Search results for " LIGANDS"
showing 10 items of 196 documents
Tenectin is a novel alphaPS2betaPS integrin ligand required for wing morphogenesis and male genital looping in Drosophila.
2010
International audience; Morphogenesis of the adult structures of holometabolous insects is regulated by ecdysteroids and juvenile hormones and involves cell-cell interactions mediated in part by the cell surface integrin receptors and their extracellular matrix (ECM) ligands. These adhesion molecules and their regulation by hormones are not well characterized. We describe the gene structure of a newly described ECM molecule, tenectin, and demonstrate that it is a hormonally regulated ECM protein required for proper morphogenesis of the adult wing and male genitalia. Tenectin's function as a new ligand of the PS2 integrins is demonstrated by both genetic interactions in the fly and by cell s…
A novel dimer of oxo-di(acetato)-bridged manganese(III) dimers complex of potential biological significance
2000
[EN] Assembly of the tetranuclear oxomanganese(III) acetato cluster [Mn4O2(O2CMe)(7)(phen)(2)](BF4) from the dinuclear oxo-di(acetato)bridged manganese(III) species [Mn2O(O2CMe)(2)(H2O)(2)(phen)(2)](BF4)(2) . 3H(2)O in aqueous/acetic acid MeOH solution occurs via the new 'dimer of dimers' Mn-III complex [Mn2O(O2CMe)(3)(H2O)(phen)(2)](BF4) . MeOH possesing an unprecedent [Mn-4(mu-O)(2)(mu-O2Me)(4) (mu-(OH2O2CMe)-O-...)(2)] core.
High Turnover Catalase Activity of a Mixed‐Valence Mn II Mn III Complex with Terminal Carboxylate Donors
2015
The neutral dimanganese(II,III) complex [Mn-2(BCPMP)-(OAc)(2)] [1; BCPMP3- = 2,6-bis({(carboxymethyl)[(1-pyridyl)-methyl] amino} methyl)-4-methylphenolato] has been synthesized and characterized. The complex contains two terminal carboxylate donors. Complex 1 was found to be an effective catalyst for the disproportionation of H2O2 with high catalytic rate and a turnover number of 7500, the highest turnover reported to date for a catalase mimic. The rates and TON were significantly higher than recorded for a dicationic dimanganese( II,III) counterpart ([Mn-2(BPBP)(OAc)(2)]center dot(ClO4)(2), 2; BPBP- = 2,6-bis{[bis(2-pyridylmethyl)amino]methyl}-4-butylphen-olato), which lacks the terminal c…
Electrostatic Tuning of the Ligand Binding Mechanism by Glu27 in Nitrophorin 7
2018
AbstractNitrophorins (NP) 1–7 are NO-carrying heme proteins found in the saliva of the blood-sucking insect Rhodnius prolixus. The isoform NP7 displays peculiar properties, such as an abnormally high isoelectric point, the ability to bind negatively charged membranes, and a strong pH sensitivity of NO affinity. A unique trait of NP7 is the presence of Glu in position 27, which is occupied by Val in other NPs. Glu27 appears to be important for tuning the heme properties, but its influence on the pH-dependent NO release mechanism, which is assisted by a conformational change in the AB loop, remains unexplored. Here, in order to gain insight into the functional role of Glu27, we examine the ef…
Two copper complexes from two novel naphthalene-sulfonyl-triazole ligands: different nuclearity and different DNA binding and cleavage capabilities.
