Three forms (cis-, trans-, /3-trans-) of [Pd(NH3)2CI2] were obtained as pure single-phase powder materials. Ab initio structure determinations using X-ray powder diffraction were carried out. The cis-Pd(NH3)2C12 [a = 6.3121(2), b = 6.4984 (2), c= 3.3886(1)A, ot = 96.604(4), /3=97.290(4), y= 104.691(2y ~, Z= 1, space group P1] and trans-Pd(NH3)2C12 [a = 6.5398 (3), b=6.8571 (4), c=6.3573 (3) A, t~ = 103.311 (5), 15 --102.454 (3), y = 100.609 (4) °, Z = 2, space group P1] phases have a typical layer-column structure, while /3-trans-Pd(NH3)2Cl 2 [a --8.1540 (2), b = 8.1482(2), c = 7.7945 (1)A, Z = 4, space group Pbca] is described as a parquet-like layer structure. Both trans phases demonstrate the order-disorder phenomenon. The possible ways of phase transitions are discussed. It is noted that the cis phase can transform into trans in the solid state without destroying the crystal body. Further transformation to /3-trans follows through a break up of the crystal body. The result was a fine yellow powder. Chemical analysis: Pd 50.50 (50.40), C1 33.41 (33.49)%. The trans compound could also be prepared by thermal transformation of cis-[Pd(NH3)2C12)] at --~523 K, but in this case the product is contaminated by other isomers. fl-trans-[Pd(NH3)2C12) ] was obtained by thermal transformation of trans-[Pd(NH3)2C12)]. The latter compound was heated in water at 363-368 K for 4h. The orange coloured product was washed and dried. Chemical analysis: Pd 50.45 (50.40), C1 33.40 (33.49)%. The trans isomer is insoluble in water.

The water-insoluble title compound, catena-poly[palladium(II)-di-mu-acetato-kappa4O:O'], [Pd(C2H3O2)2]n, was obtained from a nitratopalladium solution and acetic acid as a pale-pink powder. Ab initio crystal structure determination was carried out using X-ray powder diffraction techniques. Patterson and Fourier syntheses were used for atom location and the Rietveld technique was applied for the final structure refinement. The structure consists of palladium acetate complexes connected into polymeric chains running along b, in which two Pd atoms are bridged by two acetate groups that are in a cis configuration with respect to one another. The unique Pd atom lies on a site with 2/m symmetry and the acetate moieties have imposed m symmetry; these are joined into infinite chains running along the b direction. The shortest Pd...Pd distance in the row is 2.9192 (1) A. The planes of adjacent palladium complexes are inclined towards each other, the angle between the planes being approximately 30 degrees.

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The reaction of SnCl 2 with the Ru-Cl bond of the Grubbs I catalyst RuCl 2 (dCHPh)(PCy 3 ) 2 (1) gives the complex {[Ru(dCHPhbut containing two diethyl ether solvate molecules. The formal insertion of SnCl 2 into one Ru-Cl bond of the Hoveyda II catalyst RuCl 2 (dCH-C 6 H 4 OPrin formation of the new complex RuCl(SnCl 3 )(dCH-C 6 H 4 OPr i )(H 2 IMes) (4). The X-ray analyses of 2 and 4 show the presence of very short Ru-Sn bonds (2.5834(9) A ˚mean bond for 2 and 2.5925(12) A ˚for 4) and the retention of short RudC bonds (1.895(10) and 1.825(8) A ˚, respectively). Complex 4 shows an excellent catalytic activity for the cross-metathesis of plant oil derivatives, the C11 ω-unsaturated ester and aldehyde and the unsaturated C18 diester with acrylonitrile, and a good activity for their cross-metathesis with methyl acrylate. Good to excellent yield of R,ω-bifunctional compounds, precursors of polyesters and polyamides, were obtained. Complex 2 shows catalytic activity for the self-metathesis of C11 ω-unsaturated aldehyde at low concentration to produce C20 R,ω-dialdehyde.

