Showing papers in "Journal of Inorganic and Nuclear Chemistry in 1972"

Abstract: The i.r. and PMR spectra of 28 N-aryl salicylaldimines are reported. Assignments of characteristic i.r. bands are derived by 15N-labelling of N-p-tolylsalicylaldimine. The PMR spectra establish that the bases exist in the phenol-imine form at room temperature in deuterochloroform and that eletron withdrawing N-aryl substituents reduce the magnetic shielding of the hydroxyl proton. The i.r. spectra of 38 Co(II), Ni(II), Cu(II) and Zn(II) chelates derived from the salicylaldimines are discussed. Assignments are based on 15N-labelling of the Cu(II) complex of N-p-tolylsalicylaldimine. Support for the νCuN assignments in the i.r. spectra of the Cu(II) chelates is provided by observing the frequency shifts induced by metal ion substitution and by varying the N-aryl substituents. Electron withdrawing substituents shift νCuN to higher frequencies which is consistent with substituent-induced Cu → N π-bonding.

Abstract: The vibrational spectra of the molecular M6+O6 (M = Mo, Te, W) group in ordered perovskites of the type Ba2M2+M6+O6 are reported. These groups have symmetry Oh, whereas their site symmetry is also Oh. An assignment of the internal vibrations is presented.

Abstract: The kinetics of heterogeneous isotopic exchange of phosphate between 32P-labelled dilute orthophosphate solutions and Fe(III) phosphate complexes on the surfaces of goethite (α-FeOOH) crystals in dilute suspension are described by the Elovich Equation. Concentration-independent rate constants are obtained at 25° for the pH range 2·6–12. The reference states for the rate constants are defined with respect to an approximation for the distribution of activation energies for exchange. Rates of exchange are first order with respect to the concentration of Fe(III) phosphate surface complexes, show little or no dependence on the concentration of phosphate in solution, and are subject to acid-base catalysis involving fractional powers of H+ and OH− concentrations with a minimum rate at pH 9·0. The inert character of Fe(III) phosphate complexes is attributed to the formation of a briding ligand structure in binuclear complexes on the predominantly-exposed (100) crystal surfaces. The rate-determining step is postulated to be SN1 dissociation or SN2 bimolecular solvolysis of phosphate from Fe(III) co-ordination, in which the mechanism of catalysis is related to a hydrogen bonding stabilisation of the transition state.

Abstract: ZrMo 2 O 7 (OH) 2 (H 2 O) 2 was prepared in microcrystalline form by refluxing precipitated zirconium molybdate gels in 1–4M HCl. Macroscopic single crystals have been grown under hydrothermal conditions. In their amorphous, precipitated-gel form the gels are known to function as cation-exchangers. The crystal structure of zirconium molybdate was determined from integrated precession photographs using MoKα radiation. Crystal data: tetragonal space group 14 1 cd (No. 110); a = 11·45±0·01 A c = 12·49±0·01 A (25°C); ϱ obs = 4·0±0·1, ϱ calc = 3·774 g . cm −3 . The structure, refined by block diagonal least squares to (conventional) R = 0·037, is a three-dimensional network of cross-linked chains built-up of quite regular [ZrO 3 eq (OH 2 eq O 2 ax ]-pentagonal bipyramids and distorted cis -MoO 4 (OH)(H 2 O-octahedra. The structure is held together primarily by [Zr-O (and OH)-Mo]-bridges; chains of hydrogen bonds involving the oxo-, hydroxo-, and aquo- groups play a secondary role. Intermatomic distances and angles are normal, however, one oxygen atom has unusual coordination geometry; it forms a three-way bridge in a (symmetry-required) planar [ZrOMo 2 ]-moiety. The structure provides a rationale for the thus far observed physical and chemical properties.

Abstract: Excitation functions have been measured for a number of nuclear reactions of nickel isotopes with 5–56 MeV protons. The following peak cross-sections were determined: 58 Ni-( p , pn )-260 mb, ( p , p 2 n )-21 mb, ( p ,2 p )-540 mb, ( p ,2 pn )-350 mb, p , α )-40 mb, ( p ,2 p 2 n )-63 mb, ( p , αpn )-38 mb; 60 Ni-( p , n )-320 mb, ( p ,2 pn )-180 mb, ( p ,2 p 2 n )-200 mb, ( p , αn )-72 mb, ( p , α 2 n )-14 mb; 61 Ni-( p , n )-480 mb; 62 Ni-( p , n )-480 mb; 64 Ni( p , n )-670 mb. Cross-sections for the following reactions were determined up to E p = 56 MeV: 58 Ni-( p , αp 2 n ), ( p , α 2 pn ); 60 Ni-( p , p 3 n ), ( p , α ), ( p ,2 p 3 n ), ( p , α 2 pn ); 61 Ni-( p , α ). Measurements were also made for the cross-sections of 60 Co formation from natural nickel.

