Water-soluble metal complexes

The Rate Constants (298 K) for the on and off Reactions of NO and CO with certain Water Soluble Metal Complexes in Aqueous Solution... 

Analogously, the SAPC catalyzed hydroformylation reaction was carried out using other water-soluble metal complexes of Pt and Co. Pt complexes in the presence of an Sn co-catalyst underwent hydrolysis of the Pt-Sn bond, which led to lower reaction selectivity. With the corresponding Co catalyst, good hydroformylation selectivities and conversions could be achieved, provided excess phosphine was used. Other authors performed hydrogenation of a,(3-unsaturated aldehydes using SAPC, and Ru and Ir water-soluble complexes. 

Since the ligand is basic, various protonated species may occur in solution. Specifically, if Cl is thg total concentration of ligand in solution then, ignoring any small amount present as any water-soluble metal complex, and omitting charges for the sake of generality ... 

Bhanage BM, Shirai M, Arai M et al (1999) Multiphase catalysis using water-soluble metal complexes in supercritical carbon dioxide. Chem Commun 14 1277-1278... 

Fancy DA, Denison C, Kim K, et al. Scope, limitations and mechanistic aspects of the photo-induced cross-linking of proteins by water-soluble metal complexes. Chem Biol 2000 7 697-708. 

Baham, J. and Sposito, G., Chemistry of water-soluble, metal-complexing ligands extracted from an anaerobically digested sewage sludge, J. Environ. Qual., 12, 96, 1983. Berggren, D. et al., Metal solubility and pathways in acidified forest ecosystems of South Sweden, Sci. Total Environ., 96, 103, 1990. 

One of the major goals of our investigations has been the synthesis of phosphane-free water-soluble metal complexes with stable a-bonding that are suitable for two-phase catalysis. 

Bicontinuous microemulsions consisting of cationic surfactant AUTMAB (30-40 wt%), MMA (30-40 wt%), and 20-40 wt% of an aqueous 50 pM solution of water-soluble metal complexes such as Ru(dip)3Cl2 (dip=4,7-diphenyl-1,10-phenanthroline) have been investigated [98]. After polymerization, the microemulsion transformed into a transparent polymer film which showed a remarkable enhancement in lirminescence intensity. The emission hfetime also... 

Most water-soluble metal complexes, unlike typical organic reactants, are cations or anions and are therefore subject to Coulombic ion-ion interactions in solution. In essence, these are of two kinds the Debye-Hiickel or ionic atmosphere type, which affects the activity coefficients of the complex ion and hence the kinetics of its reactions, and ion association—usually considered simply as anion-cation pair formation.29 For cationic substrates in particular, pairing with an anionic incoming ligand may give an illusion of bimolecularity (an SN2 mechanism) when in fact the reaction may be dissociatively activated within the ion pair or encounter complex . 

More recent work on the hydrogenation of thiophenic molecules catalyzed by water-soluble metal complexes is pursuing the use of polyphosphine ligands (cf. Section 3.2.2). These studies follow the success obtained with the tridentate phosphine MeC (CH2PPh2)3 (TRIPHOS), which forms rhodium and iridium catalysts for the hydrogenation, hydrogenolysis, and desulfurization of various thiophenic... 

Water-Soluble Metal Complexes with Modified Poly(ethylene Oxide)s in Catalysis... 

Water-soluble metal complexes of rhodium with polyamidoamine-based (PAMAM-based) third-generation (32 terminal groups) dendrimers modified with diphenylphosphine groups have been used in two-phase hydroformylation of 1-octene and styrene. The selectivity in styrene hydroformylation with respect to isoaldehyde was much higher than in the case of trisulfonated triphenylphosphine... 

The stability of the host-guest complex is significantly affected by the nature and composition of the solvent in which the processes occur. This is an important factor when the reaction is carried out in aqueous medium, where hydrophobic interactions mainly contribute to the energy of complex formation due to an increase in its stability. In this regard, the use of water-soluble macrocycles with hydrophobic cavities as components of water-soluble metal complexes in two-phase catalytic systems is of particular interest [38,39]. The catalyst, soluble in the aqueous phase, can be easily separated from the water-insoluble reaction products and reused. It should be emphasized that the activity of conventional catalysts is very low for the reactions involving substrates poorly soluble in water. Due to the formation of water-soluble inclusion host-guest complexes, the macrocyclic receptors not only influence the activity and selectivity of the reaction, but also perform the function of interfacial substrate carrier in aqueous phase. 

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