Showing papers in "Journal of The Chemical Society A: Inorganic, Physical, Theoretical in 1970"
TL;DR: The hydridocarbonyltris(triphenylphosphine)rhodium(I), RhH(CO)(PPh3)3, is an efficient catalyst for hydroformylation of alkenes at 25 °C at 1 atm.
Abstract: The compound hydridocarbonyltris(triphenylphosphine)rhodium(I), RhH(CO)(PPh3)3, is an efficient catalyst for hydroformylation of alkenes at 25 °C at 1 atm. From alk-1-enes high ratios of straight chain to branched chain aldehydes can be produced. The dependence of rates and products on catalyst and substrate concentration, partial pressures of hydrogen and carbon monoxide, temperature, and added excess of triphenylphosphine are described and the suggested mechanisms discussed in relation to these results. Studies at higher temperature and pressure show that rapid and effective conversion of both a liquid alkene and also propene to give high yields of straight chain aldehyde can be achieved particularly when molten triphenylphosphine provides the solvent phase.
212 citations
TL;DR: In this article, a technique for studying orientation effects on nearly opaque single crystals with laser Raman spectroscopy is described in detail, and the instrument used in these studies is a Spex monochromator.
Abstract: A technique for studying orientation effects on nearly opaque single crystals with laser Raman spectroscopy is described in detail. The instrument used in these studies is a Spex monochromator. The scattering equations derived are applied to a study of iron(III) oxide and chromium(III) oxide.
192 citations
TL;DR: In this paper, a single-stage synthesis for a range of important hydride-, carbonyl-, and nitrosyl-containing triphenylphosphine complexes of the platinum metals is described.
Abstract: Convenient, single-stage syntheses have been devised for a range of important hydride-, carbonyl-, and nitrosyl- containing triphenylphosphine complexes of the platinum metals. The reactions are performed in homogeneous, alcoholic solutions from which the required products precipitate or crystallise cleanly; sodium borohydride, aqueous formaldehyde, and N-methyl-N-nitrosotoluene-p-sulphonamide are used as convenient sources of hydride, carbonyl, and nitrosyl ligands respectively. Abstraction of hydrogen chloride to form co-ordinatively unsaturated derivatives is achieved by introduction of triethylamine to the reaction solution. New compounds prepared and characterised include [OsH4(PPh3)3] and [Ru(NO)2(PPh3)2]. The latter compound is the first well characterised dinitrosyl of ruthenium.
154 citations
TL;DR: Raman spectra of a number of carbonate, phosphate, arsenate, vanadate, niobate, tantalate, sulphate, chromate, molybdate, and tungstate minerals have been measured over the range 140-1200 cm−1(600-1600 cm-1 for carbonates) as mentioned in this paper.
Abstract: Raman spectra of a number of carbonate, phosphate, arsenate, vanadate, niobate, tantalate, sulphate, chromate, molybdate, and tungstate minerals have been measured over the range 140–1200 cm.–1(600–1600 cm.–1 for carbonates). The internal modes of the (MOn) groups in these minerals have been assigned, and the validity of factor group and site symmetry analyses discussed. The use of Raman spectroscopy for mineral studies is discussed.
137 citations
TL;DR: Flexible polyurethane foams can be used as selective absorbents for a number of substances from dilute aqueous solutions, e.g., iodine, benzene, chloroform, and phenol.
Abstract: Flexible polyurethane foams can be used as selective absorbents for a number of substances from dilute aqueous solutions. Most of the substances absorbed are those which can be extracted from aqueous solutions by use of liquid diethyl ether, e.g., iodine, benzene, chloroform, and phenol from water; mercury(II) and gold(III) from 0·2M-hydrochloric acid; iron(III), antimony(V), thallium(III), molybdenum(VI), and rhenium(III) from 6M-hydrochloric acid; and uranium(VI) from saturated aluminium nitrate solution. The capacities of different foams for absorption vary, but are of the order of 0·5–1·5 mol kg–1 foam. Desorption can usually be achieved without difficulty. The separations require simple apparatus and are rapid and specific.The process has been shown to be absorption rather than adsorption by measuring the surface areas of the foams used. Chemical formulae of some of the absorbed species were investigated by chemical and radiochemical techniques.
