Thallium Cations Research Articles

Preparation, Crystal Structure, Vibrational Spectra, and Thermal Behavior of Tl2H2P2O6 and Tl4P2O6

AbstractThe new thallium(I) salts, Tl2H2P2O6 (1) and Tl4P2O6 (2), were prepared and structurally characterized by single‐crystal X‐ray diffraction. Compound 1 crystallizes in the monoclinic space group P21/c and compound 2 in the orthorhombic space group Pbca. Both structures feature channels occupied by the lone electron pairs of Tl+ cations. Furthermore, those are built up by discrete [H2P2O6]2– for compound 1 and [P2O6]4– units for 2 in staggered conformation for the P2O6 skeleton and the thallium cations. In Tl2H2P2O6 (1) the hydrogen atoms of the [H2P2O6]2– ion are in a “trans‐trans” conformation. The O···H–O hydrogen bonds between the [H2P2O6]2– groups consolidate the structure 1 into a three‐dimensional network. FT‐IR/FIR and FT‐Raman spectra of the crystalline title compounds were recorded and a complete assignment for the P2O64– modes is proposed. The phase purity of 1 was verified by powder diffraction measurements.

Calix[4]arene-(2,3-naphthylene-crown-6,crown-6) as an extraordinarily efficient macrocyclic receptor for the univalent thallium cation

On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Tl+ (aq) + 1·Cs+ (nb) 1·Tl+ (nb) + Cs+ (aq) taking place in the two-phase water–nitrobenzene system (1 = calix[4]arene-(2,3-naphthylene-crown-6,crown-6); aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex(Tl+,1·Cs+) = 0.3 ± 0.1. Further, the extremely high stability constant of the 1·Tl+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb(1·Tl+) = 10.0 ± 0.2. Finally, applying quantum mechanical calculations, the most probable structure of the cationic complex species 1·Tl+ was derived. In the resulting complex, the ‘central’ cation Tl+ is bound by eight strong bonds to six oxygen atoms of the crown-6 moiety and to two carbons from the respective two benzene rings of the parent ligand 1 via cation-π interaction. The interaction energy, E(int), of the considered 1·Tl+ complex was found to be −305.7 kJ/mol, also confirming the formation of this cationic species.

Silver(i) and thallium(i) cations as unsupported bridges between two metal bases

Stirring Lewis-basic transition metal complexes with the salts M[BAr(Cl)4] (M = Ag, Tl; Ar(Cl) = 3,5-C6H3Cl2) resulted in the formation of diplatinum complexes [{(Cy3P)2Pt}2(μ-Ag)][BAr(Cl)4] (3) and [{(Cy3P)2Pt}2(μ-Tl)][BAr(Cl)4] (4) and the diiron compound [{(OC)3(Me3P)2Fe}2(μ-Ag)] (5) featuring bridging, unsupported metal cations. Their properties were investigated by multinuclear NMR spectroscopy, as well as X-ray diffraction and infrared measurements.

Synthesis, characterization, single crystal X-ray structure determination and packing analysis of thallium(I) anthracene-9-carboxylate, [Tl4(H2O)2(anthracene-9-carboxylate)4

A new tetranuclear thallium complex, [Tl4(H2O)2(anthracene-9-carboxylate)4] was isolated by reaction of hot aqueous solution of thallium(1)sulphate with sodium salt of anthracene-9-carboxylic acid in water taken in appropriate stoichiometric ratio. The newly synthesized complex was characterized by elemental analysis, thermogravimetric analysis, spectroscopic studies (FT-IR, UV–Visible, and multinuclear NMR). Complex crystallizes in monoclinic crystal system with P21/n space group. X-ray crystal structure determination revealed the presence of neutral centrosymmetric tetranuclear complex which contains two symmetry independent thallium cations. Tl1 is four-coordinate and bonded to three different anthracene-9-carboxylate anions. The other thallium cation, Tl2, is three-coordinate, being surrounded by two carboxylate oxygen atoms from two different ligands; anthracene-9-carboxylate and a water molecule. The crystal lattice is stabilized by CH/OH⋯O hydrogen bonding and cation⋯π interactions.

Synthesis, structures, and solution dynamics of tetrasubstituted nine-atom germanium deltahedral clusters.

