The effect of introduction of manganese hydroxide and hydrated aluminum oxide on the pore structure and surface charge of Zr(IV), Ti(IV), and Sn(IV) oxyhydrates

The specific surface area, micropore volume, and pore size distribution for the Zr(IV), Sn(IV), and Ti(IV) oxyhydrates and double hydrates of the composition M _x Mn_1?x O _y ·nH₂O and M _x Al1_?x O _y ·nH₂O [M = Zr(IV), Sn(IV), Ti(IV), x = 0.5–0.9 were calculated. The specific surface charge and zero-charge point in 0.12 M KNO₃ were determined.     

Lanthanide bis(trifluoromethanesulfonyl)amides, synthesis, characterization and catalytic activity

The synthesis of lanthanum, neodymium and ytterbium bis(trifluoromethanesulfonyl)amides, named triflimidates, from acetates, carbonates and oxides is investigated. When the synthesis is performed in water, all the salts contain one molecule of water and the lanthanum and neodymium salts synthesized from the acetates also contain one molecule of acetic acid. After removal of the water and acetic acid in refluxing ethanol, the salts are obtained anhydrous but associated for lanthanum and neodymium, whereas the ytterbium salt is monomeric and volatile. When the synthesis is performed directly in ethanol, the neodymium salt contains two molecules of coordinated ethanol.In non-hazardous solvents, these triflimidates are better catalysts than the analogous triflates toward either Friedel-Crafts acylations, or Fries transpositions or Baeyer-Villiger oxidations. Unexpectedly, the cerium(IV) triflimidate catalyzes the oxidation of aromatic ketones to give the corresponding acids.     

Syntheses,characterization, and Mossbauer study of Sn(II and Sn(IV) complexes of the cyclopentadienedithiocarboxylate ligand

The preparation and physical characterization of the tetraethylammonium salts of bis(cyclopentadienedithiocarboxylate)stannate(II) and tris(cyclopentadienedithiocarboxylate)stannate(IV) are reported. The coupling constants for the ring protons of the coordinated and uncoordinated ligand indicate that the oxidation state variation of the metal has little effect on the electronic structure of the ligand. The Mössbauer parameters for the Sn(IV) complex (δ = 1.05 ± 0.02 mm/sec with respect to SnO₂, Line width = 1.05 mm/sec) are normal for a pseudo-octahedral complex. The values for the Sn(II) complex are somewhat abnormal for a Sn(II) complex (δ = 0.29 mm/sec, Line width = 1.65 mm/sec) and are interpreted as indicative of metalmetal bonding in the molecular structure.     

Synthesis and characterization of the first diorganotin(IV) complexes containing mixed arylazobenzoic acids and having skew trapezoidal bipyramidal geometry

Three diorganotin(IV) complexes of the type, [R₂Sn(L^aH)(L^bH)] (R = ⁿBu or Me and, L^aH and L^bH are two different 5-[(E)-2-(aryl)-1-diazenyl]-2-hydroxybenzoate residues; a: aryl = 4′-Cl-(held constant) and b: aryl = 4′-Me or 4′-Br) have been prepared either by reacting ⁿBu₂SnO, L^aHH′ and L^bHH′ (1:1:1) in anhydrous toluene or by reacting Me₂SnCl₂, L^aHNa and L^bHNa (1:1:1) in anhydrous methanol. The products were characterized by microanalysis, IR, NMR (¹H, ¹³C, ¹¹⁹Sn) and ^119mSn Mössbauer spectroscopy. A full characterization of the structures of the complexes [ⁿBu₂Sn(L^aH)(L^bH)] (1 and 2) and [Me₂Sn(L^aH)(L^bH)] (3) in the solid state were accomplished by single crystal X-ray crystallography. These complexes were found to adopt the usual dicarboxylato structural type with a skew-trapezoidal bipyramidal arrangement around the tin atom.     

