Cyclopentadienyluranium(IV)complexes with a chiral metallic center : I. Characterization of a prochiral structure by PMR spectroscopy

A range of compounds (C₅H₄R)₃UCl (R  alkyl) and the two tricyclopentadienyl compounds (C₅H₅)₂(C₅H₄R)UCl and C₅H₅(C₅H₄R)₂UCl, (R  CH(CH₃)₂) have been isolated and characterized by PMR spectroscopy. For the last compound, the PMR data indicate a magnetic non-equivalence for the cyclopentadienyl protons and for the methyl groups of R; both are due to the prochirality of the uranium atom.     

Tricyanmethanido-tris(pentahapto-cyclopentadienyl) Uran(IV): Polymere Uran-Organyle mit ungewöhnlicher Koordination am Uran(IV)

Tricyanmethanide-tris(h⁵-cyclopentadienyl)uranium (IV): Polymeric Organouranium Systems with an Unusual Coordination of the Uranium (IV)Ion (h⁵-C₅H₅)₃UCl viz. (h⁵-C₅H₄CH₃)₃UCl react in H₂O or THF with K[C(CN)₃] to give in good yields the new complexes (h⁵-C₅H₅)₃U[C(CN)₃] and (h⁵-C₅H₄CH₃)₃U[C(CN)₃] which turn out surprisingly stable relative to the organometallic starting material. The chemical and spectroscopic properties (IR, NIR/VIS and ¹H-NMR spectra) indicate the formation of extended oligomeric structures linked via C(CN)₃-bridges involving most probably linear sections: along with a trigonal planar arrangement of the three cyclopentadienyl ring normals.     

Koordinative komplexe des antibasen—basen-systems urantetrachlorid und tricyclopentadienyluran(IV)-chlorid

Novel coordination compounds of uranium tetrachloride with tricyclopentadienyluranium(IV) chloride of the compositions [(C₅H₅)₃U]₂UCl₆· 2DME, [(C₅H₅)₃U]₂UCl₆ and [(C₅H₅)₃U]UCl₅ have been synthesized by the following reactions in dimethoxyethane: (a) UCl₄ + 2TlC₅H₅, (b) UCl₄ + U(C₅H₅)₄ and (c) UCl₄ + 2(C₅H₅)₃UCl.The solvent-free compounds have been prepared in benzene in a similar manner. The physical and chemical properties of these compounds are reported.     

Zur chemie des tris(cyclopentadienyl)uran(IV)-kations in wässriger lösung : II. Oligomere metallorganische tetracyanometallat-komplexe des uran(IV): Bis(tris(pentahapto-cyclopentadienyl)uran(IV))-tetracyanonickolat(II) bzw. -platinat(II)

Novel organometallic uranium(IV) complexes of the composition [(η⁵-Cp)₃U^IV]₂[Mn^II(CN)₄] Cp = C₅H₅, M = Ni or Pt) have been prepared from Cp₃UCl and K₂[M(CN)₄] in aqueous solution. On the basis of their properties they are characterized as layered oligomeric structures involving squared arrays of both the U and M atoms within the same plane, and a presumably trigonal bipyramidal coordination of the uranium(IV) ion.     

Studies on Carboxylato Complexes of Tricyclopentadienyl Cerium (IV) Chloride and Bisindenyl Cerium (IV) Dichloride

Tricyclopentadienyl Cerium (IV) chloride and bisindenyl cerium (IV) dichloride have been treated with sodium salts of the appropriate carboxylic acids in benzene or tetrahydrofuran medium to give (C₅H₃)₃ Ce(R) and (C₉H₇)₂Ce(R)₂ wherein R is HCOO, CH₃COO, C₂H₅COO, C₃H₇COO and C₆H₅COO. The infrared spectra, thermal stabilities and other characteristics of the above compounds have been studied and reported.     

Chloroheptakis(dimethyl sulfoxide)­uranium(IV) trichloride

In the title complex, [UCl(C₂H₆OS)₇]Cl₃, the uranium metal center is coordinated in a distorted bicapped trigonal prism geometry by seven O atoms from di­methyl sulfoxide ligands and by a terminal chloride ligand. Charge balance is maintained by three outer‐sphere chloride ions per uranium(IV) metal center. Principle bond lengths include U—O 2.391 (2)–2.315 (2) Å, U—Cl 2.7207 (9) Å, and average S—O 1.540 (5) Å.     