2013
[EN] Two novel naphthalene-sulfonyl-triazole ligands, 5-amino-N1-(naphthalen-3-ylsulfony1)-1,2,4-triazole (anstrz) and 3,5-diamino-N1-(naphthalen-3-ylsulfony1)-1,2,4-triazole (danstrz), purposely designed to interact with DNA, have been prepared for the first time and then fully characterized by H-1, C-13 NMR and IR spectroscopy, mass spectrometry and elemental analysis. The crystal structures of two copper complexes of these derivatives, i.e. [Cu(anstrz)(4)(NO3)(2)]center dot 4CH(3)OH (1), mononuclear, and [Cu(danstrz)(mu-OAc)(2)](2)center dot 2(danstrz) (OAc = acetato) (2), dinuclear, have been determined by single-crystal X-ray diffraction. In both cases the ligand coordinates in a monod…
Heptacoordinated Molybdenum(VI) Complexes of Phenylenediamine Bis(phenolate): A Stable Molybdenum Amidophenoxide Radical
2013
The syntheses, crystallographic structures, magnetic properties, and theoretical studies of two heptacoordinated molybdenum complexes with N,N′-bis(3,5-di-tert-butyl-2-hydroxyphenyl)-1,2-phenylenediamine (H4N2O2) are reported. A formally molybdenum(VI) complex [Mo(N2O2)Cl2(dmf)] (1) was synthesized by the reaction between [MoO2Cl2(dmf)2] and H4N2O2, whereas the other molybdenum(VI) complex [Mo(N2O2)(HN2O2)] (2) was formed when [MoO2(acac)2] was used as a molybdenum source. Both complexes represent a rare case of the MoVI ion without any multiply bonded terminal ligands. In addition, molecular structures, magnetic measurements, ESR spectroscopy, and density functional theory calculations ind…
Designing binuclear transition metal complexes: a new example of the versatility of N,N′-bis(2-aminobenzyl)-4,13-diaza-18-crown-6
2005
[Abstract] N,N′-Bis(2-aminobenzyl)-4,13-diaza-18-crown-6 (L) is a versatile receptor able to adapt to the coordinative preferences of different metal cation guests. With first-row transition metal ions, L tends to form binuclear complexes but, depending on the nature of the particular metal ion, the structure of the binuclear complex may be very different. Herein we report a study of the structure and magnetic properties of the corresponding nickel(II) and cobalt(II) complexes. The X-ray crystal structure of the nickel complex (1), with formula [Ni2(L)(CH3CN)4](ClO4)4·CH3CN, shows that this compound presents a symmetric coordination environment with L adopting an anti arrangement. Each Ni(I…
Cubane-Type Mo3FeS44+,5+ Complexes Containing Outer Diphosphane Ligands: Ligand Substitution Reactions, Spectroscopic Studies, and Electronic Structu…
2012
A general protocol to access Mo(3)FeS(4)(4+) clusters selectively modified at the Fe coordination site is presented starting from the all-chlorine Mo(3)(FeCl)S(4)(dmpe)(3)Cl(3) (1) [dmpe = 1,2-bis(dimethylphosphane-ethane)] cluster and tetrabutylammonium salts (n-Bu(4)NX) (X = CN(-), N(3)(-), and PhS(-)). Clusters Mo(3)(FeX)S(4)(dmpe)(3)Cl(3) [X = CN(-) (2), N(3)(-) (3), and PhS(-) (4)] are prepared in high yield, and comparison of geometric and redox features upon modification of the coordination environment at the Fe site at parity of ligands at the Mo sites is also presented. The existence of the cubane-type Mo(3)FeS(4)(4+,5+) redox couple is demonstrated by cyclic voltammetry and for co…
An Intermetallic Au24Ag20 Superatom Nanocluster Stabilized by Labile Ligands
2015
An intermetallic nanocluster containing 44 metal atoms, Au24Ag20(2-SPy)4(PhC≡C)20Cl2, was successfully synthesized and structurally characterized by single-crystal analysis and density funtional theory computations. The 44 metal atoms in the cluster are arranged as a concentric three-shell Au12@Ag20@Au12 Keplerate structure having a high symmetry. For the first time, the co-presence of three different types of anionic ligands (i.e., phenylalkynyl, 2-pyridylthiolate, and chloride) was revealed on the surface of metal nanoclusters. Similar to thiolates, alkynyls bind linearly to surface Au atoms using their σ-bonds, leading to the formation of two types of surface staple units (PhC≡C-Au-L, L …
Pentamethylcyclopentadienyl-rhodium and iridium complexes containing (N^N and N^O) bound chloroquine analogue ligands: synthesis, characterization an…
2016
The synthesis and characterization of twenty new pentamethylcyclopentadienyl-rhodium and iridium complexes containing N^N and N^O-chelating chloroquine analogue ligands are described. The in vitro antimalarial activity of the new ligands as well as the complexes was evaluated against the chloroquine sensitive (CQS) NF54 and the chloroquine resistant (CQR) Dd2 strains of Plasmodium falciparum. The antimalarial activity was found to be good to moderate; although all complexes are less active than artesunate, some of the ligands and complexes showed better activity than chloroquine (CQ). In particular, rhodium complexes were found to be considerably more active than iridium complexes against t…