Crystal structures of [Pd(NH3)2X2] complexes, where X = Br or I, diamminediiodo-/-dibromopalladium(II), have been studied by X-ray powder diffraction. The series consists of five complexes: cis-[Pd(NH3)2Br2] (I) [a = 13.3202 (7), b = 12.7223 (6), c = 7.05854 (3) A, Z = 8, space group Pbca], trans-[Pd(NH3)2Br2] (II) [a = 6.7854 (3), b = 7.1057 (3), c = 6.6241 (2) A, alpha = 103.221 (3), beta = 102.514 (2), gamma = 100.386 (3) degrees, Z = 2, space group P1], beta-trans-[Pd(NH3)2Br2] (III) [a = 8.4315 (3), b = 8.4206 (3), c = 8.0916 (2) A, Z = 4, space group Pbca], cis-[Pd(NH3)2I2] (IV) [a = 13.9060 (8), b = 13.5035 (8), c = 7.5050 (4) A, Z = 8, space group Pbca], and beta-trans-[Pd(NH3)2I2] (V) [a = 8.8347 (5), b = 8.8410 (5), c = 8.6081 (2) A, Z = 4, space group Pbca]. Patterson synthesis and Rietveld refinement have been used for structural determination. Molecular structures with column- or parquet-type packing of flat complexes are characteristic of these substances. Corresponding cis- and beta-trans compounds are isostructural. The thermal transformations cis-->trans-->beta-trans (cis-->beta-trans in the case of iodine) are considered. Cl derivatives are also discussed. The transformations proceed irreversibly and are accompanied by decreasing specific volume. Owing to these features, they can be classified as chemical reactions. High-temperature X-ray powder diffraction was used to study the transformations in air. The set of data is consistent with a solid state transformation from cis to trans. According to this model, the columns of molecules remain intact during the process, and the transformation proceeds via the breaking of Pd...X and Pd...N intermolecular bonds. The powder diffraction data have been deposited in ICDD-JCPDS (45-0596, 46-0876, 46-0879, 47-1690, 48-1185).

The water-insoluble title compound, octakis(mu-acetato-kappa2O:O)octakis(mu-nitroso-kappa2N:O)octapalladium(II), [Pd8(CH3COO)8(NO)8], was precipitated as a yellow powder from a solution of palladium nitrate in nitric acid by adding acetic acid. Ab initio crystal structure determination was carried out using X-ray powder diffraction techniques. Patterson and Fourier syntheses were used for atom locations, and the Rietveld technique was used for the final structure refinement. The crystal structure is of a molecular type. The skeleton of the [Pd8(CH3COO)8(NO)8] molecule is constructed as a tetragonal prism with Pd atoms at the vertices. The eight NO- groups are in bridging positions along the horizontal edges of the prism. The N and O atoms of each nitroso group coordinate two different Pd atoms. The vertical edges present PdPd contacts with a short distance of 2.865 (1) A. These Pd atoms are bridged by a pair of acetate groups in a cis orientation with respect to each other. The complex has crystallographically imposed 4/m symmetry; all C atoms of the acetate groups are on mirror planes. The unique Pd atom lies in a general position and has square-planar coordination, consisting of three O and one N atom.

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Synthesis, Crystal Structure, and Thermal Properties of cis-Pd(NH 3 ) 2 Br 2 .-The title complex is obtained by substitution of the oxalate group in [Pd(NH 3 ) 2 (C 2 O 4 )] by bromine. This electro-neutral planar complex possesses a molecular-type crystal structure (space group Pbca, Z=8) and has a slightly distorted regular trapeze form. A cis-trans isomerization is observed at 130 • C. -(BLOKHIN, A. I.; SOLOV'EV, L. A.; BLOKHINA, M. L.; YAKIMOV, I. S.; KIRIK, S. D. ; Zh. Neorg. Khim. 43 (1998) 2, 258-262; Inst. khim. khim.-metall. protsessov Sib. otd. Ross. Akad. nauk, Krasnoyarsk, Russia; RU)