Some novel triorganotin(IV) derivatives of β, δ-triketones

Thirty triorganotin(IV) derivatives of the type R₃Sn(R′COCHCOCH₂COR″) and [R₃Sn]₂ (R′COCHCOCHCOR″) (where R = CH₃, C₂H₅, nC₃H₇, nC₄H₉ and C₆H₅ and R′ = R″ = CH₃, C₆H₅ or R′ = C₆H₅, R″ = CH₃) have been synthesised by the interaction of R₃SnCl with mono- or disodium salt of 2, 4, 6-heptanetrione, 1-phenyl-1, 3, 5-hexanetrione and 1, 5-diphenyl-1, 3, 5-pentanetrione in 1:1 and 2:1 molar ratios, respectively. The complexes have been examined by their molecular weight, IR, PMR and elemental analyses and their tentative structures assigned. Both “Z” and “E” forms have been identified in the 1:1 complexes in equilibrium with the enol form containing five coordinate tin. The 2:1 derivatives contain one five- and other four coordinated tin(IV) except the phenyl analogue where both the tins are five coordinated.     

A simple redox transmetallation synthesis of uranium tetrachloride and related preparations of uranium triiodide and chlorotris(cyclopentadienyl)uranium(IV)

Reaction of mercuric chloride with an excess of uranium metal in tetrahydrofuran (THF) yields UCl₄(THF)₃, whilst UI₃(THF)₄ is obtained from a similar reaction with mercuric iodide. Chlorotris(cyclopentadienyl)uranium(IV) has been obtained by treatment of either (C₅H₅)₂Hg and mercuric chloride, or mercuric chloride and Tl(C₅H₅) with an excess of uranium in tetrahydrofuran.     

Synthesis,characterization and structure of the Bis(methyl-cyclopentadienyl)vanadium(IV) carboxylates

The 1,1’-dimethylvanadocene dichloride ((C₅H₄CH₃)₂VCl₂) reacts in aqueous solution with various carboxylic acids giving two different types of complexes. The 1,1’-dimethylvanadocene complexes of monocarboxylic acids (C₅H₄CH₃)₂V(OOCR)₂ (R=H,CCl₃, CF₃, C₆H₅) contain two monodentate carboxylic ligands, whereas oxalic and malonic acids act as chelate compounds of the formula (C₅H₄CH₃)₂V(OOC-A-COO) (A=−, CH₂). The structure of the (C₅H₄CH₃)₂ V(OOCCF₃)₂ complex was determined by single crystal X-ray diffraction analysis. The isotropic and anisotropic EPR spectra of all the complexes prepared were recorded. The obtained EPR parameter values were found to be in agreement with proposed structures.     

Synthesis and structure of diamido ether uranium(IV) and thorium(IV) halide "ate" complexes and their conversion to salt-free bis(alkyl) complexes

The high-yield synthesis, spectroscopic and structural determination of three new uranium(IV) and thorium(IV)ate complexes supported by three different diamido ether ligands are reported. The reaction of Li2[2,6-iPr2PhN(CH2CH2)]2O (Li2[DIPPNCOCN]) with 1 equiv. of UCl4 in THF generates [DIPPNCOCN]UCl3Li(THF)2(1), while reaction in toluene/ether gives salt-free [DIPPNCOCN]UCl2.1/2C7H8(2), which was identified by paramagnetically shifted 1H NMR. Reaction of 0.5 equiv. of {[tBuNON]UCl2}2([tBuNON]=[(CH3)3CN(Si(CH3)2)]2O2-) with 3.5 equiv. LiI in toluene and a minimal amount of THF results in [tBuNON]UI3Li(THF)2(3) and is very similar in structure to 1. {[MesNON]ThCl3Li(THF)}2(4), a dimeric complex with a Th2Li2Cl6 core, is prepared by reaction of Li2[2,4,6-Me3PhN(Si(CH3)2)]2O (Li2[MesNON]) with ThCl4 in THF. The analogous reaction in toluene did not yield the salt-free complex but rather a sterically crowded diligated compound, [MesNON]2Th (5), which was also structurally characterized. Complex 5 was prepared rationally by reacting 2 equiv. Li2[MesNON] with ThCl4 in toluene. The reaction of 1 and 3 with 2 equiv. of LiCH2Si(CH3)3 generates the stable, salt-free organoactinides [DIPPNCOCN]U(CH2Si(CH3)3)2(6) and [tBuNON]U(CH2Si(CH3)3)2(7). Complex 6 was structurally characterized. These reactions illustrate the viability of ate complexes as useful synthetic precursors.     

Tin(IV) complexes of schiff bases derived from pentane-2,4-dione or 2-hydroxy-1-naphthaldehyde

The 1∶2 molar reactions of tin(IV) chloride with the Schiff bases, CH₃C(OH):CHC(CH₃):NR and 2 HOC₁₀H₆CH:NR′ (where R=C₂H₅,n-C₃H₇ orn-C₄H₉ and R′=C₆H₅, C₂H₅,n-C₄H₉ ort-C₄H₉) have resulted in the synthesis of SnCl₄·(SBH)₂ type derivatives (whereSBH represents the Schiff base molecule). These have been characterized by elemental analysis, conductivity measurements and IR spectral studies.     

