Thallium Derivatives Research Articles

Mass Measurements of Natural Products By Solution Phase Secondary Ion Mass Spectrometry Employing Silver(I) and Thallium(I) Derivatives

Mass Measurements of Natural Products By Solution Phase Secondary Ion Mass Spectrometry Employing Silver(I) and Thallium(I) Derivatives

Preparation of potentially electroactive thallium polymers derived from the acidic copolymers of maleic anhydride

Maleic anhydride copolymers with vinyl ethyl ether and N-vinyl-2-pyrrolidone were prepared in tetrahydrofuran at 60°C, using AIBN as initiator. Copoly (MA-VEE) was hydrolysed to various degrees of hydrolysis and the extent of hydrolysis monitored by i.r. Various acidic derivatives of copoly (MA-VEE), copoly(MA- N-vinyl-2-pyrrolidone) and copoly(MA-ethylene) were prepared and characterized by elemental analysis and spectroscopy. The inter- and intramolecular crosslinking of carboxylic groups in copoly(succinic acid-VEE) were studied by g.p.c. Also thallium (III) derivatives of several acidic polymers were prepared and characterized.

Thallium derivatives of p-carborane

1. Some thallium derivatives of p-carborane, containing the carborane carbon-thallium and boron-thallium bonds, were synthesized. 2. In their properties the T1 derivatives of p-carborane resemble the corresponding Tl derivatives of the o-and m-carboranes.

Pentakis(methoxycarbonyl)cyclopentadiene chemistry. Part 1. Preparation and properties of the diene, and of derivatives containing the alkali metals or thallium(I): crystal and molecular structures of HC5(CO2Me)5, Li[C5(CO2Me)5]·H2O, K[C5(CO2Me)5]·MeOH, and Tl[C5CO2Me)5

The alkali metal (Li, Na, K, Rb, and Cs) and thallium(I) derivatives of HC5(CO2Me)5 have been prepared and characterised; their i.r., u.v., 1H, and l3C n.m.r. spectra are reported and discussed. Single-crystal X-ray structure determinations have been carried out on the diene and its Li, K, and Tl salts at 295 K. In the solid, as in non-polar solvents, the diene has the fulvenoid configuration, with the acidic proton bridging two adjacent carbonyl groups. This configuration is preserved in univalent metal cation salts. Lithium is four-co-ordinate (from two carbonyl oxygens, the water molecule, and a carbonyl oxygen from a second anion). In the potassium salt, the metal is co-ordinated by methanol, and five carbonyl oxygens from three different anions; all carbonyl oxygens of each anion are likewise involved in co-ordination to three different metal atoms. In the thallium salt the metal has irregular five-co-ordination, with two chelating carbonyl groups from one anion and three from separate anions; all carbonyl oxygens of each anion co-ordinate to four different metal atoms.

The electronic structure of hydrotris(1-pyrazolyl)borate ligand by He-I and He-II photoelectron spectroscopy

The He-I and He-II excited photoelectron spectra of the sodium and thallium(I) derivatives of the hydrotris(1-pyrazolyl)borate ligand are reported. Experimental criteria as well as quantum-mechanical calculations were used to assign photoelectron bands in the low ionization energy region. The spectra indicate a minor perturbation of metal ions on ligand based molecular orbitals. The results provide an adequate description of the electronic structure of the anion ligand itself.

Thallium(I) carboxylate modification of the hunsdiecker reaction

Treatment of a Thallium(I) carboxylate with 1 molar equivalent of bromine gives the corresponding thallium(III) carboxylate dibromide. High yields of primary alkyl bromides are obtained if the thallium(III) carboxylate dibromide is treated with 0.5 mol equiv. of bromine in refluxing carbon tetrachloride. Pyrolysis of the thallium(III) derivative in the absence of added bromine gives a low yield of the corresponding alkyl bromide. The use of Thallium(I) carboxylates for the preparation of alkyl bromides in high yields is limited to the salts of primary carboxylic acids. A simple procedure for the preparation of alkyl bromides from carboxylic acids using Thallium(I) carbonate has been developed.

