Anodic Protection. Theory and Practice in the Prevention of Corrosion.: O.L. Riggs,Jr. and C.E. Locke,Plenum Press,New York, 1981, 284 pp., US$39.50.

The specific adsorption of chloride, bromide, iodide, azide, and thiocyanate has been studied at an electropolished polycrystalline silver-aqueous interface using differential capacitance measurements. For chloride, bromide, and azide, quantitative estimates of the surface concentration of specifically adsorbed anions were obtained from capacitance-potential data in mixed fluoride electrolytes having a constant ionic strength of 0.5. The dependence of the measured capacitance upon the ionic strength of sodium fluoride was also investigated in order to check the behavior of the polycrystalline surface in comparison with the predictions of conventional double-layer models. Estimates of the specifically adsorbed charge densities of chloride, bromide, and thiocyanate anions were also obtained from a “kinetic probe” technique which entailed monitoring the response of the outer-sphere reduction rate of CO(NH₃)₅F²⁺ and Co(NH₃)₆³⁺ to the addition of the appropriate adsorbing anion. At the average potential of zero charge for the polycrystalline silver surface, the standard free energies of adsorption ? Δ₃^o for chloride, bromide, and azide were found to be within ca. 5 kJ mol^?1 of the corresponding quantities obtained at mercury electrodes. However. significantly greater increases in ? Δ₃^o in the sequence Cl^? < N₃^? < Br^? are seen at silver compared to mercury. Electrochemical roughening in chloride media, giving silver surfaces displaying intense surface Raman scattering, yields only minor changes in the surface concentration of specifically adsorbed chloride anions.     

Reagents for organic synthesis,vol. 4 : By Mary Fieser and Louis F. Fieser,Wiley-Interscience,New York, 1974, 660 pp., $24.95.

NMR studies on H₂ M₃ (CO)₉ (RR′C₂) (M = Ru, Os) have shown that at least three separate fluxional processes are occurring; a mechanism involving olefin rotation has to be considered.     

Progress in inorganic chemistry,vol. 19 : Edited by S.J. Lippard,Interscience-John Wiley & Sons,New York, 1975, 367 pages, $22.50.

The preparations of [Pt(CH₃)₂(OH)₂(H₂O)₂]_n and the ion Pt(CH₃)₂²⁺(ag) are described. Their reactions with a variety of ligands are outlined.     

The Physical Chemistry of Membranes : M.E. Starzak. Academic Press,Orlando, 1984, x + 334 pp., US$47.00. Equations of Membrane Biophys. N. Lakshminarayanaiah,Academic Press,Orlando, 1984, x + 426 pp., £53.50

Changes in the adsorption profiles of 1,4-naphthohydroquinone (NHQ) on smooth polycrystalline platinum electrodes in aqueous 1 M HClO₄ brought about by varying levels of surface-active organic impurities [typified by hydroquinone (HQ) and benzene] have been studied by thin-layer electrochemical techniques, 10^?5M HQ is sufficient to alter the adsorption profile of NHQ; above 10^?4M HQ, the packing density transitions prominent from pure NHQ solutions were completely suppressed. Similar results were obtained when benzene was used as the contaminant. Packing density measurements indicated that the subject surface-active impurities inhibited formation of flat-, but not edge-, adsorbed NHQ; this is in agreement with data from a previous study [M.P. Soriaga, J.H. White, D. Song and A.T. Hubbard, J. Electroanal. Chem., 171 (1984) 359] which showed that low-levels of iodide, a surface-active anion, enforced formation of edge-adsorbed NHQ even at (low) concentrations where flat-adsrobed species would have formed from pure NHQ solutions. The presence of surface-active impurities may help account for the profound differences in adsorption measurements reported in the literature for various aromatic compounds.     

Inorgranic Reaction Mechanisms,Volume 3 (A Specialist Periodical Report of the Chemical Society,London), J. Burgess,Senior Editor,The Chemical Society,London, 1974, xvii + 500 pages, ß14.00.