Abstract: The crystal structure of tris(acetylacetonato)(1,10-phenanthroline) europium(III), Eu(C 6 H 7 O 2 ) 3 (C 12 H 8 N 2 ), has been determined by single crystal X-ray diffraction techniques. A total of 4697 independent reflections were measured by counter methods and 2855 were considered to have an intensity significantly above background. The complex crystallizes in the monoclinic space group P2 1 c with four molecules per unit cell. The cell dimensions are a 0 = 9·670(8) A , b 0 = 21·339(5) A , c 0 = 16·497(5) A and β = 116° 11(10)′. The observed and calculated densities were found to be 1·37 g/cm −3 . The structure was refined by least-squares methods and a conventional R factor of 0·0334 was obtained for 1123 reflections. The calculated R for all 2855 observed reflections is 0·065. The molecules are monomeric and the europium ion is coordinated to eight ligand atoms which form a distorted square antiprism. Six EuO bond lengths average 2·397 A and two EuN bond lengths average 2·643 A. The distortion of the antiprism reduces the symmetry sufficiently for all characteristic electronic transitions to become allowed, and the full multiplicities are seen in the emission spectrum.

Abstract: A study of the photoaquation of hexachloroplatinate(IV) to pentachloroaquoplatinate(IV) in 1 F perchloric acid medium has revealed that the overall quantum yield for this reaction is substantially greater than unity for irradiation at 270 and 365 nm, except when dissolved chlorine is present, and that the primary photoprocess is redox in nature. Accordingly, a chain mechanism involving homolytic bond cleavage of hexachloroplatinate(IV) to yield atomic chlorine and a labile platinum(III) species is proposed to account for the observed behavior. Support for the suggested reaction pathway includes evidence based on chemical scavenging experiments for the presence of chlorine atoms. In contrast to previous work on the photohydrolysis of hexabromoplatinate(IV), which occurs by a non-chain, non-redox process and which involves the lowest energy ligand-field triplet state, our results indicate that the charge-transfer singlet state is active in the photoaquation of hexachloroplatinate(IV).

Abstract: Eight new complexes are reported: [Cu(C 9 H 4 N 2 ) 2 (SCN)2], [Cu(C 9 H 4 N 2 ) 2 (SeCN)]NO 3 , [Ni(C 9 H 14 N 2 ) 2 (NCS)(NO 3 )], [Ni(C 9 H 14 N 2 ) 2 (NCSe)(NO 3 )], [Ni(C 16 H 20 N 2 ) 2 (NCSe) 2 ], [Ni(C 16 H 20 N 2 ) 2 (NCS) 2 ], [Co(C 16 H 20 N 2 ) 2 (NCS) 2 ], and [Co(C 16 H 20 N 2 ) 2 (NCSe) 2 ]. Their structures are deduced from reflectance spectra at room temperature and at liquid nitrogen temperature, visible spectra in solution, i.r. and far i.r. spectra, magnetic susceptibility measurements, and conductivity measurements in DMF. The dibenzylethylenediamine complexes are all octahedral; the benzylethylenediamine complexes are tetragonal; and all of the complexes are high spin. [Cu(C 9 H 14 N 2 ) 2 (SeCN)]NO 3 is the first copper(II) complex that we know of with a bridging SeCN group. A method of distinguishing between N-bonded and S- or Se-bonded SCN or SeCN groups, based on far i.r. spectra, is suggested.

Abstract: The combination of two bidentate ligands, the acidic thenolytrifluoroacetone and the Lewis base phenanthroline or dipyridyl, produces a very strong synergic effect in solvent extraction of lanthanides and bivalent transition metals. The stability constants of the mixed adducts have been determined in benzene, cyclohexane, carbon tetrachloride and chloroform at 25°C. In some cases, values of enthalpy and entropy changes associated with the formation of the synergic adducts have been derived from stability constants calculated at different temperatures.

