Calculation of polarization energies in some III–VII and IV–VI compounds with stereochemically active (ns)2-ions

The polarization energies of AB compounds, with A a monovalent or divalent cation with an (ns)²-lone pair and B an anion with a noble gas electronic configuration, have been calculated to investigate whether the stereochemical activity of the (ns)²-ion can be understood in an ionic picture. Computations have been performed applying the computer program EWALD. Formal ionic charges and partly estimated polarizabilities have been used. The polarization energy is shown to be predominantly due to cation polarization and may constitute an appreciable fraction of the total lattice energy. Hence, it can play a crucial role in the formation of structures, in which the (ns)²-ion is in a noncentrosymmetrical environment.     

Convenient synthesis of (triphenyl)germyl and (triphenydstannyl substituted allenes

Allenyl-germanes and -stannanes, Ph₃MC(R)CCR′R″ (M = Ge, Sn) can be obtained, generally in excellent yield, through alkylcopper(I)-induced 1,3-substitution of the propargylic chlorides Ph₃MCCCR′R″Cl. In the tin series, however transmetallation is the main process when MeCu, H₂CCHCu or PhCu are used. The allenyl compounds in which R is (trimethylsilyl)ethynyl or 4,4-dimethyl-1,2-pentadienyl can be obtained by using the organozinc compounds instead of the copper(I) compound and using tetrakis(triphenylphosphine)palladium as catalyst.     

Structural researches on organotin(iv) compounds. synthesis and structure of nitratotriphenyl(triphenylphosphine oxide)tin(iv)

A nitrato-complex of organotin(IV) containing triphenylphosphine oxide, Sn(C₆H₅)₃(NO₃) [(C₆H₅)₃PO], has been synthesized and characterized by infrared spectroscopy and X-ray structural analysis. The compound crystallizes in space group P 1¯, with a = 11.817(6), b = 11.086(6), c = 12.471(6), α = 99.6(1),β = 90.8(1), γ = 97.8(1), Z = 2. The structure has been solved from X-ray diffractometer data by Patterson and Fourier methods and refined by least-squares calculations to R = 6.4% for 4301 independent reflections. The structure consists of discrete monomer units in which tin shows trigonal bipyramidal geometry.     

Thermal studies on purine complexes. VII. 8-theophylline derivatives and their silver(I) complexes

Four theophylline derivatives: 8-ethyltheophylline (ETH), 8-isopropyltheophylline (IPH), 8-propyltheophylline (PRH), and 8-phenyltheophylline (FTH) have been synthesized and characterized by spectroscopic techniques and thermal analysis. The melting points of these theophylline derivatives increase with the molecular weight, from 263.8°C (ETH) to 384.7°C (FTH). The values of the fusion enthalpy increase in the same order, from 28.4 kJ mol⁻¹ (ETH) to 36.5 kJ mol⁻¹ (FTH).

The interaction of these theophylline derivatives with Ag(I) has been studied by means of spectroscopic techniques, TG, DTG and DSC. In all cases, the pyrolysis of these compounds gave metallic silver.     

π-Cyclopentadienyl-like derivatives of cobalt: synthesis of indenyl- and fluorenyl-bis(phosphite)-cobalt(I)

The compounds {Co(C₉H₇)[P(OR)₃]₂} (C₉H₇ = indenyl) and {Co(C₁₅H₉)[P(OR)₃]₂} (C₁₃H₉ = fluorenyl) (R = C₂H₅, i-C₃H₇) have been prepared by treating {CoBr[P(OC)₃]₃} with NaC₉H₇ and NaC₁₃H₉, respectively. The ¹H, ¹³C NMR, IR, and mass spectra of the new compounds are discussed. The preparation of {Co(C₉H₇)(CO)[P(OR)₃]} and {Co(C₁₃H₉)(CO)[P)OR)₃]} is also reported.     

The synthesis and structural study of five-coordinate triorganotin(IV) tropolonates and dibenzoylmethanates

The complexes [1,3-diphenyl-1,3-propanedionato]tricyclohexyltin(IV), (tropolonato)triphenyltin(IV), and (tropolonato)tricyclohexyltin(IV) have been prepared for the first time and have been found to be five-coordinate in the solid state. These and related five-coordinate complexes prepared previously have been studied by a variety of physical methods; ¹³C NMR, UV, IR, Raman, dipole moments and the Kerr effect. While all structures are demonstrably five-coordinate, and all chelates bidentate in the solid state, the geometries of two of the complexes in solution appear to vary somewhat from the expected fac or mer. There is evidence from the solution Kerr effect and ¹³C NMR that cyclohexyl derivatives may disproportionate.     

