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The results of the study of ternary systems containing copper, cobalt, nickel, and cadmium halides and sulfates in binary water-organic and mixed organic solvents are summarized. The influence of the donor-acceptor properties of the ternary system components, the relative dielectric permittivity, and the intermolecular association in the mixed solvent on the solubility of salts and the crystalline structure of solvates is analyzed.

Four complexes [Ni(DMA)2(H2O)4]Cl2·2H2O, [Ni(DMF)2(H2O)4]Cl2·2H2O, and [Ni(DMA)6][NiCl4], [Ni(DMF)2(H2O)2Cl2] were isolated from ternary water-organic saline systems containing nickel chloride and N, N-dimethylacetamide-water and N, N-dimethylformamide-water binary solvents. The obtained complexes were studied by X-ray structural analysis. The formation of hydrogen bonds between water molecules of the nickel ion solvate sphere, chloride ions, and non-coordinated water molecules located in the cavity of the crystal structure was detected.

Five solvates, [CdBr2(DMF)] n , [CdBr2(DMA)] n , [CdI2(DMF)] n , [Cd(DMF)6][Cd2I6], and {[Cd(DMA)6][Cd5I12] n } m , were isolated from the ternary systems CdX2–L–H2O (X = Br, I; L = N,N-dimethylacetamide, N,N-dimethylformamide) and characterized by the X-ray single crystal analysis. The structures of the first three solvates is similar to each other in structures and represent a one-dimensional polymer chain, the fourth solvate has the discrete structure containing [Cd(DMF)6]2+ and [Cd2I6]2– ions, and the fifth solvate contains discrete [Cd(DMA)6]2+ cations and the polymer anionic fragment [Cd5I12] n 2n–.

Solubility of cadmium chloride at 25°C in four ternary systems containing mixed water-organic solvents was measured by the isothermal saturation method. Dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide, and 1,4-dioxane were used as organic components. In all systems the organic component addition provides a salting-out effect within the whole range of the binary solvent compositions.

Solubility in the systems CdX2–H2O–Solv (X = Br, I; Solv = dimethyl sulfoxide, N,N-dimethyl acetamide, N,N-dimethyl formamide, and 1,4-dioxane) at 25°C was measured by the isothermal saturation method. A relation between the shape of the solubility isotherm and the structure of the binary solvent depending on its composition was found. Positions of solubility maxima and isotherms inflection points in the most cases correlate with destruction of intermolecular associates formed by solvent components.

Solubility of salts in the systems MCl2–H2O–Solv (M = Co, Ni) and CoBr2–H2O–Solv (Solv = dimethyl sulfoxide, dimethyl formamide, and dimethyl acetamide) at 25°C was measured experimentally. Dominating species of cobalt and nickel halides existing in various concentration regions were identified by analysis of electron absorption spectra. It was shown that the major factor defining solubility is the interaction of halocomplexes of metal ions with solvent molecules.

Solubility at 25°C has been determined in the MSO4–H2O–Solv systems (M = Co, Cu, or Cd; Solv = dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide, tetrahydrofuran, or dioxane) via the isothermal saturation method. Analysis of the solubility as function of the permittivity and donor power of solvents along with the information on the cations radius leads to the conclusion that ion–ion association dominates over solvation interactions in the studied systems.

A new rhodium(I) dimethyl sulfoxide (DMSO) 8-oxyquinolinato (Oxq) complex, [Rh(Oxq)(CO)(DMSO)] ( I ), has been prepared and characterized by IR, 1 H and 13 C NMR, and X-ray data. DMSO is S-coordinated in the trans -N position. The values of ν(CO), carbonyl δ 13 С, as well as δ 13 С and δ 1 H of Oxq ligand for three L trans -N complexes, [RhOxq(CO)(L)] (L = NH 3 , DMSO, and CO), define the intermediate position of DMSO within the ligand L series ranged in their net donating potency. Observed spin–spin couplings of Oxq 13 C (C2, C3, C4a, C7, C8a) and 1 H (H2) nuclei to 103 Rh provide one more tool to study long-range interactions of Oxq rings with metallocenter and remote ligand L.

