Substituent effects and activation mechanism of norbornene polymerization catalyzed by three-dimensional geometry α-diimine palladium complexes

2014 ◽  
Vol 5 (4) ◽  
pp. 1210-1218 ◽  
Author(s):  
Ping Huo ◽  
Wanyun Liu ◽  
Xiaohui He ◽  
Zhenhong Wei ◽  
Yiwang Chen
Keyword(s):  
Three Dimensional ◽  
Substituent Effects ◽  
Palladium Complexes ◽  
Activation Mechanism ◽  
Norbornene Polymerization

Synthesis, Structures, and Norbornene Polymerization Behavior of Bis(aryloxide-N-heterocyclic carbene) Palladium Complexes

2009 ◽  
Vol 28 (20) ◽  
pp. 5934-5940 ◽  
Author(s):  
Yong Kong ◽  
Hongping Ren ◽  
Shansheng Xu ◽  
Haibin Song ◽  
Binyuan Liu ◽  
...  
Keyword(s):  
Palladium Complexes ◽  
Polymerization Behavior ◽  
Norbornene Polymerization

Synthesis, structure and norbornene polymerization behavior of neutral palladium complexes

Polyhedron ◽  
2004 ◽  
Vol 23 (9) ◽  
pp. 1619-1627 ◽  
Author(s):  
Hua Liang ◽  
Jingyu Liu ◽  
Xiaofang Li ◽  
Yuesheng Li
Keyword(s):  
Palladium Complexes ◽  
Polymerization Behavior ◽  
Norbornene Polymerization

Substituent effects of two isophthalate derivatives on the construction of cadmium coordination polymers incorporating a dipyridyl ligand

2018 ◽  
Vol 74 (8) ◽  
pp. 894-900 ◽  
Author(s):  
Lin Wang ◽  
Qian-Kun Zhou ◽  
Yun Xu ◽  
Ni-Ya Li
Keyword(s):  
Coordination Polymers ◽  
Self Assembly ◽  
Three Dimensional ◽  
Substituent Effects ◽  
Dicarboxylic Acids ◽  
Two Dimensional ◽  
Reaction Conditions ◽  
Thermal Stabilities ◽  
Coordination Network ◽  
Potential Applications

In recent years, the design and construction of crystalline coordination complexes by the assembly of metal ions with multitopic ligands have attracted considerable attention because of the unique architectures and potential applications of these compounds. Two new coordination polymers, namely poly[[μ-trans-1-(2-aminopyridin-3-yl)-2-(pyridin-4-yl)ethene-κ2 N:N′](μ3-5-methylisophthalato-κ4 O 1,O 1′:O 3:O 3′)cadmium(II)], [Cd(C9H6O4)(C12H11N3)] n or [Cd(5-Me-ip)(2-NH2-3,4-bpe)] n , (I), and poly[[μ-trans-1-(2-aminopyridin-3-yl)-2-(pyridin-4-yl)ethene-κ2 N:N′](μ2-5-hydroxyisophthalato-κ4 O 1,O 1′:O 3:O 5)cadmium(II)], [Cd(C8H4O5)(C12H11N3)] n or [Cd(5-HO-ip)(2-NH2-3,4-bpe)] n , (II), have been prepared hydrothermally by the self-assembly of Cd(NO3)2·4H2O and trans-1-(2-aminopyridin-3-yl)-2-(pyridin-4-yl)ethene (2-NH2-3,4-bpe) with two similar dicarboxylic acids, i.e. 5-methylisophthalic acid (5-Me-H2ip) and 5-hydroxyisophthalic acid (5-HO-H2ip). The coordination network of (I) is a two-dimensional sql net parallel to (101). Adjacent sql nets are further linked to form a three-dimensional supramolecular framework via hydrogen-bonding interactions. Compound (II) is a two-dimensional (3,5)-connected coordination network parallel to (010) with the point symbol (63)(55647). As the other reactants and reaction conditions are the same, the structural differences between (I) and (II) are undoubtedly determined by the different substituent groups in the 5-position of isophthalic acid. Both (I) and (II) exhibit good thermal stabilities and photoluminescence properties.

scholarly journals New insights on human IRE1 tetramer structures based on molecular modeling