Abstract: The adsorption from different solutions of caesium, rubidium, potassium, sodium, lithium, silver and mercury (I) on zinc ferrocyanide has been studied. The preparation of the adsorber and its characterization are presented and discussed. The sorption of the alkali metals appears to proceed by an ion-exchange mechanism in NH4NO3 solutions. In HNO3 solutions oxidation to zinc ferricyanide and the destruction of the adsorbed species influence the behaviour of the cations.

Abstract: The electronic, ESR and i.r. spectra of a series of Cu(en) 1 X 2 , z H 2 O and Cu(bipy) 1 X 2 , z H 2 O type complexes, where X involves various anions, are reported. By correlating the three types of spectral data the local molecular structures of the copper(II) ions present in the different complexes are tentatively predicted.

Abstract: The complexes formed in the extraction of divalent cobalt, nickel and copper from sulphuric acid solutions by di-(2-ethylhexyl)-phosphoric acid (DEHPTA; HX) have been examined by measurements of apparent mol. wt and magnetic moments, electronic and i.r. spectrophotometry and thermal analyses. For the copper complex, the electron spin resonance spectrum was investigated. It is concluded that the DEHPA complexes of divalent cobalt, nickel and copper have tetrahedral, octahedral and square-planar structures with compositions CoX2.2H2O, (NiX2.2H2O)3 and (CuX2)3 respectively.

Abstract: High efficiency extraction chromatographic columns containing di(2-ethylhexyl)orthophosphoric acid (HDEHP) as the stationary phase and Celite as the inert support were prepared by a slurry packing method. Column performance was studied as a function of particle size of the support, liquid loading of HDEHP, temperature, column cross-sectional area and bed length by measuring the plate height, H, as a function of mobile phase velocity, ν, for the elutions of Cf(III) and Cm(III). In order to determine the major causes of band spreading for the elution of Cf(III), self-diffusion coefficients of Eu(III) were measured in dilute HNO3 and undiluted HDEHP as a function of temperature. H vs ν data were analyzed in terms of the reduced plate height and velocity. Comparison of calculated and experimental H vs ν and H vs capacity factor, k′, curves showed that the slow rate of extraction of Cf(III) from the stationary to the mobile phase was the major cause of band spreading at 25°C, whereas, flow phenomena were the major causes of band spreading at 75°C.

Abstract: The reaction of several variously substituted pyridines with bis(acetylacetonato)oxovanadium(IV), VO(ACA)2, has been studied. The complexes were isolated in the solid form, and it appears from their i.r. spectra that, depending on the pyridine substituent, the complexes exist as either cis- or trans-isomers (with reference to the acetylacetone rings). This structural isomerism has been confirmed by an X-ray crystallographic study.

Abstract: The ion exchange behavior of α-zirconium phosphate crystals titrated with potassium ion and the behavior of the potassium-exchanged forms titrated with HCl has been examined. The replacement of protons by potassium ion takes place in two stages. In the first stage, the α-ZrP crystals are converted to Zr(KPO4)(HPO4)·H2O and this reaction is followed by replacement of the second proton to yield Zr(KPO4)2·3H2O. The reactions are not reversible as solid solutions of hydrogen ion in the potassium phases are formed on addition of dilute hydrochloric acid to the potassium-exchanged phases. The dehydration behavior of the exchanged forms was also determined. It is also shown that the approach to equilibrium is very slow and explanations for this behavior are presented.

