Formation and Site-Selective Reactivity of a Nonsymmetric Dinuclear Iridium BisMETAMORPhos Complex

Abstract

A flexible di(sulfonamidophosphine) ligand (1 H2

Arene C(sp2)-H Metalation at NiII Modeled with a Reactive PONCPh Ligand

“…Motivated by our interest in reactive ligand systems, we recently introduced reversible cyclometalation as strategy for cooperative catalysis, using a strongly chelating P,N ligand that featured a flanking phenyl arm . Expanding on these results, we set out to investigate the potential for cyclometalation and stabilization of an agostic M–(C–H) interaction using the versatile coordination chemistry displayed by ligands of this type . Herein we report the fast and facile cyclometalation of the related 2-phosphinito-6-phenyl-pyridine (PONC Ph ) ligand L H to Ni II , leading to a complex bearing the cyclometalated phenyl group as a flanking entity.…”

Ruthenium(II) and Iridium(III) Complexes Bearing Phosphinepyridonate and Phosphinequinolinolate Chelates

“…By mixing L2 –H with the [RuCl 2 ( p ‐cymene)] 2 metal precursor, clean conversion to the corresponding Ru– 2 complex was obtained in interaction with methanol molecules. In the 1 H NMR spectrum, the expected O–H signal was shifted downfield at δ = 15.60 ppm in CDCl 3 ( α = 0.44) with a sharp signal for methanol, whereas in CD 2 Cl 2 an upfield signal at δ = 8.50 ppm along with a broad signal at δ = 3.50 ppm for methanol suggested that tautomerization through a proton shuttle to N–H occurred 26. The corresponding neutral ruthenium(II) complex Ru– 3 was obtained by mixing L2 –K, prepared in situ, with [RuCl 2 ( p ‐cymene)] 2 in 91 % isolated yield as a stable complex.…”

Intermolecular C–H activation with an Ir-METAMORPhos piano-stool complex – multiple reaction steps at a reactive ligand

“…10 Proton-transfer to the more basic sulfonamide nitrogen is favored over protonation of the S=O, but temporary formation of -OH as a kinetic intermediate can not be excluded. 16 Monitoring the unique conversion from 3 to this novel complex 4 by 31 P{ 1 H} NMR spectroscopy directly after addition of phenylacetylene at room temperature revealed the intermediacy of another species ( 31 P NMR: δ 33.1 ppm). In an attempt to characterize this complex, the reaction of phenylacetylene and complex 3 was monitored by 1 H, 31 P and 13 C NMR spectroscopy at 0 °C.…”