125 citations
TL;DR: In this article, the intermediate alkyls and acyls in the catalytic hydroformylation of alk-1-enes by use of hydridocarbonyltris(triphenylphosphine)rhodium, or, where this is not possible, to prepare analogues of similar rhodium or iridium species with less reactive metal-carbon bonds are characterized.
Abstract: An attempt has been made either to isolate and/or to characterise by i.r. and n.m.r. spectroscopy the intermediate species in the catalytic hydroformylation of alk-1-enes by use of hydridocarbonyltris(triphenylphosphine)rhodium, or, where this is not possible, to prepare analogues of similar rhodium or iridium species with less reactive metal–carbon bonds. Species of the following types have been characterised : Square alkyls and acyls : MR(CO)(PPh3)2(M = Rh, R = C2F4H; M =Ir, R = EtCO, or Ph); pentaco-ordinate alkyls and acyls : MR(CO)2(PPh3)2(M = Rh, R = C2F4H, EtCO, or PhCO; M = Ir, R = Et, Ph, EtCO, or PhCO); MR(CO)3(PPh3)(M = Rh, R = C2F4H, EtCO, or PhCO; M = Ir, R = EtCO or PhCO); Rh(C2F4H)(SO2)(CO)(PPh3)2; and octahedral alkyls and acyls: Rh(C2F4H)HCl(CO)(PPh3)2, lr(EtCO)HCl(CO)(PPh3)2. The species are shown to undergo reversible carbonylation, decarbonylation, and oxidative addition reactions and the relevance to the hydroformylation mechanism is discussed.
111 citations
TL;DR: In this article, the relationship between the e.s.r. g-values and MO expansion coefficients in tetragonal copper(II) compounds is discussed and detailed expressions for g and g⊥ are derived and all relevant integrals are evaluated, by use of Hartree-Fock wave functions.
Abstract: The relationship between the e.s.r. g-values and MO expansion coefficients in tetragonal copper(II) compounds is discussed. Detailed expressions for g‖ and g⊥ are derived and all relevant integrals are evaluated, by use of Hartree–Fock wave functions, for typical systems. The g-values of square coplanar CuCl42– are calculated from MO coefficients found by semi-empirical calculations, in good agreement with experimental values. The relative importance of the various terms is discussed and the validity of approximations made in previous work is assessed. In particular, we stress the importance of matrix elements involving charge transfer states and the need to take proper account of ligand–ligand and metal–ligand overlap integrals. We conclude that the expressions normally used in the estimation of bonding parameters from e.s.r. data are seriously incomplete, and many of the usual approximations are difficult to justify. The application of e.s.r. to the study of the binding of axial ligands is discussed. Although terms involving axial ligands make very little direct contribution to the g-values, it should be possible to detect the influence of these ligands on the equatorial metal–ligand distance by measuring g‖, even in the absence of reliable optical data on the d–d excited states. This is demonstrated by correlating e.s.r. data with a theoretical measure of the tetragonality for some tetra-ammine complexes of copper(II). It is not possible to use the anisotropy of the g-tensor in order to assess the relative extent of in-plane and out-of-plane π-bonding. However, the complete expressions derived for g‖ and g⊥ help to rationalise some features of the e.s.r. spectra of tetragonal copper(II) systems.
110 citations
TL;DR: In this article, a partial exploration of the crystallisation fields of aluminosilicate gels in presence of the mixed aqueous bases NaOH, KOH, and Me4NOH was made to examine specific chemical effects of mixed bases over and above those expected when each base is present separately.
Abstract: A partial exploration has been made of the crystallisation fields of aluminosilicate gels in presence of the mixed aqueous bases NaOH, KOH, and Me4NOH in order to examine specific chemical effects of the mixed bases over and above those expected when each base is present separately. A wide range of zeolitic phases resulted of which four, a sodalite type, an erionite type, an offretite type, and zeolite Ω(which has no natural counterpart), were especially studied, by X-ray and electron diffraction, electron microscopy, and by thermogravimetric, differential thermal, and chemical analysis. These phases proved to be silica-rich; from the known structures and the chemical results it was also possible to locate tetramethylammonium ion positions. Reasons for the non-additive chemical effects of mixed bases in zeolite crystallisation have also been given.
