Influence of O−H···OP Hydrogen Bonding on the Supramolecular Architectures of Phosphorus-Based Hydrazones:  Alternate Right- and Left-Handed Fused Helical Chains Based on O−H···OP Hydrogen Bonds in the Crystal Structure of C6H5P(O)[N(CH3)NCHC6H4-p-OH]2

2006 ◽  
Vol 6 (4) ◽  
pp. 910-914 ◽  
Author(s):  
Vadapalli Chandrasekhar ◽  
Ramachandran Azhakar ◽  
Jamie F. Bickley ◽  
Alexander Steiner
2006 ◽  
Vol 62 (5) ◽  
pp. o2043-o2044 ◽  
Author(s):  
Shao-Wen Chen ◽  
Han-Dong Yin ◽  
Da-Qi Wang ◽  
Xia Kong ◽  
Xiao-Fang Chen

The crystal structure of the title compound, C14H14ClN3O3 +·Cl−·0.5H2O, exhibits O—H...O, C—H...O, C—H...Cl, N—H...Cl and O—H...Cl hydrogen bonds. The chloride anions participate in extensive hydrogen bonding with the aminium cations and link molecules through multiple N—H+...Cl− interactions.


Author(s):  
Graham Smith ◽  
Urs D. Wermuth

In the structure of the brucinium salt of 4-aminophenylarsonic acid (p-arsanilic acid), systematically 2,3-dimethoxy-10-oxostrychnidinium 4-aminophenylarsonate tetrahydrate, (C23H27N2O4)[As(C6H7N)O2(OH)]·4H2O, the brucinium cations form the characteristic undulating and overlapping head-to-tail layered brucine substructures packed along [010]. The arsanilate anions and the water molecules of solvation are accommodated between the layers and are linked to them through a primary cation N—H...O(anion) hydrogen bond, as well as through water O—H...O hydrogen bonds to brucinium and arsanilate ions as well as bridging water O-atom acceptors, giving an overall three-dimensional network structure.


Author(s):  
Nurcan Akduran

The title compound [systematic name: 2-(N-hydroxyimino)-1,2-diphenylethanol], C14H13NO2, consists of hydroxy phenylacetophenone and oxime units, in which the phenyl rings are oriented at a dihedral angle of 80.54 (7)°. In the crystal, intermolecular O—HOxm...NOxm, O—HHydr...OHydr, O—H′Hydr...OHydr and O—HOxm...OHydr hydrogen bonds link the molecules into infinite chains along the c-axis direction. π–π contacts between inversion-related of the phenyl ring adjacent to the oxime group have a centroid–centroid separation of 3.904 (3) Å and a weak C—H...π(ring) interaction is also observed. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H...H (58.4%) and H...C/C...H (26.4%) contacts. Hydrogen bonding and van der Waals contacts are the dominant interactions in the crystal packing.


2006 ◽  
Vol 62 (4) ◽  
pp. o1295-o1297
Author(s):  
J. Suresh ◽  
V. P. Alex Raja ◽  
S. Natarajan ◽  
S. Perumal ◽  
A. Mostad ◽  
...  

In the title compound, C30H24N2O·0.5C4H8O2, the piperidone ring adopts the chair conformation and all the phenyl rings are equatorially oriented. The ethyl acetate molecule is present as a space filler and does not participate in the hydrogen-bonding network. The crystal structure is stabilized through C—H...N and C—H...O hydrogen bonds. No significant C—H...π and π–π interactions are observed.


Author(s):  
Wafa Harhouri ◽  
Salma Dhifaoui ◽  
Shabir Najmudin ◽  
Cecilia Bonifácio ◽  
Habib Nasri

In the title compound, [Mn(C44H28N4)Cl]·2C5H6N2, the MnIIIcentre is coordinated by four pyrrole N atoms [averaged Mn—N = 2.012 (4) Å] of the tetraphenylporphyrin molecule and one chloride axial ligand [Mn—Cl = 2.4315 (7) Å] in a square-pyramidal geometry. The porphyrin macrocycle exhibits a non-planar conformation with majorrufflingandsaddlingdistortions. In the crystal, two independent solvent molecules form dimers through N—H...N hydrogen bonding. In these dimers, one amino N atom has a short Mn...N contact of 2.642 (1) Å thus completing the Mn environment in the form of a distorted octahedron, and another amino atom generates weak N—H...Cl hydrogen bonds, which link further all molecules into chains along theaaxis.