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Antonio Carlesso ◽  
Johanna Hörberg ◽  
Anna Reymer ◽  
Leif A. Eriksson
Keyword(s):  
Conformational Changes ◽  
Three Dimensional ◽  
Protein Docking ◽  
Activation Mechanism ◽  
Crystallographic Structure ◽  
Face To Face ◽  
Unfolded Protein ◽  
Dynamics Simulations ◽  
The Unfolded Protein Response ◽  
Protein Response

Abstract Inositol-Requiring Enzyme 1α (IRE1α; hereafter IRE1) is a transmembrane kinase/ribonuclease protein related with the unfolded protein response (UPR) signaling. Experimental evidence suggests that IRE1 forms several three dimensional (3D) structural variants: dimers, tetramers and higher order oligomers, where each structural variant can contain different IRE1 conformers in different arrangements. For example, studies have shown that two sets of IRE1 dimers exist; a face-to-face dimer and a back-to-back dimer, with the latter considered the important unit for UPR signaling propagation. However, the structural configuration and mechanistic details of the biologically important IRE1 tetramers are limited. Here, we combine protein–protein docking with molecular dynamics simulations to derive human IRE1 tetramer models and identify a molecular mechanism of IRE1 activation. To validate the derived models of the human IRE1 tetramer, we compare the dynamic behavior of the models with the yeast IRE1 tetramer crystallographic structure. We show that IRE1 tetramer conformational changes could be linked to the initiation of the unconventional splicing of mRNA encoding X-box binding protein-1 (XBP1), which allows for the expression of the transcription factor XBP1s (XBP1 spliced). The derived IRE1 tetrameric models bring new mechanistic insights about the IRE1 molecular activation mechanism by describing the IRE1 tetramers as active protagonists accommodating the XBP1 substrate.

Three-Dimensional Correlation AnalysisA Novel Approach to the Quantification of Substituent Effects

2003 ◽  
Vol 107 (45) ◽  
pp. 9695-9704 ◽  
Author(s):  
Artem Cherkasov ◽  
Dennis G. Sprous ◽  
Ridong Chen
Keyword(s):  
Three Dimensional ◽  
Substituent Effects ◽  
Novel Approach

scholarly journals Proton release on binding of glutathione to Alpha, Mu and Delta class glutathione transferases

1999 ◽  
Vol 344 (2) ◽  
pp. 419-425 ◽  
Author(s):  
Anna Maria CACCURI ◽  
Giovanni ANTONINI ◽  
Philip G. BOARD ◽  
Michael W. PARKER ◽  
Maria NICOTRA ◽  
...  
Keyword(s):  
Flow Analysis ◽  
Three Dimensional ◽  
Kinetic Mechanism ◽  
Activation Mechanism ◽  
Dimensional Structure ◽  
Binary Complex ◽  
Stopped Flow ◽  
Binding Mechanism ◽  
Proton Extrusion ◽  
Evolutionary Pathway

Potentiometric, spectroscopic and stopped-flow experiments have been performed to dissect the binding mechanism of GSH to selected glutathione S-transferases (GSTs), A1-1, M2-2 and Lucilia cuprina GST, belonging to Alpha, Mu and Delta classes respectively. Both Alpha and Mu isoenzymes quantitatively release the thiol proton of the substrate when the binary complex is formed. Proton extrusion, quenching of intrinsic fluorescence and thiolate formation, diagnostic of different steps along the binding pathway, have been monitored by stopped-flow analysis. Kinetic data are consistent with a multi-step binding mechanism: the substrate is initially bound to form an un-ionized pre-complex [k1⩾ (2-5)×106 M-1˙s-1], which is slowly converted into the final Michaelis complex (k2 = 1100-1200 s-1). Ionization of GSH, fluorescence quenching and proton extrusion are fast events that occur either synchronously or rapidly after the final complex formation. The Delta isoenzyme shows an interesting difference: proton extrusion is almost stoichiometric with thiolate formed at the active site only up to pH 7.0. Above this pH, at least one protein residue acts as internal base to neutralize the thiol proton. These results suggest that the Alpha and Mu enzymes retain not only a similar catalytic outcome and overall three-dimensional structure but also share a similar kinetic mechanism for GSH binding. The Delta GST, which is closely related to the mammalian Theta class enzymes and is distantly related to Alpha and Mu GSTs in the evolutionary pathway, might display a different activation mechanism for GSH.

Sign in / Sign up

Export Citation Format

Share Document