on the existence of organometallic palladium(IV) complexes

The reactions of palladium(II) compounds of the type Cl₂PdL₂ with bromobis(pentafluorophenyl)thallium(III) has been reexamined. The reported preparation of the organo palladium(IV) complex Cl₂Pd(C₆F₅)₂(PPh₃)₂ could not be repeated, and instead mixtures of binuclear palladium(II) compounds, Cl₂Pd(C₆F₅)₂L₂, and mononuclear palladium(II) compounds were obtained. The binuclear are transformed into the mononuclear complexes on addition of an excess of ligand L.The chlorine bridging atoms of the binuclear complexes can be replaced by other halogens or pseudohalogens by treatment with salts of the MX type (X = Br, I, SCN).     

Selenium oxoanion compounds of palladium(II)

Three new palladium compounds, PdSeO3, PdSe2O5, and Na2Pd(SeO4)2, containing selenium oxoanions of both Se(IV) and Se(VI) have been prepared under mild hydrothermal conditions. PdSe2O5 and Na2Pd(SeO4)2 both possess one-dimensional structures. Within the structure of PdSe2O5, [PdO4] square planar building blocks are joined together through diselenite, Se2O52-, anions, and form a zigzag chain along the c axis. In Na2Pd(SeO4)2, [PdO4] units are connected by two selenate, SeO42-, anions, and extend along the a axis to form a [Pd(SeO4)2]2- chain. Na+ cations reside in the space between the [Pd(SeO4)2]2- chains and act as counter cations. Unlike above two compounds, PdSeO3 exhibits a layered structure. In the structure of PdSeO3, [PdO4] units are connected to each other by corner-sharing and form a zigzag chain along the b axis. The chains are further joined together by tridentate selenite, SeO32-, anions to form layers in the [ab] plane that stack along the c axis. Crystallographic data: (193 K; Mo Kalpha, lambda=0.71073 A): PdSeO3, monoclinic, space group P21/m, a=3.8884(5) A, b=6.4170(8) A, c=6.1051(7) A, beta=96.413(2) degrees, V=151.38(3) A3, Z=2; PdSe2O5, monoclinic, space group C2/c, a=12.198(2) A, b=5.5500(8) A, c=7.200(1) A, beta=107.900(2) degrees , V=463.8(1) A3, Z=4; Na2Pd(SeO4)2, triclinic, space group P, a=4.9349(11) A, b=5.9981(13) A, c=7.1512 (15) A, alpha=73.894(4) degrees, beta=86.124(4) degrees, gamma=70.834(4) degrees, V=192.03(7) A3, Z=1.     

Insoluble Fe(VI) compounds: effects on the super-iron battery

Cathodes composed of Fe(VI) salts are capable of three-electron reduction, and are useful for energetic super-iron batteries. This study investigates the solubility of BaFeO₄ and K₂FeO₄ Fe(VI) salts. Electrolytes are determined in which Fe(VI) has a low aqueous or non-aqueous solubility, or is insoluble. Insoluble Fe(VI) salts have the duel benefits of preventing Fe(VI) solution-phase (i) decomposition and (ii) diffusion to the anode; thereby preventing super-iron battery self-discharge. BaFeO₄ is insoluble in water, and has a solubility of less than 2×10⁻⁴ M in 5 M KOH containing Ba(OH)₂. A BaFeO₄ super-iron battery has a high discharge efficiency when containing an electrolyte of either 12 M KOH, or 6 M KOH saturated in Ba(OH)₂. Fe(VI) cathodes in non-aqueous media may be useful in providing a high-capacity Li or Li-ion super-iron battery. We illustrate that Fe(VI) salts are insoluble and chemically unreactive with a range of organic electrolytes, and can be discharged as cathodes in non-aqueous electrolytes. In acetonitrile containing 1 M LiClO₄, the discharge of an Fe(VI) cathode is demonstrated to a capacity over 394 mAh g⁻¹ K₂FeO₄.     

