Ligand SULPHOS

The tripodal ligand sulphos was obtained from benzyltris(chloromethyl)-methane by sulfonation, and subsequent reaction with the diphenylphos-phide anion in DMSO ... 

Water-solubility does not always depend solely upon the water-solubility of the functionalized ligand itself it can also arise from specific water-metal interactions. The literature reports cationic as well as zwitterionic complexes [21-24], These systems are not yet well known and some complexes can behave in an unexpected way. Thus, it has been reported that the SULPHOS-rhodium complex 14... 

No appreciable polymerization occurred in concentrated aqueous solutions of La or Nd hydroxonitrilotriacetates but, with the heavier lanthanides, dimerization, via hydroxo bridges, occurred in dilute solution. A series of mixed ligand chelate complexes was obtained with Ho and Er and 5-sulpho-salicylate (ssa) and edta, iV-hydroxyethylethylenediamine-triacetic acid, 1,2-diaminocyclohexanediamine-tetra-acetic acid (YX i.e. [M(Y)(ssa)], and iminodiacetic acetate, hydroxyethyliminodiacetic acid and nitrilotriacetic acid, [M(Y)(ssa)2] with higher carboxylates, no mixed chelate complexes were produced. In the presence of an excess of hydroxyethylethylenediamine triacetic acid (H3A), [Eu(A)(HA)] was formed. Lanthanum(m) formed 1 1 complexes with nitrilotriacetic acid and 8-hydroxyquinoline, or 2-picolinic acid and 8-hydroxyquinoline-5-sulphonic acid. 

Bianchini et al. [95] synthesized another water-soluble triphosphine, Na03S(QH4)CH2C(CH2PPh2)3, the so-called SULPHOS (49 Scheme 2). This ligand is a TRIPHOS ligand [96] with a hydrophilic tail attached to the bridgehead... 

Bianchini et al. [15] reported a sulfonated ligand for use in hydrogenation reactions. They synthesized the complex [Rh(sulphos)(cod)j (where sulphos is structure 3), which was tested in the biphasic hydrogenation of styrene. Styrene was dissolved in a 1 1 (v/v) mixture of methanol and n-heptane in the presence of... 

Several studies in this field involve the use of SULPHOS (Scheme 45), a tripodal phosphine ligand having a para-sulfonated benzylic substituent on its bridgehead carbon atom. The rhodium complexes [(COD)Rh(SULPHOS)] and [Rh(CO)2(SULPHOS)] are zwitterionic, that is, the sulfonate group acts as the... 

In order to obtain a considerable effect, the use of catalysts that are more soluble in aqueous alcohols than in neat water is required. One such ligand described recently is sulphos, forming zwitterionic complexes with rhodium, having net zero charge ... 

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