93 citations
TL;DR: The cis-isomer of di-µ-carbonyl-dicarbonyldiπ-cyclopentadienyldi-iron has been isolated by low-temperature crystallisation and its structure determined by a single-crystal X-ray analysis as discussed by the authors.
Abstract: The cis-isomer of di-µ-carbonyl-dicarbonyldi-π-cyclopentadienyldi-iron has been isolated by low-temperature crystallisation and its structure determined by a single-crystal X-ray analysis. The crystals are monoclinic, a= 8·880(2), b= 12·301(3),c= 13·140(3)A, β= 108·64(1)°. The space group is P21/c with Z= 4. After least-squares refinement with over 1500 observations R is 0·051. The i.r. spectrum of the complex has been measured in the ranges 200–1000 and 1600–2000 cm.–1 and assignments have been suggested. Study of the 1H n.m.r. spectra of the cis- and trans-isomers as a function of temperature confirms that solutions of the complex contain both isomers. Mossbauer and mass-spectral data are also presented.
92 citations
TL;DR: In this paper, the insertion reaction of amides with dipoles AB to give the adducts LM(NR2)n x(A-B-NR2x)x are described.
Abstract: Insertion reactions of amides LM–(NR2)n with the dipoles AB to give the adducts LM(NR2)n – x(A–B–NR2)x are described. The amides included the Group IVA [M(NMe2)4(M = Ti, Zr, or Hf)] and IVB [Me3M·NMe2(M = Si, Ge, or Sn)] compounds and o-C6H4O2B·NEt2, while the dipoles were PhNCO, PhNCS, MeNCS, p-MeC6H4·N:C:N·C6H4Me-p, C6H11·N:C:N·C6H11, MeO2C·C:C·CO2Me, CO2, CS2, CH2:CH·CN, PhCN, p-MeC6H4·CN, CH2:CCl(CN), C6F5·CN, CCl3·CN, [graphic omitted] and MeCH:CH·CHO. The problems discussed are the stoicheiometry of the reaction, the structure of the adducts, and the relative reactivities of the various amides and dipoles.
91 citations
TL;DR: In this paper, a new method of preparing halogenocopper(I) complexes by using tertiary phosphines as ligands and reducing agents was described, and the complexes were treated with various mono-and bi-dentate ligands.
Abstract: A new method of preparing halogenocopper(I) complexes by using tertiary phosphines as ligands and reducing agents is described. The complexes prepared have been treated with various mono- and bi-dentate ligands and structures assigned to the derivatives on the basis of their physical properties.
TL;DR: In this paper, the adsorption of carbon dioxide on magnesia was studied by measurements of the i.r. spectra of the carbon dioxide which had been adsorbed at various temperatures, supplemented by gravimetric measurements of adsorbing isotherms at temperatures ranging from −97·9 to 500 °C.
Abstract: The adsorption of carbon dioxide on magnesia (prepared by hydrolysis of magnesium methoxide) has been studied by measurements of the i.r. spectra of carbon dioxide which had been adsorbed at various temperatures, supplemented by gravimetric measurements of adsorption isotherms at temperatures ranging from –97·9 to 500 °C. Three types of adsorption were encountered: (I) a rapid physical adsorption; (II) a slow chemisorption involving the formation of a bidentate carbonate ion; and (III) a still slower chemisorption which resulted in the formation of a carbonate ion similar to that present in bulk magnesium carbonate. (I) and (II) occur at temperatures up to and including room temperature; and (II) and (III) at temperatures from that of the room upwards.
TL;DR: In this article, the rhodium(II) acetate Ru2(OCOMe)4 and its adducts with triphenylphosphine and pyridine have been characterised.