Reported are the rational synthesis, structures, and solution dynamics of three tetrasubstituted and neutral Ge9-based deltahedral clusters [Ge9R3R'](0), where R = Si(SiMe3)3 and R' = Et (1), Sn(n)Bu3 (2), or Tl (3). The first step of the synthesis is a reaction of an acetonitrile suspension of the intermetallic precursor compound K4Ge9 with {Si(SiMe3)3}Cl which produces the trisubstituted monoanions [Ge9{Si(SiMe3)3}](-). A benzene suspension of the latter is then reacted with Sn(n)Bu3Cl or TlCp to produce 2 and 3, respectively, while the same acetonitrile solution is reacted with EtBr in order to produce 1. All three structures can be viewed as tricapped trigonal prisms of Ge9 with the three "hypersilyl" substituents, Si(SiMe3)3, exo-bonded to the capping atoms. The fourth substituent in 1, the ethyl group, is exo-bonded to one of the six available Ge atoms with the Ge-C bond positioned radially to the Ge9 core. In the case of 2, on the other hand, the tin fragment is found above one of the triangular bases of the prism interacting with one or more Ge atoms in three crystallographically different molecules in the structure. Lastly, the Tl atom in the structure of 3 is found capping a pseudosquare face between two hypersilyl substituents. NMR spectroscopy indicates that all three compounds are dynamic at room temperature. Variable-temperature studies suggest that the process in 1 and 2 is intramolecular while the process in 3 involves dissociation of the Tl(+) ion from the molecule followed by association at the same or another equivalent pseudosquare face of the molecule. Thus, the latter compound may be considered to a large extent to be ionic as it is made of a thallium cation and a trisubstituted cluster anion.

Interaction of the univalent thallium cation with antamanide: Experimental and theoretical study

On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Tl+(aq) + 1·Na+(nb) ⇔1·Tl+ (nb) + Na+(aq) occurring in the two-phase water–nitrobenzene system (1=antamanide; aq=aqueous phase, nb=nitrobenzene phase) was determined as logKex (Tl+, 1·Na+)=0.7±0.1. Further, the stability constant of the 1·Tl+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C: log βnb (1·Tl+)=4.5±0.2. Finally, by using quantum mechanical DFT calculations, the most probable structure of the cationic complex species 1·Tl+ was derived. In the resulting complex, the “central” cation Tl+ is bound by four bond interactions to the corresponding four carbonyl oxygen atoms of the parent ligand 1. Besides, the whole 1·Tl+ complex structure is stabilized by two intramolecular hydrogen bonds. The interaction energy of the considered 1·Tl+ complex was found to be −359.0kJ/mol, confirming also the formation of this cationic species.

Complexation of the thallium cation with nonactin: an experimental and theoretical study

From extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements, the stability constant of the nonactin-Tl+ complex species dissolved in nitrobenzene saturated with water was determined. By using quantum–mechanical calculations, the most probable structure of this complex was predicted.

Structure-determining role of Tl+ in natural and synthetic sulfides

A crystallographic analysis is performed for the structures of TlCu2S2, TlCu7S4, TlTaS3, TlIn3S5, TlIn5S8, and TlCr2V3S8. In them the Tl+ cation is included in anion sublattices and stabilizes their regularity. The cation sublattices are substantially distorted and have additional conjugation to the anionic positions of the thallium cations. The monoclinic structures (the last three) have geometrically similar anionic and cationic “forced skeletons,” while in tetragonal (the first two) and orthorhombic symmetries they are modified by symmetry restrictions.

Influence of the Cavity Size of Water-Soluble Cryptophanes on Their Binding Properties for Cesium and Thallium Cations

The binding properties of water-soluble cryptophane 1 toward cesium and thallium cations, in basic solution, have recently been reported. In this Article, we show that water-soluble cryptophane-222 (2), cryptophane-223 (3), and cryptophane-233 (4), bearing zero, one, and two propylenedioxy linkers, respectively, also efficiently bind these two cations under similar experimental conditions. Their binding properties are thoroughly studied by (133)Cs and (205)Tl NMR spectroscopy, while the binding constants are determined by isothermal titration calorimetry (ITC) experiments under various experimental conditions. Complexation of cesium and thallium is also evidenced by electronic circular dichroism (ECD) using the enantiopure MM-2 compound. This study reveals that the cavity size of the cryptophane is not the main parameter to observe efficient binding. In contrast, the number of phenolate moieties surrounding the cryptophane backbone seems to be pivotal for the complexation of these two cations. These results are important in the field of detoxification.

