scholarly journals The head-to-head photodimer of indenoindene

IUCrData ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Heiner Detert ◽  
Nina Jacobs ◽  
Dieter Schollmeyer
Keyword(s):  
Π Interactions ◽  
Cyclobutane Ring

Irradiation of 1-(1-benzocyclobutenylidene)benzocyclobutene gives indenoindene and its head-to-head photodimer nonacyclo[9.7.7.72,10.01,11.02,10.03,8.012,17.019,24.026,31]dotriaconta-3,5,7,12,14,16,19,21,23,26,28,30-dodecaene, C32H24. The molecule is built from four essentially planar indane units attached to an elongated cyclobutane ring. In the crystal, C—H...π interactions connect molecules into layers parallel to the bc plane.

scholarly journals Chemo- and regioselective [3 + 2]-cycloadditions of thiocarbonyl ylides: crystal structures of trans-8-benzoyl-1,1,3,3-tetramethyl-7-trifluoromethyl-5-thiaspiro[3.4]octan-2-one and trans-3-benzoyl-2,2-diphenyl-4-(trifluoromethyl)tetrahydrothiophene

2018 ◽  
Vol 74 (12) ◽  
pp. 1705-1709
Author(s):  
Anthony Linden ◽  
Grzegorz Mlostoń ◽  
Paulina Grzelak ◽  
Heinz Heimgartner
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Thiophene Ring ◽  
Molecular Structures ◽  
The Other ◽  
Bond Lengths ◽  
Π Interactions ◽  
Envelope Conformation ◽  
Cyclobutane Ring

The title compounds, C19H21F3O2S and C24H19F3OS, were prepared via chemo- and regioselective [3 + 2]-cycloadditions of the respective thiocarbonyl ylides (thiocarbonyl S-methanides), generated in situ, with (E)-4,4,4-trifluoro-1-phenylbut-2-en-1-one. The thiophene ring in the crystal structure of each compound has an envelope conformation. The largest differences between the two molecular structures is in the bond lengths about the quaternary C atom of the thiophene ring; in the spirocyclic structure, the C—C bonds to the spiro C atom in the cyclobutane ring are around 1.60 Å, although this is also observed in related structures. In the same structure, weak intermolecular C—H...X (X = S, O) interactions link the molecules into extended ribbons running parallel to the [001] direction. In the other structure, weak C—H...π interactions link the molecules into sheets parallel to the (010) plane.

scholarly journals r-1,t-3-Bis[4-(dimethylamino)phenyl]-c-2,t-4-bis(pyridin-4-yl)cyclobutane

2014 ◽  
Vol 70 (3) ◽  
pp. o311-o311 ◽  
Author(s):  
Shuguang Zhang ◽  
Junpeng Zhuang
Keyword(s):  
Title Compound ◽  
Uv Light ◽  
Dimensional Structure ◽  
One Dimensional ◽  
Π Interactions ◽  
Compound C ◽  
Cyclobutane Ring

The title compound, C30H32N4, was synthesized by the photodimerization oftrans-4-{2-[4-(dimethylamino)phenyl]ethenyl}pyridine in benzene upon irradiation with UV light. This photodimer has a puckered cyclobutane ring with the four aryl substituents in anr-1,t-2,c-3,tconformation. The puckering angle of the cyclobutane ring is 32.22 (7)°, which is the largest among reported tetraaryl-substituted cyclobutanes. In the crystal, the molecules form a hollow, one-dimensional structure extending parallel to thecaxisviatwo different pairs of C—H...π interactions.

A Photoluminescent Au(I)/Ag(I)/PNN coordination complex for Relatively Rapid and Reversible Alcohol Sensing

2021 ◽  
Author(s):  
Yanhui Tao ◽  
Yuwei Wang ◽  
Shengnan Hu ◽  
David James Young ◽  
Chengrong Lu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Coordination Complex ◽  
Trinuclear Complex ◽  
Low Molecular Weight ◽  
Radiative Relaxation ◽  
Π Interactions

Trinuclear complex [Au2Ag(dppmaphen)2(CN)2]PF6 photoluminesces on exposure to low molecular weight alcohols. This emission is likely due to C-H···π interactions between the analyte and –PPh2 group, that inhibits non-radiative relaxation of...

scholarly journals Deciphering the Role of π-Interactions in Polyelectrolyte Complexes Using Rationally Designed Peptides

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2074
Author(s):  
Sara Tabandeh ◽  
Cristina Elisabeth Lemus ◽  
Lorraine Leon
Keyword(s):  
Hydrogen Bonding ◽  
Phase Separation ◽  
Liquid Phase ◽  
Charge Density ◽  
Secondary Structures ◽  
Liquid Phase Separation ◽  
Polyelectrolyte Complexes ◽  
Π Interactions ◽  
Liquid Liquid Phase Separation

Electrostatic interactions, and specifically π-interactions play a significant role in the liquid-liquid phase separation of proteins and formation of membraneless organelles/or biological condensates. Sequence patterning of peptides allows creating protein-like structures and controlling the chemistry and interactions of the mimetic molecules. A library of oppositely charged polypeptides was designed and synthesized to investigate the role of π-interactions on phase separation and secondary structures of polyelectrolyte complexes. Phenylalanine was chosen as the π-containing residue and was used together with lysine or glutamic acid in the design of positively or negatively charged sequences. The effect of charge density and also the substitution of fluorine on the phenylalanine ring, known to disrupt π-interactions, were investigated. Characterization analysis using MALDI-TOF mass spectroscopy, H NMR, and circular dichroism (CD) confirmed the molecular structure and chiral pattern of peptide sequences. Despite an alternating sequence of chirality previously shown to promote liquid-liquid phase separation, complexes appeared as solid precipitates, suggesting strong interactions between the sequence pairs. The secondary structures of sequence pairs showed the formation of hydrogen-bonded structures with a β-sheet signal in FTIR spectroscopy. The presence of fluorine decreased hydrogen bonding due to its inhibitory effect on π-interactions. π-interactions resulted in enhanced stability of complexes against salt, and higher critical salt concentrations for complexes with more π-containing amino acids. Furthermore, UV-vis spectroscopy showed that sequences containing π-interactions and increased charge density encapsulated a small charged molecule with π-bonds with high efficiency. These findings highlight the interplay between ionic, hydrophobic, hydrogen bonding, and π-interactions in polyelectrolyte complex formation and enhance our understanding of phase separation phenomena in protein-like structures.

scholarly journals Synthesis and self-assembly of a penta[60]fullerene bearing benzo[ghi]perylenetriimide units

RSC Advances ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 6002-6007
Author(s):  
Clément Drou ◽  
Théo Merland ◽  
Antoine Busseau ◽  
Sylvie Dabos-Seignon ◽  
Antoine Goujon ◽  
...  
Keyword(s):  
Self Assembly ◽  
Π Interactions

New penta(organo)fullerene bearing five benzo[ghi]perylenetriimide units has been synthesized to form self-assemblies through π–π interactions.

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