Quadratate Und Hydrogenquadratate Cyclischer Stickstoffbasen Mit Schicht-, Ketten- und Leiterstrukturen / Squarates and Hydrogensquarates of Cyclic Nitrogen Bases with Layer-, Chainand Ladder-Structures

2003 ◽  
Vol 58 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Rainer Mattes ◽  
Jörg Ebbing ◽  
Annette Grüss ◽  
Jens Köppe ◽  
Krystyna Majcher

Abstract The synthesis and single crystal X-ray structures of four adducts of squaric acid with cyclic nitrogen bases are reported. Extensive hydrogen bonding, ionic interactions and (in one case) π-π-interactions lead to layered, and to two- and three-dimensional assemblies. [Pyrimidinium][ hydrogenquadratate] (1) has a layer structure, consisting of head-to-tail infinite chains of pyrimidinium and [HC4O4]− ions, which are cross-linked by short N-H···O and C-H···O hydrogen bonds. [C9H11N2][HC4O4] ・0.5H2C4O4 (2), the adduct of a benzodiazepin and squaric acid, has a ladder-structure. Chains of [HC4O4]− ions and H2C4O4 molecules in alternating order form the ladder-beam. Layers of cations and anions in the ratio 2:1 build the crosspieces at an angle of 49° to the beam. The layers contain dimers of [HC4O4]− ions. [H2L2][HC4O4]2 (3) with L2 = 5,6,7,8,9,14,15,16,17,18-decahydrodibenzo[e,l]-1,4,8,11-tetraaza-cyclotetradecine shows zigzag chains made of [HC4O4]− ions. Between the [H2L2]2+ and the [HC4O4]− ions π-π interactions exist besides up to four N-H···O hydrogen bonds. The [H2L2]2+ ions possess two different conformations. [H2cyclam][C2O4] ·4H2O (4) contains strongly undulated layers of the composition [C4O4 ·4H2O]2−. The cations, which show two intramolecular N-H···N hydrogen bonds with N···N distances of 2.870 (3) Å , are interlinked at an angle of 41.5°.

2020 ◽  
Vol 76 (11) ◽  
pp. 1024-1033
Author(s):  
Fang-Hua Zhao ◽  
Shi-Yao Li ◽  
Wen-Yu Guo ◽  
Zi-Hao Zhao ◽  
Xiao-Wen Guo ◽  
...  

Two new CdII MOFs, namely, two-dimensional (2D) poly[[[μ2-1,4-bis(1H-benzimidazol-1-yl)butane](μ2-heptanedioato)cadmium(II)] tetrahydrate], {[Cd(C7H10O4)(C18H18N4)]·4H2O} n or {[Cd(Pim)(bbimb)]·4H2O} n (1), and 2D poly[diaqua[μ2-1,4-bis(1H-benzimidazol-1-yl)butane](μ4-decanedioato)(μ2-decanedioato)dicadmium(II)], [Cd2(C10H16O4)2(C18H18N4)(H2O)2] n or [Cd(Seb)(bbimb)0.5(H2O)] n (2), have been synthesized hydrothermally based on the 1,4-bis(1H-benzimidazol-1-yl)butane (bbimb) and pimelate (Pim2−, heptanedioate) or sebacate (Seb2−, decanedioate) ligands. Both MOFs were structurally characterized by single-crystal X-ray diffraction. In 1, the CdII centres are connected by bbimb and Pim2− ligands to generate a 2D sql layer structure with an octameric (H2O)8 water cluster. The 2D layers are further connected by O—H...O hydrogen bonds, resulting in a three-dimensional (3D) supramolecular structure. In 2, the CdII centres are coordinated by Seb2− ligands to form binuclear Cd2 units which are linked by bbimb and Seb2− ligands into a 2D hxl layer. The 2D layers are further connected by O—H...O hydrogen bonds, leading to an 8-connected 3D hex supramolecular network. IR and UV–Vis spectroscopy, thermogravimetric analysis and solid-state photoluminescence analysis were carried out on both MOFs. Luminescence sensing experiments reveal that both MOFs have good selective sensing towards Fe3+ in aqueous solution.