The complex trans-[RuPy4(CN)2] cleaves chloride bridges in the binuclear rhodium(i) and palladium(ii) complexes [Rh(CO)2Cl]2, [Rh(η4-C8H12)Cl]2, [(η4-C8H12)Rh(μ-Cl)2Rh(CO)2], [Pd(η3-C3H5)Cl]2, and [(η3-C3H5)Pd(μ-Cl)2Rh(CO)2] to form heterometallic triad complexes [(CO)2ClRh(NC)RuPy4(CN)RhCl(CO)2] (1), [(η4-C8H12)ClRh(NC)RuPy4(CN)RhCl-(η4-C8H12)] (2), [(CO)2ClRh(NC)RuPy4(CN)RhCl(η4-C8H12)] (3), [(η3-C3H5)ClPd(NC)-Ru(Py)4(CN)PdCl(η3-C3H5)] (4), and [(CO)2ClRh(NC)Ru(Py)4(CN)PdCl(η3-C3H5)] (5), respectively. In solutions, complex 3 coexists with equilibrium amounts of compounds 1 and 2; complex 5 is in the equilibrium with compounds 4 and 1. In both cases, the ratio of concentrations is close to binomial. Complexes 2 and 5 treated with [Rh(CO)2Cl]2 are converted into 1 with the simultaneous formation of [Rh(η4-C8H12)Cl]2 and [Pd(η3-C3H5)Cl]2, respectively. The δH and δC values for the ligands η4-C8H12, η3-C3H5, and CO are sensitive to the nature of the remote triad unit. The ligand effects are shown to be transmitted along the chain L′-M′-(NC)-Ru-(CN)-M″-L″.

It was proved by the IR spectroscopy that the first coordination sphere of nickel cations in the NiCl2·2DMSO·9H2O, NiCl2·5DMSO·4H2O, and NiCl2·4DMSO·2H2O compounds contains dimethyl sulfoxide and water ligands. According to X-ray structural analysis, in crystals of the NiCl2·4DMSO·2H2O compound, noncovalent contacts between sulfur atoms of neighboring dimethyl sulfoxide molecules are realized in the inner sphere of the complex.

The oxidative addition of CH 3 I to planar rhodium(I) complex [Rh(TFA)(PPh 3 ) 2 ] in acetonitrile (TFA is trifluoroacetylacetonate) leads to the formation of cationic, cis- [Rh(TFA)(PPh 3 ) 2 (CH 3 )(CH 3 CN)][BPh 4 ] ( 1 ), or neutral, cis- [Rh(TFA)(PPh 3 ) 2 (CH 3 )(I)] ( 4 ), rhodium(III) methyl complexes depending on the reaction conditions. 1 reacts readily with NH 3 and pyridine to form cationic complexes, cis- [Rh(TFA)(PPh 3 ) 2 (CH 3 )(NH 3 )][BPh 4 ] ( 2 ) and cis- [Rh(TFA)(PPh 3 ) 2 (CH 3 )(Py)][BPh 4 ] ( 3 ), respectively. Acetylacetonate methyl complex of rhodium(III), cis- [Rh(Acac)(PPh 3 ) 2 (CH 3 )(I)] ( 5 ), was obtained by the action of NaI on cis- [Rh(Acac)(PPh 3 ) 2 (CH 3 )(CH 3 CN)][BPh 4 ] in acetone at −15 °C. Complexes 1–5 were characterized by elemental analysis, 31 P{ 1 H}, 1 H and 19 F NMR. For complexes 2 , 3 , 4 conductivity data in acetone solutions are reported. The crystal structures of 2 and 3 were determined. NMR parameters of 1–5 and related complexes are discussed from the viewpoint of their isomerism.

