Thallium Complexes Research Articles

Terpyridine isomerism as a tool for tuning red-to-NIR emissive properties in heteronuclear gold(I)-thallium(I) complexes.

The polymeric linear chain [AuTl(C6Cl5)2]n reacts with three terpyridine-type ligands substituted with thiophene groups containing N-donor centres in different relative positions (L1, L2 and L3), leading to the Au(I)/Tl(I) complexes [AuTl(C6Cl5)2(L1)]n (1), [{AuTl(C6Cl5)2}2(L2)]n (2) and [AuTl(C6Cl5)2(L3)]n (3). X-Ray diffraction studies reveal that L1 acts as a chelate, while L2 and L3 act as bridging ligands, resulting in different coordination indexes for the thallium(I) centre. These structural differences strongly influence their optical properties, and while compounds 2 and 3 emit near the limit of the visible range, complex 1 emits in the infrared region. DFT calculations have also been carried out in order to determine the origin of the electronic transitions responsible for their optical properties.

Thallium(I) Complexes of Tris(pyridyl)borates and a Comparison to Their Pyrazolyl Analogues.

Thallium(I) complexes of B-methylated and B-phenylated tris(pyridyl)borates featuring trifluoromethyl groups at the pyridyl ring 6-positions have been synthesized by metathesis using the corresponding potassium salts [MeB(6-(CF3)Py)3]K and [PhB(6-(CF3)Py)3]K with thallium(I) acetate. The closely related tris(pyrazolyl)borate analogue [PhB(3-(CF3)Pz)3]Tl has also been prepared, and comparisons of structural and spectroscopic features between the two scorpionate families are presented. [MeB(6-(CF3)Py)3]Tl displays κ3-coordination of the tris(pyridyl)borate similar to that of tris(pyrazolyl)borate in [MeB(3-(CF3)Pz)3]Tl, while [PhB(6-(CF3)Py)3]Tl and [PhB(3-(CF3)Pz)3]Tl feature κ2-N,N ligand coordination modes with the B-phenyl groups flanking the thallium sites. 19F NMR spectroscopy of [MeB(6-(CF3)Py)3]Tl reveals the presence of a remarkably large 1208 Hz four-bond thallium-fluorine coupling constant in chloroform at room temperature, which is considerably larger than 878 Hz observed for the pyrazolyl borate analogue [MeB(3-(CF3)Pz)3]Tl. Although [PhB(6-(CF3)Py)3]Tl is structurally nonrigid at room temperature in chloroform, at lower temperatures, the ligand arm exchange slows down, revealing 4JTl-F = 1110 Hz. Steric demands of these ligands have been quantified using the buried volume concept. In addition, ligand transfer chemistry from [MeB(6-(CF3)Py)3]Tl and [PhB(6-(CF3)Py)3]Tl to copper(I) under ethylene and computational analyses of the various coordination modes of tris(pyrazolyl)borates and tris(pyridyl)borates are reported.

Response to oxidative stress generation in Rhodotorula glutinis and Candida tropicalis by thallium dithiocarbamate complexes

Sodium diethyldithiocarbamate trihydrate (NaEt2dtc·3H2O) and sodium piperidine dithiocarbamate monohydrate (NaPidtc·H2O) reacted with thallium(I) carbonate to produce the complexes [Tl2(Et2dtc)2] C1 and [Tl2(Pidtc)2] C2. X-ray crystallographic analysis of the complexes elucidated their triclinic P-1 and monoclinic P21/n space groups, respectively, in addition to chelation via SS atoms from the uninegative ligands. Further, this analysis revealed the complexes' assembly as one-dimensional polymers of dimeric building blocks. The complexes (50 µg/ml) caused greater growth inhibitions in two pathogenic yeasts comparing with the ligand salts and cycloheximide. The ligand salts, respectively, inhibited R. glutinis with 15.02 and 15.14 % and C. tropicalis with 11.09 and 11.45 %, while cycloheximide, C1 and C2 offered inhibitions with 26.16, 38.9 and 46.4 % in R. glutinis and 13.4, 29.8 and 38.9 % in C. tropicalis, respectively. Further, the thallium complexes significantly affected the yeasts' soluble proteins {cycloheximide, C1 and C2 afforded 7.06 ± 0.05, 6.11 ± 0.08 and 5.43 ± 0.05 mg/g fresh weight (for R. glutinis) and 7.67 ± 0.15, 7.26 ± 0.06 and 6.025 ± 0.14 mg/g fresh weight (for C. tropicalis)} and total antioxidants {cycloheximide, C1 and C2 afforded 10.15 ± 0.21, 11.27 ± 0.16 and 14.97 ± 1.3 mg/g protein (for R. glutinis) and 19.4 ± 0.65, 16.0 ± 0.24 and 17.19 ± 0.55 mg/g protein (for C. tropicalis)} in addition to the catalase and peroxidase enzyme activities.