Abstract: The protonation of rhodium(II) acetate by non-complexing, non-oxidising acids such as fluoroboric acid gives the green rhodium(II) cation Rh4+2. The interaction with triphenylphosphine and carbon monoxide lead to the complexes Rh(PPh3)3BF4 and Rh(CO)(PPh3)3BF4.The new ruthenium(II) acetate Ru2(OCOMe)4 and its adducts with triphenylphosphine and pyridine have been characterised.The methanolic fluoroboric acid solutions of RhII and RuII acetates and of Ru2(OAc)4Cl, in the presence of triphenylphosphine, are active catalysts for the homogeneous hydrogenation of alkenes, alkynes, and other unsaturated substances.
TL;DR: The binuclear and trinuclear µ-sulphido-complexes [Pt2S2(PMe2Ph)4] and [P3S2Pme2Ph6]Cl2 have been prepared by the reaction of sodium sulphide and cis-dichlorobis(dimethylphenylphosphine)platinum(II).
Abstract: The binuclear and trinuclear µ-sulphido-complexes [Pt2S2(PMe2Ph)4] and [Pt3S2(PMe2Ph)6]Cl2 have been prepared by the reaction of sodium sulphide and cis-dichlorobis(dimethylphenylphosphine)platinum(II). Their properties, reactions, and structures are discussed in this paper. In ammoniacal ethanol solution sodium sulphide reacts with cis-[PtCl2(PPh3)2] to give the complex [Pt2S(PPh3)4], probably structurally analogous to [Pt2S(CO)(PPh3)3]. The platinum(0) and palladium (0) complexes ML4[M = Pd or Pt, L = PPh3, L2=(PPh2)2C2H4] by oxidative addition of elemental sulphur give the complexes [L2MS4], which contain the novel MS4 ring system.
TL;DR: The crystal structure of triphenylphosphine oxide has been determined from three-dimensional X-ray diffraction data, by the symbolic-addition phase-determination procedure as mentioned in this paper.
Abstract: The crystal structure of triphenylphosphine oxide has been determined from three-dimensional X-ray diffraction data, by the symbolic-addition phase-determination procedure. The compound crystallises in the orthorhombic space group, Pbca, with a= 29·120, b= 9·143, c= 11·252 A, and Z= 8. The structure was refined by the full-matrix least-squares method to R 7·8%. Some bond lengths in the crystal are: P–O 1·46 and P–C (mean) 1·76 A.
TL;DR: In this article, the authors report their i.r.r and electronic spectra and discuss their structures, the effect on their spectra, and other properties of different donor atoms (N,O,S), and their relevance as models for molybdenum-containing enzymes.
Abstract: We have prepared the following complexes: for L =α-alanine and β-alanine, MoVI2O4(OH)3L; for L = 2-mercapto-ethylamine, [MoVIO2L2], [Mo5O9S3L6], [Mo4O3L5],2H2O, [Mo3OS5L4],2H2O; for L = L-cysteine methyl ester,[MoVIO2L2]. [Mo2VO3L4], [Mo2VO2S2L2]; for L = 2-mercaptoethanol, [Mo2vO3L4], [Mo2VO4L2]; and for L =L-cysteine, Na2[MoVIO2L2], dimethylformamide, Na2[MoV2O4L2],5H2O, Na2[Mo2VO2S2L2],3H2O. The oxocomplexes were prepared from aqueous solutions of molybdenum-(VI) and -(V) and the ligands. With hydrogen sulphide some of the complexes gave complexes in which bridging oxide ligands had been replaced by sulphide. The complexes are diamagnetic. We report their i.r. and electronic spectra and discuss their structures, the effect on their spectra and other properties of different donor atoms (N,O,S), and their relevance as models for molybdenum-containing enzymes.
TL;DR: The crystal structure of dimethyltin dichloride has been solved and the parameters have been refined by three-dimensional least-squares analysis as mentioned in this paper, where the environment of the tin atoms is considerably distorted from the regular tetrahedral coordination towards octahedral, because of the association between neighbouring molecules.
Abstract: The crystal structure of dimethyltin dichloride has been solved and the parameters have been refined by three-dimensional least-squares analysis. The environment of the tin atoms is considerably distorted from the regular tetrahedral co-ordination towards octahedral, because of the association between neighbouring molecules.The Mossbauer spectra of the dialkyltin dichlorides are discussed in terms of this structure, and of the dialkyltin difluorides in terms of a trans-octahedral configuration.