Structural investigations on diorgano- and triorganotin(IV) derivatives of [meso-tetra(4-sulfonatophenyl)porphine] metal chlorides

Several new complexes of organotin(IV) moieties with MCl_n[meso-tetra(4-sulfonatophenyl)porphine], (R₂Sn)₂MCl_n[meso-tetra(4-sulfonatophenyl)-porphinate]s and (R₃Sn)₄MCl_n [meso-tetra(4-sulfonatophenyl)porphinate]s, [M = Fe(III), Mn(III): n = 1, R = Me, n-Bu; Ph; M = Sn(IV): n = 2, R = Me, n-Bu] have been synthesized and their solid state configuration investigated by infrared (IR) and Mössbauer spectroscopy, and by ¹H and ¹³C NMR in D₂O.The electron density on the metal ion coordinated inside the porphyrin ring is not influenced by the organotin(IV) moieties bonded to the oxygen atoms of the side chain sulfonatophenyl groups, as it has been inferred on the basis of Mössbauer spectroscopy and, in particular, from the invariance of the isomer shift of the Fe(III) and Sn(IV) atoms coordinated into the porphyrin square plane of the newly synthesized complexes, with respect to the same atoms in the free ligand.As far as the coordination polyhedra around the peripheral tin atoms are concerned, infrared spectra and experimental Mössbauer data would suggest octahedral and trigonal bipyramidal environments around tin, in polymeric configurations obtained, respectively, in the diorganotin derivatives through chelating or bridging sulfonate groups coordinating in the square plane, and in triorganotin(IV) complexes through bridging sulfonate oxygen atoms in axial positions.The structures of the (Me₃Sn)₄Sn(IV)Cl₂[meso-tetra(4-sulfonatophenyl)porphinate] and of the two model systems, Me₃Sn(PS)(HPS) and Me₂Sn(PS)₂ [HPS = phenylsulfonic acid], have been studied by a two layer ONIOM method, using the hybrid DFT B3LYP functional for the higher layer, including the significant tin environment. This approach allowed us to support the structural hypotheses inferred by the IR and Mössbauer spectroscopy analysis and to obtain detailed geometrical information of the tin environment in the compounds investigated.¹H and ¹³C NMR data suggested retention of the geometry around the tin(IV) atom in D₂O solution.     

Complexes of TiCl4, VCl4 and SnX4 (X = Cl or Br) with Schiff bases derived from 2-aminobenzimidazole

Summary The reactions of anhydrous titanium(IV), tin(IV) and vanadium(IV) halides with Schiff bases derived from 2-aminobenzimidazole and 4-methylbenzaldehyde (abimbz) and salicylaldehyde (abisal), yield hexacoordinated complexes M(abimbz)Cl₄ and M(abisal)₂X₄ (M = Ti, Sn or V; X = Cl or Br).The compounds have been characterized by elemental analyses, magnetic measurements, e.p.r., electronic and i.r. spectral studies. I.r. spectra suggest that the Schiff base (abimbz) is coordinated as a bidentate ligand with the metal ion and the (abisal) base acts as a monodentate ligand.     

Preparation and characterization of octacyanomolybdates(IV and V) and octacyanotungstates(IV and V) with 2,2′-bipyridylium cation

Reaction of protonated 2,2′-bipyridine (bpy) with octacyanometalates(IV and V), [M(CN)₈]ⁿ⁻ (M = Mo or W, n = 3 or 4), gave the following complexes: {(bpyH)₃[M(CN)₈]·4H₂O}, {(bpyH)₃(H₃O)[M(CN)₈]·H₂O}, {(bpyH₂)₂[W(CN)₈]·3H₂O} and {(bpyH₂)K₂[W(CN)₈]·2H₂SO₄·7H₂O}. These salts were characterized by electron absorption and reflectance spectrometry, IR, Raman and ESR spectrometry, thermo gravimetry and differential thermal analysis, cyclic voltammetry and potentiometry. The solubility of the salts in water and some polar organic solvents has been measured. The intensively coloured salts of molybdenum(IV) and tungsten(IV) have been discussed in terms of the bpyH⁺-[M(CN)₈]⁴⁻ ion pairs, which exhibit an outer-sphere electron transfer between adjacent redox sites.     