A polyphosphite obtained from poly(methallyl alcohol), when treated with rhodium(I) derivatives, affords soluble and insoluble complexes, some of which are hydrogenation catalysts for olefins in toluene suspension.     

Inorganic Syntheses,Volume XXI : edited by J.P. Fackler,Jr., Wiley-Interscience,New York, 1982, xvii + 215 pages, £29.25.

The 1/1 reaction of Et₂Zn with N-t-butyliminopropanone (t-BuNC(H)C(Me)O) leads to quantitative formation of dinuclear [EtZ$\text{n(Et)(t-Bu)NC(H)=C(Me)O}$]₂ via ethyl transfer within the unstable Et₂Zn(t-BuNC(H)?C(Me)O) complex. An X-ray structure determination has shown the product to have a dinuclear structure involving a N,O-chelate bonded [Et(t-Bu)NC(H)C(Me)O]^? mono-anionic ligand and a central four membered Zn₂O₂ ring formed by intermolecular ZnO coordination. Hydrolysis of this zinc complex gives a quantitative yield of N-t-butyl-N-ethylamino propanone, which upon reaction with Et₂Zn reforms the dinuclear zinc complex.     

Reagents for Organic Synthesis : Vol. 5; by M. Fieser and L.F. Fieser,Wiley-Interscience,New York/London/Sydney/Toronto, 1975, 864 pages, $32.15, £16.15.

Phosphorus-31 NMR and X-ray crystallography show that the two similar chelating triphosphine ligands PhP(CH₂CH₂PPh₂)₂(2,2-P₃) and PhP(CH₂CH₂CH₂ PPh₂)₂(33-P₃) form cobalt(I) complexes having trigonal-bipyramidal and square-pyramidal structures, respectively. The structures and PP coupling constants of [Co(33-P₃)(P(OMe)₃)CO]BF₄·1THF and [Co(22-P₃)(P(OMe)₃)₂]BF₄ are given, and the change from square-pyramidal geometry in [Co(33-P₃)P(OMe)₃)CO]⁺ to trigonal-bipyramidal in [Co(22-P₃)(P(OMe)₃)₂]⁺ may be rationalized in terms of a decreased “chelate bite angle” for the PhP(CH₂CH₂PPh₂)₂ ligand.     

Metal Ions in Biological Systems,Volume 4. Metal Ions as Probes; : edited by Helmut Sigel,Marcel Dekker,New York, 1974, xii + 261 pages, $24.75.

Trends in ³¹P NMR coordination shifts for the complexes M(CO)₃BrL₂, [M(CO)₃L₂(NCMe)]⁺, MeC₅H₄Mn(CO)L₂ and [MeC₅H₄Mn(CO)₂]₂L₂ (M = Mn and Re;L₂ = Ph₂PCH₂PPh₂, Ph₂PCH₂CH₂PPh₂ and Ph₂PCH₂CH₂AsPh₂) are discussed.     

Metallorganische diazoalkane : XIII. Reaktionen metallorganischer diazoalkane mit P(NMe2)3 zu metallorganischen phosphazinen LnM(R)CNNP(NMe2)3

Staudinger reactions of 20 organometallic diazoalkanes and of their parent compounds CH₂N₂, HC(N₂)CO₂Et, HC(N₂)C(O)Me and HC(N₂)C(O)Ph with a strong basic phosphine P(NMe₂)₃ are described and were classified into five groups 1–5 of different reactivity.Mono-diazomethanes L_nMCHN₂ (for L_nM = Me₃Si, Me₂As) react to give (cis, trans) isomers of the corresponding phosphazines L_nMC(H)NNP(NMe₂)₃; a stepwise reaction of functional diazogroups in organometallic bis-diazoalkanes, e.g. Hg[C(N₂)CO₂Et]₂, has been observed.Different reactivity of organometallic diazoalkanes cannot be rationalized by known spectroscopic data but can be interpreted by steric effects. In analogy to reactions of isoelectronic azides a transition state of the Staudinger reaction is suggested with an attack of the basic phosphine at the electrophilic α-nitrogen atom and following rearrangement into the N_β-Staudinger adduct.Trimethylgermaniumdiazomethane, Me₃GeCHN₂, was obtained as a novel monosubstituted organometallic diazoalkane and is fully characterized.     