Thermokinetic studies of organotin(IV) carboxylates derived from para-methoxyphenylethanoic acid

Thremogravimetric (TG) studies of a new series of organotin(IV) carboxylates of the general formula R_nSnL_4-n (where R = CH₃, C₂H₅, C₄H₉, C₆H₅, C₆H₁₁ and C₈H₁₇, n = 2, 3 and L = para-methoxyphenylethanoate anion) have been carried out. Horowitz and Metzger method has been used to calculate thermokinetic parameters. It has been found that diorganotin dicarboxylates have larger activation energy than those of corresponding triorganotin carboxylates. Furthermore, the activation energy, Gibb’s free energy, entropy and enthalpy of diorganotin compounds shows the following trend, (CH₃)₂SnL₂ < (C₂H₅)₂SnL₂ < (C₄H₉)₂SnL₂ < (C₈H₁₇)₂SnL₂. This is attributed to steady increase in chain length of the alkyl groups. However, triorganotin compounds do not show such behavior.     

Alkoxy Derivatives of Tricyclopentadienyl Cerium (IV)

Tricyclopentadienyl cerïum(IV) chloride has been treated with various primary and secondary alcohols in benzene medium in the presence of triethylamine to give compounds, (C₅H₅)₃Ce(OR) wherein R may be CH₃ C₂H₃, n-C₂H₃, iso-C₃H₇, N-C₄H₉, iso-C₄H₉ and iso-C₃H₁₁. Infrared spectra and some physical characteristics of all these compounds and reported.     

Thiocarboxylato Complexes of Biscyclopentadienyl and Bisindenyl Titanium (IV)

Reactions of biscyclopentadienyl (and bisindenyl) titanium (IV) dichlorides with sodium salts of various thiocarboxylic acids in tetrahydrofuran medium, yield the complexes of the general formula (D) ²Ti(SCOR) ² where D is cyclopentadienyl or indenyl group and R? H, CH₃, C₂H₅, C⁴H⁵ or p-C⁴H⁴CH³ group. The foul smelling complexes are monomeric in nature. The IR spectra, thermal stabilities and Some physical characteristics of these complexes have been studied.     

Self-assembly of triorganotin(IV) or diorganotin(IV) moieties and 2-methylpyrazine-5-acid: Syntheses, characterizations and crystal structures of monomeric, polymeric or tetranuclear macrocyclic compounds

A series of diorganotin(IV) and triorganotin(IV) compounds of the type [R₂Sn(pca)₂ClSnR₃]₂ (RPhCH₂1, 2-ClC₆H₄CH₂2, 2-FC₆H₄CH₂3, 4-FC₆H₄CH₂4, 4-CNC₆H₄CH₂5, 4-ClC₆H₄CH₂6, 2,4-Cl₂C₆H₃CH₂7; Hpca2-methylpyrazine-5-acid), [(ⁿBu)₃Sn(pca)]_∞8, [(CH₃)₂Cl₂Sn(pca)Sn(CH₃)₂(pca)]_∞9, {[(ⁿBu)₂Sn(pca)]₂O}₂10 and {[Ph₂Sn(pca)]₃O₂[Ph₂Sn(OCH₃)]} 11 have been obtained by reactions of 2-methylpyrazine-5-acid with triorganotin(IV) chloride, diorganotin(IV) dichloride, and diorganotin(IV) oxide. All compounds were characterized by elemental, IR, and NMR spectra analyses. The crystal structure of compounds 1, 8-11 were determined by X-ray single crystal diffraction, which revealed that compound 1 was tetranuclear macrocyclic structures with seven-coordinate and five-coordinate tin atoms, compounds 8 and 9 were polymeric chain structures with five-coordinate and seven-coordinate tin atoms, compounds 10 and 11 were monomeric structures with six-coordinate and five-coordinate tin atoms.     

Silica-supported cyclopentadienyl-rhodium(I), -cobalt(I), and -titanium(IV) complexes

