Cluster chemistry. Part 18. Isocyanide complexes derived from [Ru3(CO)12]: crystal and molecular structures of [Ru3(CO)12 –n(CNBut)n](n= 1 or 2)

The reaction between [Ru3(CO)11(CNBut)] and [Pt(η-C2H4)(PPh3)2] at -30° affords a thermally unstable intermediate complex (A), which decomposes at room temperature affording, inter alia, [Ru2Pt(CO)7(PPhd3)3 (1), [RuPt2(CO)5(PPh3)3] (2), [RuPt2(CO)6(CNBut)(PPh3)] (5) and [Ru2Pt2- (CO)9(CNBut)(PPh3)] (6). The hexanuclear complexes [Ru2Pt4(CO)5-n(CNBut)(PPh3)4+n] [n = 0 (17) and 1 (18)] are obtained, with [Ru2Pt(CO)5(CNBut)(PPh3)4] (16), from reactions at 80°. Related Ru2Pt and RuPt, complexes are obtained from reactions between complex (A) and CO, CNBut, Pme3, P(C6H4Me-p)3, or P(OMe)3; related reactions between [Ru3(CO)11(CNBut)] and [Pt{P(C6H4Me-p)3}4], and between [Ru3(CO)10(CNBut)2] and [Pt(η-C2H4)(PPh3)2, are also described. The crystal structure of [RuPt2(CO)5(PPh3)3] has been determined by single-crystal X-ray diffraction methods at 295(1) K and refined by least squares to a residual of 0.035 for 6774 'observed' reflections. Crystals are triclinic, P 1, a 15.893(5), b 15.400(5), c 12.651(4) Ǻ, α 57.04(2), β 77.09(3), γ 84.10(3)°, Z 2. Crystals of the dibenzene solvate of the complex are monoclinic, P 21/c, a 11.868(4), b 18.647(8), c 29.24(1) A, β 98.35(3)°, Z 4, the structure being refined to a residual of 0.057 for 4530 'observed' reflections. Ligand dispositions are compared in detail with those observed in the analogous compound previously described with the methyldiphenylphosphine Iigand.

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A Solvent-Dependent and Electrochemically Controlled Self-Assembling/Disassembling System

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20031647 ◽

2003 ◽

Vol 68 (9) ◽

pp. 1647-1662 ◽

Cited By ~ 2

Author(s):

Valeria Amendola ◽

Massimo Boiocchi ◽

Yuri Diaz Fernandez ◽

Carlo Mangano ◽

Piersandro Pallavicini

Keyword(s):

Equilibrium Mixture ◽

Bidentate Ligand ◽

Molecular Structures ◽

The Self ◽

Molar Ratio ◽

Crystal And Molecular Structures ◽

Self Assembling ◽

Irreversible Oxidation ◽

Irreversible Reduction ◽

Metal Ligand

The bis-bidentate ligand R,S-1,2-diphenyl-N,N'-bis(2-quinolinemethylidene)ethane-1,2-diamine (ligand 4), containing two (iminomethyl)quinoline moieties separated by a cis-1,2-diphenylethylene spacer, forms stable complexes with both CuI and CuII. With CuII, the monomeric 1:1 complex [CuII(4)]2+ is obtained both in CH3CN and CH2Cl2. With CuI and overall 1:1 metal/ligand molar ratio, an equilibrium mixture is obtained in CH3CN, consisting of [CuI(4)2]+, [CuI2(4)2]2+ and [CuI2(4)(CH3CN)4]2+. The preponderant species is the two-metal one-ligand "open" complex [CuI2(4)(CH3CN)4]2+, in which each Cu+ cation is coordinated in a tetrahedral fashion by one (iminomethyl)quinoline unit and by two CH3CN molecules. Precipitation from the equilibrium mixture yields only crystals of [CuI2(4)(CH3CN)4](ClO4)2·2CH3CN, whose crystal and molecular structures have been determined. On the other hand, in the poorly coordinating CH2Cl2 solvent, only the dimeric helical [CuI2(4)2]2+ complex is obtained, when the overall metal/ligand 1:1 molar ratio is chosen. Addition of large quantities of acetonitrile to solutions of [CuI2(4)2]2+ in dichlorometane results in the formation of [CuI2(4)(CH3CN)4]2+, i.e. in the solvent-driven disassembling of the CuI helicate. While electrochemistry in CH3CN is poorly defined due to the presence of more than one CuI species, cyclic voltammetry experiments carried out in CH2Cl2 revealed a well defined behavior, with irreversible oxidation of [CuI2(4)2]2+ and irreversible reduction of [CuII(4)]2+ taking place at separate potentials (∆E ≈ 700 mV). Irreversibility and separation of the redox events are due to the self-assembling and disassembling processes following the reduction and oxidation, respectively.

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