Competition between π-Arene and Lone-Pair Halogen Coordination of Silylium Ions?
摘要:
In 2,6-diarylphenylSiR(2) cations, the 2,6-diarylphenyl (m-terphenyl) scaffold blocks incoming nucleophiles and stabilizes the positive charge at silicon by lateral ring interactions. Direct ortho-halogen and pi-electron-rich face coordination to silicon has been seen. For a series of cations bearing 2,6-difluoro-2',6'-dimethyl-X(n)-substituted rings, the relative contribution of these two modes of stabilization has been assessed. Direct coordination from an aryl fluoride is found to be comparable to that from the mesityl pi-face.
Synthesis of a D3-symmetric “trefoil” knotted cyclophane
作者:Karla I. Arias、Eli Zysman-Colman、Jon C. Loren、Anthony Linden、Jay S. Siegel
DOI:10.1039/c1cc11209k
日期:——
A D3-symmetric knotted cyclophane, with a subgraph of trefoil topology, was synthesized by cyclization of a D3-symmetric scaffold. Control of configuration at the three metal-based stereocenters arises from a bascule/pivot mechanism.
Intramolecular Halogen Stabilization of Silylium Ions Directs Gearing Dynamics
作者:Paola Romanato、Simon Duttwyler、Anthony Linden、Kim K. Baldridge、Jay S. Siegel
DOI:10.1021/ja9109665
日期:2010.6.16
2,6-Bis(2,6-difluorophenyl)phenyldimethylsilanium ion (1a) adopts a ground-state C(2) trigonal-bipyramidal geometry in which fluorines from opposing 2,6-difluorophenyl groups coordinate to the apical positions of the pentavalent silyl cation. Exchange of fluorine at silicon occurs by a disrotatory gearing mechanism wherein one fluorine remains coordinated to silicon throughout the circuit. The "cogwheel" transition state is C(2)-symmetric, with one ring having a dihedral angle of 0 degrees and the other a dihedral angle of 90 degrees. This correlated dynamic process is a function of the coordinating halogen. The chloro derivative (1b) adopts a similar ground-state geometry,
Competition between π-Arene and Lone-Pair Halogen Coordination of Silylium Ions?
作者:Paola Romanato、Simon Duttwyler、Anthony Linden、Kim K. Baldridge、Jay S. Siegel
DOI:10.1021/ja2040392
日期:2011.8.10
In 2,6-diarylphenylSiR(2) cations, the 2,6-diarylphenyl (m-terphenyl) scaffold blocks incoming nucleophiles and stabilizes the positive charge at silicon by lateral ring interactions. Direct ortho-halogen and pi-electron-rich face coordination to silicon has been seen. For a series of cations bearing 2,6-difluoro-2',6'-dimethyl-X(n)-substituted rings, the relative contribution of these two modes of stabilization has been assessed. Direct coordination from an aryl fluoride is found to be comparable to that from the mesityl pi-face.
Synthesis of New Donor‐Substituted Biphenyls: Pre‐ligands for Highly Luminescent (C^C^D) Gold(III) Pincer Complexes
latter can successfully be transmetalated to K[AuCl4] forming non‐palindromic [(C^C^D)AuIII] pincer complexes featuring a lateral pyridine (D=N) or N‐heterocycliccarbene (NHC, D=C’) donor. The latter is the first report on a pincer complex with two formally anionic sp2 and one carbenic carbon donor. The [(C^C^D)AuIII] complexes show intense phosphorescence in solution at room temperature. We discuss the
我们在此报告了制备吡啶和咪唑取代的2,2'-二卤代联苯的新合成策略。这些结构是适合配制成各自锡酚的预配体。后者可以成功地金属化为K [AuCl 4 ],形成具有侧吡啶(D = N)或N-杂环卡宾(NHC,D = C' )的非回文[[C ^ C ^ D)Au III ]钳形配合物) 捐赠者。后者是有关具有两个正式的阴离子sp 2和一个羧基碳供体的钳形配合物的首次报道。[(C ^ C ^ D)Au III配合物在室温下在溶液中显示强烈的磷光。我们讨论已制定的多步骤策略,并探讨综合挑战。制备的配合物已得到充分表征,包括X射线衍射分析。已通过吸收和发射光谱以及在准相对论两组分TD-DFT和GW / Bethe-Salpeter能级(包括自旋-轨道耦合)上研究了金(III)配合物的光物理性质。因此,我们阐明了非回文夹钳配体的电子影响,并揭示了所采用的不同配体的非辐射弛豫途径。