C,N-chelated organotin(IV) trifluoroacetates. Instability of the mono- and diorganotin(IV) derivatives.

The C,N-chelated tri-, di- and monoorganotin(IV) halides react with equimolar amounts of CF₃COOAg to give corresponding C,N-chelated organotin(IV) trifluoroacetates. The set of prepared tri-, di- and monoorganotin(IV) trifluoroacetates bearing the L^CN ligand (where L^CN is 2-(N,N-dimethylaminomethyl)phenyl-) was structurally characterized by X-ray diffraction analyses, multinuclear NMR and IR spectroscopy. In the case of triorganotin(IV) trifluoroacetates and (L^CN)₂Sn(OC(O)CF₃)₂, no tendency to form hydrolytic products, or instability towards the moisture was observed. L^CNRSn(OC(O)CF₃)₂ (where R is n-Bu or Ph) and L^CNSn(OC(O)CF₃)₃ forms upon crystallization from THF in the air mainly dinuclear complexes in which the two tin atoms are interconnected either by hydroxo-bridges or by an oxo-bridge and/or by a bridging trifluoroacetate(s). In the case of hydrolysis of L^CN(n-Bu)Sn(OC(O)CF₃)₂, a zwitterionic stannate of formula L^CN(n-Bu)Sn(OC(O)CF₃)₂·CF₃COOH was isolated from the mother liquor, too. Products of hydrolysis of L^CN(n-Bu)Sn(OC(O)CF₃)₂ and L^CNSn(OC(O)CF₃)₃, and some other oxygen bridged organotin(IV) compounds containing the same ligand, were tested as possible catalysts of some transesterification reactions as well as in direct dimethyl carbonate (DMC) synthesis from CO₂ and methanol.     

n-Butylammonium carboxylates/Tf2O: ionic liquid based systems for the synthesis of unsymmetrical imides via a Ritter-type reaction

We have developed a new method for the preparation of unsymmetrical imides using liquid carboxylate salts via a Ritter-type process. The reactions were carried out with nitriles and n-butylammonium carboxylates as ionic liquids in the presence of triflic anhydride (Tf₂O) as the promoter. Mild reaction conditions, simplicity of the procedure, and proton-free conditions are the main advantages of this procedure.     

Complexes of zinc,cadmium and mercury(II) with the zwitter-ionic form of NN′-ethylenebis (salicylideneimine)

The Schiff base NN′-ethylenebis(salicylideneimine), H₂ salen reacts with hydrous and anhydrous Zinc, Cadmium and Mercury(II) salts to give complexes M(H₂ salen)X₂·nH₂O (M = Zn, Cd, Hg; XCl, Br, I, NO₃; MZn, X₂SO₄; n = 0?2). Spectroscopic and other evidence indicated that; (i) halide and sulphate are coordinated to the metal ion, whereas the nitrate group is ionic in mercury nitrate compound and covalently bonded in zinc and cadmium nitrato complexes, (ii) the Schiff base is coordinated through the negatively charged phenolic oxygen atoms and not the nitrogen atoms, which carry the protons transferred from phenolic groups on coordination, (iii) therefore the coordination numbers suggested are 4-, in mercury and 4- or 6- in zinc and cadmium Schiff base complexes.     

Synthesis and spectral studies of diorganotin(IV) dialkyldithiophosphates

Two series of diorganotin(IV) dialkyldithiophosphates, [RR′Sn{SSP(OR″)₂}₂](R = Me or Et; R′= Ph; R″ = Et, Prⁿ, Prⁱ or Buⁿ) and [RR′Sn(Cl){SSP(OR″)₂}] (R = R′= Me, Et or Ph; R″ = Ph; R″ = Et, Prⁱ or Buⁿ) were prepared and characterised by i.r. and NMR (¹H, ¹³C, ³¹P, ¹⁹⁹Sn) spectroscopy. The NMR data indicate five and six coordinate geometries for [RR′Sn(Cl){SSP(OR″)₂}] and [RR′Sn{SSP(OR″)₂}₂] complexes, respectively. The chloro complexes showed ²J (PSn) whereas such couplings were not observed in the spectra of [RR′Sn{SSP(OR″)₂}₂].     

