Crystal structure refinement for trans-[Pd(NO3)2(H2O)2]

Single crystals of trans-[Pd(NO₃)₂(H₂O)₂] were obtained, and the crystal structure of this complex, previously obtained for polycrystals, was refined. Crystal data (BRUKER X8APEX diffractometer): a = 4.9973(7) Å, b = 10.5982(14) Å, c = 11.7008(17) Å, V = 619.70(15) ų, space group Pbca, Z = 4, d _calc = 2.856 g/cm³. The structure is composed of neutral complexes with a trans configuration. The square plane environment of the Pd atom is formed by four oxygen atoms (Pd-O(NO₃) 1.999(5) Å, Pd-O(H₂O) 2.030(5) Å) and completed to a distorted bipyramid by two intramolecular contacts (Pd…O(NO₃) 2.926 Å). The shortest hydrogen bonds are O…H 2.72 Å.     

Crystal structure of sodium dichlorobis(acetylacetonato)rhodiate(iii) monohydrate Na[Rh(C5H7O2)2Cl2] · H2O. pseudoperiodicity as the consequence of the packing law of complexes in crystals

The crystal structure of Na[Rh(acac)₂Cl₂] · H₂O (acac) =C ₅H₇O ₂ ^? )is determined The crystals are triclinic, space group P1, with unit cell dimensions a =12.616(2), b =8.411(4), c =8.499(4) å,a =108.37(4), Β =95.47(4), γ =110.45(4)?, V =780.3(6) å ³, Z =2, d _calc =1.758 g/cm ³, R =0.0461. The strong pseudoperiodicity observed experimentally (no reflections with odd indices h) led to a set of experimental data obtained in the unit cell that is reduced along the a axis (“Syntex P2 ₁ ” automatic diffractometer, λMoK _α, graphite monochromator), 1466 measured and 1302 observed I_hkl included in the calculation. This is due to the alternation of the central atoms of octahedral complex onions at intervals of 1/2a. The Rh- 0 and Rh- Cl distances are, on the average, 2.001(3) and 2.325(2), respectively. The cis- angles of ClRhO type are close to 90?, and the average value of the ORhO chelate angle is 95.1? (within 3Σ with Σ ? 0.1?). The average interatomic distances and bond angles (according to types) in the acac ligand are as follows: O- C 1.274, (C- C)_ring 1.397, C_ring- C_sub 1.506 å with Σ not higher than 0.006 å,RhOC 122.2?, (OCC) _ring 126.4?, (OCC)_term 114.2?, (CCC)_ring 127.3?, (CC)_ringc_sub 119.3? (Σ within 0.2– 0.6?). The distorted octahedron around the Na ion consists of five O atoms (of the H₂O molecule and the neighboring acac ligands, distances within 2.364– 2.409 å) and one Cl ion lying at a distance of 2.970 å. The structure in general is of ribbon type: Rh_1,2 and Na octahedra are linked by a common edge O(2′)O(1) and common face O(3)O(4′)O(2′) into infinite ribbons, which are extended along the [100] axis and which are translationally identical in the [010] and [001] directions. The H ₂O molecule forms two Cl(l)...H₂O...Cl(2′) hydrogen bonds: 3.116 and 3.179 å, respectively, which link the Rh octahedra into infinite chains in the [120] direction.     

New data on the structure of α-<Emphasis Type="Italic">trans</Emphasis>-[Pd(NH<Subscript>3</Subscript>)<Subscript>2</Subscript>Cl<Subscript>2</Subscript>]

Single crystal X-ray diffraction was applied for re-determination of the crystal structure of α-trans-[Pd(NH₃)₂Cl₂]. It has been demonstrated that, in contrast to the literature data, the structure is disordered. This model does not require excess over-stoichiometric palladium. Two crystals obtained in the same experiment illustrate possible variations in the packing of the molecules of the complex.     