Cumulative author index: Vol. 126(1977)–150(1978)

The synthesis of μ-[phenyl(dicyclohexylphosphonio)ethenidyl]-μ-(diphenylphosphido)hexacarbonyldiiron, Fe₂(CO)₆[CC(PCy₂H)Ph](PPh₂) via nucleophilic attack by dicyclohexylphosphine at the β-carbon atom of the σπ-acetylide in Fe₂(CO)₆(CCPh)(PPh₂) is described. This complex, which contains a one-carbon 3-electron bridging ligand has been characterised by microanalysis, infrared, mass, Mössbauer and ³¹P NMR spectroscopy and by a single crystal X-ray structure determination. Crystals are monoclinic, space group P2₁/c with a 10.932(3), b 8.983(2), c 38.644(6) Å, β 94.48(2)°. With four molecules per unit cell and a formula weight of 764.4, the calculated density of 1.342 g cm^?3 agrees with the measured value of 1.34 g cm^?3. The structure was solved by heavy atom methods and refined by least squares techniques with iron and phosphorus atoms having anisotropic thermal parameters, to R and R_w values of 0.068 and 0.075 respectively. In the binuclear molecule an ironiron bond of length 2.550(2) Å is bridged by a diphenylphosphido group and the carbon atom of an unusual dipolar ligand Cy₂(H)P⁺C(Ph)C^?. In the bridging one-carbon-3-electron ligand the coordinated carbon atom is trigonal and the atoms P(1), C(8), C(31), C(7) are virtually coplanar. Structural parameters are compared with those of other complexes containing bridging one-carbon, 3-electron and two-carbon, 3-electron ligands. Nucleophilic attack by phosphorus and nitrogen nucleophiles on σπ-acetylides appears to be a general route to these ligands.     

Advances in inorganic chemistry and radiochemistry,vol. 18: Edited by H.J. Emeléus and A.G. Sharpe,Academic Press,New York/San Francisco/London, 1976, vii + 414 pages, $35.50.

The catinic complex trans-[FeCl(CCHPh)(depe)₂]⁺ (depe = bis(diethylphosphino)ethane has been prepared by interaction of trans-[FeCl₂(depe)₂] with penylacetylene in methanol solution in the presence of NaX (X = BPh₄ or PF₆.     

Topics in current chemistry volume 92 : (Managing Editor,F.L. Boschke), Springer-Verlag,Berlin-Heidelberg-New York, 1980, 178 pages.

A novel route for the synthesis of metal—tetraazadiene complexes is reported involving the direct transfer of a Ar₂N₄ ligand from [Ni(Ar₂N₄)₂] to Ni⁰ and Pt⁰ centres in the presence of t-butylisocyanide, resulting in [M(Ar₂N₄)(t-BuNC)₂] species. For M  Pt the latter complexes can also be prepared by reaction of the zerovalent isocyanide complex with the appropriate azide or by addition of t-BuNC to [Pt(Ar₂N₄)(COD)].     

Polarographic studies on bipyridine complexes: III. Polarography of tris(2,2′-bipyridine) complexes of chromium(I), chromium(0), vanadium(0), titanium(0) and molybdenum(0)

