The structure of nitratotriphenylstannyltin(II): A compound with a tin(IV)tin(II) bond

A compound of formula [Sn^II(NO₃) [(C₆H₅)₃ Sn^IV], containing a tin(IV)tin(II) bond, has been prepared, and its crystal structure is determined.     

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.     

A pyrolysis/gas chromatography—mass spectrometry and thermogravimetry/differential thermal analysis study of bis(diethyldithiocarbamato)diphenyl tin (IV)

The P/GC—MS and TG/DTA analysis, in an inert atmosphere, of bis(diethyldithiocarbamato)diphenyl tin (IV) indicates that the thermal decomposition proceeds in two consecutive stages. Loss of the dithiocarbamate ligands and the phenyl groups occurs within the temperature range of 210–380°C leaving tin (II) sulphide as residue. The stability of the phenyl radical as a reactive intermediate, together with the unidentate bonding of the dithiocarbamate ligand, dramatically influence the major mode of thermal decomposition.     

A thermogravimetry/differential thermal analysis,evolved gas analysis and pyrolysis/gas chromatography—mass spectrometry study of tetrakis (diethyldithiocarbamato)tin(IV)

The thermal decomposition of tetrakis(diethyldithiocarbamato)tin(IV) has been studied by TG/DTA, EGA and P/GC-MS techniques. From the P/GC-MS analysis, it is apparent that the denticity of the dithiocarbamate ligand influences the mechanism of decomposition. Initially, the monodentate ligands decompose by a radical mechanism to form tetraethylthiuramdisulphide which decomposes further into carbon disulphide and diethylamine. The intermediate formed, bis(diethydithiocarbamato)tin(II), decomposes in two different ways. The bidentate ligands decompose with the liberation of carbon disulphide and tetraethylthiourea, whereas the monodentate ligands, formed as a result of the high temperatures, decompose to produce S-ethyl N,N-diethyldithiocarbamate and ethylisothiocyanate. The overall thermal decomposition mechenism of tetrakis(diethyldithiocarbamato)tin(IV) is complex and the primary decomposition involved both ionic and radical recombination reactions.     

Reactions of collman complex with tin(IV) and germanium(IV) porphyris,formation of [tin(II) and germanium(II) porphyrins] tetracarbonyliron and crystal structure of [2,3,7,8,12,13,17,18-octaethylporphinato tin(II)] tetracarbonyliron

The action of Na₂Fe(CO)₄ with tin(IV) and germanium(IV) porphyrins affords metal(II) porphyrin complexes [(por)M(II)Fe(CO)₄] (por = porphyrinate, M - Sn(II) or Ge(II)). The molecular structure of [(oep)Sn(II)Fe(CO)₄] was solved by X-ray diffraction techniques. The molecular structure of [(oep)Sn(II)Fe(CO)₄] was solved by X-ray diffraction techniques : the Sn coordination is square pyramidal with the iron in axial position (Sn-Fe = 2.492(1)Å) whereas the Fe coordination is trigonal bipyramidal. Mössbauer parameters provide convincing evidence for the formal zero oxidation state of the iron atom.     

A thermogravimetry/differential thermal analysis and pyrolysis/gas chromatography—mass spectrometry study of several tin(IV) dithiocarbamate complexes in an air atmosphere

Our P/GC—MS system has been modified such that pyrolysis can be performed in an air atmosphere. Several tin(IV) dithiocarbamate complexes have been prolysed in air in order to rationalise the precise role oxygen in the decomposition process. Further, the effectiveness of the P/GC—MS technique in separating pyrolysis products from individual decomposition stages was investigated using tetrakis(diethyldithiocarbamato)tin(IV) which, from standard TG studies, is known to decompose in air in two stages. It is doubtful, whether complete separation was achieved due to the similarity of products obtained from each stage of decomposition, however, the general method has potential.     

Isotopic effects of carbon and nitrogen in low-temperature photochemical reactions

Isotopic effects of carbon and nitrogen in the low-temperature photodecomposition of benzoyl peroxide and diazoaminobenzene have been observed and discussed in terms of preferential electronic energy transfer to species containing lighter isotopes.     

