scholarly journals Interplay between Polymorphism and Isostructurality in the 2-Fur- and 2-Thenaldehyde Semi- and Thiosemicarbazones

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 993
Author(s):  
Marcin Swiatkowski ◽  
Agata Trzesowska-Kruszynska ◽  
Agnieszka Danielewicz ◽  
Paulina Sobczak ◽  
Rafal Kruszynski
Keyword(s):  
Crystal Structures ◽  
Electron Density ◽  
Self Assembly ◽  
Crystal Packing ◽  
The Self ◽  
Polymorphic Forms ◽  
Full Interaction ◽  
Crystal Packing Effects ◽  
Packing Effects

The four compounds, namely: 5-nitro-2-furaldehyde thiosemicarbazone (1); 5-nitro-2-thiophene thiosemicarbazone (2); 5-nitro-2-furaldehyde semicarbazone (3); and 5-nitro-2-thiophene semicarbazone (4) were synthesized and crystallized. The three new crystal structures of 1, 2, and 4 were determined and compared to three already known crystal structures of 3. Additionally, two new polymorphic forms of 1 solvate were synthesized and studied. The influence of the exchange of 2-thiophene to 2-furaldehyde as well as thiosemicarbazone and semicarbazone on the self-assembly of supramolecular nets was elucidated and discussed in terms of the formed synthons and assemblies accompanied by Full Interaction Maps analysis. Changes in the strength of IR oscillators caused by the molecular and crystal packing effects are described and explained in terms of changes of electron density.

Three different fluoro- or chloro-substituted 1′-deoxy-1′-phenyl-β-D-ribofuranoses

2014 ◽  
Vol 70 (4) ◽  
pp. 400-404
Author(s):  
Jan W. Bats ◽  
Aleksandra Živković ◽  
Jörg Parsch ◽  
Joachim W. Engels
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Benzene Ring ◽  
Crystal Packing ◽  
Double Layers ◽  
Substitution Pattern ◽  
Contact Distance ◽  
Substituted 1 ◽  
Crystal Packing Effects ◽  
Packing Effects

Crystal structures are reported for three fluoro- or chloro-substituted 1′-deoxy-1′-phenyl-β-D-ribofuranoses, namely 1′-deoxy-1′-(2,4,5-trifluorophenyl)-β-D-ribofuranose, C11H11F3O4, (I), 1′-deoxy-1′-(2,4,6-trifluorophenyl)-β-D-ribofuranose, C11H11F3O4, (II), and 1′-(4-chlorophenyl)-1′-deoxy-β-D-ribofuranose, C11H13ClO4, (III). The five-membered furanose ring of the three compounds has a conformation between a C2′-endo,C3′-exotwist and a C2′-endoenvelope. The ribofuranose groups of (I) and (III) are connected by intermolecular O—H...O hydrogen bonds to six symmetry-related molecules to form double layers, while the ribofuranose group of (II) is connected by O—H...O hydrogen bonds to four symmetry-related molecules to form single layers. The O...O contact distance of the O—H...O hydrogen bonds ranges from 2.7172 (15) to 2.8895 (19) Å. Neighbouring double layers of (I) are connected by a very weak intermolecular C—F...π contact. The layers of (II) are connected by one C—H...O and two C—H...F contacts, while the double layers of (III) are connected by a C—H...Cl contact. The conformations of the molecules are compared with those of seven related molecules. The orientation of the benzene ring is coplanar with the H—C1′ bond or bisecting the H—C1′—C2′ angle, or intermediate between these positions. The orientation of the benzene ring is independent of the substitution pattern of the ring and depends mainly on crystal-packing effects.

scholarly journals Self-Assembly of Shape-Tunable Oblate Colloidal Particles into Orientationally Ordered Crystals, Glassy Crystals and Plastic Crystals

Soft Matter ◽  
2021 ◽  
Author(s):  
Jiawei Lu ◽  
Xiangyu Bu ◽  
Xinghua Zhang ◽  
Bing Liu
Keyword(s):  
Crystal Structures ◽  
Self Assembly ◽  
Colloidal Particles ◽  
Building Blocks ◽  
Fundamental Question ◽  
The Self ◽  
Plastic Crystals ◽  
Self Assembled ◽  
Glassy Crystals ◽  
The Relationship