Trans-[RuPy4(CN)2 cleaves chloro-rhodium bridges in rhodium(I) binuclear complexes, [Rh(CO)2Cl]2, [Rh(Cod)Cl]2, and [(Cod)RhCl2Rh(CO)2] yielding heterometallic triad complexes, [(CO)2ClRh(NC)RuPy4(CN)RhCl(CO)2] (I), [(Cod)ClRh(NC)RuPy4(CN)RhCl(Cod)] (II), and [(Cod)ClRh(NC)RuPy4(CN)RhCl(CO)2] (III), respectively. In solutions, III coexists with equilibrium amounts of I and II in the near-binomial proportions. Under action of [Rh(CO)2Cl]2, II transforms into I with parallel formation of [Rh(Cod)Cl]2. Ligand effect transmission along the L-Rh-NC-Ru-CN-Rh-L′ chain is studied by 1H and 13C NMR. Chemical shifts δ1H and δ13C of Ru-bound Py ligands are sensitive to the nature of Rh-bound ligands. Values of δ1H and δ13C of Cod and 13C of CO ligands are sensitive to the ligands at the remote end of the L-Rh-NC-Ru-CN-Rh-L′ chain. Reaction of trans-[RuPy4(CN)2] with Rh2(OAc)4 yields an apparently linear polymer [-Rh(OAc)4Rh-NCRuPy4CN-]. Upon action of [Rh(CO)2Cl]2, the polymer decomposes yielding I and Rh2(OAc)4. X-ray structure data for I are given.

The geometry of binuclear rhodium(I) complexes, [Rh(μ-Cl)(CO)2]2 and [Rh(μ-RCOO)(CO)2]2 (R = H, CH3, CF3), was optimized by the DFT method; the vibrational spectra and the δ13C chemical shifts were calculated. The calculations were performed using the B3LYP hybrid functional and four basis sets. The calculations with the LanL2DZ basis set reflect all trends in the variation of the characteristics predicted using augmented basis sets and observed in the experiment. The Rh → CO electron density transfer along the π-bond and δ13C increase, while the bond orders, the intrinsic frequencies, and the force constants of the carbonyl groups in the carboxylate complexes decrease following a decrease in the substituent electronegativity in the series CF3 > H > CH3. It was found that the ratio of the ν(CO) intensities in the IR spectra can be used to derive information on the dihedral angle between the Rh(CO)2 planes in the binuclear complexes. Calculations were carried out for a tetranuclear model system [Rh(HCOO)(CO)2]4, which can be treated as an elementary unit of the infinite chains of metal atoms in [Rh(μ-RCOO)(CO)2]2 stack crystals. A local minimum was found on the potential energy surface corresponding to the geometric structure of the crystal fragments.

Cationic methyl complex of rhodium(III), cis-[Rh(Acac)(PPh3)2(CH3)(Py)][BPh4] (1) as a single isomer with Py in the trans to PPh3 position, is formed upon the reaction of cis-[Rh(Acac)(PPh3)2(CH3)(CH3CN)][BPh4] with pyridine in methylene chloride solution.Complex 1 was characterized by elemental analysis and by 31P{1H} and 1H NMR spectra.Cationic pentacoordinate acetyl complexes, trans-[Rh(Acac)(PPh3)2(COCH3)][BPh4] (2) and trans-[Rh(BA)(PPh3)2(COCH3)][BPh4] (3), are prepared by action of carbon monoxide on cis-[Rh(Acac)(PPh3)2(CH3)(CH3CN)][BPh4] and cis-[Rh(BA)(PPh3)2(CH3)(CH3CN)][BPh4], respectively, in methylene chloride solutions.Complexes 2 and 3 were characterized by elemental analysis and by IR, 31P{1H}, 13C{1H} and 1H NMR. According to NMR data, 2 and 3 in solution are non-fluxional trigonal bipyramids with β-diketonate and acetyl ligands in the equatorial plane and axial phosphines.In solutions, 2 and 3 gradually isomerize into octahedral methyl carbonyl complexes trans-[Rh(Acac)(PPh3)2(CO)(CH3)][BPh4] (4) and trans-[Rh(BA)(PPh3)2(CO)(CH3)][BPh4] (5), respectively.Complexes 4 and 5 were characterized by IR, 31P{1H}, 13C{1H} and 1H NMR, without isolation.Upon the action of PPh3 on cis-[Rh(Acac)(PPh3)2(CH3)(CH3CN)][BPh4] and cis-[Rh(BA)(PPh3)2(CH3)(CH3CN)] [BPh4], reductive elimination of the methyl ligand as a phosphonium salt, [CH3PPh3][BPh4], occurs to give square planar rhodium(I) complexes [Rh(Acac)(PPh3)2] and[Rh(BA)(PPh3)2], respectively. The reaction products were identified in the reaction mixtures by 31P{1H} and 1H NMR.

