Oligophosphan-Liganden

Formic acid dehydrogenation catalysed by ruthenium complexes bearing the tripodal ligands triphos and NP3

“…Complexes 1 and 2 were prepared according to literature procedures. 12,13 Formic acid and N,N-dimethyloctylamine were The formic acid to amine ratio was determined by 1 H NMR spectroscopy on a Bruker Avance 400 spectrometer. Ru(acac) 3 and the HCOOH-NEt 3 (5 : 2) mixture were purchased from commercial suppliers and used without further purification.…”

“…This behaviour again suggests a rapid formate exchange at higher temperatures. 13 C{ 1 H} NMR spectra in acetone-d 6 of a mixture of 1′ with 2 equiv. of HCOONHEt 3 and 1 equiv.…”

“…4h The beneficial stabilizing effect of tetradentate ligands such as PP 3 (PP 3 = tris-[2-(diphenylphosphino)ethyl]phosphine) together with Fe(BF 4 ) 2 •6H 2 O to promote the catalytic activation of HCOOH, originally reported in 1991, 9 was recently reinvestigated, showing an outstanding performance with TON = 92 000 and high TOF = 9425 h −1 at 80 °C in propylene carbonate as a solvent. 10 Interestingly, the same ligand was used together with Co(BF 4 ) 2 •6H 2 O for the reduction of CO 2 and bicarbonate with hydrogen to formates at 60-80 °C under a total pressure CO 2 + H 2 = 60-100 bar, giving a maximum 94% yield after 20 h. 11 Here we report on the dehydrogenation of formic acid/ amines in the presence of the facially capping 1,1,1-tris-(diphenylphosphinomethyl)ethane (triphos) and related tetradentate tris[2-(diphenylphosphino)ethyl]amine (NP 3 ), either used in situ together with Ru(acac) 3 as a ruthenium source or as ligands for known complexes such as [Ru(κ 3 -triphos)(MeCN) 3 ]-(OTf ) 2 (1), 12 [Ru(κ 4 -NP 3 )Cl 2 ] (2) 13 and cis-[Ru(κ 3 -triphos)(CO)-(H) 2 ] (3, 14 see Scheme 1). The catalytic tests are complemented by 31 P{ 1 H} NMR studies based on stoichiometric reactions, which gave information on the nature of some of the species which are formed upon reaction with formate and formic acid/ amine adduct, respectively, under different experimental conditions.…”

Coupling of terminal alkynes by RuHXL2 (X=Cl or N(SiMe3)2, L=PiPr3)

“…Here we present the catalytic reactivity of RuXHL 2 with terminal alkynes together with a mechanistic study. Ruthenium has good precedent for dimerization of terminal alkynes [20,[22][23][24][25][26][27][28][29].…”

cis-Dichloro[tris(diphenylphosphinoethyl)amine]ruthenium(II)–chloroform–water (1/2.5/1)

“…The title compound, (I), displays interesting catalytic properties, as shown by Fontal & Suarez (1985) in the case of hydrogenation and hydroformylation, as well as others (Dahlenbourg et al, 1991), in 1-alkyne dimerization reactions, but in spite of a good spectroscopic characterization, especially through 1 H and 31 P NMR spectroscopic analyses, the crystal structure of (I) is hitherto unreported.…”