Dipyridinium tetraisothiocyanatodioxotungstate(VI) and related compounds

Eight tetraisothiocyanatodioxotungstate(VI) salts with general formula, (BH)₂[WO₂(SCN)₄] (where B = pyridine, piperidine, quinoline, isoquinoline, 2-, 3-, and 4-picolines) are reported. These salts have been prepared by the reaction of sodium tungstate dihydrate with ammonium thiocyanate in the presence of HCl and isolated as pyridinium or related salts. The compounds have been characterized by elemental analysis, IR and electronic absorption spectra, conductance and magnetic susceptibility measurements, TGA/DTA, and molecular modelling studies The text was submitted by the authors in English.     

Rhenium(VI) compounds in the reactions with hydroxylamine

Rhenium complexes formed by reversible acid-base reactions with hydroxylamine (HAM) chloride in alkaline and acidic media have been studied by means of electronic absorption spectroscopy and electron paramagnetic resonance (EPR). A stable diamagnetic complex of rhenium(VI) with amide forms of HAM has been shown to be formed in an alkaline medium. Under action of acid, three rhenium(VI) complexes with protonated amido ligands and chloride ions has been shown to form. EPR spectral parameters have been determined. Conditions for using the complexes in analysis have been proposed.     

Reaction of palladium (I) carbonyl acetate with phosphorus-containing ligands and the molecular structure of tris(triphenylphosphine)palladium

Conclusions Neutral and cationic carbonyl-containing palladium (II) complexes with phosphine ligands have been synthesized; they are not very stable in solution and undergo disproportionation to give palladium (0) and (II) compounds. The structure of one of these disproportionation products, namely, tris(triphenylphosphine)palladium, was solved by x-ray structural analysis.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 894–897, April, 1987.     

Mono- and dinuclear five-coordinate cyclometalated palladium(II) compounds

Reaction of cyclometalated halide-bridged Pd(II) complexes 1-4 with the tertiary triphosphine ligand (Ph2PCH2CH2)2PPh (triphos) yielded complexes [((Ph2PCH2CH2)2PPh-P,P,P)Pd(N(Cy)=(H)C)C6H2(C(H)=N(Cy))Pd((Ph2PCH2CH2)2PPh-P,P,P)][ClO4]2 5, [Pd(C6H4-N=NC6H5)((Ph2PCH2CH2)2PPh-P,P,P)][ClO4] 6, and [Pd(R-C6H3C(H)=NCy)((Ph2PCH2CH2)2PPh-P,P,P)][ClO4] (7; R = 4-CHO, 8; 3-CHO). Spectroscopic and analytic data suggest five-coordination on the palladium atom, which, for complexes 5, 6, and 7, was confirmed by X-ray crystallography. The geometry around palladium may be view as a distorted trigonal bipyramid, with the palladium, nitrogen, and terminal phosphorus atoms in the equatorial plane. Compound 5 is the first doubly cyclometalated palladium(II) compound with two pentacoordinated metal centers. The structure of 6 comprises two discrete cations with slightly different geometries, showing the importance of crystal packing forces in order to determine the coordination arrangement.     

Coordination compounds of palladium(II) and platinum(II) with benzotriazoles

Summary The nitrogen-donor ligands 1-methylbenzotriazole (1Mebta), 5-methylbenzotriazole (5MebtaH), 5-chlorobenzotriazole (5ClbtaH) and 5-nitrobenzotriazole (5NO₂btaH) react with palladium(II) and platinum(II) to give cis-[PdL₂Cl₂], cis-[PtL₂Cl₂] (L = 1Mebta, 5MebtaH, 5ClbtaH or 5NO₂btaH), [Pt(5ClbtaH)₄]Cl₂, [Pd-(5MebtaH)Cl₂]₂, [Pd(5ClbtaH)Cl₂]₂ and [Pd(5NO₂btaH)-Cl₂]₂. The complexes were characterized by physicochemical and spectroscopic methods. The benzotriazoles act as monodentate ligands binding through N(3). Monomeric square planar structures are assigned for the 12 complexes and [Pt(5ClbtaH)₄]Cl₂ in the solid state. Centrosymmetric, chloro-bridged, dinuclear square planar structures of C_2h symmetry are proposed for the 11 palladium(II) compounds.     