Calix[4]arene-bis(t-octylbenzo-18-crown-6) as an extraordinarily effective macrocyclic receptor for the univalent thallium cation

From extraction experiments and $$ \gamma $$ -activity measurements, the exchange extraction constant corresponding to the equilibrium Tl+ (aq) + 1·Cs+ (org) ⇔ 1·Tl+ (org) + Cs+ (aq) taking place in the two-phase water–phenyltrifluoromethyl sulfone (abbrev. FS 13) system (1 = calix[4]arene-bis(t-octylbenzo-18-crown-6); aq = aqueous phase, org = FS 13 phase) was evaluated as log K ex (Tl+, 1·Cs+) = 1.7 ± 0.1. Further, the extraordinarily high stability constant of the 1·Tl+ complex in FS 13 saturated with water was calculated for a temperature of 25 °C: log β org(1·Tl+) = 13.1 ± 0.2. Finally, by using quantum mechanical DFT calculations, the most probable structure of the cationic complex species 1·Tl+ was derived. In the resulting 1·Tl+ complex, the “central” cation Tl+ is bound by eight bond interactions to six oxygen atoms from the respective 18-crown-6 moiety and to two carbons of the corresponding two benzene rings of the parent receptor 1 via cation–π interaction.

Structural, Spectroscopic, and Computational Studies on Tl4Si5O12: A Microporous Thallium Silicate

Single crystals of the previously unknown thallium silicate Tl4Si5O12 have been prepared from hydrothermal crystallization of a glassy starting material at 500 °C and 1 kbar. Structure analysis resulted in the following basic crystallographic data: monoclinic symmetry, space group C2/c, a = 9.2059(5) Å, b = 11.5796(6) Å, c = 13.0963(7) Å, β = 94.534(5)°. From a structural point of view the compound can be classified as an interrupted framework silicate with Q(3)- and Q(4)-units in the ratio 2:1. Within the framework 4-, 6-, and 12-membered rings can be distinguished. The framework density of 14.4 T-atoms/1000 Å(3) is comparable with the values observed in zeolitic materials like Linde type A, for example. The thallium cations show a pronounced one-sided coordination each occupying the apex of a distorted trigonal TlO3 pyramid. Obviously, this reflects the presence of a stereochemically active 6s(2) lone pair electron. The porous structure contains channels running along [110] and [-1 1 0], respectively, where the Tl(+) cations are located for charge compensation. Structural investigations have been completed by Raman spectroscopy. The interpretation of the spectroscopic data and the allocation of the bands to certain vibrational species have been aided by DFT calculations, which were also employed to study the electronic structure of the compound.

Complexation of the thallium cation with dibenzo-30-crown-10: extraction and theoretical study

From extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements, we determined the stability constant of the dibenzo-30-crown-10·Tl+ complex species dissolved in nitrobenzene saturated with water. By using quantum–mechanical calculations, we then predicted the most probable structure of this complex species. .

Interaction of the thallium cation with 1,3-alternate-25,27-bis(1-octyloxy)calix[4]arene-crown-6: Experimental and theoretical study

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Tl+ (aq)+1·Cs+ (nb)⇔1·Tl+ (nb)+Cs+ (aq) taking place in the two–phase water–nitrobenzene system (1=1,3-alternate-25,27-bis(1-octyloxy)calix[4]arene-crown-6; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as logKex (Tl+, 1·Cs+)=−2.1±0.1. Further, the stability constant of the 1·Tl+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C: logβnb(1·Tl+)=11.6±0.2. Finally, by using quantum mechanical DFT calculations, the most probable structures A and B of the cationic complex species 1·Tl+, which are obviously in a dynamic equilibrium, were indicated. In both of these structures of the resulting 1·Tl+ complex, the “central” cation Tl+ is bound by eight strong bond interactions to six oxygen atoms from the 18-crown-6 moiety and to two carbons of the respective two benzene rings of the parent ligand 1 via cation-π interaction.