Ligand effects on the Pt(II) → Pt(0) reduction of dichlorobis(tertiary phosphine)platinum(II) complexes: Correlations between electrochemical data,spectroscopic data,and electronic ligand parameters

Cyclic voltammetry has been employed to study the diffusive, irreversible platinum(II) → platinum(0) reduction of three sets of structurally related complexes: cis-[PtCl₂P{p-C₆H₄X}₃)₂] (X = H, CH₃, Cl, F, OCH₃, N(CH₃)₂); cis-[PtCl₂(PPh₂R)₂] (R = CH₃, n-C₃H₇, n-C₅H₁₁, n-C₆H₁₃, n-C₁₂H₂₅) and cis-[PtCl₂(PR₃)₂] (R = CH₃, C₂H₅, CH₂ch₂CN). Relationships between the peak potentials for the Pt(II) → Pt(0) reduction and thermodynamic parameters which measure the electronic properties of the ligands are shown to exist for complexes of P{p-C₆H₄X}₃ ligands, implying a thermodynamic origin for the sensitivity of the peak potentials to structural change. Complexes of both P{p-C₆H₄X}₃ and PPh₂R ligands show correlations between peak potentials for reduction and the ³¹P{¹H} NMR spectroscopic parameter, ¹J(¹⁹⁵Pt, ³¹P). Correlations with values of δ(³¹P) exist in both cases, but a correlation with the coordination chemical shift, Δδ(³¹P), exists for complexes of PPh₂R, and not for complexes of P{C₆H₄X}₃. Complexes of PR₃ ligands show no correlation between the peak potentials measured for the Pt(II) → Pt(0) reduction and electronic or spectroscopic parameters, except possibly ¹J(¹⁹⁵Pt, ³¹P).     

Paramagnetic transition metal carbonyls : IV. ESR study of anions derived from (CO)5MnPbPh3 and (CO)4CoPbPh3 by high energy radiation

Exposure of (CO)₅MnPbPh₃ to ⁶⁰Co γ-ray at 77 K gave one major paramagnetic species detectable by ESR spectroscopy. This exhibited an anisotropic hyperfine interaction with ⁵⁵Mn, near free-spin g-values, and a small, almost isotropic coupling to ²⁰⁷Pb. The form of the A(⁵⁵Mn) and g-tensor components suggest an orbital of d_z² symmetry on manganese for the unpaired electron, but this cannot be directed along the MnPb bond since the ²⁰⁷Pb hyperfine coupling indicates a very low spin-density on lead. We suggest that the centre is formed by electron addition to manganese to give a formal d⁷ centre, with concomitant loss of one equatorial carbonyl ligand. We defind z as the direction of the lost ligand. A second centre, detected at high gain, having a large hyperfine coupling to ²⁰⁷Pb and a 31 G coupling to ⁵⁵Mn is tentatively identified as the parent cation.In marked contrast, the molecule (CO)₄CoPbPh₃ gave a single centre having comparable ⁵⁹Co hyperfine and g-tensor components, but also a very large hyperfine coupling to ²⁰⁷Pb (ca. 3300 G). Thus, in this case, an electron gain centre (d⁹) has been formed, the electron being accomodated in the highest MO having a large d_z² component on cobalt (z being now the CoPb direction).Reasons for the adoption of these different structures are discussed.     

Low oxidation state ruthenium chemistry : IV. The reactions of M(CO)2(PPh3)3 complexes (M = Fe,Ru) and the hydrogenation and isomerization of alkenes catalyzed by RuL(CO)2(PPh3)2 (L = H2, PPh3)

The complexes M(CO)₂(PPh₃)₃ (I, M = Fe; II, M = Ru) readily react with H₂ at room temperature and atmospheric pressure to give cis-M(H)₂(CO)₂(PPh₃)₂ (III, M = Fe;IV,M = Ru). I reacts with O₂ to give an unstable compound in solution, in a type of reaction known to occur with II which leads to cis-Ru(O₂)(CO)₂(PPh₃)₂(V). Even compound IV reacts with O₂ to give V with displacement of H₂; this reaction has been shown to be reversible and this is the first case where the displacement of H₂ by O₂ and that of O₂ by H₂ at a metal center has been observed. III and IV are reduced to M(CO)₃(PPh₃)₂ by CO with displacement of H₂; Ru(CO)₃- (PPh₃)₂ is also formed by treatment of IV with CO₂, but under higher pressure. Compounds II and IV react with CH₂CHCN to give Ru(CH₂CHCN)(CO)₂- (PPh₃)₂(VI) which reacts with H₂ to reform the hydride IV.cis-Ru(H)₂(CO)₂(PPh₃)₂(IV) has been studied as catalyst in the hydrogenation and isomerization of a series of monoenes and dienes. The catalysts are poisoned by the presence of free triphenylphosphine. On the other hand the ready exchange of H₂ and O₂ on the “Ru(CO)₂(PPh₃)₂” moiety makes IV a catalyst not irreversibly poisoned by the presence of air. It has been found that even Ru(CO)₂(PPh₃)₃(II) acts as a catalyst for the isomerization of hex-1-ene at room temperature under an inert atmosphere.     

