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Denticity

About: Denticity is a research topic. Over the lifetime, 17851 publications have been published within this topic receiving 309492 citations.


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Journal ArticleDOI
TL;DR: In this article, Heck et al. synthesize PdII complexes of donor-functionalized heterocyclic carbene ligands through a route involving carbene transfer from AgI carbene precursors.

471 citations

Journal ArticleDOI
TL;DR: The coordination geometry of divalent calcium ions has been investigated by analyses of the crystal structures of small molecules containing this cation that are found in the Cambridge Structural Database, protein crystal structures in the Protein Databank, and by ab initio molecular orbital calculations on hydrated structures of the form Ca[H2O]n2+·mH 2O as mentioned in this paper.
Abstract: The coordination geometry of divalent calcium ions has been investigated by analyses of the crystal structures of small molecules containing this cation that are found in the Cambridge Structural Database, protein crystal structures in the Protein Databank, and by ab initio molecular orbital calculations on hydrated structures of the form Ca[H2O]n2+·mH2O, in which there are n water molecules in the first coordination shell and m water molecules in the second coordination shell (hydrogen bonded to water molecules in the first shell). Calcium ions in crystal structures generally bind to oxygen atoms in ligands (rather than any other element), and their preferred coordination numbers range from 6 to 8. In protein crystal structures the tendency of calcium to bind water molecules is less than for magnesium (1.5 versus 2.2 water molecules on the average per metal ion site, respectively). The ratio of bidentate to monodentate binding of calcium ions to carboxylate groups is similar for small molecules and prote...

468 citations

Journal ArticleDOI
TL;DR: In this article, three multidentate amines, tetramethylethylenediamine (TMEDA), N,N,NN, N',N' and N'N' were used as new ligands in the copper mediated atom transfer radical polymerization (ATRP) of styrene, methyl acrylate and methyl methacrylate.
Abstract: Three multidentate amines, tetramethylethylenediamine (TMEDA), N,N,N‘,N‘,N‘‘-pentamethyldiethylenetriamine (PMDETA) and 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) have been successfully used as new ligands in the copper mediated atom transfer radical polymerization (ATRP) of styrene, methyl acrylate and methyl methacrylate. All the polymerizations were well controlled with a linear increase of molecular weights (Mn) with conversion and relatively low polydispersities throughout the reactions. Compared to the 2,2‘-bipyridine (bipy) based ligands, most multidentate amines are less expensive and the polymerization mixtures are less colored. In particular, the use of the tridentate PMDETA and the tetradentate HMTETA as the ligands resulted in faster polymerization rates for styrene and methyl acrylate than those using bipy as the ligand. This may be in part attributed to the fact that the coordination complexes between copper and the simple amines have lower redox potentials than the copper−bipy co...

428 citations

Journal ArticleDOI
TL;DR: In this article, the stereochemical properties of over 120 pyrazole-based chelating ligands, studied by single-crystal X-ray crystallography were analyzed.

426 citations

Journal ArticleDOI
Tamio Hayashi1
TL;DR: Chiral monophosphines have been prepared from enantiomerically pure 2, 2'-dihydroxy-1,1'-binaphthyl and demonstrated to be highly efficient chiral ligands for transition-metal-catalyzed organic transformations, especially for reactions where chelating bisphosphine ligands cannot be used.
Abstract: Chiral monophosphines, whose chirality is due to biaryl axial chirality, have been prepared from enantiomerically pure 2, 2'-dihydroxy-1,1'-binaphthyl and demonstrated to be highly efficient chiral ligands for transition-metal-catalyzed organic transformations, especially for reactions where chelating bisphosphine ligands cannot be used. The high efficiency is observed in palladium-catalyzed asymmetric hydrosilylation of a wide variety of olefins such as alkyl-substituted terminal olefins and in asymmetric reactions via pi-allylpalladium intermediates represented by asymmetric reduction of allylic esters with formic acid.

416 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023461
2022964
2021386
2020423
2019444
2018447