Shedding light on the bonding, photophysical and magnetotropic properties of triangular Pt3complexes and their “open-face” TlPt3half-sandwiches

The molecular and electronic structures, stabilities, bonding features, magnetotropic and spectroscopic properties of the triangular Pt(3)(μ(2)-L)(3)(L')(3) clusters and their [(μ(3)-Tl)Pt(3)(μ(2)-L)(3)(L')(3)](+) (L = CO, SnR(2), SnH(2), SiR(2), SiH(2), CH(3)CN, PH(2), C(6)F(5), SO(2) or HCN and L' = CO, PH(3), CH(3)CN, C(6)F(5), HCN) half-sandwiches have been studied by means of density functional theory (DFT) calculations. It is found that the optimized Pt-Pt intermetallic distances in the clusters are well below the sum of the van der Waals radii of the two Pt metal atoms (3.44 Å). The triangular Pt(3)(μ(2)-L)(3)(L')(3) clusters trap a thallium(I) cation forming stable "open face" half-sandwiches. The distance between Tl(I) and the centroids of the Pt(3) rings in the half-sandwiches is calculated to be within the range 2.52-2.86 Å. Energy decomposition analysis (EDA) calculations using a dispersion corrected B3LYP-D functional reveal that the interaction of Tl(I) with the Pt(3) ring in the half-sandwiches is dominated by the interplay of electrostatic and orbital interactions with a small contribution from dispersion forces as well. In addition, charge decomposition analysis (CDA) calculations indicate strong donor-acceptor interactions between Tl(I) and the rings. The estimated proton affinities (PAs) of the triangular Pt(3)(μ(2)-L)(3)(L')(3) clusters illustrate their relatively strong π-basic character. Furthermore, an excellent linear relationship between the PAs of the Pt(3)(μ(2)-L)(3)(L')(3) clusters and the bond dissociation energies (D(0)) of the [(μ(3)-Tl)Pt(3)(μ(2)-L)(3)(L')(3)](+) half-sandwiches was established. The magnetotropicity of these systems was studied by calculating the NICS(zz)-scan profiles. The spectroscopic properties of the triangular Pt(3) clusters and their TlPt(3) half-sandwiches were studied by means of TDDFT calculations. The simulated absorption spectra are dominated by strong absorption bands in the UV region. The emission band maxima of the triangular Pt(3) clusters are predicted to lie within the IR region. In order to gain insight into the phosphorescence process of these systems, we have optimized their first triplet excited state, T(1). The estimated deep HOMO energy for these compounds makes them promising candidates for use as "hole" blocking materials in LED devices. Also, it is expected to exhibit small non-radiative decay rate constants due to their relatively large S(0)-T(1) energy difference making them suitable PHOLED emitters or dopants in organic polymer matrices constituting the recombination layer of an OLED device.

Voltammetric and electrochemical gravimetric selective detection of interactions between Tl(I) and guanine and the influence on activity of DNA drug-intercalators

The interactions of Tl(I), a well known toxic species, with selected oligonucleotides were examined. The oligonucleotide sequences selected for the investigation were taken from gene hOGG1 responsible for repairing of DNA damage. Cyclic voltammetry was particularly useful, since nitrogen N-7 in guanine can be electrooxidized while its binding with Tl(I) leads to the loss of electroactivity. So, this selected interaction could be quantitatively used in drawing Scatchard's plot and calculating the binding constants and the number of active sites in guanine molecules occupied by one metal ion. Further, we have shown that the presence of Tl(I) leads to a decrease in activity of doxorubicin (DOX), a popular anticancer drug, vs. DNA. The obtained circular dichroism (CD) spectra and the measurements with an electrochemical quartz crystal microbalance (EQCM) led to a conclusion that in the presence of monovalent thallium cations the DNA double helix was neither damaged/oxidized nor its conformation changed substantially.

Water-Soluble Molecular Capsule for the Complexation of Cesium and Thallium Cations

