Different solvents yield alternative crystal forms through aromatic, halogen bonding and hydrogen bonding competition

CrystEngComm ◽  
2015 ◽  
Vol 17 (4) ◽  
pp. 877-888 ◽  
Author(s):  
Solhe F. Alshahateet ◽  
Mohan M. Bhadbhade ◽  
Roger Bishop ◽  
Marcia L. Scudder
Keyword(s):  
Hydrogen Bonding ◽  
Acetic Acid ◽  
Halogen Bonding ◽  
Crystal Forms ◽  
X Ray ◽  
X Ray Crystallography ◽  
Protic Solvents

X-ray crystallography shows that entirely different structures are produced when the dichlorodiquinoline derivative is crystallised from aprotic dimethylformamide or from protic solvents like methanol or acetic acid, demonstrating the importance of solvent choice in yielding alternative crystal forms.

Systhesis, Characterization and Spectroscopic Properties of (2E,6E)-2,6-Bis(2,3,4-tri-methoxy-benzylidene)cyclohexanone

2011 ◽  
Vol 396-398 ◽  
pp. 2338-2341
Author(s):  
Xing Chuan Wei ◽  
Zhi Li Liu ◽  
Kun Zhang ◽  
Zhi Yun Du ◽  
Xi Zheng
Keyword(s):  
Crystal Structure ◽  
Acetic Acid ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Spectroscopic Properties ◽  
Spectral Studies ◽  
Double Bonds ◽  
X Ray ◽  
Π Interactions ◽  
X Ray Crystallography

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.

scholarly journals Vibrational Resonant Inelastic X-Ray Scattering Inliquid Acetic Acid: A Ruler for Molecular Chain Lengths

2020 ◽  
Author(s):  
Viktoriia Savchenko ◽  
Iulia-Emilia Brumboiu ◽  
Victor Kimberg ◽  
Michael Odelius ◽  
Pavel Krasnov ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonding ◽  
Acetic Acid ◽  
Molecular Chain ◽  
X Ray ◽  
X Ray Scattering ◽  
Localized Excitations ◽  
Vibrational Excitations ◽  
Chain Lengths ◽  
Ray Scattering

Abstract Quenching of vibrational excitations in resonant inelastic X-ray scattering (RIXS) spectra of liquid acetic acid is observed. At the oxygen core resonance associated with localized excitations at the O-H bond, the spectra lack the typical progressionof vibrational excitations observed in RIXS spectra of comparable systems. We interpret this phenomenon as due to strong rehybridization of the unoccupied molecular orbitals as a result of hydrogen bonding. This allows us to address the molecular structure of the liquid, and to determine a lower limit for the average molecular chain length.

A comparative study of 2,4-quinazolinediones by X-ray crystallography. The role of the OMe group on the hydrogen bonding motifs formation

2012 ◽  
Vol 11 (4) ◽  
pp. 259-265
Author(s):  
Leticia Guerrero ◽  
Ruben Montalvo ◽  
Ignacio A. Rivero ◽  
Victor Barba
Keyword(s):  
Hydrogen Bonding ◽  
Comparative Study ◽  
X Ray ◽  
X Ray Crystallography

Effects of solvents on the crystal structure of cross-linked lysozyme crystals

2018 ◽  
Vol 32 (19) ◽  
pp. 1840041
Author(s):  
Yohei Yamada ◽  
Shota Toyama ◽  
Tomoki Yabutani
Keyword(s):  
Crystal Structure ◽  
Acetic Acid ◽  
Hydrochloric Acid ◽  
Dimethyl Sulfoxide ◽  
Optical Microscopy ◽  
Immersion Test ◽  
X Ray ◽  
Lattice Constants ◽  
X Ray Crystallography ◽  
Lysozyme Crystals

The effects of solvents on the structural stability of cross-linked lysozyme crystals were investigated by an immersion test using alkaline (0.1 M ammonia [NH3] and 0.1 M sodium hydroxide [NaOH]), acidic (0.1 M acetic acid [CH3COOH] and 0.1 M hydrochloric acid [HCl]) and organic (50% [v/v] and undiluted ethanol, acetone, 2-propanol and dimethyl sulfoxide [DMSO]) solvents. The morphology and lattice constants were monitored by optical microscopy and X-ray crystallography. The cross-linked crystals exhibited good stability against NH3, CH3COOH, HCl, ethanol, acetone and 2-propanol. However, samples preserved in DMSO and NaOH were severely degraded.