2012 ◽  
Vol 67 (12) ◽  
pp. 1273-1281 ◽  
Author(s):  
Peter G. Jones ◽  
Piotr Kuś ◽  
Ina Dix

The structures of seven benzene derivatives [1,2,3-tri(bromomethyl)benzene, (1); 3,5- di(bromomethyl)bromobenzene, (2); 2,5-di(bromomethyl)bromobenzene, (3); 4-(bromomethyl)-2,5- dibromotoluene, (4); 4-(bromomethyl)bromobenzene, (5); 2,3-di(bromomethyl)bromobenzene, (6) and (bromomethyl)-p-dibromobenzene, (7)] with bromo and bromomethyl (and in one case methyl) substituents are presented and analysed in terms of Br···Br interactions up to 4.0 A° , supported by hydrogen bonds H···Br. Some interactions of the type Br···π and π···π are encountered and play a subordinate role in the packing. Despite the close chemical similarity of the compounds, some of which are isomers with permuted substituent positions, the packing motifs are highly variable. Compounds 2-5 are based on layer structures with Brn (n=3, 4) and/or mixed Br/C rings. Compounds 1, 6 and 7 display three-dimensional packings of differing complexity, but with interpretable substructures; 1 can be analysed in terms of ribbons of linked Br3 and Br4 rings; 6 displays chains of linked Br3 triangles; 7 consists of ribbons of linked Br4 quadrilaterals.


IUCrData ◽  
2018 ◽  
Vol 3 (4) ◽  
Author(s):  
Hui Zhao

The title molecule, C11H6F5NO, lies on a mirror plane in the orthorhombic unit cell, with only two F atoms each of the difluoro and trifluoromethyl substituents lying out of the plane. In the crystal, molecules are linked by C—H...O, C—H...N and C—H...F hydrogen bonds, forming a layer structure parallel to the (001) plane. Weak π–π interactions promote the formation of a three-dimensional network.


IUCrJ ◽  
2014 ◽  
Vol 1 (2) ◽  
pp. 136-150 ◽  
Author(s):  
Palash Sanphui ◽  
Geetha Bolla ◽  
Ashwini Nangia ◽  
Vladimir Chernyshev

Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR),p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM–INA cocrystal and a binary adduct ACM–PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM–PAM and ACM–CPR, and the piperazine salt ACM–PPZ were solved from high-resolution powder X-ray diffraction data. The ACM–INA cocrystal is sustained by the acid...pyridine heterosynthon and N—H...O catemer hydrogen bonds involving the amide group. The acid...amide heterosynthon is present in the ACM–PAM cocrystal, while ACM–CPR contains carboxamide dimers of caprolactam along with acid–carbonyl (ACM) hydrogen bonds. The cocrystals ACM–INA, ACM–PAM and ACM–CPR are three-dimensional isostructural. The carboxyl...carboxyl synthon in ACM–PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM–PPZ salt and ACM–nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM–PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior stability, faster dissolution rate and is able to overcome the hydration tendency of the reference drug.


Author(s):  
R. A. Nagalakshmi ◽  
J. Suresh ◽  
S. Maharani ◽  
R. Ranjith Kumar ◽  
P. L. Nilantha Lakshman

The title compound, C23H21N3, comprises a 2-amino-3-cyanopyridine ring fused with a cyclopentane ring. The later adopts an envelope conformation with the central methylene C atom as the flap. The benzyl and andp-tolyl rings are inclined to one another by 56.18 (15)°, and to the pyridine ring by 81.87 (14) and 47.60 (11)°, respectively. In the crystal, molecules are linked by pairs of N—H...Nnitrilehydrogen bonds, forming inversion dimers with anR22(12) ring motif. The dimers are linked by C—H...π and π–π interactions [centroid–centroid distance = 3.7211 (12) Å], forming a three-dimensional framework.


2011 ◽  
Vol 396-398 ◽  
pp. 2338-2341
Author(s):  
Xing Chuan Wei ◽  
Zhi Li Liu ◽  
Kun Zhang ◽  
Zhi Yun Du ◽  
Xi Zheng

In this paper, (2E,6E)-2,6-Bis(2,3,4-tri-methoxy -benzylidene)cyclohexanone (omitted as tmbcho) (1) was obtained by the reaction of acetic acid, tetrahydrofuran, cyclohexanone and 2,3,4-tri-methoxy-benzaldehyde. Three non-classic hydrogen bonds were observed in the compound. X-ray crystallography shows that the crystal structure is stabilized by intermolecular C-H•••π interactions and it contains plenty of conjugated double bonds. The title compound was characterized by UV-vis and fluorescent spectral studies.


2000 ◽  
Vol 55 (3-4) ◽  
pp. 299-316 ◽  
Author(s):  
Dagmar Henschel ◽  
Karna Wijaya ◽  
Oliver Moers ◽  
Armand Blaschette ◽  
Peter G. Jones