The chemistry and the sterechemistry of Poly(N-Alkyliminoalanes: XIII. The crystal and molecular structure of the hexamers (ClAlN-i-Pr)6 and (Me0.83H0.17AlN-i-Pr)6MeAlN-i-Pr)6

The crystall and molecular structures of (ClAlN-i-Pr)₆ (I), and of (Me_0.83H_0.17AlN-i-Pr)₆(MeAlN-i-Pr)₆ have been determined by single crystal three-dimensional X-ray analysis. Block-matrix least-squares refinements led to conventional R factor of 0.039 for I and 0.037 for II. The compounds are isostructural, as the cage molecules consist of a prismatic hexagonal framework, (AlN)₆, similar to that observed for the parent hydrogenated analogue (HAlN-i-Pr)₆.Some differences in bond distances and angles are discussed, in connection with the different Al-bonded substituents. Crystal data: I, trigonal space group R$\text{3}$; a = 17.083(2), c = 9.652(1); Z = 3; D_c 1.46 g cm^?3; II, trigonal space group R$\text{3}$, a = 17.378(3), c = 9.706(3) »; Z = 3; D_c 1.15 g cm^?3.     

Complexes of organometallic compounds : XXXIX. synthesis,infrared and mössbauer studies on monoorganotin(IV) complexes with tridentate ligands

Novel complexes RClSntrid, where R is Me, Ph, n-Oct, and trid^2? are dianions of tridentate “planar” ligands with ONO and SNO donor atoms, were synthesized and investigated in the solid state by infrared and Mössbauer spectroscopy. Possible configurations are discussed; polymeric trigonal bipyramidal structures seem to occur, although five-coordinated monomers as well as octahedral dimers (via oxygen or sulfur bridges) are not excluded.     

The reaction of allene with β-diketonatoiridium(I) complexes: formation and crystal structure of a new bis-β-allylic derivative of iridium(III)

The reaction of allene with (Hfacac)Ir(η-C₈H₁₄)₂ to give a new bis-η-allylic complex of iridium(III) containing an allene tetramer is described; the X-ray structure of this compound is reported.     

Polymer films on electrodes: Part II. Film structure and mechanism of electron transfer with electrodeposited poly(vinylferrocene)

The structure and properties of electrodeposited poly(vinylferrocene) (PVF) films on platinum electrodes (PVF/Pt) were examined by electron microscopy, X-ray photoelectron spectroscopy, various electrochemical techniques and measurements of the film resistance. The data were consistent with a mechanism in which the polymer films are permeable to dis-solved reactants. A theoretical treatment of this situation for chronoamperometry is presented. The oxidation and reduction of a variety of dissolved reactants with redox potentials far removed from that of the PVF/PVF⁺ system at PVF/Pt occurred by diffusion of the electroactive species through the polymer film and subsequent reaction at the platinum surface.     

A dinuclear hydride complex of platinum(I) containing both bidentate and monodentate bis(diphenylphosphino)methane ligands: the crystal structure of [Pt2H(Ph2PCH2PPh2)(μ-Ph2PCH2PPh2)2][PF6]

The crystal structure of the title compound has been determined from 6049 X-ray diffractometric intensities with I > 3σ(I), and refined by a least-squares procedure to R = 0.050. The crystals are monoclinic, space group P2₁/n, a = 13.702(2) b = 14.255(2), c = 39.556(6) Å, β = 94.75(1)°, Z = 4. The structure of the cation displays two different coordination modes of the Ph₂PCH₂PPh₂ ligands. Two of these are bidentate, bridging the Pt-Pt bond [2.769(1)Å] to form a Pt₂(μ-Ph₂PCH₂PPh₂)₂ nucleus, while the third acts as a monodentate two-electron donor. The hydrido ligand was not located, but its position is inferred from the coordination geometry of the platinum atom to which it is bonded. The metalligand distances are: Pt-P(trans to P) 2.248(3)–2.289(4) and Pt—P(trans to Pt) 2.347(4) Å.     