Complexes [Rh(µ-RCOO)(CO2)]2 , where R = H, CH3,CF3 (I, II, III, respectively) are synthesized by reacting anhydrous carboxylic acids with Rh(Acac)(CO2) crystals. In compounds I, II, III, and trans-Rh(RCOO)(PPh3)2(CO), where R = H, CH3, CF3 (IV, V, VI, respectively), ν(CO) and 1J(CRh) increase and δ13C decreases with the increasing electronegativity of R (CH3 < H < CF3). In the case complexes IV, V, and VI, the values of δ31P and 1 J(PRh) decrease in the same order. Complexes I and V are studied by X-ray diffraction analysis. Intramolecular (2.946 A) and intermolecular (3.127 A) Rh-Rh distances in a columnar structure I are close, i.e., the structure contains infinite chains of metal atoms. Interaction of IV with chlorinated solvents results in trans-RhCl(PPh3)2(CO). When heated with an excess of PPh3 in propanol-2, compound IV transforms to HRh(PPh3)3(CO). The latter reaction was suggested as a basis of a new method that can be used to obtain HRh(PPh3)3(CO).

Ruthenium(II) bisbipyridyl complexes cis-[Ru(bpy)2(L)NO2](BF4) (bpy is 2,2'-bipyridyl) with 4-substituted pyridine ligands L = 4-(Y)py (Y = NH2, Me, Ph, and CN) were obtained. The equilibrium constants of the reversible nitro-nitrosyl transition [Ru(bpy)2(L)NO2]+ + 2H+ ↔ [Ru(bpy)2(L)NO]3+ + H2O were measured in solutions with pH 1.5-8.5 (ionic strength 0.4). The constants correlate with the protonation constants of free ligands 4-(Y)py.

The electronic absorption spectra of ruthenium nitrosyl complexes with nitrogen-containing heterocyclic ligands were analyzed on the basis of ab initio and CINDO/CI semiempirical calculations of free ligands L and complexes trans-[Ru(NO)(NH3)4(L)]3+ (L = pyridine, pyrazine, nicotinamide, isonicotinamide, l-histidine, imidazole). Spectral manifestations of a strong covalent Ru-NO bond were observed to conclude that the oxidation states of Ru and NO in the RuNO3+ group are expedient to represent as Ru(III) and NO0. Introduction of a nitrosyl group into the inner coordination sphere of Ru(II) complexes with nitrogen-containing heterocyclic ligands much affects the entire spectral patterns and denudes these ligands of the capacity to exhibit chromophoric properties.

Oxidation of rhodium(I) carbonyl chloride, [Rh(CO) 2 Cl] 2 , with copper(II) acetate or isobutyrate in methanol solutions yields binuclear double carboxylato bridged rhodium(II) complexes with RhRh bonds, [Rh(μ-OOCRκO)(COOMeκC)(CO)(MeOH)] 2 , where R=CH 3 or i -C 3 H 7 . According to X-ray data, surrounding of each rhodium atom in these complexes is close to octahedral and consists of another rhodium atom, two oxygens of carboxylato ligands, terminal carbonyl group, C-bonded methoxycarbonyl ligand, and axial CH 3 OH. Methoxycarbonyl ligand is shown to originate from CO group of the parent [Rh(CO) 2 Cl] 2 and OCH 3 group of solvent. N- and P-donor ligands L ( p -CH 3 C 6 H 4 NH 2 , P(OPh) 3 , PPh 3 , PCy 3 ) readily replace the axial MeOH yielding [Rh(μ-OOCRκO)(COOMeκC)(CO)(L)] 2 . The X-ray data for the complex with R= i -C 3 H 7 , L=PPh 3 showed the same molecular outline as with L=MeOH. Electronic effects of axial ligands L on the spectral parameters of terminal carbonyl group are essentially the same as in the known series of rhodium(I) complexes (an increase of δ 13 C and a decrease of ν (CO) with strengthening of σ-donor and weakening of π-acceptor ability of L).

The hydration shell of the complex ions [Ru(NH3)5pyz]2+ and [Ru(CN)5pyz]3- was simulated on the basis of ab initio Hartree-Fock calculations in the supermolecular approximation, within the framework of the multicavity polarizable continuum model. In calculations of the spectral characteristics of complexes with a pronounced nonuniformity of electron density distribution, it is primarily necessary to take into account the shift of energy levels of particular fragments under the action of the electrostatic potential produced by the solvation surrounding. Consideration of the charge transfer between the complex and the outer-sphere water molecules has no significant effect on the calculated electronic spectrum; the transferred electron density is below 1e.

