Water-soluble Phosphane Research Articles

Synthesis, characterization and antioxidant activity of new copper(i) complexes of scorpionate and water soluble phosphane ligands

New copper(I) complexes have been synthesised from the reaction of CuCl with potassium hydrotris(4-bromo-1H-pyrazol-1-yl)borate, KTp4Br or lithium bis(3,5-dimethylpyrazol-1-yl)acetate, Li[L2CO2] ligands and 4- or 2-(diphenylphosphane)benzoic acid or tris(m-sulfonatophenyl)posphine trisodium salt (TPPTS) coligands. The complexes obtained have been characterized by elemental analyses and FT-IR in the solid state, and by NMR (1H and 31P[1H]) and electrospray mass spectrometry (ESI-MS) in solution. Single crystal structural characterisation was undertaken for the [Cu[PPh2(4-C6H4COOH)](Tp4Br)] derivative, an interesting dimeric supramolecular assembly. A chemiluminescence study has demonstrated the superoxide scavenging activity of these new copper complexes. The Comet assay was used to evaluate the impairment of DNA in rat epithelial cells exposed to different reactive nitrogen species. In addition, the same complexes were included in this study to determine their efficacy as antioxidants in mitigating oxidative DNA damage. The parameter tail moment, used as an index of DNA damage, showed that the complex [Cu[PPh2(4-C6H4COOH)](Tp4Br)] remarkably inhibited DNA strand breaks induced by the different nitrogen oxide species. The other copper complexes under study showed a different ability to reduce tail moment values depending on the type of RNOS donor used.

Titanium-containing epoxidation catalysts

Complex [RuCl{κ3(N,N,N)-Tp}(PPh3)(PTA)] (κ3(N,N,N)-Tp = hydridotris(pyrazolyl)borate) containing the water-soluble phosphane 1,3,5-triaza-7-phosphatricyclo[3.3.1.13,7]decane (PTA) reacts with terminal alkynes producing to the corresponding neutral alkynyl complexes [Ru(CCR){κ3(N,N,N)-Tp}(PPh3)(PTA)] (R = Ph (1a), nBu (1b), 1-cyclopentenyl (1c), p-methoxyphenyl (1d), 6-methoxynaft-2-yl (1e)). When halide is extracted from complex [RuCl{κ3(N,N,N)-Tp}(PPh3)(PTA)] followed by treatment with propargyl alcohols, the corresponding allenylidene complexes [Ru{κ3(N,N,N)-Tp}(PPh3)(PTA)(CCCPh2)][X] (X = PF6 (2a), CF3SO3 (2b)) and [Ru{κ3(N,N,N)-Tp}(PPh3)(PTA)(CCCC12H8)][PF6] (3) result. Electrophilic attack on the complexes thus obtained leads chemoselectively to the alkynyl complexes [Ru(CCR){κ3(N,N,N)-Tp}(PPh3)(1-CH3-PTA)][CF3SO3] (R = Ph (4a), nBu (4b), and 1-cyclopentenyl (4c)) and to the dicationic allenylidene complexes [Ru{κ3(N,N,N)-Tp}(PPh3)(1-H-PTA)(CCCC12H8)][PF6]2 (5) and [Ru{κ3(N,N,N)-Tp}(PPh3)(1-CH3-PTA)(CCCPh2)][CF3SO3]2 (6).

Aqueous catalytic Pauson-Khand-type reactions of enynes with formaldehyde: transfer carbonylation involving an aqueous decarbonylation and a micellar carbonylation.

One rhodium(I) complex catalyzes two processes in an overall Pauson–Khand-type reaction of enynes such as 1 with formaldehyde in an aqueous medium to give bicyclic cyclopentenones such as 2 in excellent yields. The use of a water-soluble phosphane ligand in conjunction with a hydrophobic phosphane ligand in the presence of a surfactant promotes the decarbonylation of formaldehyde in the aqueous phase and the carbonylation of enynes in the micellar phase. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2003/z51384_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Convenient Synthesis of New Anionic Water-Soluble Phosphanes and Applications in Inter- and Intramolecular Heck Reactions

The versatile preparation of new anionic water-soluble ligands derived from triphenylphosphane is described based on halogen-lithium exchange followed by CO2 quenching. Efficient inter- and intramolecular Heck reactions have been disclosed. Comparison with other anionic and cationic ligands showed that meta substitution on the aromatic ring enhanced the reactivity.

Biphasic Catalyzed Telomerization of Butadiene and Ammonia: Kinetics and New Ligands for Regioselective Reactions

The kinetics of the palladium-catalyzed biphasic telomerization of butadiene and ammonia (shown here) was studied. From the results, a model for the reaction mechanism explaining the regioselectivities obtained was deduced. Several water-soluble phosphanes were used as ligands in this reaction, confirming the model. In one case the target product 1 was obtained with 94 % regioselectivity.

ChemInform Abstract: Water Soluble Phosphanes. Part 9. Nucleophilic Phosphanylation of Fluoroaromatic Compounds with Carboxyl, Carboxymethyl, and Aminomethyl Functionalities — An Efficient Synthetic Route to Amphiphilic Arylphosphanes.

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