Phosphine substitution and phosphine induced reductive elimination reactions: synthesis of zerovalent ruthenium fluorophosphine complexes from hydrido(acetato)tris(triphenylphosphine)ruthenium(II)

Substitution of PPh₃ from the bidentate acetatohydridoruthenium(II) complex RuH(CH₃OCO)(PPh₃)₃ with various ligands, L, leads to unidentate acetatohydrido compounds with replacement of one, two or all PPh₃ ligands depending on L (L = t-BuNC, PF₂NMe₂, P(OCH₂)₃CMe, P(OMe)₃, dppe). On the other hand acetic acid elimination from RuH(CH₃OCO)(PPh₃)₃ occurs with fluorophosphines to yield zerovalent ruthenium complexes RuL′₅ (L′ = PF₂NMe₂, PF₂NC₄H₈), RuL₄(PPh₃) (L′ = PF₃) and RuL₃(PPh₃)₂ (L′ = PF₃).     

New imine-phosphine chelating agents and their molybdenum(O) derivatives

The aldehyde o-Ph₂PC₆H₄CHO condenses with a variety of functionalized amines to afford several new ligand which form stable mono- and bimetallic complexes with molybdenum(O).     

The synthesis and characterization of neptunium hydroxysulfate,Np(OH)2SO4

Neptunium (IV) hydroxysulfate, Np(OH)₂SO₄, was synthesized using hydrothermal techniques. The X-ray powder diffraction pattern indicates that the compound is isomorphous with the Th(IV) and U(IV) analogs. Cell constants for the three compounds clearly show the effects of the actinide contraction. Visible and near-ir spectra are consistent with the presence of Np(IV) and are compared to spectra of Np(IV) in acidic solution. The ir spectrum contains bands which are assigned to the hydroxy and sulfate groups.     

Studies of layered uranium(VI) compounds. I. High proton conductivity in polycrystalline hydrogen uranyl phosphate tetrahydrate

We have found that hydrogen uranyl phosphate tetrahydrate HUO₂PO₄·4H₂O has a high proton conductivity. The ac conductivity was 0.4 ohm^?1 m^?1 at 290°K measured parallel to the faces of sintered disks of the compound. The activation energy was found to be 31 ± 3 kJ mole^?1. The values of conductivity were between 3 and 10 times lower when measured perpendicular to the disk faces due to preferred orientation of the plate-like crystals. Both the powder and sintered disks are stable in air and insoluble in phosphoric acid solution of pH 2.5. Experiments are described which enable possible grain boundary contributions to the conductivity to be determined in such hydrates. The extrinsic grain boundary contribution to the conductivity was found to be small from experiments in which the pH in a solution cell was varied. The abnormally high bulk H⁺ conductivity thus inferred is attributed primarily to the high concentration of H⁺, which exists as H₃O⁺ in the interlamellar hydrogen-bonded network. A Grotthus-type mechanism of conduction is proposed which involves intermolecular transfer steps (hopping) and intramolecular transfer steps, in comparable numbers, the former facilitated by the high concentration of H₃O⁺ ions in the structure, and the latter most likely facilitated by the high concentration of H-bond vacancies.     

New nitrosyl(perfluorocarboxylato) complexes of the platinum metals

Perfluorocarboxylic acids (R_FCOOH) (R_F = CF₃,C₂F₅ and (for Rh) C₆F₅) react with the species [M(NO)₂(PPh₃)₂] (M = Ru, Os) and [M′(NO)(PPh₃)₃] (M′ = Rh, Ir) to yield new nitrosyl complexes [Ru(OCOR_F)₃(NO)(PPh₃)₂], [OsH(OCOR_F)₂(NO)(PPh₃)₂], [Os(OCOR_F)(NO)₂(PPh₃)₂][OCOR_F], [Ir(OCOR_F)(NO)(PPh₃)₂][OCOR_F] and [Rh(OCOR_F)₂(NO)(PPh₃)₂].     

Cationic cobalt(I) carbonyl complexes containing secondary or tertiary phosphines. A direct synthesis from cobalt(II) salts

Cobalt(I) carbonyl complexes of formula [Co(CO)_n(P)_5?n]ClO₄ (n = 1, 2, 3; P = secondary or tertiary phosphine) have been prepared by reaction of CO under ambient conditions with Co(ClO₄)₂ · 6H₂O and phosphine in isopropyl alcohol. The chemical and spectroscopic properties of these complexes are described and the stoichiometry and mechanism of the carbonylation reaction discussed.     

Electrochemical synthesis of polypyrrole/poly-N-(p-nitrophenyl)pyrrole co-polymer

Copolymers of pyrrole and N-(p-nitrophenyl)pyrrole have been synthesized electrochemically. Cyclic voltammetric studies show that the electroactivities of both nitrobenzene and polypyrrole are apparent in the copolymer. Growth of poly-N-(p-nitrophenyl)pyrrole films is self-limiting an stops at 200 to 300 nm. Copolymerization allows thick and freestanding films incorporating the nitrophenyl moiety to be grown.     

New syntheses of platinum (IV) and platinum (VI) fluorides

γ-Ray and peroxide-initiated additions of dimethylether to F-cyclobutene, F-cyclopentene, and F-cyclohexene give mixtures of $\text{cis-}$ and $\text{trans-}$ adducts in each case, with a clear preference for $\text{trans}$-addition with F-cyclobutene. Selective bromination of the adducts occurs but the position of chlorination depends dramatically on solvent. Fluorination with cobalt trifluoride is very efficient.     

