Stabilization of the tautomers HP(OH)2 and P(OH)3 of hypophosphorous and phosphorous acids as ligands

Treatment of [CpRu(PPh(3))(2)Cl] 1 with the stoichiometric amount of H(3)PO(2) or H(3)PO(3) in the presence of chloride scavengers (AgCF(3)SO(3) or TlPF(6)) yields compounds of formula [CpRu(PPh(3))(2)(HP(OH)(2))]Y (Y = CF(3)SO(3) 2a or PF(6) 2b) and [CpRu(PPh(3))(2)(P(OH)(3))]Y (Y = CF(3)SO(3) 3aor PF(6) 3b) which contain, respectively, the HP(OH)(2) and P(OH)(3) tautomers of hypophosphorous and phosphorous acids bound to ruthenium through the phosphorus atom. The triflate derivatives 2a and 3a react further with hypophosphorous or phosphorous acids to yield, respectively, the complexes [CpRu(PPh(3))(HP(OH)(2))(2)]CF(3)SO(3) 4 and [CpRu(PPh(3))(P(OH)(3))(2)]CF(3)SO(3) 5 which are formed by substitution of one molecule of the acid for a coordinated triphenylphosphine molecule. The compounds 2 and 3 are quite stable in the solid state and in solutions of common organic solvents, but the hexafluorophosphate derivatives undergo easy transformations in CH(2)Cl(2): the hypophosphorous acid complex 2b yields the compound [CpRu(PPh(3))(2)(HP(OH)(2))]PF(2)O(2) 6, whose difluorophosphate anion originates from hydrolysis of PF(6)(-); the phosphorous acid complex 3b yields the compound [CpRu(PPh(3))(2)(PF(OH)(2))]PF(2)O(2) 7, which is produced by hydrolysis of hexafluorophosphate and substitution of a fluorine for an OH group of the coordinated acid molecule. All the compounds have been characterized by elemental analyses and NMR measurements. The crystal structures of 2a, 3a and 7 have been determined by X-ray diffraction methods.     

Synthesis,catalytic properties and biological activity of new water soluble ruthenium cyclopentadienyl PTA complexes [(C5R5)RuCl(PTA)2] (R = H,Me; PTA = 1,3,5-triaza-7-phosphaadamantane)

The new water soluble ruthenium complexes [(C5R5)RuCl(PTA)2] (R = H, Me; PTA = 1,3,5-triaza-7-phosphaadamantane) were synthesised and characterised. Their evaluation as regioselective catalysts for hydrogenation of unsaturated ketones in aqueous biphasic conditions and as cytotoxic agents towards the TS/A adenocarcinoma cell line is briefly presented.     

Cu(I) and Ru(II) complexes with elemental phosphorus as ligand: Synthesis and properties

New complexes of Cu(I) and Ru(II) with elemental (white) phosphorus (P₄), [Cu(C₅H-i-Pr₄)(η²-P₄)], [Cu(C₅H-i-Pr₄)(μ,η^2:1-P₄)Cu(C₅H-i-Pr₄)], and [Ru(C₅Me₅)(PCy₃)(η²-P₄)Cl], are synthesized with tetraphosphorus molecule as bidentate η²-ligand. The complexes are obtained by reacting elemental phosphorus with the Cu carbonyl(tetraisopropylcyclopentadienyl) complex [Cu(C₅H-i-Pr₄)(CO)] or with Ru(II) (pentamethylcyclopentadienyl)(tricyclohexylphosphine) chloride, [Ru(C₅Me₅)(PCy₃)Cl]. The structures and compositions of the obtained complexes are studied by ¹H, ³¹P NMR method and elemental analysis. The P₄ molecule is connected to Cu(I) and Ru(II) fragments through the P-P edge due to a side coordination.     

A secretory phospholipase A2-mediated neuroprotection and anti-apoptosis

Background  

Phospholipase A₂ liberates free fatty acids and lysophospholipids upon hydrolysis of phospholipids and these products are often associated with detrimental effects such as inflammation and cerebral ischemia. The neuroprotective effect of neutral phospholipase from snake venom has been investigated.     

[(η5-C5HR4)CuCO] (R = CHMe2) – A Remarkably Stable Copper Carbonyl Complex and its Reaction with P4

Carbonyl(tetraisopropylcyclopentadienyl)copper has been synthesized and isolated and can be stored at room temperature for several days. [(C₅HR₄)Cu(CO)] (R = CHMe₂) has been characterized by ¹H and ¹³C NMR, C,H analysis, mass spectrometry, and IR spectroscopy. Its reaction with white phosphorus yields a mixture of [(C₅HR₄)Cu(η²-P₄)] with edge-opened P₄ coordinated to a Cu^III atom and [(C₅HR₄)Cu(μ,η^2:1-P₄)Cu(C₅HR₄)] with an additional Cu(C₅HR₄) fragment coordinated to one atom of the P₄ ligand (R = CHMe₂).     

Novel bimetallic Ru-Pt and Fe-Pt Complexes [M(C5R5)(L)2(μ,η1:η2-P4{Pt(PPh3)2})]Y: Synthesis, structure, and exchange processes

Novel bimetallic Ru-Pt and Fe-Pt complexes, [M(C₅R₅)(L)₂(η¹-P₄)]Y (M = Ru, Fe; R = H, Me; L = PPh₃, 1/2Dppf (Ph₂P(C₅H₄)Fe(C₅H₄)PPh₂), 1/2Dppe (Ph₂PCH₂CH₂PPh₂); Y = PF₆, CF₃SO₃, BPh₄) were synthesized for the first time by the reaction of η¹-tetraphosphorus complexes of ruthenium(II) and iron(II), [M(C₅R₅)(L)₂(η¹-P₄)]Y with platinum(0) complex [Pt(η²-C₂H₄)(PPh₃)₂] in acetone. The structures and compositions of the title complexes were studied by the ³¹P NMR, correlated ³¹P-³¹P NMR COSY, NOESY, ¹H-spectroscopy, and elemental analysis. The carbene-like fragment Pt(PPh₃)₂ generated in situ was found to be inserted at the P-P bond of the η¹-coordinated tetraphosphorus and migrate between the phosphorus atoms of the obtained ligand μ, η¹: η²-P₄. The exchange process in the novel complexes was investigated. Original Russian Text ? D.N. Akbayeva, 2007, published in Koordinatsionnaya Khimiya, 2007, Vol. 33, No. 9, pp. 673–680.