The electronic structure of complexes [Ru(XY)L5]q (L = NH3, Cl-, CN-; XY = NO, CO, N2) was represented as a combination of valence schemes based on ab initio and semiempirical quantum-chemical calculations. It was found that schemes corresponding to a covalent π bond between Ru(III) and NO contribute most in the case of the complexes containing a {RuNO}3 + group, which makes possible the nitroso ligands in these compounds to be considered as uncharged NO molecules. The necessity of inclusion of electron correlation in the description of π interactions between the metal and ligands was shown.

The substitution of the CO ligand in rhodium(I) β-ketoiminato complexes Rh(R1{O,N}R2)(CO)2 ({O,N}=R1C(O)CHC(NH)R2; R1, R2=CF3, Me, CMe3 in several combinations) by phosphorus ligands PZ3 (PZ3=PCy3, PPh3, P(OPh)3, P(NC4H4)3) leads to Rh(R1{O,N}R2)(CO)(PZ3) complexes characterised by 31P{1H}-NMR and X-ray methods. The stronger σ-donor PZ3 ligands (PZ3=PCy3, PPh3) substitute almost exclusively the CO group trans to N, forming P-trans-to-N isomers. The complexes Rh(CF3{O,N}Me)(CO)(PCy3) (II), Rh(CF3{O,N}CMe3)(CO)(PCy3) (III), Rh(CF3{O,N}Me)(CO)(PPh3) (IV) and Rh(CF3{O,N}CMe)(CO)(PPh3) (V) are of a square-planar geometry with a slight tetrahedral distortion around the rhodium atom in II, III and V. The RhP(PCy3) bonds are slightly longer than the RhP(PPh3) bonds. The reaction of stoichiometric amounts of the less basic P(OPh)3 or P(NC4H4)3 ligands leads to the formation of both isomers of the Rh(R1{O,N}R2)(CO)(P(OPh)3) or Rh(R1{O,N}R2)(CO)(P(NC4H4)3) complex in comparable yields. The RhP(P(OPh)3) distance (2.195(2) A) in the isomer of Rh(CF3{O,N}CMe3)(CO)(P(OPh)3) with P(OPh)3 coordinated trans to N (VI) is ca. 0.04 A longer than in the isomer of that complex with P(OPh)3 coordinated trans to O (VII). The CO substitution in Rh(R1{O,N}R2)(CO)2 by PZ3 ligands (PPh3, PCy3, P(OPh)3) causes the shortening of the RhC(CO) bond by ca. 0.04 A compared to Rh(CF3{O,N}Me)(CO)2 (I), making difficult the coordination of another PZ3 ligand, especially one with stronger σ-donor properties. The more π-acceptor P(OPh)3 ligands form bis-phosphito complexes and Rh(CF3{O,N}CMe3){P(OPh)3}2 (VIII) exhibits inequivalence of the two P(OPh)3 ligands in solution (31P-NMR) as well as in solid form (X-ray).

Ab initio quantum-chemical calculations of Ru(II) complexes have been fulfilled with consideration for solvation within the framework of the polarized continuum model. Energy levels of fragments of Ru(II) complexes with organic ligands are shifted relative to each other by electrostatic interactions with the solvation shells.

The results of ab initio quantum-chemical calculations of isolated ruthenium(II) complexes cis- [Ru(bpy)2(bipy)(X)]44q (bpy is 2,2'-bipyridyl, bipy is 4,4'-bipyridyl; X = NH3, Cl-, Br-, CN-, NO-2, ONO-, MeCN, and NO+) are presented. Analysis of the charge distributions and the orbital structures of the complex ions points to absence of strong π-acceptor bonds Ru-bpy, Ru-bipy, and Ru-X (X = NO+), to delocalization of π-electron density under the action of strong donors X, to localized nature of lowest unoccupied molecular orbitals, and to special position of the nitrosyl complexes in this series.

