Synthesis and catalytic activity of uranium(IV) tetraphenylporphinate chloride

Conclusions The synthesis of a new complex, uranium(IV) tetraphenylporphinate chloride, was reported. This complex is an active catalyst for the oxidation of cholesterol.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2131–2132, September, 1986.     

Synthesis and structure of rhenium(IV) chloride complexes with acetonitrile

Cis and trans isomers of the tetrachlorodiacetonitrile rhenium(IV) complex were synthesized and isolated. The structure of cis-ReCl₄(N≡C-CH₃)₂ was studied by X-ray crystallography. It was shown that the coordination polyhedron of the central Re(IV) atom is formed by the four chlorine atoms and the nitrogen atoms of two coordinated acetonitrile molecules. The vibrational (IR and Raman) spectra of the cis isomer of the complex in solid state were interpreted by factor-group analysis. A comparison of the IR spectra of two isomers confirmed that they are cis and trans isomers.     

Synthesis and ion-exchange properties of cerium(IV) molybdate

Cerium(IV) molybdate, prepared under the optimum conditions of concentration, acidity etc., shows exchange capacity of 0.96 meq per g of exchanger. The sorption of a large number of metal ions has been investigated and the compound shows promising behaviour as cation exchanger. Numerous separations of analytical and radiochemical interest have been performed on the columns of this exchanger with great efficiency.     

Synthesis of the alkaloids julandine and ipalbidine-use of silicon (IV) chloride

Titanium (IV) chloride and silicon (IV) chloride with high oxygen affinity are the best Lewis acid catalysts, of a number tested, for cyclisation of an enamine-ketone (1) leading to the alkaloid, julandine (2); cyclisation of (6) in methanol solution without catalyst yields $\text{O}$-methylipalbidine (7) .     

Synthesis and properties of a thermally stable methyltitanium(IV) compound: Cyclopentadienylmethyldichlorotitanium(IV)

η⁵C₅H₅Ti(CH₃)Cl₂ and η⁵-C₅H₅Ti(C₂H₅TiCl₂ have been synthesized. The reactivity of the methyl compound is much greater than that of the closely related sandwich compound, (η⁵-C₅H₅)₂Ti(CH₃)Cl, but the thermal stability is comparable.     

Interaction of tin (IV) chloride with sulfolane and between tin (IV) chloride and lithium chloride in sulfolane solution

Tin (IV) chloride reacts with sulfolane (S) to form a cis-octahedral adduct SnCl₄·S₂. Solutions of lithium chloride and tin (IV) chloride in sulfolane contain the complex ions SnCl ₅ ^– and SnCl ₆ ^2– at 11 and 21 mole ratios of constituents, respectively. The complexes are characterized by conductimetry and by Mössbauer, IR, and Raman spectroscopy.     

Sulphoxide complexes of oxovanadium(IV) chloride and oxovanadium(IV) sulphate

Summary Ten complexes of VOCl₂ and VOSO₄ with several aliphatic and aromatic sulphoxides were prepared and studied systematically. Three were reported previously, and we have extended studies of them. The isolated complexes were characterized by elemental analysis, conductivity, thermal analysis, i.r. and electronic spectroscopy.     

Synthesis and acid-base and complex-forming properties of 1,4,7,10-tetrakis(dihydroxyphosphorylmethyl)-1,4,7,10-tetraazacyclododecane

Conclusions A new complexone, 1,4,7,10-tetrakis(dihydroxyphosphorylmethyl)-1,4,7,10-tetraazacyclododecane, has been synthesized and its acid-base and complex-forming properties have been studied. It shows a very high complexing capability and marked selectivity for cations of large ionic radius (Cd²⁺, Hg²⁺, Pb²⁺, La³⁺).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 844–849, April, 1984.     

Synthesis and acid-base and thermochromic properties of 5-(2-thiazolyl)-substituted formazans

As compared with benzothiazolylformazans, the thiazole ring of synthesized 5-substituted thiazolylformazans weakens their acidic properties and decreases their tendency to form intramolecular hydrogen bonds. The thiazolylformazans have positive red-blue thermochromism. Their IR and UV spectra are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 460–463, April, 1977.     