A novel desulphination path to tris(polyfluorophenyl)thallium(III) compounds

Tris(polyfluorophenyl)thallium(III) compounds, R 3T1 (R = C 6F 5, p-HC 6F 4, or o-HC 6F 4) have been prepared by reaction between the corresponding bromobis(polyfluorophenyl)thallium(III) derivatives and barium or thallous polyfluorobenzenesulphinates in pyridine.

Thallium(I) derivatives of some aminoacids and other acidic ligands. Studies in solution and the solid state

Thallium(I) derivatives of a number of acidic ligands, including some aminoacids, carboxylic acids, phenols and thiols, have been prepared and characterised by mass-, U.V., and I.R. spectroscopy. Interaction between thallium(I) and certain of these ligands in aqueous solution has been studied by U.V and fluorescence spectroscopy, and formation constants measured in some cases. It is concluded that neither property is of particular utility in characterising the interaction of thalium(I) with biological macromolecules.

Stable Thallium(I) Derivatives ofN-Alkyl-arylsulfonamides as Intermediates in the Preparation ofN-Alkyl-N-triflyl-(or tresyl)-arylsulfonimides

Stable Thallium(I) Derivatives of<i>N</i>-Alkyl-arylsulfonamides as Intermediates in the Preparation of<i>N</i>-Alkyl-<i>N</i>-triflyl-(or tresyl)-arylsulfonimides

The nuclear magnetic resonance spectra of porphyrins. Part X. Carbon-13 nuclear magnetic resonance spectra of some meso-tetraarylporphyrins and their metal chelates

The 13C n.m.r. spectra of meso-tetraphenylporphyrin (TPP), the zinc(II), cadmium(II), bis[mercury(II) acetate], and various thallium(III) derivatives, and some related analogues are reported and assigned. In meso-tetra-(o-tolyl)-porphyrin and meso-tetra-(1-naphthyl)porphyrin only one species was observed. The introduction of zinc(II), cadmium(II), or bis[mercury(II) acetate] into the TPP nucleus does not significantly change the 13C shifts, but the thallium(II) derivative shows both extensive TI–13C couplings and non-equivalence of o-phenyl carbon atoms, the latter being due to the exoplanar position of the thallium atom. Specific TI–13C couplings to the o-phenyl carbon atoms are also observed.

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, MMe 3 and LiMMe 4 are compared with NMR data for the novel tin—Group III-metal bonded species, Li[Me 3SnMMe 3] (M  Al, Ga, In and Tl) and for Li[(Me 3Sn) 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 2 J(SnCH), 2 J(TlCH), 3 J(SnMCH) and 3 J(TlSnCH) are reported as a function of M and as a function of the number of Me 3Sn groups bond to thallium in the [(Me 3Sn) n TIME 4− n ] −anions. Proposals concerning the factors governing the changes in these coupling constants and the chemical shifts are presented.

Stability of thallium(I) transition metal carbonyls

Thallium(I) derivatives of metal carbonyl anions are generally stable with weakly basic anions whereas disproportionation to thallium(III) derivatives occurs with more strongly basic anions.

The nuclear magnetic resonance spectra of porphyrins. Part VIII. The 13C nuclear magnetic resonance spectra of some porphyrins and metalloporphyrins

The 13C n.m.r. spectra of the methyl esters of the four coproporphyrin type-isomers and deuteroporphyrin-IX, and of octaethylporphyrin, and the zinc(II), thallium(III), and some diprotonated derivatives are reported and assigned. An immediate differentiation between the coproporphyrin type-isomers is provided by the spectra; the shifts of the meso and ‘pyrrole’ ring carbons are influenced by the adjacent peripheral substituents. The pattern of these carbon chemical shifts, when taken with other evidence, supports the 18 atom π-electron delocalisation pathway in these molecules. This conclusion is contrary to that of other workers, and illustrates the dangers of relying solely on 13C shifts. A novel phenomenon in the spectra is line-broadening of the ‘α-pyrrole’ carbon resonances in the neutral molecules, but not in the diprotonated or metal derivatives. This is attributed to NH tautomerism, and support for this is obtained from the spectra of the N-deuteriated species. Protonation of coproporphyrins gives upfield shifts of the ‘α-pyrrole’ carbons and downfield shifts of the ‘β-pyrrole’ and meso-carbon resonances; analogous behaviour has been observed earlier in other nitrogen heterocycles. The thallium(III) derivatives show extensive Tl–13C couplings, the two-bond Tl–‘α-pyrrole’ carbon couplings (15–20 Hz) being substantially less than the three-bond Tl–‘β-pyrrole’ carbon (104–109 Hz) and Tl–meso-carbon (145–147 Hz) couplings; comparisons can again be drawn with other metal–carbon couplings. These couplings appear to be primarily due to the contact mechanism.