Striking stability of a mixed-valence thallium(III)-thallium(I) complex in some solvents

At the dissolution of solid anhydrous thallium(III) trifluoromethanesulfonate, Tl(CF3SO3)3, or thallium(III) trifluoroacetate, Tl(CF3COO)3, in dimethylsulfoxide (dmso) or N,N,N’,N’-tetramethylurea (tmu), intensely red-colored complexes are formed. This red thallium complex is stable for years in dmso, while it is reduced fairly rapidly to thallium(I) in tmu with a half-life time of an hour. At the dissolution of Tl(CF3SO3)3 in N,N-dimethylpropyleneurea (dmpu) an immediate reduction to thallium(I) takes place. A stable colorless aqueous thallium(III) solution is obtained at the dissolution in acidic water. Stable dmso solutions and solid dmso solvates of thallium(III) perchlorate, nitrate and trifluormethanesulfonate can be prepared by adding dmso to concentrated acidic aqueous thallium(III) solutions. These experimental observations conclude that the pure solids Tl(CF3SO3)3 and Tl(CF3COO)3 play an essential role in the formation of the red-colored thallium complexes. 205Tl NMR data show that the red thallium complex contains equal amounts of thallium(III) and thallium(I). The structure of the red thallium complex in dmso, as determined by EXAFS, has Tl–O bond distances of 2.216(3) and 2.80(2) Å, which are in very close agreement with the bond distances obtained in the pure dmso solvates of the thallium(III) and thallium(I) ions, respectively, and a Tl···Tl distance of 3.49(1) Å bridged by oxygen atoms. From the EXAFS data it is impossible to distinguish if dmso molecules and/or trifluoromethanesulfonate ions act as bridges. DFT calculations could eliminate some structures due to the irrelevant structural parameters or the energetics of the proposed reactions.

Synthesis and Structural Characterization of Phosphanide Gold(III)/Gold(I) Complexes and Their Thallium(III) and Gold(III) Precursors

In this paper, we describe a series of diphenylphosphane and diphenylphosphanide gold(III) and gold(III)/gold(I) complexes containing 3,5-C6Cl2F3 as aryl ligands at gold that have been synthesized due to the arylating and oxidant properties of the new polymeric thallium(III) complex [TlCl(3,5-C6Cl2F3)2]n (1). Its reaction with [Au(3,5-C6Cl2F3)(tht)] (tht = tetrahydrothiophene) produces the gold(III) complex [Au(3,5-C6Cl2F3)3(tht)] (2), which allows the synthesis of the diphenylohosphane derivative [Au(3,5-C6Cl2F3)3(PPh2H)] (3). Its treatment with acetylacetonate gold(I) derivatives leads to two novel AuIII/AuI phosphanido-bridged complexes, [PPN][Au(3,5-C6Cl2F3)3(µ-PPh2)AuCl] (4) and [PPN][{(3,5-C6Cl2F3)3Au(µ-PPh2)}2Au] (5). All these complexes have been characterized, and the crystal structures of 1, 2, 4 and 5 have been established by single crystal X-ray diffraction methods, showing a novel polymeric arrangement in 1.

Metal Complexes of the Perfluorinated Trityl Alkoxide [(C6F5)3CO]−

AbstractHerein we investigate sodium, magnesium, zinc, titanium, silver and thallium complexes based on the perfluorinated trityl alcohol (C6F5)3COH (1) with respect to their structural motifs. The coordination compounds were prepared by alkane or salt elimination reactions in non‐polar solvents. XRD analysis revealed a monomeric structure for Ti[OC(C6F5)3]2[OCH(CH3)2]2 (2), dimers for [Mg(OC(C6F5)3)2]2 (3), [Zn(OC(C6F5)3)Et]2 (4) and [Tl(OC(C6F5)3)]2 (5) as well as tetrameric structural motifs for the homoleptic sodium and silver compounds with the general formula [M(OC(C6F5)3)]4: A distorted [NaO]4 cube is observed for [Na(OC(C6F5)3)]4 (6) whereas [Ag(OC(C6F5)3)]4 (7) exhibits a planar [AgO]4 square. Metal fluorine contacts play an important role in all molecular structures presented herein.