Tautomerism and acid-base properties of tetrazoles (review)

The prototropic tautomerism and acid-base properties of tetrazoles are discussed in this review. Major attention is directed to the factors that determine the state of the tautomeric equilibria, the acidities and basicities of tetrazoles, and the reactivities of tetrazoles. The available data are interpreted from the point of view of quantum-chemical calculations and modern concepts regarding the behavior of weak organic bases in solutions of acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 867–879, July, 1980.     

Synthesis and some properties of furylacrylates of aluminium(III) and titanium(IV)

Summary Compounds of the type [M(OPrⁱ)_m–n(FA)_n] (where m = 3 and n = 1 to 3 when M = Al; and m = 4 and n = 1 to 4 when M = Ti) have been synthesised by the reactions of aluminium and titanium isopropoxides with furylacrylic acid (HFA) in benzene. The corresponding tertiary butoxide derivatives, [M(OBu^t)_m–n(FA)_n], were also obtained by the alcohol-interchange technique. These compounds have been characterised by elemental analysis, and i.r. and p.m.r. spectra.     

Pentacoordinated Tin(IV) chloride complexes

Preparation and I.R. spectra of tin(IV) chloride complexes with acridine and piperazine have been described and their structures have been suggested.     

Insights into the acid-base properties of Pt(IV)-diazidodiam(m)inedihyroxido complexes from multinuclear NMR spectroscopy

Platinum(IV) am(m)ine complexes are of interest as potential anticancer pro-drugs, but there are few reports of their acid-base properties. We have studied the acid-base properties of three photoactivatable anticancer platinum(IV)-diazidodiam(m)ine complexes (cis,trans,cis-[Pt(IV)(N(3))(2)(OH)(2)(NH(3))(2)], trans,trans,trans-[Pt(IV)(N(3))(2)(OH)(2)(NH(3))(2)], and cis,trans-[Pt(IV)(N(3))(2)(OH)(2)(en)]) using multinuclear NMR methods and potentiometry. In particular, the combination of both direct and indirect techniques for the detection of (15)N signals has allowed changes of the chemical shifts to be followed over the pH range 1-11; complementary (14)N NMR studies have been also carried out. A distinct pK(a) value of approximately 3.4 was determined for all the investigated complexes, involving protonation/deprotonation reactions of one of the axial hydroxido groups, whereas a second pH-dependent change for the three complexes at approximately pH 7.5 appears not to be associated with a loss of an am(m)ine or hydroxido proton from the complex. Our findings are discussed in comparison with the limited data available in the literature on related complexes.     

Synthesis and mesomorphic properties of some platinum(II) and oxovanadium(IV) complexes

The synthesis and mesomorphic properties of a homologous series of N-(2-hydroxy-4-n-alkoxybenzylidene)-4'-n-decylphenylanilines and their platinum(II) and oxovanadium(IV) complexes are reported. All the ligands and their metal chelates exhibit enantiotropic mesophases, predominantly smectic A and smectic C phases. The transition temperatures and enthalpies have been determined for most of the compounds. The platinum(II) complexes have higher melting points and mesophase thermal stabilities. However, the oxovanadium(IV) complexes have a wider thermal range for the mesophase. Both platinum(II) and oxovanadium(IV) complexes containing only a chain on the biphenyl moiety exhibit a nematic phase.     

Synthesis, structure, and thermal properties of soluble hydrazinium germanium(IV) and tin(IV) selenide salts