Diorganophosphinoalkyl-dimethylzinnchloride: Synthese,struktur und reaktionsverhalten

Phosphinoalkylchlorostannanes of the type Me₂Sn(Cl)(CH₂)_nPR¹R² (n = 2,3) (I–VIII) are synthesized by a redistribution reaction of the tetraorganostannanes Me₃Sn(CH₂)_nPR¹R² (n = 2,3) with trimethyltin chloride. In non-coordinating solvents the tin atom in I–IV is tetracoordinated, whereas NMR data indicate an intramolecular SnP interaction for V–VIII. In the solid state compound III exists as an 1:1 adduct with trimethyltin chloride. With methyl iodide compounds I–VIII form the phosphonium stannates Me₂SnCl) (I) (CH₂)_nP+R¹R²Me (XI–XIII). Compounds I–VIII are suitable starting materials for the synthesis of the tin hydrides Me₂Sn(H)(CH₂)_nPR¹R² (XIV–XVI) and the distannanes [Me₂Sn(CH₂)_nPR¹R²]₂ (XVII–XIX). The reaction of I–VIII with sodium in liquid ammonia or with lithium in THF, respectively, yields solutions of the corresponding alkali stannides Me₂Sn(M)(CH₂)_nPR¹R² (M = Li, Na).     

The reactions of diphenylcarbazide and diphenylcarbazone with cations : Part IV. Cations of Mn,Fe, Co,Ni, Cu,Zn, Cd,Sn And Pb

Of the cations mentioned in the title, only Pb(IV) and Sn(IV) do not react with diphenylcarbazone. The compositions of the carbazone complexes were determined by Job's method; the formula proved to be M(HD)_n according to the valence of the cation. Diphenylcarbazide forms metal complexes only after its oxidation to diphenylcarbazone. Oxidation of carbazide by the metal ion itself occurs with copper(II) and iron(III).     

New di- and triorganotin(IV) complexes of tripodal Schiff base ligand containing three imidazole arms: Synthesis, structural characterization, anti-inflammatory activity and thermal studies

Some new tri- and diorganotin(IV) complexes of the general formula, R₃Sn(H₂L) and R′₂Sn(HL) [where R = Me, n-Pr, n-Bu and Ph; R′ = Me, n-Bu, Ph and n-Oct; H₃L = Schiff base (abbreviated as tren(4-Me-5-ImH)₃) derived from condensation of tris(2-aminoethyl)amine (tren) and 4-methyl-5-imidazolecarboxaldehyde (4-Me-5-ImH)] have been synthesized. The coordination behaviour of Schiff base towards organotin(IV) moieties is discussed on the basis of infrared and far-infrared, ¹¹⁹Sn Mössbauer and multinuclear (¹H, ¹³C and ¹¹⁹Sn) magnetic resonance (NMR) spectroscopic studies. Thermal studies of all of the synthesized organotin(IV) complexes have been carried out using TG, DTG and DTA techniques. The residues thus obtained from pyrolysis of the studied complexes have been characterized by X-ray powder diffraction analysis and IR. The newly synthesized complexes have been tested for their anti-inflammatory activity and toxicity (LD₅₀).     