Polarographic analytical determination of Hg(II), Cu(II), Cd(II), As(III), Sb(III), Ti(IV) and U(VI) in the presence of Fe(III)

The analytical determination of Hg(II), Cu(II), Cd(II), As(III), Sb(III), Ti(IV) and U(VI) in the presence of Fe(III) and 1 M H₂SO₄ are investigated using the polarographic technique. The wave corresponding to the reduction of Fe(III) to Fe(II) was found to be completely suppressed by the addition of 1% pyrogallol. Thus, different mixtures of these elements, viz. Hg(II), Cu(II), Cd(II), As(III) and Fe(III)-mixture (A), Cu(II), Cd(II), Sb(III), As(III) and Fe(III)-mixture (B), and Cu(II), Cd(II), Ti(IV), U(VI) and Fe(III)-mixture (C), were quantitatively determined using 1% pyrogallol and 1 M H₂SO₄ as supporting electrolyte. The i₁/c results give excellent correlations in each case, as indicated from the results of leastsquares regression analysis.     

The synthesis and reactivity of ferrocenyloxy)-2-tetrahydropyran

Ferrocenylboronic acid was prepared in good yield via the base hydrolysis of ferrocenylboron dibromide. The ferrocenylboronic acid was converted into hydroxyferrocene which was treated with 2,3-dihydropyran to give (ferrocenyl oxy)-2-tetrahydropyran. Lithiation of this pyran gave the corresponding 2-lithiated ferrocene, which was used to prepare some 1,2-disubstituted ferrocenes including 1-carboxy-2-acetoferrocene (“ferrocenyl-aspirin”).     

Studies of layered uranium(VI) compounds. III. Structural investigations of hydrogen uranyl phosphate and arsenate tetrahydrates below the respective transition temperatures of 274 and 301°K

The layered hydrates HUO₂PO₄·4H₂O (HUP), and HUO₂AsO₄·4H₂O (HUAs), which are protonconducting solid electrolytes above the conductivity transitions at 274 and 301°K, respectively, have been shown, using powder X-ray diffraction, to change from tetragonal to orthorhombic symmetry below these temperatures. For HUP the unit-cell dimensions were a = 6.985(5) and c = 17.45(1)Å at 290°K, and a = 6.966(5), b = 7.004(5), and c = 17.43(1)Å at 260°K. The values for HUAs were a = 7.150(2) and c = 17.608(5)Å, at 305°K, and a = 7.128(2), b = 7.168(2), and c = 17.613(5)Å at 293°K. The enthalpies of these displacive-type transitions were found from differential scanning calorimetry to be less than 0.5 kJ per mole of water for both compounds. Such a small value indicates that the rigid-like water lattices existing below the transitions do not become liquid-like above the transitions. The infrared spectra of HUP and HUAs both above the transitions, and down to 80°K, showed clear evidence of the presence of H₃O⁺ ions, showing that the conductivity transitions are not caused by a loss of carriers. Rather, the antiferroelectric ordering, known to exist for HUAs, would appear to cause the conductivity drop. Upon this indication of ordering within the water layers, two possible related H-bond ordered structures have been proposed which are consistent with the observed twinning behavior and cell symmetry. The same ordered structures are suggested for HUP from our observations of the twinning behavior.     

Stability and thermodynamics of La(III)-, Pr(III)-, Nd(III)-, Gd(III)- and Eu(III)-p-nitrobenzaldehyde thiosemicarbazone systems

Three complexes containing bidentate N-2,3-dimethylphenylglycine, (2,3-HDPG), N-2,4-dimethylphenylglycine, (2,4-HDPG) and N-2-ethylphenylglycine, (2-HEPG) acids have been prepared and characterized. These compounds have the general formula Zn(2,3-DPG)₂·2 H₂O, Zn(2,4-DPG)₂ and Zn(2-EPG)₂·2 H₂O, respectively. The structure of the complexes as inferred from their chemistries have been found to be compatible with the infrared spectral data. The thermal behaviour of these complexes has been studied from their TG, DTG and DSC diagrams obtained in a dynamic atmosphere of pure air. Heats of dehydration have been calculated from DSC curves.     

Alkoxide attack at carbonyl and hydrosulphide attack at isocyanide in the mixed carbonyl-isocyanide cation [OsCl(CO)2(CNR)(PPh3)2]+. A new synthesis of π-bound isothiocyanate (RNCS) complexes

[OsCl(CO)₂(CNR)(PPh₃)₂]⁺ (R = p-tolyl) reacts with OMe^? to give OsCl(CO₂Me)(CO)(CNR)(PPh₃)₂ but reaction with SH^? produces the π-bound p-tolylisothiocyanate complex, Os(η²-SCNR)(CO)₂(PPh₃)₂, which can be protonated or methylated at N to yield complexes containing bidentate thiocarboxamido-ligands.