scholarly journals 7,7′,8,8′-Tetramethoxy-4,4′-dimethyl-3,3′-bicoumarin

2009 ◽  
Vol 65 (6) ◽  
pp. o1294-o1295
Author(s):  
Hoong-Kun Fun ◽  
Samuel Robinson Jebas ◽  
Mehtab Parveen ◽  
Zakia Khanam ◽  
Raza Murad Ghalib

In the crystal structure, the title compound, C24H22O8, lies on a twofold rotation axis and the asymmetric unit comprises one half-molecule. The dihedral angle formed by the coumarin unit with the symmetry-related part is 74.78 (14)°. One of the methoxy groups attached to the coumarin unit is considerably twisted, making an angle of 87.17 (17)° with respect to the coumarin unit; the other is twisted by 0.66 (19)°. No classical hydrogen bonds are found in the sturcture; only a weak C—H...π interaction and short intramolecular O...O contacts [2.683 (2)–2.701 (2) Å] are observed.

2015 ◽  
Vol 71 (6) ◽  
pp. o425-o425 ◽  
Author(s):  
Farook Adam ◽  
Nadiah Ameram ◽  
Wai Mun Tan

There are two molecules in the asymmetric unit of the title compound, C9H10N2OS. In one, the dihedral angle between the aromatic ring and the carbamothioyl group is 52.31 (7)° and in the other it is 36.16 (6)°. Each molecule features an intramolecular N—H...O hydrogen bond, which generates anS(6) ring and the O and S atoms have anantidisposition. In the crystal, molecules are linked by N—H...S and N—H...O hydrogen bonds, generating separate [130] and [1-30] infinite chains. Weak C—H...O and C—H...S interactions are also observed.


2014 ◽  
Vol 70 (9) ◽  
pp. o917-o918 ◽  
Author(s):  
Błażej Dziuk ◽  
Bartosz Zarychta ◽  
Krzysztof Ejsmont

The asymmetric unit of the title compound, C2H8N+·C4H5O4−, consists of two allylammonium cations and two hydrogen succinate anions (Z′ = 2). One of the cations has a near-perfectsyn-periplanar (cis) conformation with an N—C—C—C torsion angle of 0.4 (3)°, while the other is characterized by agaucheconformation and a torsion angle of 102.5 (3)°. Regarding the anions, three out of four carboxilic groups are twisted with respect to the central C–CH2–CH2–C group [dihedral angles = 24.4 (2), 31.2 (2) and 40.4 (2)°], the remaining one being instead almost coplanar, with a dihedral angle of 4.0 (2)°. In the crystal, there are two very short, near linear O—H...O hydrogen bonds between anions, with the H atoms shifted notably from the donor O towards the O...O midpoint. These O—H...O hydrogen bonds form helical chains along the [011] which are further linked to each other through N—H...O hydrogen bonds (involving all the available NH groups), forming layers lying parallel to (100).


2007 ◽  
Vol 63 (3) ◽  
pp. m892-m894 ◽  
Author(s):  
Basem Fares Ali ◽  
Rawhi Al-Far

The asymmetric unit of the title compound, (C5H4Br2N)2[SnBr6], contains one cation and one half-anion. The anion exhibits a distorted octahedral arrangement about the Sn atom, which lies on a crystallographic twofold rotation axis. In the crystal structure, intermolecular hydrogen bonds and short Br...Br interactions cause the formation of a supramolecular architecture, in which they may be effective in the stabilization of the structure.


2014 ◽  
Vol 70 (10) ◽  
pp. o1122-o1123
Author(s):  
Julio Zukerman-Schpector ◽  
I. Caracelli ◽  
Hélio A. Stefani ◽  
Amna N. Khan ◽  
Edward R. T. Tiekink

In the title compound, C15H20BrNO2, there are two independent molecules (AandB) comprising the asymmetric unit and these adopt very similar conformations. InA, the dihedral angle between the CO2and MeC=CMe2groups is 80.7 (3)°, and these make dihedral angles of 3.5 (3) and 84.09 (16)°, respectively, with the bromobenzene ring. The equivalent dihedral angles for moleculeBare 78.4 (3), 2.1 (3) and 78.37 (12)°, respectively. The most prominent interactions in the crystal packing are amine-N—H...O(carbonyl) hydrogen bonds between the two independent molecules, resulting in non-centrosymmetric ten-membered {...OC2NH}2synthons. Statistical disorder is noted for each of the terminal methyl groups of the ethyl residues.