TL;DR: In this paper, the imbibition of sodalite and cancrinite during their hydrothermal formation from kaolinite has been studied, and the results have been interpreted in terms of a Donnan equilibrium.
Abstract: The imbibition of salts by sodalite and cancrinite during their hydrothermal formation from kaolinite has been studied. Isotherm contours recalling those of Langmuir's isotherm were observed in sodalite for NaCl, NaBr, NaClO3, NaClO4, and Na2CO3. These results have been interpreted in terms of a Donnan equilibrium, in which solid-phase activities were calculated on the experimentally justified assumption that each sodalite cage is capable of accommodating a particular number of each kind of guest molecule, which number varies with the size of the guest. The stoicheiometry, thermal stability, chemical reactivity, and crystallization kinetics of representative compounds have been discussed, and the possible importance of salt inclusion in other zeolitic materials has been noted.
TL;DR: The structure determinations were made for cancrinite nitrate (R= 0·12) and for a basic can-crinite containing some intercalated silicate (R = 0·07).
Abstract: Cancrinite has been synthesized in the sodalite crystallization field at 80° by addition of sodium nitrate, chromate, or molybdate. The crystals then contain these salts as guest species in place of the carbonate often found in natural cancrinites.This promotion of the formation of cancrinite was ascribed to association of anions with certain aluminosilicate species in solution, which then yielded cancrinite nuclei. As these grow into crystallites by addition of further anion–aluminosilicate complexes, the salt is incorporated into the 11-hedral cancrinite cages and into the wide channels enclosed by these. This behaviour was studied by investigations of conditions of synthesis and by chemical and thermal analyses, i.r. measurements, X-ray powder photography, and crystal-structure determinations based on powder data.The structure determinations were made for cancrinite nitrate (R= 0·12) and for a basic cancrinite containing some intercalated silicate (R= 0·07). The structures were compared with one recently determined for a natural cancrinite. In addition, partial refinement of two other cancrinites rich in sodium chromate and sodium molybdate served to locate these anions.
TL;DR: The crystal structure of the trans-isomer of di-µ-carbonyl-dicarbonyl di-π-cyclopentadienyldi-iron has been determined by three-dimensional methods as discussed by the authors.
Abstract: The crystal structure of the trans-isomer of di-µ-carbonyl-dicarbonyl-di-π-cyclopentadienyldi-iron has been redetermined by three-dimensional methods. The space group is P21/c with a= 7·046(1), b= 12·453(2), c= 7·990(1)A, β= 108·44(1)°, and Z= 2. The 904 reflections measured by counter diffractometry were used in the refinement by block-diagonal least-squares methods. With individual anisotropic thermal parameters and no allowance for hydrogen atom contributions, R= 0·044, WR= 0·056.Bond lengths and angles are: Fe–Fe 2·534(2); Fe–C(bridge) 1·910, 1·918(5); Fe–C(terminal) 1·748(6); Fe–C(ring) 2·082–2·121(8); C–O(bridge) 1·188(6); C–O(terminal) 1·157(7); and C–C 1·346–1·405(11)A; and Fe–C(bridge)–Fe 82·9(2); C(bridge)–Fe–C(bridge) 97·1(4); C(bridge)–Fe–C(terminal) 93·7(2); Fe–C(bridge)–O 138·4–139·1(3); and Fe–C(terminal)–O, 178·4(8)°.The identity of the Fe–Fe distance in both cis- and trans-isomers makes it unlikely that the former is stabilised preferentially by a π- or δ-contribution to the metal–metal bond as has been suggested.
TL;DR: In this paper, two classes of β-diketone complexes of CuI, AgI, and AuI have been prepared viz: class (i) L2M(β-dikaetone), M = Cu, L = Ph3P, β-Diketones = conjugate base of acac, benzoylacetone (ba), trifluoro-acetylacetone(tfa), or hexafluoroacetyl acetone (hfa).
