338730-94-2Relevant academic research and scientific papers
Synthesis of New Donor-Substituted Biphenyls: Pre-ligands for Highly Luminescent (C^C^D) Gold(III) Pincer Complexes
Feuerstein, Wolfram,Holzer, Christof,Gui, Xin,Neumeier, Lilly,Klopper, Wim,Breher, Frank
, p. 17156 - 17164 (2020/11/30)
We herein report on new synthetic strategies for the preparation of pyridine and imidazole substituted 2,2’-dihalo biphenyls. These structures are pre-ligands suitable for the preparation of respective stannoles. The 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-heterocyclic carbene (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 developed multistep strategy and touch upon synthetic challenges. The prepared complexes have been fully characterized including X-ray diffraction analysis. The gold(III) complexes’ photophysical properties have been investigated by absorption and emission spectroscopy as well as quantum chemical calculations on the quasi-relativistic two-component TD-DFT and GW/Bethe–Salpeter level including spin–orbit coupling. Thus, we shed light on the electronic influence of the non-palindromic pincer ligand and reveal non-radiative relaxation pathways of the different ligands employed.
Intramolecular halogen stabilization of silylium ions directs gearing dynamics
Romanato, Paola,Duttwyler, Simon,Linden, Anthony,Baldridge, Kim K.,Siegel, Jay S.
supporting information; scheme or table, p. 7828 - 7829 (2010/08/05)
2,6-Bis(2,6-difluorophenyl)phenyldimethylsilanium ion (1a) adopts a ground-state C2 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 Cs-symmetric, with one ring having a dihedral angle of 0° and the other a dihedral angle of 90°. This correlated dynamic process is a function of the coordinating halogen. The chloro derivative (1b) adopts a similar ground-state geometry, but exchange of chlorine at silicon follows a conrotatory process.
