scholarly journals Higher MLCT lifetime of carbene iron(ii) complexes by chelate ring expansion

2021 ◽  
Author(s):  
Thomas Reuter ◽  
Ayla Kruse ◽  
Roland Schoch ◽  
Stefan Lochbrunner ◽  
Matthias Bauer ◽  
...  
Keyword(s):  
Chelate Ring ◽  
Ring Expansion

High octahedricity and rigidity enable the high 9.2 ps 3MLCT lifetime of the iron(ii) complex [Fe(dpmi)2]2+ possessing only two carbene donor sites.

Effect of Chelate Ring Expansion on Jahn–Teller Distortion and Jahn–Teller Dynamics in Copper(II) Complexes

2012 ◽  
Vol 51 (14) ◽  
pp. 7851-7858 ◽  
Author(s):  
Katharina Mack ◽  
Anica Wünsche von Leupoldt ◽  
Christoph Förster ◽  
Maria Ezhevskaya ◽  
Dariush Hinderberger ◽  
...  
Keyword(s):  
Chelate Ring ◽  
Ring Expansion ◽  
Teller Distortion ◽  
Jahn Teller ◽  
Jahn Teller Distortion

Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds

2020 ◽  
Author(s):  
Nathan O'Brien ◽  
Naokazu Kano ◽  
Nizam Havare ◽  
Ryohei Uematsu ◽  
Romain Ramozzi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ring Expansion ◽  
Bicyclic Compound ◽  
Compound A ◽  
Ligand System ◽  
Large Bulk ◽  
Rearrangement Reaction ◽  
Hydride Abstraction ◽  
Pentacoordinated Phosphorus ◽  
Acids And Bases

<div>The isolation and reactivities of two pentacoordinated phosphorus–tetracoordinated boron bonded compounds were</div><div>explored. A strong Lewis acidic boron reagent and electron-withdrawing ligand system were required to form the</div><div>pentacoordinated phosphorus state of the P–B bond. The first compound, a phosphoranyl-trihydroborate, gave a THF</div><div>stabilised phosphoranyl-borane intermediate upon a single hydride abstraction in THF. This compound could undergo a</div><div>unique rearrangement reaction, that involved a two-fold ring expansion, to give an unusual fused bicyclic compound or it</div><div>could act as a mono-hydroboration reagent. The hydroboration reactivity of the intermediate was found to be more reactive</div><div>towards alkynes over alkenes with good to moderate regioselectivity towards the terminal carbon. The second compound,</div><div>a phosphoranyl-triarylborate, was found to have a vastly different reactivity to the trihydroborate as it was highly stable</div><div>towards acids and bases. This is thought to be due to the large bulk around the P–B bond as shown in the crystal structure</div>

Concise Synthesis of GB22 by Endo-Selective Siloxycyclopropane Arylation

2019 ◽  
Author(s):  
Hannah E. Burdge ◽  
Takuya Oguma ◽  
Takahiro Kawajiri ◽  
Ryan Shenvi
Keyword(s):  
Intramolecular Cyclization ◽  
Cross Coupling ◽  
Building Blocks ◽  
Ring Expansion ◽  
Dual Catalysis ◽  
Acid Labile

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>

Concise Synthesis of GB22 by Endo-Selective Siloxycyclopropane Arylation

2019 ◽  
Author(s):  
Hannah E. Burdge ◽  
Takuya Oguma ◽  
Takahiro Kawajiri ◽  
Ryan Shenvi
Keyword(s):  
Intramolecular Cyclization ◽  
Cross Coupling ◽  
Building Blocks ◽  
Ring Expansion ◽  
Dual Catalysis ◽  
Acid Labile

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>

The structure of [Cu(bipy)3][Cu(bipy)(ala)(ClO4)2]ClO4 � a Compound with Two Different Coordination Modes in the same Complex

2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Mircea Braban ◽  
Ionel Haiduc
Keyword(s):  
Solid State ◽  
Chelate Ring ◽  
Octahedral Complex ◽  
State Structure ◽  
Complex Species ◽  
Solid State Structure ◽  
Coordination Modes ◽  
Coordination Center ◽  
Self Assembled ◽  
Chelate Rings

The paper describes the solid state structure of a compound of composition [Cu(bipy)3][Cu(bipy)(ala) (ClO4)2]ClO4, in which both the cation and anion are octahedral complex species with copper(II) as coordination center. The cation contains three chelate rings formed by bipy; the anion contains in the quatorial plane a CuONC2 chelate ring formed by the alaninato ligand and a CuN2C2 chelate ring formed by bipy, with two monodentate perchorato ligands in axial positions completing the six-coordination. In the crystal p-p stackings lead to a supramolecular self-assembled structure.

The empirical conformational surface of the co(ethylenediamine) ring

1990 ◽  
Vol 55 (6) ◽  
pp. 1427-1434 ◽  
Author(s):  
František Pavelčík ◽  
Eva Luptáková
Keyword(s):  
Potential Surface ◽  
Chelate Ring ◽  
Statistical Treatment ◽  
Mirror Image ◽  
Fold Axis ◽  
Empirical Potential ◽  
Reduction Of Dimensionality ◽  
Envelope Conformation ◽  
Structural Correlation ◽  
Structural Database

The conformational surface of the Co(en) chelate ring was studied by the method of structural correlation. The reduction of dimensionality of the conformation problem was achieved by employing the pseudorotation concept. The empirical potential surface was obtained by statistical treatment of 743 independent conformations from the Cambridge Structural Database. The theoretical potential surface was obtained by molecular mechanics. The minimal-energy conformation is gauche with the Co atom on the two-fold axis. Conformational flexibility also includes an envelope conformation with the N atom bent out of the plane. The transition between the mirror-image symmetrical conformations can occur by a pseudorotation pathway and is accompanied by increased planarity of the ring. The transition state is an envelope conformation with an out-plane Co atom.

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