Polarograms and cyclic voltammograms for tris(2,2′-bipyridine) complexes of V(0), Cr(0), Cr(I), Ti(0) and Mo(0) in N,N-dimethylformamide are reported. The reversible half-wave potentials for the following redox systems in lower oxidation states are determined: Cr(?I)/Cr(?II), Cr(?II)/Cr(?III), V(I)/V(0), V(0)/V(?I), V(?I)/V(?II), V(?II)/V(?III), Ti(0)/Ti(?I), Ti(?I)/Ti(?II), Mo(?I)/Mo(?II) and Mo(?II)/Mo-(?III). On the basis of the half-wave-potential shift caused by the methyl substitution of ligands, it is concluded that each excess electron of the reductant species of the redox systems, V(bipy)₃^?/V(bipy)₃^2?, Cr(bipy)₃/Cr(bipy)₃^?, Cr(bipy)₃^?/Cr(bipy)₃^2? and Cr(bipy)₃^2?/Cr(bipy)₃^3? (bipy=2,2′-bipyridine), occupies a ligand π^*-orbital and that of the V(bipy)₃²⁺/V(bipy)₃⁺ and V(bipy)₃⁺/V(bipy)₃ systems a metal t_2g-orbital. The apparent π-character of the excess electron of the redox systems Cr(bipy)₃⁺/Cr(bipy)₃ and V(bipy)₃/V(bipy)₃^? is discussed. It is pointed out that the relative electron affinities of trisbipyridine complexes can be determined from the half-wave potential data. The lowest π^*-orbitals of V(bipy)₃^?, Cr(bipy)₃ and Fe(bidy)₃²⁺ become higher in this order. This suggests that the electrostatic interaction between a π^*-electron and the residual charge on the central metal ion predominantly accounts for the observed π^*-level shift.     

Electrodes of Conductive Metallic Oxides : Part B. S. Trasatti (Editor). Studies in Physical and Theoretical Chemistry,Vol. 11. Elsevier,Amsterdam, 1981, xvi + 366 pp. $72.25, Dfl.170.00.

Chronoamperometry, chronocoulometry and chronopotentiometry were applied to measure apparent diffusion coefficients, D_app, for Mo(CN)₈^4?, W(CN)₈^4?, Fe(CN)₆^3? and Fe(CN)₆^4? bound electrostatically within coatings of protonated poly(4-vinylpyridine) on graphite electrodes. The relative advantages of the three experimental techniques are discussed. Values of D_app for the incorporated anions showed a strong decrease as the anion concentration within the coating increased until a steady value was reached at anion concentrations near 1 M. Some of the factors that may contribute to this behavior are discussed.     

William B. Guenther,Chemical Equilibrium. A Practical Introduction for the Physical and Life Sciences,Plenum Press,New York-London (1975), 248 pp., price U.S. $ 23.40

The adsorption and related interfacial behavior of uracil at a mercury electrode/electrolyte solution interface has been studied by differential capacitance and maximum bubble pressure methods in 0.5 M NaF plus 0.01 M Na₂HPO₄ buffer pH 8.0. At concentrations below 24 mM uracil is adsorbed in a flat orientation on the electrode surface and occupies an area of 63 Ų. At higher concentrations and at potentials close to ?0.5 V the adsorbed uracil undergoes a reorientation and adopts a perpendicular stance on the electrode surface where it occupies an area of 39 Ų. In this perpendicular stance uracil undergoes a strong intermolecular stacking interaction with its neighbors similar to that observed between adjacent pyrimidines in nucleic acids.     

Rapid spectrophotometric determination of cerium(IV), arsenic(III), and nitrite with perphenazine

Perphenazine dihydrochloride, PPN, is proposed as a new reagent for the spectrophotometric determination of cerium(IV), arsenic(III), and nitrite. The reagent forms a red-colored species with cerium(IV) instantaneously in 3.5–5.5 M phosphoric acid medium. The red species exhibits maximum absorbance at 516 nm. A 15-fold molar excess of PPN is necessary for the full development of the color intensity. Beer's law is obeyed over the cerium concentration range 0.4–20 ppm and Sandell's sensitivity is found to be 0.016 μg/ cm². The effects of acidity, time, order of addition of reagents, temperature, reagent concentration, and diverse ions are reported. The proposed method offers the advantages of good sensitivity, simplicity, rapidity, selectivity, and a wider range of determination without the need for heating or extraction. Arsenic(III) and nitrite are also indirectly determined. The method is extended to the determination of cerium content in synthetic mixture corresponding to misch metal.     