Crystallization of the 10-23 DNA enzyme using a combinatorial screen of paired oligonucleotides

1999 ◽  
Vol 55 (11) ◽  
pp. 1885-1892 ◽  
Author(s):  
Jacek Nowakowski ◽  
Peter J. Shim ◽  
Gerald F. Joyce ◽  
C. David Stout
Keyword(s):  
Crystal Formation ◽  
High Quality ◽  
Acid Complex ◽  
Crystal Forms ◽  
X Ray ◽  
X Ray Crystallography ◽  
Crystallization Solution ◽  
Varying Length ◽  
Standard Set

One of the most difficult steps in the X-ray crystallography of nucleic acids is obtaining crystals that diffract to high resolution. The choice of the nucleotide sequence has proven to be more important in producing high-quality crystals than the composition of the crystallization solution. This manuscript describes a systematic procedure for identifying the optimal sizes of a multi-stranded nucleic acid complex which provide high-quality crystals. This approach was used to crystallize the in vitro evolved 10-23 DNA enzyme complexed with its RNA substrate. In less than two months, 81 different enzyme–substrate complexes were generated by combinatorial mixing and annealing of complementary oligonucleotides which differed in length, resulting in duplexes of varying length, with or without nucleotide overhangs. Each of these complexes was screened against a standard set of 48 crystallization conditions and evaluated for crystal formation. The screen resulted in over 40 crystal forms, the best of which diffracted to 2.8 Å resolution when exposed to a synchrotron X-ray source.

Structural Variations in Tetrasilver(I) Complexes of Pyrazolate-bridged Compartmental N-Heterocyclic Carbene Ligands

2009 ◽  
Vol 64 (11-12) ◽  
pp. 1542-s1554 ◽  
Author(s):  
Maria Georgiou ◽  
Simone Wöckel ◽  
Vera Konstanzer ◽  
Sebastian Dechert ◽  
Michael John ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Carbene Ligands ◽  
Structural Variations ◽  
X Ray ◽  
Face To Face ◽  
Tert Butyl ◽  
X Ray Crystallography

A set of pyrazole-bridged bis(imidazolium) compounds [H3L1]X2 - [H3 L4]X2 (L1 = 3,5-bis[1-(tert-butyl)imidazolium-1-ylmethyl]-1H-pyrazole; L2 = 3,5-bis[1-(tert-butyl)imidazolium- 1-ylmethyl]-4-phenyl-1H-pyrazole; L3 = 3,5-bis[1-(1-adamantyl)imidazolium-1-ylmethyl]-1Hpyrazole; L4 = 3,5-bis[1-(1-adamantyl)imidazolium-1-ylmethyl]-4-phenyl-1H-pyrazole; X = Cl−, BF4 − or PF6 −) has been prepared, and three compounds have been characterized by X-ray crystallography. The unique [H3L4][H2L4](PF6)3 features a dimeric face-to-face arrangement of two molecules due to the involvement of both the pyrazole-NH and the imidazolium C2H in hydrogen bonding. [H3L1]X2 - [H3L4]X2 serve as precursors for silver(I) complexes with compartmental pyrazolate-bridged bis(NHC) ligands. The complexes have been readily prepared by the Ag2O route and feature either the known [(L1−4)2Ag4]2+ or the new [(H2L1)4Ag4]8+ motif, depending on the solvent for the reaction (MeCN or acetone). [(H2L1)4Ag4](PF6)8 contains a central (pzAg)4 ring with pendant imidazolium side arms. Upon further reaction with Ag2O in MeCN it was found to undergo transformation to the corresponding [(L1)2Ag4](PF6)2. All complexes have been thoroughly studied by NMR spectroscopy in solution, and preliminary luminescence data of [(H2L1)4Ag4](PF6)8 have been recorded