[Ni(en)3](ReO4)2: Synthesis, crystal structure and thermal properties

The crystal structure of [Ni(en)₃](ReO₄)₂ (en is ethylenediamine) is studied: a = 8.3997(2)?, b = 15.6167(5)?, c = 14.2406(4)?, β = 100.378(1)°, V = 1837.46(9) OA³, P2₁/c space group, Z = 4, and d _x = 2.673 g/cm³. It is shown that packing of the complex cations can be considered as single-layer pseudohexagonal. Thermal decomposition of the salt in a hydrogen atmosphere at 550°C is used to obtain a mixture of nickel with a nanocrystalline Re_0.87Ni_0.13 solid solution (a = 2.733(2)?, c = 4.400(3)?, P6₃/mmc space group; CSR size is ∼14 nm).     

Crystal structure of [Co(NH3)5Cl]2(W10O32)·4H2O

By single crystal X-ray diffraction the crystal structure of the complex salt [Co(NH₃)₅Cl]₂(W₁₀O₃₂)·4H₂O is determined and the IR spectrum is interpreted. The crystal chemical analysis of the structure of complex cations and decatungstate anions and their packing in the structure is performed.     

New crystal modification of the di(nitrato)di(aqua)palladium(II) complex β-trans-[Pd(NO3)2(H2O)2]

Single crystals of a new modification of the di(nitrato)di(aqua)palladium(II) complex β-trans-[Pd(NO₃)₂(H₂O)₂] were obtained. Their crystal structure was determined: monoclinic crystal system, a = 5.7469(4) Å, b = 5.3942(6) Å, c = 10.0956(10) Å, β = 97.401(3)°, P2₁/c, Z = 2, d _calc = 2.851 g/cm³, Bruker X8 APEX CCD, MoK _α , 836 independent reflections, room temperature. The square-plane coordination of the Pd atom is formed by four oxygen atoms (Pd-O(NO₃) 2.003(3) Å and Pd-O(H₂O) 2.021(4) Å) and completed to a distorted bipyramid by two intramolecular contacts (Pd…O(NO₃) 2.893 Å). A comparative crystal-chemical analysis with α-trans-[Pd(NO₃)₂(H₂O)₂] was carried out.     

Crystal structure of [CoEn3]2(W7O24)·6H2O

Crystal structure of a complex salt [CoEn₃]₂(W₇O₂₄)·6H₂O is determined by X-ray crystallography. Powder X-ray diffraction is applied for the phase identification of the products of thermal decomposition of the salt in the helium atmosphere.     

A study of complexation between crystalline <Emphasis Type="Italic">trans</Emphasis>-[Pd(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>(NO<Subscript>3</Subscript>)<Subscript>2</Subscript>] and acetylacetone

Complexation between crystalline trans-[Pd(H₂O)₂(NO₃)₂] and acetylacetone was studied. The complexes Pd₂(Acac)₂(μ-NO₃)₂(I) and Pd₂(Acac)₂(μ-Acac)(μ-NO₃)(II) were obtained and examined by elemental analysis, X-ray powder diffraction analysis, differential scanning calorimetry, simultaneous thermal analysis, mass spectrometry, and vibrational spectroscopy.     

X-ray structure of KCs[Pd(NO3)4]·0.5H2O

A new Pd nitrate complex KCs[Pd(NO₃)₄]·0.5H₂O is synthetized. Its crystal structure contains isolated complex anions [Pd(NO₃)₄]²⁻, cations K⁺, Cs⁺, and crystallization water. Square-planar coordination around Pd is achieved by oxygen atoms of monodentate nitrate ligands. The coordinated nitrate ligands are all oriented in the same way, in a “basket”-like arrangement. The coordination around Pd is completed to 4+1 by forming Pd...Pd contacts of 3.564 ?. Original Russian Text Copyright ? 2009 by S. P. Khranenko, I. A. Baidina, N. V. Kuratieva, and S. A. Gromilov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 1, pp. 173–176, January–February, 2009.     

Properties of nitric acid palladium solutions with a high metal concentration

Nitric acid solutions (c _Pd up to 3.2 M) with variable HNO₃ concentration were studied by electronic spectroscopy, ¹⁴N and ¹⁷O NMR, acid-base titration, gravimetry, and other methods. Solid phases that precipitated on storing these solutions were studied by X-ray phase analysis, thermogravimetry, and IR spectroscopy. The conditions for stability of particular Pd(II) species were determined, and specific features of aging of such highly concentrated palladium solutions were revealed. A procedure for palladium isolation as [Pd(NH₃)₄](NO₃)₂ from nitric acid solutions in 98% yield was developed.