The conditions of formation of heterometallic complexes in the GeCl4 (SnCl4)-citric acid-M(CH3COO)2-H2O systems. The crystal and molecular structures of [M(H2O)6][Ge(HCit)2] · 4H2O (M = Mg, Mn, Co, Cu, Zn) and [M(H2O)6][Sn(HCit)2] · 4H2O (M = Mg, Co, Ni)

Fourteen bis(citrato)germanates(IV) and bis(citrato)stannates(IV) were prepared, in particular, [M(H₂O)₆][Ge(HCit)₂] · 4H₂O (M = Mg (I), Mn (II), Fe (III), Co (IV), Ni (V), Cu (VI), Zn (VII)) and [M(H₂O)₆][Sn(HCit)₂] · nH₂O (M = Mg, n = 4 (VIII); Mn, n = 2 (IX); Fe, n = 4 (X); Co, n = 4 (XI); Ni, n = 4 (XII); Cu, n = 4 (XIII); Zn, n = 3 (XIV)) (H₄Cit is citric acid). The purity and the composition of the products were determined by a set of physicochemical methods including elemental analysis, thermogravimetry, and IR spectroscopy. The structures of I, II, IV, VI, VII, VIII, XI, and XII were determined by X-ray diffractometry. All eight crystals composed of centrosymmetrical octahederal [M(H₂O)₆]²⁺ cations, [Ge(HCit)₂]^2? (or [Sn(HCit)₂]^2?) anions, and crystal water molecules are isostructural. The structural units in I, II, IV, VI, VII, VIII, XI, and XII are connected by systems of hydrogen bonds to form a three-dimensional framework.     

Studies on C-heterocyclic tin compounds. The synthesis and spectral characterization of some thienyl tetraorganotin(IV) compounds

The synthesis of a series of tetraorganotin(IV) compounds containing selectively the 2-thienyl, 3-thienyl, 5-methyl-2-thienyl, 5-t-butyl-2-thienyl, 4-methyl-2-thienyl and 3-(2-pyridyl)-2-thienyl groups [L], of formula R_4-nSn[L]_n (R = Ph, p-tolyl, Me, cyclopentyl, cyclohexyl; n = 1–4) is reported. Features of structural interest deduced from ^119mSn Mössbauer and NMR (¹³C and ¹¹⁹Sn modes) spectra are considered.     

Syntheses and characterization of triorganotin complexes: X-ray crystallographic study of triorganotin pyridinedicarboxylates with trinuclear, 1D polymeric chain and 2D network structures

A series of new triorganotin(IV) pyridinedicarboxylates [(C₂H₅)₃NH][(Me₃Sn)₃(2,6-pdc)₂(H₂O)₂] (1), [(C₂H₅)₃NH][(Ph₃Sn)₃(2,6-pdc)₂(H₂O)₂] (2), [(C₂H₅)₃NH]{[(PhCH₂)₃Sn]₃(2,6-pdc)₂(H₂O)₂} (3), [Me₃Sn(3,5-pdc)]_n (4), [Ph₃Sn(3,5-pdc)]_n (5), [(PhCH₂)₃Sn(3,5-pdc)]_n (6), [(Me₃Sn)₂(2,5-pdc)]_n (7), [(Ph₃Sn)₂(2,5-pdc)]_n (8) and {[(PhCH₂)₃Sn]₂(2,5-pdc)}_n (9) were synthesized by the reaction of trimethyltin(IV), triphenyltin(IV) or tribenzyltin(IV) chloride with 2,6(3,5 or 2,5)-H₂pdc (pdc = pyridinedicarboxylate) when triethylamine was added. Complexes 1-9 have been characterized by elemental, IR, ¹H, ¹³C and ¹¹⁹Sn NMR analyses. Among them complexes 1, 5 and 7 have also been characterized by X-ray crystallographic diffraction analyses. Complex 1 has a trinuclear structure and forms a 2D supramolecular structure due to the coordinated water molecules via hydrogen bonds to the pendant O atoms of the carboxyl groups and the N atoms derived of the pyridine ring. Complex 5 forms a 1D polymeric chain by the intermolecular Sn?N (N atom derived of pyridine ring) interactions. Complex 7 has a network structure where 2,5-pyridinedicarboxylate acts as a tetradentate ligand coordinated to trimethyltin(IV) ions.     

