Stereochemical Control of Transition Metal Complexes by Polyphosphine Ligands

Abstract

he returned to the University of Tubingen where he presently is preparing his Habilltation. His research Interest Include the design of polyphosphine ligands, transition metal chemistry, and the application of multinuclear NMR spectroscopy to organometalllc chemistry In solution and in the solid state.

Fluxionality and Phosphane Arm-off Reactions of Octahedral Ruthenium(II) Complexes with the Tripodal Polyphosphane MeC(CH2PPh2)3

“…ϩ (L ϭ coordination sphere [5] , dissociation of a phosphane arm to provide the more flexible κ ϪP two equivalents of the potentially chelating ligands L. These results prompted the present comparative study of bonds (M ϭ Rh, Ir) can also lead to structural fluxionality at higher temperatures. For instance dissociation of a tri-fluxionality and phosphane arm-off reactions for analogous isoelectronic octahedral Ru II complexes.…”

Pyrazole as a Donor Function in Neopentane-Based Tripod Ligands RCH2C(CH2pyrazol-1-yl)3–n(CH2PR2)n – Synthesis and Coordination Chemistry

“…A special route into the chemisgands by tripod metal templates has found widespread ap-try of such ligands based upon the aminolytic cleavage of plication [2] and catalytic applications of tripod metal neopentane-based oxetanes has recently been reported [6] templates are a rapidly developing field [3] . As a special type and some particular cases based on the nucleophilic substiof tripod ligands, molecules containing three different do-tution of functionalized neopentane derivatives by azide nor groups bonded to a neopentane backbone are known [7] .…”

“…CH 3 C(CH 2 PPh 2 ) 3 in preparative and in catalytic chemistry [3] [4] . Nevertheless, the potential offered by neopentaneSpecial emphasis is put on the introduction of the pyrazolyl donor function, the reason being that this type of based tripod ligands is still far from being fully exploited.…”

“…The use of azide as a nucleophile for the substitution of difunctional oxetanes has been reported previously [20a] . Use of 8 as the electrophilically-substituted oxetane instead of O(CH 2 ) 2 C(CH 2 Cl) 2 [20a] was found to increase the yield of 9c from 25% to around 90%, as inferred from the transThe diastereotopicity of the protons of some of the CH 2 formation of 9c to the corresponding amine 9d by PPh 3 Functionalization of the CH 2 OH group at the backbone of tripod ligands is generally hampered by difficulties [21] . resulting in a high yield of 9e [20c] .…”

Ruthenium-catalysed hydrogenation of esters using tripodal phosphine ligands

“…However, the synthesis of tripodal phosphine ligands with dialkylphosphanyl moieties is most challenging. Hence, to date, few alkyl TriPhos derivatives have appeared in the literature even though they may be attractive for transition metal complex formation and catalysis [23,24,25]. Furthermore, recent work suggests that mixed P/N donor ligands offer clear benefits in terms of performance, but some of these ligands also involve convoluted syntheses.…”