Thermal reactions of Ru3(CO)12 with hexa-2,4-diyne-1,6-diol and 1,4-diphenyl-1,3-butadiyne were studied. Reaction of the triruthenium cluster with HOCH2C2C2CH2OH results in substitution of two CO groups and coordination of the diyne ligand to a ruthenium triangle in parallel μ3,η2-mode via one of the conjugated triple bonds. The structure of the final product Ru3(CO)10(μ3,η2-HOCH2C2C2CH2OH) was determined by a single-crystal X-ray study. The analogous reaction with PhC2C2Ph affords the binuclear ruthenium complex Ru2(CO)6, (μ3,η4-C(Ph)C(C2Ph)C(C2Ph)C(Ph)). The starting diyne ligand in this complex is dimerized forming a ruthenacyclopentadiene ring Ru-C(Ph)=C(R)C(R)=C(Ph). As a whole, the structural unit obtained can be rationalized as a cluster skeleton containing two d- and four p-elements arranged into nido pentagonal bipyramid with eight skeletal electron pairs; this cluster pattern is very typical for the iron subgroup alkyne polynuclear complexes.

Reactions of two isoelectronic tetranuclear M 4 (CO) 12 clusters (M = Rh,Co) ( I , III ) with the chromium-arenetricarbonyl complex Cr(Co) 3 ( η 6 -PhC 2 Ph)( II ) yield a product of metal carbonyl fragments in addition to the free triple bond of diphenylacetylene. The cobalt cluster reaction results in partial destruction of the cluster tetranuclear framework and formation of the Co 2 (CO) 6 ( μ 4 , η 2 : η 6 -PhC 2 Ph)Cr(CO) 3 complex, obtained earlier starting from the binuclear Co 2 (CO) 8 compound. In the case of a rhodium cluster addition of a tetranuclear carbonyl fragment takes place, yielding the Rh 4 (CO) 9 ( μ 5 , η 2 : η 6 -PhC 2 Ph)Cr(CO) 3 ( IV ) cluster. The crystal and molecular structure of IV reveals an unusual interaction between the Cr(CO) 3 fragment and a rhodium atom of the tetranuclear Rh 4 cluster core. 13 C NMR spectroscopic data show that the solid state structure is retained in solution.

The photochemical behaviour of [RuL 2 (BL)X] + ( 1 ) and [L 2 XRu(BL)RuXL 2 ] 2+ ( 2 ) (L≡2,2′-bipyridyl (bpy), 1,10-phenanthroline(phen); BL≡4,4′-bipyridyl (4,4′bpy), pyrazine (pyz) and trans -1,2-bis(diphenylphosphino)ethylene (dppene); X≡Cl, NO 2 ) in acetonitrile and methanol solutions during steady state irradiation at λ = 450 nm was studied. Compounds 1 and 2 (L≡bpyX≡Cl) with both bridging and terminal dppene ligands were found to be photochemically inert. The irradiation of compounds 1 and 2 with BL≡pyz and 4,4′-bpy resulted in the formation of solvate complexes [RuL 2 (Solv)X] + ( 3 ) in both acetonitrile and methanol; however, the photolysis of 2 proceeded via a mixture (1:1) of 1 and 3 in the first step. The quantum yields of the processes under study are discussed in terms of the excited states.

Dark and photochemical reactions of Co 3 Rh(CO) 12 with diphenylacetylene yield two butterfly clusters with the alkyne inserted into the tetrametal framework. One of them is the previously unknown cluster Co 3 Rh(μ - CO) 2 (CO) 8 (μ 4 ,η 2 , - PhC 2 Ph). It was characterized by X-ray crystallography (dark violet compound crystallizing in monoclinic space group C 2/ c , a = 15.665(2), b = 17.947(5), c = 9.078(1) A, β = 93.91(1)°, v = 2546.1(8) A 3 , Z = 4). The 13 C NMR study showed that the solid state structure is retained in solution. The second product is the Co 2 Rh 2 (μ - CO) 2 (CO) 8 (μ 4 ,η 2 - PhC 2 Ph) cluster obtained earlier and identified herein by its 13 C NMR spectrum. The formation of this cluster is evidently caused by bimolecular metal-metal exchange between cluster molecules in the course of the reaction.