Abstract: Two classes of β-diketone complexes of CuI, AgI, and AuI have been prepared viz.: class (i) L2M(β-diketone), M = Cu, L = Ph3P, β-diketone = conjugate base of acetylacetone (acac), benzoylacetone (ba), trifluoro-acetylacetone (tfa), or hexafluoroacetylacetone (hfa), and M = Ag, L = Ph3P, β-diketone = ba or hfa; and class (2) LM(β-diketone), M = Ag, L = Ph3P, β-diketone = acac or tfa, and M = Au, L = Ph3P, Ph2EtP, Et3P, (Ph·Me)3P, or Ph3As, β-diketone = acac or ba. On the basis of molecular-weight data, and i.r. and n.m.r. spectral studies the complexes of CuI and AgI are shown to contain oxygen-bonded β-diketones irrespective of their composition, whereas those of AuI contain carbon-bonded ligands in all cases. The stereochemical consequences of these observations are discussed.
TL;DR: In this article, the rate law for HOONO formation in perchloric acid solutions was found to be of the form (a, b, and c are constants)d[HOONO]//dt=a[H+][H2O2][HNO2]//b+c[H 2O2], which is consistent with a mechanism in which NO+ is formed as an intermediate.
Abstract: The kinetics of the formation of peroxynitrous acid (HOONO), and its decay to nitrate ion have been studied in perchloric acid solutions (0·01 to 1·0 mol I–1) by the stopped-flow method. The rate law for the formation process was found to be of the form (a, b, and c are constants)d[HOONO]//dt=a[H+][H2O2][HNO2]//b+c[H2O2], which is consistent with a mechanism in which NO+ is formed as an intermediate. Peroxynitrous acid decays immediately after it forms with a first-order rate constant at 273·7 K, kd, given by: 102kd=(5·27 ± 0·10)+(59·6 ± 0·8)[H+] s–1. At 298·1 K, activation parameters for the acid independent pathway are ΔH‡= 19·6 ± 0·2 kcal mol–1 and ΔS‡= 7·4 ± 0·7 cal mol–1 K–1(1 cal = 4·1868 J), and for the acid dependent pathway are ΔH‡= 14·8 ± 0·2 kcal mol–1 and ΔS‡= 5·3 ± 0·7 cal mol–1 K–1. The spectrum of peroxynitrous acid was recorded using a continuous-flow mixing cell.
TL;DR: In this article, a planar asymmetric Pd unit was used to analyze bridge splitting reactions with mono-and bi-dentate ligands bearing nitrogen or phosphorous as donor atoms.
Abstract: I.r. spectra of palladium(II) halogeno-bridged complexes of the type [Pd(N–C)X]2= azobenzene-2-C,N; NN-dimethylbenzylamine-2-C,N; and 2-methoxy-3-NN-dimethylaminopropyl; X = Cl or (Br) have been recorded in the range (600–120 cm.–1). The bridging-halogen stretching frequencies are discussed on the basis of a planar asymmetric Pd[graphic omitted]Pd unit.Bridge-splitting reactions with mono- and bi-dentate ligands bearing nitrogen or phosphorous as donor atoms are reported and the structures of the resulting products are interpretated on the basis of their far-i.r. spectra. We have also established that the v(Pd–Cl) frequency in the products in the range 300–280 cm.–1 with chloride in the trans-position to the phenyl or alkyl groups.
TL;DR: In this paper, the Lentz technique was applied to trimethylsilylation of hemimorphite Zn4(OH)2,Si2O7,H2O by varying time, temperature, and acidity of reaction medium.
Abstract: The products formed in the trimethylsilylation of hemimorphite Zn4(OH)2,Si2O7,H2O by the Lentz technique were studied by varying time, temperature, and acidity of the reaction medium. Conversion of the mineral into the trimethylsilyl derivative of the anion Si2O76– without appreciable by-products was achieved by allowing the finely ground material to react with trimethylsilyl chloride in the presence of isopropyl alcohol and hexamethyldisioxane. The proportion of the expected dimeric derivative was independent of reaction conditions over a wide range. The mechanism of trimethylsilylation is discussed.
TL;DR: In this article, the dimeric dichloropentamethylcyclopentamylcyclopentadienyl-rhodium and -iridium complexes, [{M(C5Me5)Cl2}2], reacted in ethanol in the presence of sodium carbonate with butadiene, cycloheptatriene, and 6,6-diphenylfulvene.