The crystal structures of two hydrazinium-based germanium(IV) and tin(IV) selenide salts are determined. (N(2)H(5))(4)Ge(2)Se(6) (1) [I4(1)cd, a = 12.708(1) Angstroms, c = 21.955(2) Angstroms, Z = 8] and (N(2)H(4))(3)(N(2)H(5))(4)Sn(2)Se(6) (2) [P, a = 6.6475(6) Angstroms, b = 9.5474(9) Angstroms, c = 9.8830(10) Angstroms, alpha = 94.110(2) degrees, beta = 99.429(2) degrees, gamma = 104.141(2) degrees, Z = 1] each consist of anionic dimers of edge-sharing metal selenide tetrahedra, M(2)Se(6)(4-) (M = Ge or Sn), separated by hydrazinium cations and, for 2, additional neutral hydrazine molecules. Substantial hydrogen bonding exists among the hydrazine/hydrazinium molecules as well as between the hydrazinium cations and the selenide anions. Whereas the previously reported tin(IV) sulfide system, (N(2)H(5))(4)Sn(2)S(6), decomposes cleanly to microcrystalline SnS(2) when heated to 200 degrees C in an inert atmosphere, higher temperatures (>300 degrees C) are required to dissociate selenium from 1 and 2 for the analogous preparations of single-phase metal selenides. The metal chalcogenide salts are highly soluble in hydrazine, as well as in a variety of amines and DMSO, highlighting the potential usefulness of these compounds as precursors for the solution deposition of the corresponding metal chalcogenide films.     

Synthesis and acid-base transformations of (4-styrylpyridinio)-alkanesulfonates

(4-Styrylpyridinio)alkanesulfonates were synthesized by condensation of 2-(4-methylpyridinio)- and 2-(4-ethylpyridinio)-1-ethanesulfonates with aromatic aldehydes, and also by quaternization of 4-styrylpyridine by sulfoalkylating agents. For the p- and o-hydroxystyrylpyridinium compounds in aqueous solutions, the pK _a values were determined spectrophotometrically. It is believed that the planarity of the o-hydroxypyridinium compounds is disturbed because of the reaction of the hydroxy and the -sulfonatomethyl groups.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1357–1362, October, 1986.     

Synthesis, structure and magnetic properties of trans-tetrachloro-bis-(pyridine)-rhenium(IV)

trans-Tetrachloro-bis-(pyridine)-rhenium(IV) crystals were obtained by reaction of (pyH)₂ReCl₆ with pyridine in a sealed tube. The title compound crystallizes in the monoclinic space group C2/m with Z=2. The Re atom has special position of site symmetry 2/m. The environment about the Re atoms can be described as a slightly distorted octahedron with pyridine ligands occupying axial positions and four chloride ligands in the equatorial plane. Magnetic susceptibility measurements over the temperature range of 1.72–300 K were carried out using a SQUID magnetometer. The magnetic interactions are antiferromagnetic with the Néel point at 9.2 K.     

Synthesis, properties and structures of eight-coordinate zirconium(IV) and hafnium(IV) halide complexes with phosphorus and arsenic ligands

Eight-coordinate [MX(4)(L-L)(2)] (M = Zr or Hf; X = Cl or Br; L-L = o-C(6)H(4)(PMe(2))(2) or o-C(6)H(4)(AsMe(2))(2)) were made by displacement of Me(2)S from [MX(4)(Me(2)S)(2)] by three equivalents of L-L in CH(2)Cl(2) solution, or from MX(4) and L-L in anhydrous thf solution. The [MI(4)(L-L)(2)] were made directly from reaction of MI(4) with the ligand in CH(2)Cl(2) solution. The very moisture-sensitive complexes were characterised by IR, UV/Vis, and (1)H and (31)P NMR spectroscopy and microanalysis. Crystal structures of [ZrCl(4)[o-C(6)H(4)(AsMe(2))(2)](2)], [ZrBr(4)[-C(6)H(4)(PMe(2))(2)](2)], [ZrI(4)[o-C(6)H(4)(AsMe(2))(2)](2)] and [HfI(4)[o-C(6)H(4)(AsMe(2))(2)](2)] all show distorted dodecahedral structures. Surprisingly, unlike the corresponding Ti(iv) systems, only the eight-coordinate complex was found in each system. In contrast, the ligand o-C(6)H(4)(PPh(2))(2) forms only six-coordinate complexes [MX(4)[-C(6)H(4)(PPh(2))(2)]] which were fully characterised spectroscopically and analytically. Surprisingly the tripodal triarsine, MeC(CH(2)AsMe(2))(3), also produces eight-coordinate [MX(4)[MeC(CH(2)AsMe(2))(3)](2)] in which the triarsines bind as bidentates in a distorted dodecahedral structure. There is no evidence for seven-coordination as found in some thioether systems.