The shapes of colloidal particles are crucial to the self-assembled superstructures. Understanding the relationship between the shapes of building blocks and the resulting crystal structures is an important fundamental question....

scholarly journals Self-assembly of fluoride-encapsulated polyhedral oligomeric silsesquioxane (POSS) nanocrystals

CrystEngComm ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 710-723 ◽  
Author(s):  
Ellen Heeley ◽  
Youssef El Aziz ◽  
Christopher Ellingford ◽  
Albina Jetybayeva ◽  
Chaoying Wan ◽  
...  
Keyword(s):  
Self Assembly ◽  
Alkyl Chain ◽  
Crystal Packing ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
The Self ◽  
Fluoride Ion ◽  
Electron Withdrawing Group ◽  
Oligomeric Silsesquioxane

The self-assembly and crystal packing of a unique series of nanocrystalline fluoride ion-encapsulated polyhedral oligomeric silsesquioxane (F-POSS) compounds, with substituted electron-withdrawing group (EWG) perfluorinated alkyl chain arms of varying lengths, were investigated.

scholarly journals Evidence of crystal packing effects in stabilizing high or low spin states of iron(ii) complexes with functionalized 2,6-bis(pyrazol-1-yl)pyridine ligands

2017 ◽  
Vol 46 (12) ◽  
pp. 4075-4085 ◽  
Author(s):  
Nathalie Bridonneau ◽  
Luca Rigamonti ◽  
Giordano Poneti ◽  
Dawid Pinkowicz ◽  
Alessandra Forni ◽  
...  
Keyword(s):  
Crystal Packing ◽  
Spin States ◽  
Pyridine Ligands ◽  
Intermolecular Contacts ◽  
Crystal Packing Effects ◽  
Packing Effects

High or low spin states in iron(ii) complexes with functionalised 2,6-bis(pyrazol-1-yl)pyridine ligands are efficaciously driven by intermolecular contacts.

Polymorphism of tubulin assembly in vitro

1989 ◽  
Vol 94 (3) ◽  
pp. 479-488
Author(s):  
PAULA KARECLA ◽  
ELIZABETH HIRST ◽  
PETER BAYLEY
Keyword(s):  
Self Assembly ◽  
Basic Structure ◽  
Limited Range ◽  
The Self ◽  
Tubulin Dimer ◽  
Thin Sectioning ◽  
Associated Proteins ◽  
Bona Fide ◽  
Polymorphic Forms

Polymorphism in the self-assembly of tubulin dimer and microtubule protein (tubulin plus the microtubule-associated proteins) has been investigated as a function of systematic variation of solution composition (i.e. buffer ion, [glycerol] and [Mg2+]). The nature of the assembly product was examined using negative staining and thin sectioning electron microscopy. The morphology of the product of assembly of tubulin dimer was found to be strongly influenced by the concentration of glycerol and Mg2+ in Pipes and Mes buffers; the effects are less marked in phosphate buffer. Formation of bona fide microtubules in O.l M-Pipes occurs for a limited range of solution conditions (e.g. with [glycerol] <2 M and [Mg2+]<1mM). Conditions of elevated [glycerol] and [Mg2+], which enhance the rate and extent of assembly, have the adverse effect of strongly promoting the formation of polymorphic forms in addition to, and in place of, the normal microtubule morphology. In both Pipes and Mes buffers, increasing [glycerol] from 1 to 3 M favours the formation of extended multiply curved sheets, apparently made up from a basic structure with an S-like crosssection. By contrast, increasing [Mg2+] promotes the formation of junctions between microtubule walls, giving products whose cross-section shows multiple hook-like appendages, attached to closed microtubules. The assembly of tubulin dimer in a typical ‘dimer assembly buffer’ (e.g. 0.05-0.1 MMes, with 1–3.4M-glycerol and 2–7mM-Mg2+), invariably produces substantial proportions of nonmicrotubule structures such as open sheets, ribbons, and hooked structures. We conclude that the self-assembly of tubulin dimer exclusively into bona fide microtubules occurs over a very restricted range of solution conditions in the normally used Pipes- and Mes-based buffers. Deviation from these conditions readily promotes the formation of mixtures of polymorphic forms. Many buffer systems used for the assembly and disassembly of microtubules composed of tubulin dimer appear likely to promote the formation of structures related to, but significantly different from, normal microtubules. This represents a cautionary factor in the interpretation of in vitro assembly and disassembly properties of microtubules

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