Abstract: Complexes formed by interaction of excess 2,6-lutidine N-oxide (LNO) with various metal nitrates and thiocyanates were prepared and characterized by means of spectral, magnetic and conductance studies, as follows: [M(LNO) 6 ](NO 3 ) 3 (M = Cr, Fe), involving distorted octahedral complex cations and ionic nitrate; [M(LNO) 2 (ONO 2 )(O 2 NO)] (MMn, Co, Ni, Zn), pentaco-ordinated neutral complexes, containing one mono- and one bi-dentate nitrato groups; [Cu(LNO) 2 (ONO 2 ) 2 ], planar, and [Cd(LNO) 4 (ONO 2 ) 2 ], hexaco-ordinated, with monodentate nitrato ligands; [(LNO)(SCN) 2− Mg(LNO) 2 Mg(NCS) 2 (LNO)], dimeric, pentaco-ordinated, LNO-bridged, with N-bonded thiocyanate; [(NCS) 2 Hg(LNO) 2 Hg(SCN) 2 ], dimeric, tetrahedral, LNO-bridged, with S-bonded thiocyanate; [(LNO) 2 (SCN)M(NCS) 2 M(NCS)(LNO) 2 ] (M  Co, Ni), pentaco-ordinated dimers with terminal isothiocyanato as well as bridging NCS groups; and [Cu(LNO) 2 (NCS) 2 ] x , hexaco-ordinated polymeric complex with bridging NCS ligands. [Fe(LNO) 6 ](NO 3 ) 3 is the first example of a compound characterized by the Fe III O 6 moiety and exhibiting spin-free-spin-paired equilibria; the polymeric [Cu(LNO) 2 (NCS) 2 ] x exhibits a subnormal magnetic moment. The influence of the steric effects of LNO on the types of complexes formed is discussed.

Abstract: Cu(I) halide complexes of bis(diphenylphosphino)methane (DPM) and 1,2-bis(diphenylphosphino)ethane (DPE) with Cu(I) X L ratio 2:1, 3:2, 4:3, 1:1 and 2:3 ( X = Cl, Br and often I; L = DPE for 2:3, DPM and DPE for the other complexes) were isolated and characterized by analytical data, conductivity and mole. wt. measurements, i.r. and NMR spectra. Almost always complexes are polymorphic and adducts with solvent of crystallization are frequent.

Abstract: The following previously-unreported resonance activation integrals I 0 were determined: 46 Ca, 0·32±0·12b; 84 Sr, 10·6±1·1b; 130 Ba, 270±70b; 152 Gd, 3000±300b; 158 Gd, 84±20b. In addition, I 0 values for 21 nuclides were redetermined. The determinations were based on cadmium ratio measurements and on known values for the thermal neutron activation cross-sections. Small samples of 197 Au ( σ 0 = 98·8b; I 0 = 1550b) were used as flux monitors. The thermal neutron activation cross-section for 152 Gd was found to be 1100±100b.

Abstract: The complexes formed by zinc(II), cadmium(II) and mercury(II) thiocyanates with pyridine, 2-methyl-, 3-methyl-, 4-methyl-, 2,4-dimethyl-, 2,6-dimethyl-, 2-ethyl-, 3-ethyl-, 4-ethyl-pyridines, aniline, 2-methyl-, 3-methyl-, 4-methyl- and 3-chloro- anilines have been prepared. These complexes have been examined spectroscopically (down to 222 cm−1) in the solid state and the possible structures are discussed.

Abstract: Potentiometric studies on the free ligands and the metal complexes of indium(III) with thiomalic, malic and aspartic acid have yielded stepwise protonation constant of the ligands and the formation constants of the complexes. Thermodynamic formation constants have been obtained by extrapolation of the values at various ionic concentrations. The values of overall changes in ΔG°, ΔH°, ΔS° accompanying the reactions have been evaluated at 35°. The trend in the stability constant values of indium(III) complexes has been found to be thiomalic > malic > aspartic.

Abstract: The compound, MoCl2(CO)2£(CH3)2C6H53 is believed to be the first uncharged hepta-coordinate organometallic molecule containing only monodentate ligands for which a structure has been determined by X-ray crystallography The angular symmetry of the ligands bonded to the molybdenum atom approximates most closely to Cs One of the MoP bond lengths is unusually long (2·62 A) and there is evidence that this is an inherently weak bond The molecule of methanol of crystallisation is situated in the lattice in a way which indicates that there may be a bifurcated hydrogen bond between the methanol and the two chlorine atoms on the complex

Abstract: Two crystal phases of strontium-nickel oxides, SrNiO3 and compounds with composition near Sr2Ni2O5, containing tetra- and tri-valent nickel ions respectively, have been synthesized in oxidation atmosphere. SrNiO3 synthesized under high pressures of oxygen above 50 atm has a hexagonal unit cell with a = 5·355 ± 0·001, c = 4·860 ± 0·001 A and is isostructural with BaNiO3 with perovskite-like structure. The phase with composition near Sr2Ni2O5 with hexagonal unit cell has been synthesized above 600°C and at 1 atm of wet oxygen gas. The existence of water has a remarkable effect to form both the compounds of SrNiO3 and Sr2Ni2O5.