New coordination compounds of palladium(II) with iminodiacetic acid

Summary Iminodiacetic acid (IDA) forms 1:1 or 1:2 complexes with Pdll at room temperature and pH 6.0. The solid compounds have been characterized by elemental analysis, titrimetry, magnetic measurements, i.r. spectroscopy and thermal studies. The far i.r. spectra show peaks that can be assigned to Pd-Cl, Pd-N and Pd-O vibrations. On the basis of these studies tentative structures for the isolated substances are proposed.     

On the existence of free doubly negative molecular ions

We present a theoretical analysis on the existence of doubly negative molecular ions in the gas phase. A thorough investigation involves the discussion of two main problems: the stability of the system with respect to dissociation and the stability to the loss of an electron. An adequate treatment of both problems requires the choice of proper basis sets as well as the application of higher levels of theory. As an example the BeF ₄ ^2? dianion is studied in detail. Here we use configuration interaction and many-body Green's function approaches. Strong basis set dependencies in the calculations are observed which have no analogy in neutral systems.     

Rapid chemical synthesis of four ferrate(VI) compounds

The preparation of four novel Fe(VI) salts, including PbFeO₄, ZnFeO₄, CdFeO₄ and HgFeO₄ is demonstrated. These Fe(VI) salts were synthesized from a solid phase reaction merely by grinding K₂FeO₄ with M (C₂H₃O₂)₂.nH₂O (M = Pb²⁺, Zn²⁺) or M (NO₃)₂.nH₂O (M = Cd²⁺, Hg²⁺) at room temperature. A rapid and efficient reaction occurred upon grinding the solid reactants to afford high yield ferrate(VI) salts which were characterized by XRD, EDS and FTIR techniques. All of the synthesized ferrates were rather stable and could be stored at room temperature for more than a month with no significant decomposition.     

On the possibility of the existence of molecular nitrogen allotropes

The possibility of the existence of nitrogen molecules with an even number of atoms of composition N₄, N₆, N₈, and N₁₀ has been discussed with the use of the QCISD and G3 quantum-chemical methods. From these data, a conclusion has been made that three new nitrogen allotropes with an even number of atoms in a molecule can exist, namely, N₄ shaped as a rectangle and regular tetrahedron and N₆ with a shape remotely resembling an “open book.” The bond lengths and bond and torsion angles in each of these molecules have been reported.     

Reactions of platinum(O) and palladium(O) complexes with mercury(II) compounds: New methods for the synthesis of organic platinum and palladium derivatives

Conclusions A new group of reactions between Pt^o and Pd^o complexes with organic and heteroorganic Hg^II compounds was found and studied. The reaction involves the insertion of L_nM^o into the bond between mercury and the heteroelement. The bimetallic compounds formed may be isolated or undergo immediate demercuration leading to divalent platinum and palladium -derivatives, depending on the nature of the substituents and ligands and reaction conditions.Article published by a decision of the editorial board of this journal, dated December 3. 1981.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2069–2089, September, 1982.     

On the synthesis of xenon(VI) fluorobismuthate(V)

The reaction between bismuth pentafluoride and excess liquid xenon hexafluoride yields a white diamagnetic solid XeF₆.BiF₅. On the basis of its Raman and infrared spectra the 1:1 compound could be formulated as XeF₅⁺BiF₆^-. The Strong fluorine-bridge interaction between cation and anion distorts the anion from O_h symmetry.     

Mass spectrometry of polyaromatic sulfur compounds in the presence of palladium(II)

Electrospray ionization mass spectrometry (ESI-MS) and tandem MS in an ion trap were used to explore the reduction of a PdCl(2) solution and the role of the metal in the formation of organosulfur radical cations. For tandem MS experiments, a 32 Da neutral loss (M - S), was observed for dibenzothiophene, thianthrene and benzonaphthothiophene, whereas both 32 and 33 Da neutral losses were observed for 2-methyldibenzothiophene and 4,6-dimethyldibenzothiophene. The effects of several variables on the formation of molecular ions or molecular fragments were studied to optimize radical cation formation, including the concentration ratio between PdCl(2) and sulfur and the collision energy. Electrochemical and chromatographic data were used to provide an explanation for the relative sensitivity observed for a mixture of polyaromatic sulfur heterocycles.