The reaction of Rh6(CO)16 with two equivalents of Me3 NO in the presence of a substituting ligand (L = NCME, Py, P(OPh)3) affords a mixture of isomers of the general formula Rh6(CO)14L2. The substituting ligands occupy two terminal sites in the structure of the parent cluster. For L = P(OPh)3 three isomers (I-III) were separated from the reaction mixture. The structure of the first isomer (I) has been established by X-ray analysis. This compound crystallizes in two polymorphic modifications, monoclinic and triclinic; both of which consist of identical molecules and differ only in the packing of the molecules in the crystals. It should be noted that both polymorphic forms contain in the unit cells the racemic mixture (RR and SS) of the Rh6(CO)14{P(OPh)3} 2 molecules. This octahedral cluster may be considered as a derivative of the parent Rh6(CO)16 cluster with two terminal CO groups in trans positions at Rh(1) and Rh(2) atoms substituted by phosphite ligands. The structures of two other disubstituted clusters, (II) and (III) were established by 31P NMR spectroscopy. Phosphite ligands in these compounds occupy the terminal sites at the adjacent rhodium atoms of the Rh6 octahedron but differ in their mutual orientation. Other disubstituted derivatives (L = NCME, Py) are labile compounds and exist in solution as inseparable mixtures of the isomers characterized by 1H and 13C NMR spectroscopy. A mechanism of interconversion of the isomers is proposed.

The electronic structure and spectra of [Ru(NH3)5pyz]2+ and [(NH3)5Ru-pyz-Ru(NH3)5]4+ are calculated by the INDO (CINDO-E/S) method. Changes in molecular orbitals, charge distributions, and bond order indices of the pyrazine molecule and [Ru(NH3)5pyz]2+ complex in the [(NH3)5Ru-pyz-Ru(NH3)5]4+ binuclear complex are analyzed.

The reaction of Cr(CO)3(NH3)3 with diphenylacetylene affords as a main product the complex with Cr(CO)3 moiety bound to a phenyl ring of diphenylacetylene; Cr(CO)3(η6-PhC2Ph) (I). Complex I readily reacts with Co2(CO)8 yielding the mixed metal complex Cr(CO)3(η6:η2-PhC2Ph)Co2(CO)6 (II). The reaction proceeds with retention of the Cr(CO)3 (η6-arene) structural unit, the Co2(CO)6 fragment being bound to the triple bond of diphenylacetylene in μ2,η2-mode. The structure of II was determined by single crystal X-ray analysis. The complex crystallizes in space group P21/c with unit cell parameters a 8.666(3) A, b 18.046(3) A, c 15.155(6) A. β 97.57(3)°, V 2349(2) A3, Z = 4, Dx = 1.70 g/cm3. The structure was solved by direct methods and refined by full-matrix least-squares technique to R and Rw values of 0.032 and 0.034, respectively, for 3655 observed reflections. The data obtained show that two structural units in II, Cr(CO)3(η6-Ph-) and Co2(CO)6(μ2,η2-CC), are distorted due to steric repulsion between these metal carbonyl moieties. The Cr(CO)3 fragment is shifted from the centre of the phenyl ring and slightly tilted with respect to the phenyl ring plane. The Co2C2 tetrahedron in the Co2(CO)6(μ2,η2-CC) moiety is distorted in such a way that two of the four CoiCj bonds are elongated.

Two major products of the photoreaction between Rh6(CO)16 and bis-(diphenylphosphinoethane) (dppe) were isolated and characterized as Rh6(CO)14(μ2, η2 -Ph2P(CH2)2 PPh2) with μ2-bridging bidentate dppe and Rh6(CO)15(η1-Ph2P(CH2)2P (O)Ph2) where one P atom of dppe is terminally coordinated, the other being oxidized and thus non-coordinated. Substitution of the labile acetonitrile ligand in Rh6(CO)15,NCMe by dppe yields Rh6(CO)15 2(μ2,η1:η1-Ph2P(CH2)2PPh2) with dppe bridging two Rh6 cores. The structures of Rh6(CO)14(μ2,η2 -Ph2P(CH2)2PPh2) and Rh6(CO)15PPh 3 have been determined by single-crystal X-ray diffraction studies. Solution structures of Rh6(CO)14(μ2,η2-Ph2P(CH2)2PPh 2), Rh6(CO)15PPh3, Rh6(CO)15(η1- Ph2P(CH2)2 P(O)Ph2) and Rh6(CO)152(μ2,η1:η1-Ph2P(CH2) 2PPh2) have been established by IR, and 13C and 31P NMR spectroscopy.