The silylated cyclopentadiene derivative, (MeO)₃Si(CH₂)₃C₅H₅, synthesised from commerically-available (MeO)₃Si(CH₂)₃Cl, has been used to prepare the complexes [η⁵-(MeO)₃Si(CH₂)₃C₅H₄]Rh(CO)₂, [η⁵-(MeO)₃Si(CH₂)₃C₅H₄]Rh(COD) (COD = cyclo-octa-1,5-diene), and [η⁵-(MeO)₃Si(CH₂)₃C₅H₄]₂TiCl₂. The complex [η⁵-(MeO)₃Si(CH₂)₃C₅H₄]TiCl₃, prepared by reaction of NaC₅H₄(CH₂)₃Si(OMe)₃ with TiCl₄ (1/1 molar ratio) and also by reaction of [η⁵-(MeO)₃Si(CH₂)₃C₅H₄]Ti(OEt)₃ with CH₃COCl, proved to be very unstable. Attempts to synthesise the complex [η⁵-(MeO)₃Si(CH₂)₃C₅H₄](η⁵-C₅H₅)TiCl₂, either by reaction of [η⁵-(MeO)₃Si(CH₂)₃C₅H₄]TiCl₃ with NaC₅H₄ or reaction of (η⁵-C₅H₅)TiCl₃ with NaC₅H₄(CH₂)₃Si(OMe)₃, gave none of the expected product and only (η⁵-C₅H₅)₂TiCl₂ could be isolated from these reactions. The cyclo-octadiene rhodium complex supported on silica has been shown to be an efficient cyclotrimerization catalyst, and the silica-supported titanium complex (SIL-(CH₂)₃C₅H₄)₂TiCl₂ is, after reduction with butyllithium, an efficient and selective catalyst for the hydrogenation of alk-1-enes.     

Structural characterization of a seven-coordinated organotin(IV) complex: Tris(dimethyl sulphoxide)nitratodiphenyltin(IV) nitrate

A seven-coordinated organotin(IV) compound has been obtained and its IR spectroscopic properties and X-ray crystal structure are reported. Crystals are monoclinic (p2₁/c) with unit-cell dimensions: a 16.017(9), b 10.365(5), c 15.994(8) Å, β 96.1(1)°, Z = 4. The structure has been determined from diffractometer data (Cu-K_a radiation) by conventional Patterson and Fourier techniques and refined by block-diagonal least-squares procedure to an R value of 0.093 for 4298 independent reflections. The structure consists of monomeric seven-coordinated cations [Sn(C₆H₅)₂NO₃{(CH₃)₂SO}₃] and NO₃- anions. Coordination around tin is pentagonal bipyramidaI with the bidentate nitrate group and the three dimethyl sulphoxide molecules in the equatorial positions and the two phenyl rings at the apices. Literature on seven-coordinated tin(IV) compounds and nitratotin(IV) complexes is quoted and discussed.     

Monocyclopentadienyl titanium(IV) alkyl xanthate complexes

Titanium(IV) alkyl xanthates of the types CpTi(S₂COR)Cl₂, CpTi(S₂COR)₂Cl and CpTi(S₂COR)₃, where R = CH₃, C₂H₅, C₃H₇, C₄H₉ and C₅H₁₁, have been prepared by the reaction of monocyclopentadienyl titanium(IV) trichloride with potassium alkyl xanthates in anhydrous dichloromethane. Conductance and infrared studies suggest that these complexes are non-electrolytes in which all of the xanthate ligands are bidentate. Proton nmr spectra of these complexes indicate that there is rapid rotation of the cyclopentadienyl ring about the metal-ring axis and for the CpTi(S₂COR)₃ complexes non-equivalence of the alkylxanthate ligands was observed.     

Polymerization of substituted olefins initiated by organometallic compounds of titanium (IV)

Polymerization tests were carried out in homogeneous systems on various substituted olefins CH₂=CRZ (R = H or CH₃; Z = CN, COOR, C₆H₅ or OCOR) with compounds of titanium (IV) Ti X_4?x Y_x (X and/or Y = Cl, OR, NR₂, C₅H₅, OCH₂ CF₃, CH₃, C₆H₅ …) or with the bimetallic complex CH₃Ti(OR)₃, Al(CH₃)₃. The activity of the initiator varies with the co-ordination environment of the titanium and to a considerable extent with the functional groups linked to the olefin.     

Synthese und spektroskopische Untersuchungen von Di-t-Butylzinn(IV)-dicarboxylaten

Synthesis and Spectroscopic Studies of Di-t-butyltin(IV) dicarboxylates Five Di-t-butyltin(IV) dicarboxylates t-Bu₂Sn(O₂CR)₂ (R ? CH₃, C(CH₃)₃, C₆H₅, C₆H₄NH₂-2, C₅H₄N-2) have been synthesized by reaction of Di-t-butyltinoxide (t-Bu₂SnO)₃ with corresponding ligands and studied by ¹H-, ¹³C-, ¹¹⁹Sn n.m.r. and infrared spectroscopy. The compounds are monomeric in CD₂Cl₂- or CDCl₃-solution and have pentacoordinated tin atoms with exception of the picolinate. The coordination takes place through the carboxylic oxygen atoms. In the Di-t-butyltin(IV)di-2-picolinate the tin atom is hexacoordinated by intramolecular tin-nitrogen-interaction.