Zwitterionic Metal Complexes of the New Triphosphine NaO3S(C6H4)CH2C(CH2PPh2)3 in Liquid Biphasic Catalysis: An Alternative to Teflon "Ponytails" for Facile Catalyst Separation without Water

Hydrogenation of Arenes and Heteroaromatics

“…It was observed that nitrogen compounds did not inhibit the hydrogenation; on the contrary, a promoting effect was observed. Later, rhodium and ruthenium catalysts with the polydentate watersoluble ligands (NaO 3 S(C 6 H 4 )CH 2 ) 2 C(CH 2 PPh 2 ) 2 (Na 2 DPPPDS) [62] and NaO 3 S(C 6 H 4 )CH 2 C(CH 2 PPh 2 ) 3 (Nasulphos) [63], which differ from traditional water-soluble phosphines for the presence of the hydrophilic groups in the ligand backbone were successfully employed to hydrogenate BT under biphasic conditions ( Fig. 16.7) [39 b, 59, 60, 64, 65].…”

Immobilization of Optically Active Rhodium-Diphosphine Complexes on Porous Silica via Hydrogen Bonding

“…Previous examples involve, in fact, the sulphonation of the ligand framework prior to introduction of the phosphino groups. [9,10,11] The simple reaction of [(R)-(R)-BDPBzPSO 3 ]Na with [Rh(nbd)Cl] 2 yields 1. Compounds 2 and 3 have similarly been prepared by reaction of the corresponding diphosphine ligand with [Rh(nbd)Cl] 2 , followed by addition of silver triflate as chloride scavenger.…”

Zwitterionic Relatives of Cationic Platinum Group Metal Complexes: Applications in Stoichiometric and Catalytic σ‐Bond Activation

“…[128] The subsequent crystallographic characterization of 124, [129] 125, [130] and the iridium analogue of 122 [131] suggests that in this class of zwitterions, the sulfonate anion is spatially separated from the formally cationic PGM fragment. Although sulfonated phosphine ligands for use in preparing water-soluble transition metal complexes with applications in aqueous biphasic catalysis had been described previously, [132] the unique solubility profile of these zwitterionic sulphos complexes provided an entry point for the development of non-aqueous (alcohol/hydrocarbon) biphasic methods; 122 and 123 are not soluble in pure water, hydrocarbons, or diethyl ether, but do dissolve in light alcohols, such as methanol or ethanol, or in 1:1 (v/v) alcohol-water mixtures.…”

“…For example, the hydroformylation of 1-hexene employing 123 as a pre-catalyst in methanol/isooctane afforded primarily alcohols under conditions whereby the related cationic catalyst system [(triphos)Rh(dmad)] + BPh 4 À (triphos = k 3 -CH 3 C(CH 2 PPh 2 ) 3 ; dmad = dimethylacetylene dicarboxylate) produced aldehydes preferentially (Scheme 30). [128,131] The selective production of aldehydes can be achieved by using 123 in a mixture of methanol/isooctane/water, although under these conditions the overall conversion is lower.…”