Communications [1–3] have described the results of the studies of catalytic activity of a number of rhodium, palladium, iridium, and ruthenium complex compounds in the reaction of liquid-phase oxidation of 1-octene with molecular oxygen. In this communication we present the data on the catalytic properties of some of these metal complexes in an immobilized form. The principle of immobilization of metal complexes is based on the known ability of the transition metals (M) cyanides to act as metal-containing ligands coordinating to other transition metals (M') through the nitrogen atom of the cyanide groups to form M–CN– M' bridges [4–9]. The catalysts studied in this work were prepared by fixing a metal on the surface of the carrier (alumina), on which Ni(II) cyanide was preliminary applied. Thus, the data presented here characterize the catalytic activity of immobilized bimetallic compositions Ni–CN–M'Ln, where Ln is a set of the ligands forming the coordination sphere of the transition metal M'. As a quantitative characteristic of the catalytic activity of the compositions we used, as in [1, 2], the initial rate of oxidation of 1-octene (W0) determined from the curve of the rate of oxygen consumption extrapolated to zero time.

The reaction of catalytic liquid-phase oxidation of olefins by molecular oxygen belongs to the most promising processes of organic synthesis and is a subject of numerous publications (see [1–3] for example). We have shown recently [4] that mononuclear rhodium organometallic complexes are active catalysts of the 1-octene oxidation by molecular oxygen. In this communication we present preliminary results of studying catalytic properties of complexes containing several metal centers, namely binuclear complexes of rhodium (+1), rhodium (+3), iridium (+1), palladium (+2), and triad complexes containing the ruthenium (+2) complex trans-[Ru(py)4(CN)2] as a central unit and rhodium (+1) or palladium (+2) complexes as terminal fragments.

Bands resulting from contact outer-sphere anion-anion interactions, have been found in the electronic absorption spectra of systems containing simultaneously the anions [FeNO(CN) 5 ] 2– or [Co edta] – and nucleophilic anions ( I − , SC N − and S 2 O 3 2 − ) ; the fraction of complex anions occurring in the contact interaction with nucleophilic anions can be as high as several tens of percent in concentrated solutions.

Reactions of H 2 Os 3 (CO) 10 with the diyne ligand HOCH 2 C 2 C 2 CH 2 OH and its dicobalthexacarbonyl derivatives {CO 2 (CO) 6 }(μ 2 ,η 2 -HOCH 2 C 2 C 2 CH 2 OH) and {Co 2 (CO) 6 } 2 (μ 2 ,η 2 : μ 2 ,η 2 -HOCH 2 C 2 C 2 CH 2 OH) have been studied. The reaction of the uncomplexed ligand yields the cluster with the completely rearranged starting ligand. The structure of this compound was determined by a single-crystal X-ray study. The rearranged ligand forms a pseudo-furan ring with the C CH 3 substituent in the α-position. The reactions of H 2 Os 3 (CO) 10 with the both dicobalthexacarbonyl derivatives yield the (μ-H)(μ-OH)Os 3 (CO) 10 cluster ar the main osmium-containing product. The structure of this compound was also established by a single-crystal X-ray study.

Compounds (Ia)-(Ic) are the first examples of Rh6(CO)IsL complexes, where L is a neutral ligand. Products (Ia)-(Ic) are stable upon storage in the air. The nitrile is readily replaced in solution by other ligands such as CO, PPha, Py, and I-, which holds special interest for the selective synthesis of monosubstituted derivatives of Rh6(CO)16. IR spectrum of (Ia) in CHCIa (vCO, cm-1): 2104 w, 2068 v.s, 2040 w, 2018 sh, 1792 br.m; (vCN, cm-Z): 2364 v.w. ZSC {IH} NMR spectrum in CDCI S (6, ppm, JRh-C, Hz): 3.34 (CHs), 123.55 (CN), 179.00 d (ICO, J = 70.5), 180.27 d (4CO, J = 70.5), 181.78 d (4CO, J = 70.5), 183.18 d (2CO, J = 70.5), 230.79 q (ICO, J = 25.4), 233.95 q (iCO, J = 25.4), 240.65 q (2CO, J = 25.4).