Direct Synthesis of 6H-Chromeno[3,4-b]quinolin-6-ol Derivatives from Substituted 3-Nitro-2H-chromenes and 2-Nitrobenzaldehydes Mediated by Fe/AcOH System

Synthesis ◽  
2017 ◽  
Vol 50 (06) ◽  
pp. 1350-1358 ◽  
Author(s):  
Cunde Wang ◽  
Xushun Qing ◽  
Ting Wang ◽  
Chenlu Dai ◽  
Zhenjie Su
Keyword(s):  
Acetic Acid ◽  
Nucleophilic Addition ◽  
Aldol Condensation ◽  
Direct Synthesis ◽  
Reductive Cyclization ◽  
Quinoline Derivatives ◽  
Acid System ◽  
X Ray ◽  
X Ray Crystallography ◽  
Sequential Reduction

An efficient iron/acetic acid system-mediated reductive cyclization reaction of substituted 2-aryl-3-nitro-2H-chromenes with substituted 2-nitrobenzaldehydes for the synthesis of 6-aryl-6H-chromeno[3,4-b]quinolines was developed. This reaction involves the sequential reduction, hydrolysis, aldol condensation, intramolecular addition, and the nucleophilic addition of substituted 2-aryl-3-nitro-2H-chromenes with substituted 2-nitrobenzaldehydes to give the corresponding 6H-chromeno[3,4-b]quinolines. This transformation provides a straightforward synthetic protocol for constructing substituted 6H-chromeno[3,4-b]quinoline derivatives. The structures of three typical products were confirmed by X-ray crystallography.

Molecular tectonics — Use of urethanes and ureas derived from tetraphenylmethane and tetraphenylsilane to build porous chiral hydrogen-bonded networks

2004 ◽  
Vol 82 (2) ◽  
pp. 386-398 ◽  
Author(s):  
Dominic Laliberté ◽  
Thierry Maris ◽  
James D Wuest
Keyword(s):  
Hydrogen Bonding ◽  
Asymmetric Catalysis ◽  
Crystal Engineering ◽  
Three Dimensional ◽  
Enantiomerically Pure ◽  
X Ray ◽  
Molecular Tectonics ◽  
X Ray Crystallography ◽  
Open Networks ◽  
Hydrogen Bonded

Tetraphenylmethane, tetraphenylsilane, and simple derivatives with substituents that do not engage in hydrogen bonding typically crystallize as close-packed structures with essentially no space available for the inclusion of guests. In contrast, derivatives with hydrogen-bonding groups are known to favor the formation of open networks that include significant amounts of guests. To explore this phenomenon, we synthesized six new derivatives 5a–5e and 6a of tetraphenylmethane and tetraphenylsilane with urethane and urea groups at the para positions, crystallized the compounds, and determined their structures by X-ray crystallography. As expected, all six compounds crystallize to form porous three-dimensional hydrogen-bonded networks. In the case of tetraurea 5e, 66% of the volume of the crystals is accessible to guests, and guests can be exchanged in single crystals without loss of crystallinity. Of special note are: (i) the use of tetrakis(4-isocyanatophenyl)methane (1f) as a precursor for making enantiomerically pure tetraurethanes and tetraureas, including compounds 5b, 5c; and (ii) their subsequent crystallization to give porous chiral hydrogen-bonded networks. Such materials promise to include chiral guests enantioselectively and to be useful in the separation of racemates, asymmetric catalysis, and other applications.Key words: crystal engineering, molecular tectonics, hydrogen bonding, networks, porosity, urethanes, ureas, tetraphenylmethane, tetraphenylsilane.

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