Self-assembly of Zn(salphen) complexes: Steric regulation, stability studies and crystallographic analysis revealing an unexpected dimeric 3,3′-t-Bu-substituted Zn(salphen) complex

2010 ◽  
Vol 39 (19) ◽  
pp. 4541 ◽  
Author(s):  
Marta Martínez Belmonte ◽  
Sander J. Wezenberg ◽  
Robert M. Haak ◽  
Daniele Anselmo ◽  
Eduardo C. Escudero-Adán ◽  
...  
Keyword(s):  
Self Assembly ◽  
Crystallographic Analysis ◽  
Stability Studies

Self-assembly patterns of non-metalloid silver thiolates: structural, HR-ESI-MS and stability studies

2021 ◽  
Author(s):  
Anastasia Chupina ◽  
Pavel A Abramov ◽  
Vadim V. Yanshole ◽  
Veronica S. Sulyaeva ◽  
Vasily Kokovkin ◽  
...  
Keyword(s):  
Self Assembly ◽  
Stability Studies ◽  
Esi Ms ◽  
Thiolate Complexes

Screening of AgNO3/AgStBu solutions in DMF, DMSO and NMP resulted in an isolation of three novel nanosized silver/thiolate complexes with a torus-like {Ag20(StBu)10} core. The structures of [NO3@Ag20(StBu)10(NO3)9(DMF)6] (1) and...

scholarly journals X-Ray Crystallographic Analysis, EPR Studies, and Computational Calculations of a Cu(II) Tetramic Acid Complex

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Dimitrios Matiadis ◽  
Dimitrios Tsironis ◽  
Valentina Stefanou ◽  
Olga Igglessi–Markopoulou ◽  
Vickie McKee ◽  
...  
Keyword(s):  
Self Assembly ◽  
Copper Ions ◽  
Copper Ion ◽  
Spectroscopic Properties ◽  
Crystallographic Analysis ◽  
Computational Techniques ◽  
Tetramic Acid ◽  
Acid Complex ◽  
X Ray ◽  
Computational Calculations

In this work we present a structural and spectroscopic analysis of a copper(II) N-acetyl-5-arylidene tetramic acid by using both experimental and computational techniques. The crystal structure of the Cu(II) complex was determined by single crystal X-ray diffraction and shows that the copper ion lies on a centre of symmetry, with each ligand ion coordinated to two copper ions, forming a 2D sheet. Moreover, the EPR spectroscopic properties of the Cu(II) tetramic acid complex were also explored and discussed. Finally, a computational approach was performed in order to obtain a detailed and precise insight of product structures and properties. It is hoped that this study can enrich the field of functional supramolecular systems, giving place to the formation of coordination-driven self-assembly architectures.

Shape-persistent macrocycles — Self-assembly reactions and characterization by hyperpolarized 129Xe NMR spectroscopy**In memory of Professor Michael M. Pollard.

2011 ◽  
Vol 89 (10) ◽  
pp. 1264-1276 ◽  
Author(s):  
Katie Campbell ◽  
Kristopher J. Ooms ◽  
Michael J. Ferguson ◽  
Peter J. Stang ◽  
Roderick E. Wasylishen ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Self Assembly ◽  
Chemical Shifts ◽  
Crystallographic Analysis ◽  
Temperature Dependent ◽  
129Xe Nmr ◽  
Spectroscopic Analyses ◽  
Conjugated Macrocycles ◽  
Hyperpolarized 129Xe ◽  
Solvent Molecules

The use of three shape-persistent, conjugated macrocycles 2a–2c as ligands for self-assembly reactions is described. The macrocycles have been characterized through a combination of spectroscopic analyses and, for compounds 2b and 2c, X-ray crystallographic analysis. Whereas the reaction of 2a with the cis-Pt(II) species 3 successfully provides the porous solid 4a, the analogous reaction of 2b and 2c with 3 leads only to mixtures of products. The application of continuous-flow hyperpolarized 129Xe NMR spectroscopy to investigate the solid-state pores of macrocycles 2b and 2c and the supramolecular complex 4a as a function of temperature is described. All three species show permanent porosity upon removal of co-crystallized solvent molecules. Using trends in the 129Xe chemical shifts and temperature-dependent dynamics of Xe atoms in the solids, information is obtained on the nature of the pores in these systems. Using the 129Xe NMR data for complex 4a, the effective heat of adsorption (ΔHads) was calculated to be ~29 kJ mol–1.

scholarly journals Polyphosphate Poly(amine) Nanoparticles: Self-Assembly, Thermodynamics, and Stability Studies

Langmuir ◽  
2019 ◽  
Vol 35 (44) ◽  
pp. 14300-14309 ◽  
Author(s):  
Victor Ezequiel Cuenca ◽  
Hernan Martinelli ◽  
Maria de los Angeles Ramirez ◽  
Hernan Alejandro Ritacco ◽  
Patrizia Andreozzi ◽  
...  
Keyword(s):  
Self Assembly ◽  
Stability Studies

A regular thymine tetrad and a peculiar supramolecular assembly in the first crystal structure of an all-LNA G-quadruplex