2018 ◽  
Vol 74 (7) ◽  
pp. 690-694 ◽  
Author(s):  
Ian W. Windsor ◽  
Ronald T. Raines

Crystal structures of inactive variants of HIV-1 protease bound to peptides have revealed how the enzyme recognizes its endogenous substrates. The best of the known substrates is, however, a nonnatural substrate that was identified by directed evolution. The crystal structure of the complex between this substrate and the D25N variant of the protease is reported at a resolution of 1.1 Å. The structure has several unprecedented features, especially the formation of additional hydrogen bonds between the enzyme and the substrate. This work expands the understanding of molecular recognition by HIV-1 protease and informs the design of new substrates and inhibitors.


Author(s):  
Hansu Im ◽  
Jineun Kim ◽  
Changeun Sim ◽  
Tae Ho Kim

The title compound, (systematic name:N,N′-dibenzyl-3,3′-dimethoxy-1,1′-biphenyl-4,4′-diamine), C28H28N2O2, was synthesized by the reduction of a Schiff base preparedviaa condensation reaction betweeno-dianisidine and benzaldehyde under acidic conditions. The molecule lies on a crystallographic inversion centre so that the asymmetric unit contains one half-molecule. The biphenyl moiety compound is essentially planar. Two intramolecular N—H...O hydrogen bonds occur. The dihedral angle between the terminal phenyl and phenylene rings of a benzidine unit is 48.68 (6)°. The methylene C atom of the benzyl group is disordered over two sets of sites, with occupancy ratio 0.779 (18):0.221 (18). In the crystal, molecules are connected by hydrogen bonding betweeno-dianisidine O atoms and H atoms of the terminal benzyl groups, forming a one-dimensional ladder-like structure. In the data from DFT calculations, the central biphenyl showed a twisted conformation.


2014 ◽  
Vol 70 (11) ◽  
pp. 424-426 ◽  
Author(s):  
Hope T. Sartain ◽  
Richard J. Staples ◽  
Shannon M. Biros

We report here the crystal structure of a ten-coordinate lanthanum(III) metal coordinated by five bidentate ethylenediamine ligands, [La(C2H8N2)5]Cl3·C2H8N2·CH2Cl2. One free ethylenediamine molecule and three Cl−anions are also located in the asymmetric unit. The overall structure is held together by an extensive hydrogen-bonding network between the Cl−anions and the NH groups on the metal-bound ethylenediamine ligands. The free ethylenediamine molecule is held in an ordered position by additional hydrogen bonds involving both the chlorides and –NH groups on the metal-bound ligands. One highly disordered molecule of dichloromethane is located on an inversion center; however, all attempts to model this disorder were unsuccessful. The electron density in this space was removed using the BYPASS procedure [van der Sluis & Spek (1990).Acta Cryst.A46, 194–201].


2007 ◽  
Vol 63 (3) ◽  
pp. o1173-o1175
Author(s):  
Stephanie M. Witko ◽  
Mark Davison ◽  
Hugh W. Thompson ◽  
Roger A. Lalancette

In the title crystal structure, C9H14O3·H2O, the water molecule accepts a hydrogen bond from the carboxyl group [O...O = 2.6004 (13) Å and O—H...O = 163°], while donating hydrogen bonds to the ketone [O...O = 2.8193 (14) Å and O—H...O = 178 (2)°] and the acid carbonyl groups [O...O = 2.8010 (14) Å and O—H...O = 174 (2)°]. This creates a network of hydrogen bonds confined within a continuous flat ribbon two molecules in width and extending in the [101] direction.


2014 ◽  
Vol 70 (4) ◽  
pp. 392-395 ◽  
Author(s):  
Inese Sarcevica ◽  
Liana Orola ◽  
Mikelis V. Veidis ◽  
Sergey Belyakov

A new polymorph of the cinnamic acid–isoniazid cocrystal has been prepared by slow evaporation, namely cinnamic acid–pyridine-4-carbohydrazide (1/1), C9H8O2·C6H7N3O. The crystal structure is characterized by a hydrogen-bonded tetrameric arrangement of two molecules of isoniazid and two of cinnamic acid. Possible modification of the hydrogen bonding was investigated by changing the hydrazide group of isoniazidviaanin situreaction with acetone and cocrystallization with cinnamic acid. In the structure of cinnamic acid–N′-(propan-2-ylidene)isonicotinohydrazide (1/1), C9H8O2·C9H11N3O, carboxylic acid–pyridine O—H...N and hydrazide–hydrazide N—H...O hydrogen bonds are formed.


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