked into a three-dimensional framework by C—H...O hydrogen bonds. Molecules of N,N-bis(3′-nitrophenylsulfonyl)-4-iodoaniline, 4-IC6H4N(SO2C6H4NO2-3′)2 (3), lie across twofold rotation axes in space group C2/c and they are linked into chains by paired I...O=S interactions: these chains are linked into sheets by a C—H...O hydrogen bond, and the sheets are linked into a three-dimensional framework by aromatic π...π stacking interactions. In N-(4′-iodophenylsulfonyl)-3-nitroaniline, 3-O2NC6H4NHSO2C6H4I-4′ (4), there are R^2_2(8) rings formed by hard N—H...O=S hydrogen bonds and R^2_2(24) rings formed by two-centre I...nitro interactions, which together generate a chain of fused rings: the combination of a C—H...O hydrogen bond and aromatic π...π stacking interactions links the chains into sheets. Molecules of N-(4′-iodophenylsulfonyl)-4-methyl-2-nitroaniline, 4-CH3-2-O2NC6H3NHSO2C6H4I-4′ (5), are linked by N—H...O=S and C—H...O(nitro) hydrogen bonds into a chain containing alternating R^2_2(8) and R^2_2(10) rings, but there are no I...O interactions of either type. There are two molecules in the asymmetric unit of N-(4′-iodophenylsulfonyl)-2-nitroaniline, 2-O2NC6H4NHSO2C6H4I-4′ (6), and the combination of an I...O=S interaction and a hard N—H...O(nitro) hydrogen bond links the two types of molecule to form a cyclic, centrosymmetric four-component aggregate. C—H...O hydrogen bonds link these four-molecule aggregates to form a molecular ladder. Comparisons are made with structures retrieved from the Cambridge Structural Database.


2005 ◽  
Vol 60 (9) ◽  
pp. 978-983 ◽  
Author(s):  
Sevim Hamamci ◽  
Veysel T. Yilmaz ◽  
William T. A. Harrison

Two new saccharinato-silver(I) (sac) complexes, [Ag(sac)(ampy)] (1), and [Ag2(sac)2(μ-aepy)2] (2), [ampy = 2-(aminomethyl)pyridine, aepy = 2-(2-aminoethyl)pyridine], have been prepared and characterized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X-ray diffraction. Complexes 1 and 2 crystallize in the monoclinic space group P21/c and triclinic space group P1̄, respectively. The silver(I) ions in both complexes 1 and 2 exhibit a distorted T-shaped AgN3 coordination geometry. 1 consists of individual molecules connected into chains by N-H···O hydrogen bonds. There are two crystallographically distinct dimers in the unit cell of 2 and in each dimer, the aepy ligands act as a bridge between two silver(I) centers, resulting in short argentophilic contacts [Ag1···Ag1 = 3.0199(4) Å and Ag2···Ag2 = 2.9894(4) Å ]. Symmetry equivalent dimers of 2 are connected by N-H···O hydrogen bonds into chains, which are further linked by aromatic π(py)···π(py) stacking interactions into sheets.


2018 ◽  
Vol 74 (5) ◽  
pp. 534-541 ◽  
Author(s):  
Ammara Shahid ◽  
Ambreen Aziz ◽  
Sajida Noureen ◽  
Maqsood Ahmed ◽  
Sammer Yousuf ◽  
...  

The biologically transformed product of estradiol valerate, namely 3,7α-dihydroxyestra-1,3,5(10)-trien-17-one monohydrate, C18H22O3·H2O, has been investigated using UV–Vis, IR, 1H and 13C NMR spectroscopic techniques, as well as by mass spectrometric analysis. Its crystal structure was determined using single-crystal X-ray diffraction based on data collected at 100 K. The structure was refined using the independent atom model (IAM) and the transferred electron-density parameters from the ELMAM2 database. The structure is stabilized by a network of hydrogen bonds and van der Waals interactions. The topology of the hydrogen bonds has been analyzed by the Bader theory of `Atoms in Molecules' framework. The molecular electrostatic potential for the transferred multipolar atom model reveals an asymmetric character of the charge distribution across the molecule due to a substantial charge delocalization within the molecule. The molecular dipole moment was also calculated, which shows that the molecule has a strongly polar character.


1996 ◽  
Vol 92 (2) ◽  
pp. 231 ◽  
Author(s):  
Nicola J. Baxter ◽  
Michael P. Williamson ◽  
Terence H. Lilley ◽  
Edwin Haslam

2017 ◽  
Vol 73 (11) ◽  
pp. 1700-1703 ◽  
Author(s):  
Suk-Hee Moon ◽  
Joobeom Seo ◽  
Ki-Min Park

The asymmetric unit of the title compound, [Co(NO3)2(C12H12N2S)2]n, contains a bis(pyridin-3-ylmethyl)sulfane (L) ligand, an NO3−anion and half a CoIIcation, which lies on an inversion centre. The CoIIcation is six-coordinated, being bound to four pyridine N atoms from four symmetry-relatedLligands. The remaining coordination sites are occupied by two O atoms from two symmetry-related nitrate anions in a monodentate manner. Thus, the CoIIcentre adopts a distorted octahedral geometry. Two symmetry-relatedLligands are connected by two symmetry-related CoIIcations, forming a 20-membered cyclic dimer, in which the CoIIatoms are separated by 10.2922 (7) Å. The cyclic dimers are connected to each other by sharing CoIIatoms, giving rise to the formation of an infinite looped chain propagating along the [101] direction. Intermolecular C—H...π (H...ring centroid = 2.89 Å) interactions between one pair of correspondingLligands and C—H...O hydrogen bonds between theLligands and the nitrate anions occur in the looped chain. In the crystal, adjacent looped chains are connected by intermolecular π–π stacking interactions [centroid-to-centroid distance = 3.8859 (14) Å] and C—H...π hydrogen bonds (H...ring centroid = 2.65 Å), leading to the formation of layers parallel to (101). These layers are further connected through C—H...O hydrogen bonds between the layers, resulting in the formation of a three-dimensional supramolecular architecture.


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