Abstract: The dimeric dichloropentamethylcyclopentadienyl-rhodium and -iridium complexes, [{M(C5Me5)Cl2}2], reacted in ethanol in the presence of sodium carbonate with butadiene, cycloheptatriene, and 6,6-diphenylfulvene, giving pentamethylcyclopentadienyl-rhodium(III) or -iridium(III) complexes of π-1-methylallyl, π-cyclohepta-2,4-dienyl, and (1,1-diphenylmethyl) cyclopentadienyl. Under similar conditions with [{Rh(C5Me5)Cl2}2], norbornadiene and dicyclopentadiene gave pentamethylcyclopentadienyl-rhodium(I) diene complexes; ethylene gave bis(ethylene)-rhodium(I) and -iridium(I) complexes. A hydrido-intermediate is implied in these reactions and both the hydrido- and deuterio-chloro(triphenyl phosphine) pentamethylcyclopentadienyliridium complexes were isolated and characterised. With cyclopentadiene, [{Rh(C5Me5)Cl2}2] gave the cation and (cyclopentadienyl)-endo-H-pentamethylcyclopentadienerhodium(I). (Cyclopentadienyl)exo-H-pentamethylcyclopentadienerhodium(I) was obtained by reduction of [Rh(C5Me5)(C5H5)]+ with sodium borohydride and was much more reactive than the endo-H-isomer. With halogenating agents [Rh(C5Me5)(C5H5)]+ was the product, whereas the endo-H-isomer underwent cleavage to [{Rh(C5Me5)X2}2] and [{Rh(C5H5)X2}2]. [{Ir(C5Me5)Cl2}2] reacted with cyclopentadiene to give only the [Ir(C5Me5)(C5H5)]+ cation, which on reduction, gave a mixture of two isomers, exo-H-[Ir(C5Me5H)(C5H5)] and [Ir(C5Me5)(C5H6)]. The mass spectra of some new complexes and of (C5Me5H) are recorded.
TL;DR: Mixtures of magnesium and manganese chlorides with citric and isocitric acids have been titrated potentiometrically at the glass electrode with tetramethylammonium hydroxide at 25° and an ionic strength 0·1 as mentioned in this paper.
Abstract: Mixtures of magnesium and manganese chlorides with citric and isocitric acids have been titrated potentiometrically at the glass electrode with tetramethylammonium hydroxide at 25° and an ionic strength 0·1 The stability constants have been calculated by a novel computer technique based on the Schwarzenbach procedure The results have been compared with the available literature data The usefulness of the technique is discussed
TL;DR: The use of a blue solution of RuII in methanol as a starting material for the preparation of ruthenium complexes has been investigated, with various ligands, e.g. amines, nitriles, azobenzene, thiols, tertiary phosphines, and carbon monoxide, and olefins; some 28 new complexes have been characterised as discussed by the authors.
Abstract: The use of a blue solution of RuII in methanol as a starting material for the preparation of ruthenium complexes has been investigated, with various ligands, e. g. amines, nitriles, azobenzene, thiols, tertiary phosphines, and carbon monoxide, and olefins; some 28 new complexes have been characterised.
