Cooperative effects in π-ligand bridged dinuclear complexes

1994 ◽  
Vol 475 (1-2) ◽  
pp. 233-240 ◽  
Author(s):  
Ulrich Behrens ◽  
Jürgen Heck ◽  
Michiel Maters ◽  
Gerlinde Frenzen ◽  
Annie Roelofsen ◽  
...  
2021 ◽  
Author(s):  
Haosheng Liang ◽  
Jordan Rio ◽  
Lionel Perrin ◽  
Pierre-Adrien Payard

Halide salts facilitate the oxidative addition of organic halides to Pd(0). This phenomenon originates from a combina-tion of anionic, cationic and Pd-Pd cooperative effects. Exhaustive computational exploration at the DFT level of the com-plexes obtained from [Pd0(PPh3)2] and a salt (NMe4Cl or LiCl) showed that chlorides promote phosphine release, leading to a mixture of mononuclear and dinuclear Pd(0) complexes. Anionic Pd(0) dinuclear complexes exhibit a cooperativity between Pd(0) centers which favors the oxidative addition of iodobenzene. The higher activity of Pd(0) dimers toward oxidative addition rationalizes the previously reported kinetic laws. In the presence of Li+, the oxidative addition to mon-onuclear [Pd0L(Li2Cl2)] is estimated barrierless. LiCl coordination polarizes Pd(0), enlarging both the electrophilicity and the nucleophilicity of the complex, which promotes both coordination of the substrate and the subsequent insertion into the C-I bond. These conclusions are paving the way to the rational use of salt effect in catalysis for the activation of more challenging bonds.


1992 ◽  
Vol 611 (5) ◽  
pp. 35-42 ◽  
Author(s):  
J�rgen Heck ◽  
P. Maurice ◽  
J. A. Hermans ◽  
Alex B. Scholten ◽  
W. P. J. H. Bosman ◽  
...  

1989 ◽  
Vol 86 ◽  
pp. 841-846 ◽  
Author(s):  
Maurizio Casarin ◽  
Gaetano Granozzi
Keyword(s):  

2021 ◽  
Vol 22 (5) ◽  
pp. 2599
Author(s):  
Mégane Collobert ◽  
Ozvan Bocher ◽  
Anaïs Le Nabec ◽  
Emmanuelle Génin ◽  
Claude Férec ◽  
...  

About 8% of the human genome is covered with candidate cis-regulatory elements (cCREs). Disruptions of CREs, described as “cis-ruptions” have been identified as being involved in various genetic diseases. Thanks to the development of chromatin conformation study techniques, several long-range cystic fibrosis transmembrane conductance regulator (CFTR) regulatory elements were identified, but the regulatory mechanisms of the CFTR gene have yet to be fully elucidated. The aim of this work is to improve our knowledge of the CFTR gene regulation, and to identity factors that could impact the CFTR gene expression, and potentially account for the variability of the clinical presentation of cystic fibrosis as well as CFTR-related disorders. Here, we apply the robust GWAS3D score to determine which of the CFTR introns could be involved in gene regulation. This approach highlights four particular CFTR introns of interest. Using reporter gene constructs in intestinal cells, we show that two new introns display strong cooperative effects in intestinal cells. Chromatin immunoprecipitation analyses further demonstrate fixation of transcription factors network. These results provide new insights into our understanding of the CFTR gene regulation and allow us to suggest a 3D CFTR locus structure in intestinal cells. A better understand of regulation mechanisms of the CFTR gene could elucidate cases of patients where the phenotype is not yet explained by the genotype. This would thus help in better diagnosis and therefore better management. These cis-acting regions may be a therapeutic challenge that could lead to the development of specific molecules capable of modulating gene expression in the future.


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