The mechanism of formation of volatile hydrides by tetrahydroborate(III) derivatization: A mass spectrometric study performed with deuterium labeled reagents

In order to clarify the mechanism of hydride formation, the isotopic composition of arsine, stibine, bismuthine, germane, stannane and hydrogen selenide formed by derivatization with either NaBD₄ (TDB) or NaBH₄ (THB) with inorganic As(III), Sb(III), Bi(III), Ge(IV), Sn(IV) and Se(IV) in aqueous reaction media and under various reaction conditions was determined. Batch hydride generation and gas chromatography–mass spectrometry (GC–MS) were employed. The analyte, present in 0.5–5 ml of acid solution (0.1–10 M in HCl or HNO₃ or HClO₄) was derivatized with 1 ml of 0.25–0.5 M TDB / THB in 0.1 M NaOH solution. For TDB derivatization in H₂O reaction media, almost pure BiD₃ and SbD₃ were always obtained for Bi(III) and Sb(III). Nearly pure AsD₃ could be obtained only under some reaction conditions. In general, for As(III), the isotopic composition of the arsines depends strongly on reaction conditions and included all possible AsH_nD_3−n from almost pure AsD₃ to almost pure AsH₃. For Ge(IV) and Sn(IV), the isotopic composition of generated GeH_nD_4−n and SnH_nD_4−n depends on reaction conditions, but pure GeD₄ and SnD₄ could never be obtained. Pure H₂Se was obtained in all cases, independent of reaction conditions. The occurrence of side reactions involving D–H exchange in TBD during its hydrolysis and before the derivatization step, as well as on recently formed hydrides following derivatization was investigated. D–H exchange in TDB during acid hydrolysis appears to occur to a limited extent. Amongst the hydrides, H₂Se undergoes H–D exchange whereas germane and stannane do not exchange at all. Arsine undergoes D–H exchange at elevated acidities (pH < 0) whereas stibine and bismuthine do not exchange significantly during the generation and stripping steps.A reaction model for hydride generation is proposed accounting for primary reactions giving rise to hydride formation through reaction intermediates, as well as side reactions involving D–H exchange and decomposition of reactive hydroboron species, reaction intermediates and final products. Hydrides are formed by direct hydrogen transfer from boron to the analyte atom, most likely through concerted mechanisms taking place via reaction intermediates.     

The preparation and 119Sn and 19F NMR spectra of some trifluoromethylphenyltin(IV) compounds

The preparation of a series of new trifluoromethylphenyltin(IV) compounds, Bu_nSn(C₆H₄CF₃-3)_4-n, (C₆H₄CF₃-3)SnCl₃, (C₆H₄CF₃-2)SnCl₃, and some related adducts with 2,2¹-bipyridyl and 1,10-phenanthroline, is described. ¹¹⁹Sn and ¹⁹F chemical shifts have been determined, together with values of J(¹¹⁹Sn=F) and ³J(¹¹⁹Sn=H_itortho), and the possibility of a “through space” tinfluorine coupling mechanism is also discussed.     

A proton NMR investigation of metalmetal bonding in trimethyltin-aluminium, -gallium, -indium and -thallium organometallic compounds

Proton NMR data for the Group III methyl derivatives, MMe₃ and LiMMe₄ are compared with NMR data for the novel tin—Group III-metal bonded species, Li[Me₃SnMMe₃] (M  Al, Ga, In and Tl) and for Li[(Me₃Sn)_n-TlMe_4?n] (n = 0 to 4), reported here for the first time.The presence of tinmetal bonding in these derivatives is established by the observed tin-across-metal coupling constants and for the thallium derivatives by the additional observation of thallium-across-tin coupling.The variation in the magnitudes of ²J(SnCH), ²J(TlCH), ³J(SnMCH) and ³J(TlSnCH) are reported as a function of M and as a function of the number of Me₃Sn groups bond to thallium in the [(Me₃Sn)_nTIME₄?_n]^?anions. Proposals concerning the factors governing the changes in these coupling constants and the chemical shifts are presented.