( N,N-dimethylbenzylamine-2- C,N)palladium(II) and -platinum(II) complexes containing N-substituted salicylaldimines

Reactions of the thallium(I) derivatives of alkyl and aryl salicyladimines, TlSalNR, and the quadridentate Schiff base N,N′-ethylenebis(salicylaldimine), Tl 2-Salen, with [( N,N dimethylbenzylamine-2- C,N) MCl] 2 ([DmbaMCl] 2; M = Pd, Pt) give the complexes DmbaMSalNR and [DmbaM] 2Salen. The 1H NMR spectra show them to have two coordinated nitrogen atoms trans. 3 J( 195Pt 1H) has been measured for a number of protons in the platinum derivatives.

Reactions of condensed N-heteroaromatic molecules. Part I. Alkylation by thallium(I) ethoxide

Thallium(I) derivatives of carbazole, phenothiazine, and (to a lesser extent) dibenz[b,f]azepine (iminostilbene) may be readily alkylated by reactions with n-alkyl iodides and bromides under extremely mild conditions. 10,11-Dihydrodibenz[b,f]azepine (iminobibenzyl) is essentially unreactive and this, together with the complete inactivity of secondary alkyl halides, is indicative of serious steric constraints on the transition states for the alkylations via thallium(I) derivatives. The method is particularly valuable for alkylation of carbazoles having base-sensitive carbonyl and vinyl ring substituents.

Studies on some alkyl(cyano)thallium derivatives

Abstract Seven new alkyl(cyano)thallium derivatives have been synthesized. The observed linear relation between ν(Tl-CN) and ν(CN) frequencies in these compounds could be interpreted in terms of the strength of Tl-ligand interaction.

Thallium(I) and (III) arene sulphinates

A number of thallium(I) and (III) derivatives of benzene-sulphinic acid and p-toluene sulphinic acid have been prepared. The infra-red spectra suggest O-sulphinate structures for the thallium(I) derivatives and S-sulphinate structures for the thallium(III) derivatives. The mass spectra are reported: the thallium(I) derivative fragments with loss of SO 2.

Thallium(I) derivatives of β-diketones, phenols and carboxylic acids

A number of thallium(I) derivatives of β-diketones, phenols, and carboxylic acids have been prepared. The u.v. spectra in a variety of aprotic and protic solvents have been observed and interpreted. The results suggest that the thallium–oxygen bond in these derivatives has considerably more covalent character than the analogous alkali-metal–oxygen bonds. The mass spectra have been recorded, and dimeric species observed. Attempts to prepare complexes of these derivatives are reported.

Thallium derivatives of imidazole, triazole, and related heterocycles

A number of air- and water-stable thallium(I) and dimethylthallium(III) derivatives of imidazole, triazole, and related species have been prepared. Vibrational, n.m.r., and mass spectra are reported, and are consistent with a polymeric structure for these derivatives in the solid state.

Preparation and reactions of methyl(allyl)thallium(III) derivatives

Several methyl(allyl)thallium derivatives have been prepared for the first time. The IR and PMR spectra of these compounds indicate the presence of σ-allylthallium bonds. In the cleavage reactions of these compounds with tetramethyltin in methanol or with metal salts such as Hg(OCOCH 3) 2, PdX 2 (X  OCOC 2H 5 and Cl) and RhCl 3·3H 2O, preferential cleavage of the allylthallium bond occurs to give propylene in the case of tetramethyltin and allylic derivatives of the metals in the other cases.