Abstract: A microcrystalline cerium(IV) phosphate with formula CeH2P2O8.1.33H2O has been synthesized and characterized by its X-ray diffraction pattern. Thermal stability, chemmial stability in solutions of various mineral acids, uptake curves for alkali metal ions and water vapour adsorption isotherms have been determined. Its ion-exchange properties are compared with those of amorphous and fibrous cerium(IV) phosphate.

Abstract: A variety of complexes of the general formulae L Au X and L Au X 3 ( L = neutral ligand; X = Cl, Br, I) have been prepared and their i.r. spectra studied in the region 145–600 cm −1 . The apparent trans -bond weakening effects of L are compared.

Abstract: Californium dioxide was prepared by oxidation with high pressure molecular oxygen and by atomic oxygen. The CfO2 has a fcc structure with an expansion corrected lattice parameter of 5·310 ± 0·002 A. Several areas of oxide stability in the range CfOχ(2·00 > χ > 1·50) are reported and these phases have a rhombohedral structure. The phase transition temperature between the body-centered cubic Cf2O3 and monoclinic Cf2O3 is ∼ 1400°C.

Abstract: Stability constants are reported for simple and mixed dl(X)- and meso(Y)-tartaric acid complexes of Fe(III), La(III) and Nd(III), at 25 ± 0·1°C and μ = 0·1 M(NaClO 4 ). A pH titration method was used. As expected on the basis of the greater basicity of the meso-isomer, values of K MY 1 and K MY 2 for the ferric complexes are greater than the correscponding K MX 1 and K MX 2 by factors of ∼ 10. In the rare-earth systems, K MY 1 > K MX 1 , but in contrast to the ferric systems K MY 2 ≅ K MX 2 . In the ferric and La mixed-systems, the 1:1 complexes show a preference for the dissimilar ligand, whereas in the Nd system the opposite is the case.

Abstract: The magnetic properties over the temperature range from 80°–300°K are reported for a number of copper(II) complexes with N-hydroxyalkylsalicylideneimines having empirical formulae (A) Cu(Sal·N·ROH)X and (B) Cu(Sal·N·RO), where Sal·N = · ·C 6 H 4 · H = N·, ROH = CH 2 CH 2 OH, CH 2 CH(CH 3 )OH, C(CH 3 ) 2 CH 2 OH and CH 2 CH 2 CH 2 OH, and X = Cl − , NO 3− and ClO 4− . Their magnetic properties differ depending upon the attached anion X or the R group. Of the (A) type of complexes, Cu(Sal·N·CH 2 CH 2 OH)Cl, Cu(Sal·N·CH 2 CH 2 OH)ClO 4 ·H 2 O and Cu(Sal·N·CH 2 CH(CH 3 )OH) ClO 4 ·C 2 H 5 OH exhibited antiferromagnetic behavior conforming to the Bleaney-Bowers equation, while the other complexes showed normal paramagnetic properties. For the (B) type of complexes, Cu(Sal·N·CH 2 CH 2 CH 2 O) exhibited antiferromagnetic behavior typical of binuclear copper(II) complexes, whereas the other complexes had ferromagnetic properties. The diffuse reflectance and i.r. spectra of these complexes have been measured in order to obtain information about their structure.

Abstract: The synthesis and properties of uranyl complexes with tetradentate ligands of formula UO 2 (saldiamine). L (where saldiamine is the Schiff base N,N′diamine bis(salicylideneimine), L is a solvent molecule and the diamines are ethylenediamine, (+) propylenediamine, (+) and meso butanediamine, (+) and meso cyclohexanediamine, (−) and meso stilbenediamine) are reported. I.R., electronic and circular dichroism spectra are also discussed.

Abstract: Potentiometric methods have been used to determine stability constants for the cyanide complexes of Cu(I), Ag(I) and Au(I) in aqueous solution. For Cu(I) the constants determined were log β2 = 21·7, log β3 = 26.8 and log β4 = 27·9, and for Ag(I), log β2 = 20·9 and log β3 = 21·8. For Au(I), E0 for Au(CN)2− was found to be −0·50V, which was combined with a previous estimate of the Au+(aq)/Au(s) standard reduction potential (+1·668V) to give log β2 = 36·6.