Analytical characterization of CuInS(2) semiconductor material

Systematic analytical procedures have been developed for determination of the stoichiometry of CuInS(2) and estimation of trace elements, including dopants and impurities, in the material. Samples of CuInS(2) are digested in an oxidizing acid to ensure completely transformation into Cu(2+), In(3+) and SO(4)(2-) ions. The stoichiometry determination is made sequentially by controlled potential electro-deposition of copper, followed by its EDTA titration, titrimetric determination of indium and gravimetric determination of sulphate, in a single sample solution. The relative errors for the determination of Cu and In are found to be -0.08% and +0.11% respectively, fulfilling the requirement for accurate stoichiometry assessment; that for S is -0.66%, which though rather high is still acceptable. For the determination of trace elements in CuInS(2), multistage combined procedures are employed. Cu in the sample solution is removed by electro-deposition and In by extraction of HInBr(4) with isopropyl ether, then most of the trace elements are finally determined by atomic-absorption spectrometry, and the rest by neutron-activation analysis. All the steps involved in the procedures have been optimized by using radioisotopes as tracers. By the procedures developed, a wide range of trace elements in CuInS(2), down to submicrogram level, can be determined.     

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.     

Group IB organometallic chemistry: XXXIII. ArAuPPh3, ArAu(CNR), (ArAu)n and Ar4Cu2Au2 compounds in which the aryl group contains 2-MeO, 2,6-(MeO)2, 2-Me2N, 2-Me2NCH2 and (S)- or (R)-2-Me2NCHMe substituents as potential ligands

The synthesis and structural characterization by ¹H NMR and ¹⁹⁷Au Mössbauer spectroscopy as well as by chiral labelling of the built-in ligands of three different types of arylgold(I) compounds is described.¹⁹⁷Au Mössbauer data revealed that the benzyl- and arylgold(I) triphenylphosphine complexes which bear potential coordinating substituents at an ortho position still contain linearly coordinated Au^I with 2c-2e gold(I)carbon bonds. The observation of isochronous NME resonances in (S)-2-Me₂NCH(Me)C₆H₄AuPPh₃ confirms that no additional intramolecular AuN coordination occurs in solution. Preliminary results of an X-ray diffraction study of 2,6-(MeO)₂C₆H₃AuPPh₃ are reported (R = 0.040, PAuC₁ angle 172.6°. Unsymmetrical AuC₁C₂ and AuC₁C₆ angles of 126.4 and 117.4°, respectively).Pure, uncomplexed arylgold(I) compounds have been isolated from the reaction of diarylgoldlithium compounds (arylaurates) with trimethyltin bromide. (S)-2-Me₂NCHMeC₆H₄Au has a dimeric structure which most likely consists of two monomeric units associated by intermolecular AuN coordination thus forming a ten-membered chelate ring. The structure of insoluble 2-Me₂NCH₂C₆H₄Au and 2-Me₂NC₆H₄Au are less clear. The former compound probably has a structure similar to (S)-2-Me₂NCHMeC₆H₄Au (IS/QS values for two-coordinate Au^I centers). However, the strongly deviating IS and QS values of 2-Me₂NC₆H₄Au indicate that a polynuclear structure for this compound similar to that proposed for 2-Me₂NC₆H₄Cu cannot be excluded (a polymeric structure containing 2-Me₂NC₆H₄ groups which span three Au atoms by 3c-2e Au₂C bonds and AuN coordination).The mixed Au/Cu cluster (2-Me₂NCH₂C₆H₄)₄Au₂Cu₂ is accessible via the $\text{1}\text{2}$ reaction of (2-Me₂NCH₂C₆H₄)₄Au₂Li₂ with CuI. Molecular weight and ¹H NMR studies point to a tetranuclear structure in solution, while mass spectrometry shows fragment ions with m/e corresponding to (2-Me₂NCH₂C₆H₄)₃Au₂Cu₂⁺, (2-Me₂NCH₂C₆H₄)₃Cu₂Au⁺, (2-Me₂NCH₂C₆H₄)₂CuAu₂⁺ and of (2-Me₂NCH₂C₆H₄)₂Au⁺.