2017 ◽  
Vol 73 (11) ◽  
pp. 1735-1738
Author(s):  
Michael A. Land ◽  
Katherine N. Robertson ◽  
Jason A. C. Clyburne

The title compound, C20H22O3, was formed in the reaction between 2,4,6-trimethylbenzoic acid andN,N-diisopropylethylamine in the presence of 1,3-dichloro-1,3-bis(dimethylamino)propenium hydrogen dichloride, and was recrystallized from diethyl ether solution. It is the first exclusively alkyl-substituted benzoic anhydride to have been structurally characterized. The asymmetric unit consists of a half molecule, the other half of which is generated by twofold rotation symmetry; the dihedral angle between the symmetry-related aromatic rings is 54.97 (3)°. The geometric parameters of the aromatic ring are typical of those for 2,4,6-trimethylphenyl substituted groups. The C=O and C—O bond lengths are 1.1934 (12) and 1.3958 (11) Å, respectively, and the angle between these three atoms (O=C—O) is 121.24 (9)°. In the crystal, molecules are linked by weak C—H...O hydrogen bonds and C—H...π interactions. The packing features wavy chains that extend parallel to [001].


2009 ◽  
Vol 65 (6) ◽  
pp. o1331-o1331 ◽  
Author(s):  
Hai-Jun Xu ◽  
Yi-Jie Pan ◽  
Li-Jing Cui

The asymmetric unit of the title compound, C8H6N8·2H2O, contains one half-molecule, with the benzene ring on a centre of symmetry, and two uncoordinated water molecules. The benzene ring is oriented at a dihedral angle of 34.43 (12)° with respect to the tetrazole ring. Strong O—H...N hydrogen bonds link the water molecules to the N atoms of the tetrazole ring. In the crystal structure, strong intermolecular O—H...O and O—H...N hydrogen bonds link the molecules into a network. One of the water H atoms is disordered over two positions and was refined with occupancies of 0.50.


2007 ◽  
Vol 63 (11) ◽  
pp. o4374-o4375 ◽  
Author(s):  
Mustafa Odabaşoğlu ◽  
Orhan Büyükgüngör

The crystal structure of the title compound, C7H7F3N+·C8H3Cl2O4 −, is stabilized by five N—H...O, one O—H...O, two C—H...O and three C—H...X (X = F, Cl) hydrogen bonds. Intramolecular O—H...O and C—H...X hydrogen bonds generate edge-fused [S(7)R 4 4(24)S(7)R 2 2(10)S(7)R 4 4(24)S(7)] motifs. The cations and anions are linked to each other by C—H...O hydrogen bonds, forming a chain along the c axis. This chain and the other hydrogen bonds form [R 3 2(6)R 1 2(4)S(7)R 1 2(4)R 4 4(18)R 5 5(24)R 4 4(18)R 1 2(4)R 1 2(4)S(7)R 1 2(4)R 3 2(6)] motifs. The dihedral angle between the planes of the aromatic rings in the cation and anion is 34.86 (1)°.


2015 ◽  
Vol 71 (12) ◽  
pp. o912-o913 ◽  
Author(s):  
P. S. Manjula ◽  
B. K. Sarojini ◽  
B. Narayana ◽  
K. Byrappa ◽  
S. Madan Kumar

The title compound, C10H9FN4S, crystallizes with two molecules (AandB) in the asymmetric unit. The dihedral angle between the planes of the trizole and fluorobenzene rings is 7.3 (3)° in moleculeAand 41.1 (3)° in moleculeB. MoleculeAfeatures an intramolecular C—H...S hydrogen bond, which closes anS(6) ring. In the crystal,A+Bdimers linked by pairs of N—H...S hydrogen bonds occur, generatingR22(8) loops. Weak π–π stacking contacts [centroid–centroid separation = 3.739 (6) Å] are also observed.


2014 ◽  
Vol 70 (9) ◽  
pp. o970-o970 ◽  
Author(s):  
Rosa Carballo ◽  
Arantxa Pino-Cuevas ◽  
Ezequiel M. Vázquez-López

The asymmetric unit of the title compound, C9H9N3OS, contains two approximately planar molecules (r.m.s. deviations for 14 non-H atoms = 0.094 and 0.045 Å), with different conformations. In one of them, the C=O group issynto the S atom and in the other it isanti. Each molecule features an intramolecular N—H...N hydrogen bond, which generates anS(5) ring. In the crystal, molecules are linked by N—H...O and N—H...S hydrogen bonds, generating discrete networks; thesynmolecules form [010] chains and theantimolecules form (100) sheets.


Author(s):  
Augusto Rivera ◽  
Jicli José Rojas ◽  
Jaime Ríos-Motta ◽  
Michael Bolte

The crystal structure of the title compound, C25H24N2O2, at 173 K has monoclinic (C2/c) symmetry. The molecule is located on a crystallographic twofold rotation axis with only half a molecule in the asymmetric unit. The imidazolidine ring adopts a twist conformation, with a twist about the ring C—C bond. The crystal structure shows theanticlinaldisposition of the two (2-hydroxynaphthalen-1-yl)methyl substituents of the imidazolidine ring. The structure displays two intramolecular O—H...N hydrogen bonds, each forming anS(6) ring motif.


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