Jahn-teller splitting of the 3s → 3p transition of sodium isolated in A·Xenon matrix

The rose center in BaF₂ is investigated by resonant Raman scattering. The spectra obtained at liquid-helium temperature show multiple order and combination bands of the internal local modes (up to the sixth order), and associated side bands of the lattice. The temperature dependence of the linewidth of the local-mode transitions has been investigated and is explained as being due to anharmonic coupling to the lattice.     

Metallophosphoranes: Carbonyl substitution reactions and the X-ray crystal structure of cis-Cat2PMn(CO)4P(OPh)3 (Cat = benzodioxyl)

Cat₂PMn(CO)₅ (1, cat =

) is found to undergo carbonyl substitution reactions with phosphorus donors to give the isolable products cat₂PMn(CO)₄L, where L = cis-PPh₃ (2); trans-PPh₃ (3); cis-P(OMe)₃ (4); and cis-P(OPh)₃ (5). No evidence for CO insertion into the pentacoordinate PMn bond is observed. The X-ray crystal structure of 5 shows that the crystals are monoclinic, space group P2₁/n. The unit cell parameters are: a 10.523(2), b 25.765(5), c 13.344(2) Å, β 99.11(2)°, and Z = 4. Full matrix least squares refinement reached R= 0.054 for 3099 observed reflections. The pentacoordinate phosphorus adopts a distorted trigonal bipyramid geometry with the Mn in an equatorial position. Noteworthy is the small equatorial OPO angle of 110.1(2)°.     

Reactivity of cyclopalladated compounds: VIII. Synthesis of cyclometallated compounds with an oxygen as the donor atom. Crystal and molecular structure of (8-methylquinoline-C,N)-(1-methoxynaphthalene-8-C,O)palladium(II)

Treatment of 1-methoxynaphthalene (MXNH) with n-butyllithium in a diethyl ether/n-hexane solution gives 1-methoxynaphthalene-8-lithium (MXNLi) in 30% yield as an insoluble material. This compound reacts with PdCl₂(SEt₂)₂ to give bis(1-methoxynaphthalene-8-C,O)palladium(II) (I)_and with PtCl₂(SEt₂)₂ to give cis- and trans-(1-methoxynaphthalene-8-C,O)(1-methoxynaphthalene-8-C)(diethylsulfide)platinum(II) (II), which are non-rigid molecules in solution. With the cyclopalladated dimers [{$\text{Pd(CN}$)Cl₂}₂], MXNLi gives the palladobicyclic compounds: ($\text{N∩C)P}$$\text{d(C∩O}$) (III). An X-ray diffraction study of compound IIIa where N∩N = 8-methylquinoline-C,N reveals the planarity of the molecule, shows that it has a cis configuration with respect to the PdC bonds, and confirms that the oxygen atom of MXN is bonded to palladium: PdO 2.236(4) Å. The geometry of IIIa is maintained in solution, whereas the corresponding compounds IIIb and IIIc in which N∩C is benzo[h]quinoline-9-C,N and N,N-dimethyl-1-naphthylamine-8-C,N, respectively, appear to be mixtures of cis and trans isomers in solution. With PMe₂Ph I and II give trans-Pd(MXN)₂(PMe₂Ph)₂ and cis-Pt(MNX)₂(PMe₂Ph)₂, respectively, in which the methoxynaphthalene is bound to the metals via the 8-carbon of the naphthalene ring. Only one phosphine ligand adds to compounds IIIb and IIIc with displacement of the O → Pd bond. One carbon monoxide ligand can be added to the platinum compound II to give Pt(MXN)₂(SEt₂)CO which in solution exists as two isomers in equilibrium.     

The densities and molar volumes of molten lead(II) dodecanoate/dodecanoic acid mixtures over their complete composition range: Evidence for non-ideal behaviour

Data are presented for the densities and molar volumes of the molten system lead(II) dodecanoate/dodecanoic acid over its complete composition range. For equimolar mixtures, plots of molar volume against temperature show curvature at high temperatures, suggesting deviations from ideal behaviour. Support for this comes from a plot of molar volume at constant temperature against acid mole fraction. Densities and molar volumes are reported for lead (II) carboxylate/carboxylic acid (0.5 mole fraction) and for pure carboxylic acid for the even chain acids C₁₀ to C₁₈. The molar volumes at constant temperature in these cases are linear functions of chain length, although the volume occupied per methylene group in equimolar mixtures is suggested to be slightly smaller than with pure soap or pure acid. An explanation for non-ideal behaviour becoming more marked at higher temperature is given in terms of acid monomer-dimer equilibria.