Abstract In a study aim ed at the „deconstruction“ of the supramolecular aggregate 3(18C6) · 2HN( SO2Me)2 (1,18C6 = 18-crown-6), which is known to display a ladder structure with two isotactic [18C6 - Me SO2N(H)SO2Me···)∞ polymers forming the uprights and symmetrically N - H···O bonded 18C6 rings providing the rungs, the following crystalline complexes were isolated and (except for 2b) characterized by low-temperature X-ray diffraction: 18C6-ClN (SO2Me)2 (2a, triclinic, space group P1̅, Z = 2), 18C6-PhN (SO2Me)2 (2b), 18C6 -MeN(SO2Me)2 (3, monoclinic, P21/c, Z = 8), Bz18C6-HN(SO2Me)2 (4, Bz18C6 = benzo-18-crown-6, monoclinic, P21/n, Z = 4), 18C6-2 MeN (SO2Me)2 (5, triclinic, P1̅, Z = 1), 18C6-Me2SO- HN( SO2Me) (SO2Ph) (13, triclinic, P1̅, Z = 2), and 18C6-H2OMe2SO·2HN(SO2Me)2 (14, triclinic, P1̅, Z = 2). Each of the one-dimensional polymers 2a (syndiotactic), 3 (disyndiotactic) and 4 (isotactic) mimics a single upright of 1; in contrast to 1 and 2a, where the intra-catemer connectivity solely relies on S - Me ··· crow n and crown ··· O = S hydrogen bonds, this bonding system is reinforced in 3 by N -Me ··· crown and in 4 by N - H ··· crown hydrogen bonds. Complex 5 is monomeric and matches a fragment formally extruded from the catemer 3; moreover, 3 and 5 represent a rare case of two structurally characterized 18C6 complexes containing the same uncharged guest species in distinct molecular ratios. The surprising structure of the quaternary adduct 14 exhibits an [18C6 ··· MeSO2N(H)SO2Me ··· ]∞ chain, which can be regarded both as an isolated, though unmodified upright from the ladder 1 and, being syndiotactic, as a stereochemical analogue of 2a; the potentially rung-forming *NH functions in the chain are blocked by hydrogenbonded side chains of the type * N - H ··· water ··· sulfoxide ··· H - N (SO2Me)2. The ternary complex 13 consists of chains [18C6 ··· Me2SO ··· H - N (SO2Ph)SO2Me···]∞ and is not closely related to the other structures


2012 ◽  
Vol 68 (6) ◽  
pp. o1711-o1711 ◽  
Author(s):  
Vandavasi Koteswara Rao ◽  
Matthias Zeller ◽  
Sherri R. Lovelace-Cameron

The asymmetric unit of the title compound, C10H8N2·C8H6O4, consists of one half-molecule of each moiety, 4,4′-bipyridine (bpy) and terephthalic acid (bdc), both being located on crystallographic inversion centers. They are linked together via strong intermolecular O—H...N hydrogen bonds, forming infinite chains propagating along [1-21]. The chains are further connected through C—H...O interactions giving sheets in (012). The sheets are linked via π–π interactions between the bpy rings and the bdc–bpy rings [centroid–centroid distances = 3.690 (2) and 3.869 (2) Å], resulting in the formation of a three-dimensional supramolecular layer-like structure.


Author(s):  
Robert A. Toro ◽  
Analio Dugarte-Dugarte ◽  
Jacco van de Streek ◽  
José Antonio Henao ◽  
José Miguel Delgado ◽  
...  

The structure of racemic (RS)-trichlormethiazide [systematic name: (RS)-6-chloro-3-(dichloromethyl)-1,1-dioxo-3,4-dihydro-2H-1λ6,2,4-benzothiadiazine-7-sulfonamide], C8H8Cl3N3O4S2 (RS-TCMZ), a diuretic drug used in the treatment of oedema and hypertension, was determined from laboratory X-ray powder diffraction data using DASH [David et al. (2006). J. Appl. Cryst. 39, 910–915.], refined by the Rietveld method with TOPAS-Academic [Coelho (2018). J. Appl. Cryst. 51, 210–218], and optimized using DFT-D calculations. The extended structure consists of head-to-tail dimers connected by π–π interactions which, in turn, are connected by C—Cl...π interactions. They form chains propagating along [101], further connected by N—H...O hydrogen bonds to produce layers parallel to the ac plane that stack along the b-axis direction, connected by additional N—H...O hydrogen bonds. The Hirshfeld surface analysis indicates a major contribution of H...O and H...Cl interactions (32.2 and 21.7%, respectively). Energy framework calculations confirm the major contribution of electrostatic interactions (E elec) to the total energy (E tot). A comparison with the structure of S-TCMZ is also presented.


IUCrData ◽  
2016 ◽  
Vol 1 (10) ◽  
Author(s):  
S. Naveen ◽  
Seranthimata Samshuddin ◽  
Manuel Rodrigues ◽  
Dandavathi Arunkumar ◽  
N. K. Lokanath ◽  
...  

In the title hydrated hydrazine compound, C12H17N3O·H2O, the C=N bond adopts an E conformation. In the crystal, water molecules bridge the hydrazine molecules, via N—H...O and O—H...O hydrogen bonds, forming sheets parallel to the bc plane. There are C—H...π interactions present within the sheets, and further C—H...π interactions link the sheets to form a three-dimensional structure.


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