TL;DR: In this article, three methods for the preparation of silylplatinous complexes are described, viz. reaction of R31SiLi compounds with cis-[PtCl2(PR23)2] and [PtCL2(Ph2PCH2CH2PPh2](R13Si = MePh2Si), respectively; and reaction of trichlorosilane or triarylsilanes, R3SiH, with trans-[ptHCl(PMe2Ph)2], where X = Cl or Br and Q
Abstract: Three methods are described for the preparation of silylplatinous complexes, viz. (a) reaction of R31SiLi compounds with cis-[PtCl2(PR23)2] and [PtCl2(Ph2PCH2CH2PPh2)] to give cis-[Pt(SiR13)2(PR23)2](R13Si = MePh2Si, R23P = Me2PhP or R13Si = Me2PhSi, R23P = MePh2P) and [Pt(SiR13)2(Ph2PCH2CH2PPh2)](R13Si = MePh2Si), respectively; (b) reaction of trichlorosilane or triarylsilanes, R3SiH, with trans-[PtHCl(PMe2Ph)2] to give trans-[PtCl(SiR3)(PMe2Ph)2](R = Cl, C6F5, or XC6H4 where X = H, p-OMe, p-NMe2, m-CF3, p-CF3, m-F, p-F, p-Cl, p-Me); (c) reaction of triarylsilanes, R3SiH, with [PtX2(QMe2Ph)2] compounds, where X = Cl or Br and Q = P or As, in benzene–triethylamine to give trans-[PtX(SiR3)(QMe2Ph)2] derivatives (e.g., R3Si = MePh2Si or R = XC6H4, where X = H, p-OMe, p-NMe2, and m- or p-F, -Cl, -CF3, and -Me). Triphenylgermane behaves analogously in reactions (b) and (c), and triethylstannane in reaction (b).Features of the n.m.r. and i.r. spectra are discussed, and the very low values of ν(Pt–Cl) and ν(Pt–Br) in the trans-[PtX(SiR13)(PR23)2] compounds are ascribed to the large inductive trans-effect of silicon. The cleavages of the Pt–Si bonds in some of these compounds by halogen, hydrogen chloride, methyl iodide, thiophenol, and hydrogen are described.
TL;DR: In this article, partial center shifts (p.c.q.s.s) were derived from the Mossbauer spectra of a large number of low-spin compounds.
Abstract: The Mossbauer spectra of a large number of iron(II) low-spin compounds are reported. Together with the Mossbauer spectra of other low-spin compounds reported in the literature, we have derived partial centre shifts (p.c.s.) for 37 ligands and partial quadrupole splittings (p.q.s.) for 16 ligands. There is an inverse correlation between the p.c.s. values and spectrochemical ranking of ligands. With this correlation the position of hydride in the spectrochemical series has been re-examined. The p.c.s. values should also be helpful in the preparation of compounds in which the iron(II) exhibits intermediate spin or a high-spin–low-spin equilibrium.The p.c.s. values are related to the total σ-donor plus π-acceptor properties of the ligands, while the differences in c.s. between the cis–trans pairs may be used to separate the σ- and π-effects. Our results indicate that SnCl3– is a good π-acceptor (comparable to ArNC) but a rather poor σ-donor.The 2 : 1 trans-cis quadrupole splitting ratio holds for such ligands as Cl–, SnCl3–, RNC, and CN–, and the q.s. values are used, in conjunction with other spectroscopic data, to assign the stereochemistry of many of the isomers in this study. The 2 : 1 q.s. ratio is explained in terms of a simple molecular orbital model. The p.q.s. values can be useful for examining the bonding properties of many ligands, and can provide complementary bonding information to that obtained from the p.c.s. values.Many of the spectra in this study were distinctly asymmetric. With this Goldanskii asymmetry, a method for obtaining the sign of the field gradient in these compounds is tentatively proposed.
TL;DR: In this paper, the trinuclear cluster compounds [Pt3(CO)3L4], [PPh3,PPh2Me, and PPh2Et] were obtained by decomposition of the complexes [Ptp2L2] 2L2], where the carbonyl groups are both terminal and bridging.
Abstract: New trinuclear cluster compounds [Pt3(CO)3L4](L = PPh3, PPh2Me, and PPh2Et) and [Pt3(CO)3L3](L = PPh2PhCH2) are obtained by decomposition of the complexes [Pt(CO)2L2]; however their preparation is generally more convenient without the isolation of [Pt(CO)2L2], from an alkali tetrachloroplatinate, a phosphine, and carbon monoxide.Further rearrangement and absorption of carbon monoxide by the trinuclear cluster compounds give the tetranuclear species [Pt4(CO)5L4] and [Pt4(CO)5L3]. The [Pt4(CO)5L4] species have been obtained in two isomeric forms, in the first the carbonyl groups are both terminal and bridging (L = PPh2PhCH2 or AsPh3), and in the second only bridging (L = PPh3 or PPhMe2).Some unusual properties of these cluster compounds, such as lability and associated variability in the co-ordination numbers, are noted.