2014 ◽  
Vol 70 (2) ◽  
pp. 362-370 ◽  
Author(s):  
Irene Russo Krauss ◽  
Gary Nigel Parkinson ◽  
Antonello Merlino ◽  
Carlo Andrea Mattia ◽  
Antonio Randazzo ◽  
...  
Keyword(s):  
Self Assembly ◽  
Supramolecular Assembly ◽  
Building Blocks ◽  
Crystallographic Analysis ◽  
Order Structure ◽  
Promising Tool ◽  
G Quadruplex ◽  
Nuclease Resistance ◽  
Diagnostic Applications ◽  
Structural Descriptions

Locked nucleic acids (LNAs) are formed by bicyclic ribonucleotides where the O2′ and C4′ atoms are linked through a methylene bridge and the sugar is blocked in a 3′-endoconformation. They represent a promising tool for therapeutic and diagnostic applications and are characterized by higher thermal stability and nuclease resistance with respect to their natural counterparts. However, structural descriptions of LNA-containing quadruplexes are rather limited, since few NMR models have been reported in the literature. Here, the first crystallographically derived model of an all-LNA-substituted quadruplex-forming sequence 5′-TGGGT-3′ is presented refined at 1.7 Å resolution. This high-resolution crystallographic analysis reveals a regular parallel G-quadruplex arrangement terminating in a well defined thymine tetrad at the 3′-end. The detailed picture of the hydration pattern reveals LNA-specific features in the solvent distribution. Interestingly, two closely packed quadruplexes are present in the asymmetric unit. They face one another with their 3′-ends giving rise to a compact higher-order structure. This new assembly suggests a possible way in which sequential quadruplexes can be disposed in the crowded cell environment. Furthermore, as the formation of ordered structures by molecular self-assembly is an effective strategy to obtain nanostructures, this study could open the way to the design of a new class of LNA-based building blocks for nanotechnology.

Synthesis and Self-Assembly of 9,9'-Spirobifluorene-2,2',7,7'-tetracarboxylic Acid and Its Tetraamide. Non-Catenated Formation of Achiral Grid Layers with Large Chiral Pores

2006 ◽  
Vol 71 (2) ◽  
pp. 139-154 ◽  
Author(s):  
Petr Holý ◽  
Martin Havlík ◽  
Miloš Tichý ◽  
Jiří Závada ◽  
Ivana Císařová
Keyword(s):  
Self Assembly ◽  
Crystallographic Analysis ◽  
Tetracarboxylic Acid

The title tetrasubstituted spirobifluorenes 3a, 3b have been designed to serve as convenient achiral tectons for self-assembly of 2D layers with large chiral pores. The underlying stereochemical concept has been confirmed by the results of crystallographic analysis of tetraacid 3a. Self-assembly of isosteric tetraamide 3b led to markedly different results.

Quaternary structure of Limulus polyphemus hemocyanin

1978 ◽  
Vol 36 (2) ◽  
pp. 176-177
Author(s):  
T. Wichertjes ◽  
E.J. Kwak ◽  
E.F.J. Van Bruggen
Keyword(s):  
Electron Microscopy ◽  
Functional Properties ◽  
Horseshoe Crab ◽  
Temperature Jump ◽  
Quaternary Structure ◽  
Crystallographic Analysis ◽  
Limulus Polyphemus ◽  
Oxygen Binding ◽  
X Ray ◽  
Intact Molecule

Hemocyanin of the horseshoe crab (Limulus polyphemus) has been studied in nany ways. Recently the structure, dissociation and reassembly was studied using electron microscopy of negatively stained specimens as the method of investigation. Crystallization of the protein proved to be possible and X-ray crystallographic analysis was started. Also fluorescence properties of the hemocyanin after dialysis against Tris-glycine buffer + 0.01 M EDTA pH 8.9 (so called “stripped” hemocyanin) and its fractions II and V were studied, as well as functional properties of the fractions by NMR. Finally the temperature-jump method was used for assaying the oxygen binding of the dissociating molecule and of preparations of isolated subunits. Nevertheless very little is known about the structure of the intact molecule. Schutter et al. suggested that the molecule possibly consists of two halves, combined in a staggered way, the halves themselves consisting of four subunits arranged in a square.

Some Observations on Intra-Mitochondrial Crystals

1977 ◽  
Vol 35 ◽  
pp. 406-407
Author(s):  
J. A. Clarke ◽  
D. N. Landon ◽  
P. R. Ward
Keyword(s):  
Cytochrome B ◽  
Mitochondrial Myopathy ◽  
Crystallographic Analysis ◽  
Mitochondrial Membranes ◽  
Electron Microscopes ◽  
Muscle Biopsies

Intra-mitochondrial crystals have been noted in muscle biopsies from patients in a wide variety of diseased states. As far as we are aware, none of these crystals have been subjected to detailed crystallographic analysis. Recently, similar crystals were observed in a biopsy from a patient with a mitochondrial myopathy, characterised by a deficiency in reducible cytochrome b (Morgan-Hughes, J. A., Darveniza, P., Kahn, S. N., Landon, D. N., Sherratt, R. M., Land, J. M. and Clark, J. B., 1977, Brain, In Press). Aldehyde-fixed, osmicated resin imbedded material was examined using Siemens, JEOL and Phillips electron microscopes with goniometer specimen stages. The crystals generally lay between the outer and inner mitochondrial membranes and measured 1 - 3 μm in length and 0.1 - 0.3 μm in width. Characteristically, these crystals revealed specific periodicities.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

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