Synthesis and structural investigation of a new cadmium cyclohexaphosphate Cd[3,4-(CH3)2C6H5NH3]4P6O18·6H2O

Single crystals of a new cyclohexaphosphate, are synthesised and investigated by X-ray diffraction. This compound crystallizes in the triclinic system with the space group P-1 and cell parameters a=7.773(4), b=9.238(3), c=18.532(7) Å, α=88.57(3), β=88.10(4), γ=67.35(4)°, Z=1 and V=1227(1) ų. The three-dimensional network is built up from parallel (0 0 1) layers of [CdP₆O₁₈(H₂O)₆]⁴⁻ between which the organic molecules are inserted. The Cd atoms, in 1(a) sites, adopt an octahedral coordination. The 3,4-xylidinium cations exercise an electrostatic interaction on the inorganic anion and establish strong H-bonds with their oxygen atoms.     

Syntheses and structural study of trinuclear iron acetates [Fe3O(CH3COO)6(H2O)3]Cl· 6H2O and [Fe3O(CH3COO)6(H2O)3] [FeCl4]· 2CH3COOH

The structure of two trinuclear iron acetates [Fe₃O(CH₃COO)₆(H₂O)₃]Cl· 6H₂O (I) and [Fe₃O(CH₃COO)₆(H_2O)₃][FeCl₄] · 2CH₃COOH (II) was determined by X-ray diffraction analysis. Crystals I and II are ionic and belong to the orthorhombic system with parameters a = 13.704(3), b = 23.332(5), c = 9.167(2) Å, R = 0.0355, space goup P2₁2₁2 for I and a = 10.145(4), b = 15.323(6), c = 22.999(8) Å, R = 0.0752, space group Pbc2₁ for II. The complex cation [Fe₃O(CH₃COO)₆(H₂O)₃]⁺ has a μ₃-O-bridged structure typical for trinuclear iron (III) compounds. As shown by Mössbauer spectroscopy, the iron(III) ions are in the high-spin state. In trinuclear cations, antiferromagnetic exchange interaction takes place between the Fe(III) ions with the exchange parameter J = -26.69 cm^?1 for II (Heisenberg-Dirac-Van Vleck model for D_3h, symmetry).     

Synthesis and crystal structure of [(Ph3P)2N] [Ni2(CO)6H]

The interstitial dihydride dianion [Ni₁₂(CO)₂₁H₂]^2? is readily converted by carbon monoxide (25°C, 1 atm) into a mixture of tetracarbonylnickel and a new colourless hydride carbonyl monoanion, which has been characterized by X-ray diffraction as [Ni₂(CO)₆H]^?.     

Reactivity of Ph2P(Se)CH2C6H4CH2P(Se)Ph2 with [M3(CO)12] (M=Ru or Fe). Synthesis and characterization of the new carbene cluster [Ru3(mu3-Se)(mu3-H)(mu2-PPh2)(CO)6(mu2-CHC6H4CH2PPh2)

The reactions of [M3(CO)12] (M=Ru or Fe) with 1,2 bis[(diphenylphosphino)methyl]benzene diselenide (dpmbSe2) in hot toluene afford a variety of phosphine-substituted selenido carbonyl clusters. They belong to the following three families: (i) 50-electron clusters with a M3Se2 core (2, 3, 5-7), (ii) 48-electron clusters with a M3Se core (1, 8), (iii) 34-electron clusters with a M2Se2 core (4). All these species derive from the P=Se bond cleavage. Cluster 1, which contains a hydrido, a phosphido, and a carbene ligand, is produced by multiple fragmentation of the diphosphine. This fragmentation appears related to the presence of the selenido ligand on the cluster, as the reaction of [Ru3(CO)12] with dpmb (not selenized) produces only carbonyl substitution by the phosphine to give [Ru3(CO)10(mu-dpmb)] (9). All the clusters synthesized have been characterized by spectroscopic techniques, and in some cases fluxional behavior has been detected in solution by NMR analysis. The structures of 1, 2, and 7-9 have been determined by X-ray diffraction methods.