Search results for "complexes"
showing 10 items of 875 documents
Synthesis of pyrido[2,1-a]isoquinolin-4-ones and oxazino[2,3-a]isoquinolin-4-ones: New inhibitors of mitochondrial respiratory chain
2013
International audience; Benzo[a]quinolizine is an important heterocyclic framework that can be found in numerous bioactive compounds. The general scheme for the synthesis of these compounds was based on the preparation of the appropriate dihydroisoquinolines by Bischler-Napieralski cyclization with good yields, followed by the Pemberton method to form the oxazinones or pyridones derivatives via acyl-ketene imine cyclocondensation. All the synthesized compounds were assayed in vitro for their ability to inhibit mitochondrial respiratory chain. Most of the tested compounds were able to inhibit the integrated electron transfer chain, measured as NADH oxidation, which includes complexes I, III …
Male infertility and mitochondrial DNA
2004
The mitochondrial machinery plays a key role in the energy production and maintenance of spermatozoa motility. In this paper 200 idiopathic oligo-asthenozoospermic patients were classified on the basis of rapid progressive motility ("a") and sperm concentration. Mitochondrial enzymatic activity was studied and correlated to the viability of sperm cells. Mitochondrial DNA purified from both motile and non-motile sperm of the same individuals was amplificated using PCR. Results suggested that only motile sperm have organelles functional in oxygen consumption, unequivocally demonstrating that motility depends on the mitochondrial activity. Mitochondrial DNA of oligo-asthenozoospermic patients …
Badanie metodą inwersyjnej chromatografii gazowej wpływu wielkości podstawnika na właściwości inkluzyjne kaliksarenów
2009
Badano wpływ wielkości alifatycznego podstawnika na zdolności inkluzyjne kaliksarenów {kaliks[4]arenu(K4), p-izopropylokaliks[4]arenu (IPK4) i p-tert-butylokaliks[4]arenu (TBK4)}. Oceny wpływu dokonywano za pomocą metody QSRR przy użyciu inwersyjnej chromatografii gazowej. W charakterze solutów użyto szeregu alifatycznych alkoholi, homologów benzenu i homologów pirydyny. Na podstawie indeksów retencji Kovatsa i wykresów zależności właściwej objętości retencji od temperatury wrzenia [Vg=f(Tw)] stwierdzono, że tylko podstawione kaliksareny wykazują właściwości inkluzyjne w stosunku do niższych alkoholi.
Effect of temperature and ligand protonation on the electronic ground state in Cu( ii ) polymers having unusual secondary interactions: a magnetic an…
2018
International audience; Two new copper(II) polymeric complexes, {[Cu(HPymat)(H2O)](NO3)}n (1) and [Cu2(Pymat)2(H2O)3]n (2), have been synthesized using the Schiff base ligand H2Pymat [H2Pymat = (E)-2-(1-(pyridin-2-yl)-methyleneamino)terephthalic acid]. Complex 1 is a cationic 1D polymer, whereas complex 2 is a two dimensional polymer. Both complexes were crystallographically, spectroscopically and magnetically characterized. Theoretical studies were performed and the catecholase activity of the complexes was also examined. Complex 1 is a ferromagnetically coupled complex with J = 2.8 cm−1 and 2 shows antiferromagnetic coupling with J = −1.6 cm−1. Both complexes show notable features in the …
Resolution of β-aminophosphines with chiral cyclopalladated complexes
2005
Abstract Resolution of the racemic chiral β-aminophosphines Ph 2 PCH 2 CH(Ph)NH(Ar) ( L 1 for Ar = C 6 H 5 and L 2 for Ar = 2,6-C 6 H 3 i Pr 2 ) has been investigated by use of different cyclopalladated complexes as chiral agents. The resulting complexes afford diastereomeric adducts in a 1:1 ratio. After successive crystallizations from ethanol, a d.e. of 98% was achieved for one aminophosphine palladium complex, while no significant d.e. was obtained after crystallizations from chlorinated solvents. The X-ray structure analysis has pointed out intermolecular hydrogen interactions N–H⋯Cl between the P,N ligand and the chloride ion, which are responsible for the formation and stabilization …
Ditopic Aza-Scorpiand Ligands Interact Selectively with ds-RNA and Modulate the Interaction upon Formation of Zn2+ Complexes
2021
Nucleic acids are essential biomolecules in living systems and represent one of the main targets of chemists, biophysics, biologists, and nanotechnologists. New small molecules are continuously developed to target the duplex (ds) structure of DNA and, most recently, RNA to be used as therapeutics and/or biological tools. Stimuli-triggered systems can promote and hamper the interaction to biomolecules through external stimuli such as light and metal coordination. In this work, we report on the interaction with ds-DNA and ds-RNA of two aza-macrocycles able to coordinate Zn2+ metal ions and form binuclear complexes. The interaction of the aza-macrocycles and the Zn2+ metal complexes with duple…
Relation entre transitivité et structure de communauté dans les réseaux complexes
2011
The relation between community structure and other topological properties in complex networks, has not been analyzed clearly. In this preliminary study, we explore experimentally the potential link between transitivity and community structure. We study the evolution of transitivity based on the quality of the community structure on artificially generated networks. Then we observe the evolution of community structure according to transitivity value. The results show a relationship between high transitivity and community structure. Additional analytical work is needed to identify the exact nature of this relationship.
Antiproliferative Properties of a Few Auranofin-Related Gold(I) and Silver(I) Complexes in Leukemia Cells and their Interferences with the Ubiquitin …
2020
A group of triethylphosphine gold(I) and silver(I) complexes, structurally related to auranofin, were prepared and investigated as potential anticancer drug candidates. The antiproliferative properties of these metal compounds were assessed against two leukemia cell lines, i.e., CCRF-CEM and its multidrug-resistant counterpart, CEM/ADR5000. Interestingly, potent cytotoxic effects were disclosed for both series of compounds against leukemia cells, with IC50 values generally falling in the low-micromolar range, the gold derivatives being on the whole more effective than the silver analogues. Some initial structure-function relationships were drawn. Subsequently, the ability of the study compo…
All-atom simulations to studying metallodrugs/target interactions.
2021
Abstract Metallodrugs are extensively used to treat and diagnose distinct disease types. The unique physical–chemical properties of metal ions offer tantalizing opportunities to tailor effective scaffolds for selectively targeting specific biomolecules. Modern experimental techniques have collected a large body of structural data concerning the interactions of metallodrugs with their biomolecular targets, although being unable to exhaustively assess the molecular basis of their mechanism of action. In this scenario, the complementary use of accurate computational methods allows uncovering the minutiae of metallodrugs/targets interactions and their underlying mechanism of action at an atomic…
Modular organization in the reductive evolution of protein-protein interaction networks
2006
Analysis of the reduction in genome size of Buchnera aphidicola from its common ancestor E. coli shows that the organization of networks into modules is the property that seems to be directly related with the evolutionary process of genome reduction.