Binding properties of cesium and thallium cations by an enantiopure cryptophane derivative PP-1 have been investigated in water under basic conditions. The binding process has been evidenced using electronic circular dichroism (ECD), and binding constants of the Cs(+)@PP-1 and Tl(+)@PP-1 complexes have been determined from isothermal titration calorimetry (ITC) experiments in LiOH/H(2)O, NaOH/H(2)O, and KOH/H(2)O solutions. In addition, Tl(+)@PP-1 complex has been characterized for the first time by (205)Tl NMR spectroscopy. Cryptophane 1 exhibits an exceptionally high affinity for thallium and cesium cations in a large range of experimental conditions (nature, concentration of the counterion, and temperature). For example, binding constants as high as 2.9 × 10(9) M(-1) and 5.3 × 10(8) M(-1) have been measured by ITC at 298 K in NaOH/H(2)O (0.1 M) solution, for the Tl(+)@PP-1 and Cs(+)@PP-1 complexes, respectively. The high affinity of cryptophane 1 for Cs(+) and Tl(+) cations is preserved at higher LiOH, NaOH, and KOH concentrations and under extreme basic conditions, revealing the stability and the great selectivity of this supramolecular system toward Li(+), Na(+), and K(+) cations.

Experimental and theoretical study of the complexation of the thallium cation with a hexaarylbenzene-based receptor

From extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements, the stability constant of a hexaarylbenzene-based receptor. Tl+ complex species dissolved in nitrobenzene saturated with water was determined. By using the quantum-mechanical density functional level of theory calculations, the most probable structure of this complex was derived. .

Synthesis and Crystal Structure of AgTl3(Cr2O7)2

Red single crystals of AgTl3(Cr2O7)2 were prepared via high oxygen pressure synthesis as well as by hydrothermal autoclave techniques. Initially, AgTl3(Cr2O7)2 was obtained from a reaction of stoichiometric mixtures of Ag2O, Cr and TlNO3 under elevated oxygen pressures. Following an optimized approach, the title compound can be synthesized at mild hydrothermal conditions, starting from AgNO3, TlNO3 and K2Cr2O7 in aqueous solution. AgTl3(Cr2O7)2 crystallizes in space group C2/c (no. 15) with a = 10.3638(3), b = 10.4817(3), c = 13.4717(4) Å , β = 106.55(1)°, V = 1402.80(5) Å3, and Z = 4. The structure refinement was based on 3554 independent reflections and resulted in R1 = 2.13 %, wR2 = 4.54 %. The crystal structure contains independent Cr2O7 2− anions, which are surrounded by silver and thallium cations forming layers that are stacked perpendicular to the bc plane.

Behavior of Cesium and Thallium Cations inside a Calixarene Cavity As Probed by Nuclear Spin Relaxation. Evidence of Cation−π Interactions in Water

We have studied the complexes formed between the p-sulfonatocalix[4]arene and cesium or thallium metal cation, first by carbon-13 longitudinal relaxation of the calixarene molecule at two values of the magnetic field B(0). From the longitudinal relaxation times of an aromatic carbon directly bonded to a proton, thus subjected essentially to the dipolar interaction with that proton, we could obtain the correlation time describing the reorientation of the CH bond. The rest of this study has demonstrated that it is also the correlation time describing the tumbling of the whole calixarene assembly. From three non-proton-bearing carbons of the aromatic cycles (thus subjected to the chemical shift anisotropy and dipolar mechanisms), we have been able to determine the variation of the chemical shift anisotropy when going from the free to the complex form of the calixarene. These variations not only provide the location of the cation inside the calixarene cavity but also constitute a direct experimental proof of the cation-pi interactions. These results are complemented by cesium and thallium relaxation measurements performed again at two values of the magnetic field B(0). An estimation of the mean distance between the cation and the calixarene protons could be obtained. These measurements have also revealed an important chemical shift anisotropy of thallium upon complexation.

A Systematic Study on the Crystal Structures of TlMX4 (M = Al, Ga; X = Cl, Br, I)

AbstractTlAlCl4 and TlGaCl4 crystallize isotypic in the BaSO4 structure type. Both, TlAlI4 and TlGaI4 crystallize isotypic in a distorted LiAlCl4 structure type. In contrast to the tetrachloro and tetraiodo compounds, the tetrabromoaluminate and ‐gallate crystallize not isotypic with each other. TlAlBr4 is found to crystallize isotypic with KAlBr4 whilst TlGaBr4 crystallizes in its own structure type. Despite the high diversity in structure types adopted by the studied TlMX4 compounds, all of them can be regarded as distortions from the BaSO4 structure type resulting from rotation of the MX4 tetrahedra against each other. Because of this, low symmetry coordination environments around the thallium cation are generated. Comparison with isotypic alkali metal compounds shows that the strongly distorted thallium surroundings cannot be attributed to a stereochemical activity of the 6s2 lone pair.