Synthesis and characterisation of some mixed ligand complexes of thallium (i) metal with isonitrosoethylmethyl ketone

The present investigation has been undertaken to examine complex formation by thallium (I) derivatives of 2-nitro phenol (ONP), 2,4-dinitrophenol (DNP), 2,4,6-trinitrophenol (TNP), 1-nitroso-2-naphthol (1N2N), 8-hydroxyquinoline (8HQ), and 2-aminobenzoic acid (OABA) with Isonitrosoethylmethyl Ketone. They have general formula [ML (HL′)], where M = Tl (I), L = deprotonated ONP, DNP, TNP, 8-HQ, 1N2N and OABA and L′ = Isonitrosoethylmethyl Ketone. Isonitrosoethylmethyl Ketone is ambidentate ligand and can donate through oxygen or nitrogen or both. The preparation of mixed ligand complex with the thallium (I) salt of 2,4-dinitrophenol and 2,4,6-trinitrophenol with the Isonitrosoethylmethyl Ketone (INEMK) have very low yield.

Chemical effect on Lγ4 and Lγ5 X-ray lines in Thallium complexes

The previous outcomes of Wavelength Dispersive X-ray Fluorescence (WDXRF) technique were strictly restricted to the compositions of varieties of the materials where non-destructive and non-intrusive features can be persecuted. At present, the advancement in WDXRF spectrometer has made a huge impact on the chemical profiles in distinct chemical materials. The present work offers useful insights regarding the chemical effect in various Tl complexes viz., Tl pure, Tl(NO3)3, Tl2O3, TlI, TlCl and Tl2SO4 on the Lγ4 and Lγ5 X-ray lines. To our best knowledge, the data associated with the Lγ4 and Lγ5 X-ray lines of Tl complexes were not reported in the literature. The obtained findings indicate that the Lγ4 X-ray line emitted from different Tl complexes exhibit energy shift ~ (4–7.21) eV while the Lγ5 X-ray line shows ~ (1.4–4.4) eV with respect to that emitted from the pure Tl. In general, the Tl+3 complexes show large energy shifts and relative intensity ratios as compared to the Tl+1 complexes for both X-ray lines. The sharply diverging profile changes observed in different Tl complexes can be understood in terms of the mixed-valence states, relative intensity ratio, effective charge, core-valence exchange interactions, crystal effect and distinct ligands. Additionally, the possible correlation between energy shifts and factors affecting these are also examined in the present work.

Structural and Luminescence Properties of Heteronuclear Gold(I)/Thallium(I) Complexes Featuring Metallophilic Interactions Tuned by Quinoline Pendant Arm Derivatives of Mixed Donor Macrocycles.

Reaction of the heterometallic complex [{Au(C6F5)2}Tl]n with the quinoline pendant arm derivatives L1 and L2 of the mixed donor macrocycles [12]aneNS2O and PhenNS2 affords the new Au(I)/Tl(I) complexes [{Au(C6F5)2}Tl(L1)] (1), [{Au(C6F5)2}Tl(L2)] (2), [{Au(C6F5)2Tl}{Au(C6F5)2Tl(L1)}]2 (3), and [{Au(C6F5)2Tl}{Au(C6F5)2Tl(L2)}]n (4) depending on the reaction molar ratios used. These complexes present different optical properties strictly related to their structural features and to the presence of Au(I)···Tl(I) metallophilic interactions, which are finely tuned by the coordinating quinoline moiety and have been studied experimentally and theoretically via TD-DFT calculations.

Three isomers in a (hydrogen l-Cysteinato)-thallium(I): Crystal structure, spectroscopic and thermal properties

The isolation of thallium(I) complexes [Tl2(HCys)2]n (1) and [Tl4(HCys)4]n (2) {H2Cys = l-Cysteine} from aqueous solution by means of crystallization is reported herein. Polar crystals of 1 and 2 were crystallized in P21 and P212121 space groups respectively. Elemental analysis, XRD, IR, UV–Vis, TG-DSC and a single crystal X-ray diffraction were applied for characterizing the compounds. Linkage isomers 1 and 2 have 1D and 2D coordination polymeric structures respectively. The lone pair electrons of thallium(I) in 1–2 are stereo-chemically active. In 1, each of two independent Tl+ ions is coordinated by three HCys− ions forming TlS3O irregular polyhedron that is linked to each other by vertexes in an infinite chain. In 2, four independent Tl+ ions are coordinated by HCys− ions through S and O atoms, forming Tl1S3O2, Tl2S4, Tl3S3, Tl4S3 irregular polyhedrons. The crystallographic independent HCys− ions are linked to the metal ion differently, two are μ3-S,S,S-, one is μ4-O,S,S,S-, and one is μ4-O,O',S,S,S-coordinated ligands. The amine group of compounds 1 and 2 is in the form of an ammonium ion (–NH3+). The structures of 1–2 are stabilized by NH⋯O hydrogen bonds, thallophilic Tl⋯Tl and anagostic Tl⋯HC interactions. The spectroscopic and thermal properties of compounds were analyzed.

Halide and Thiocyanate Metal Acid Complexes Extraction in the Water – Ethoxylated Nonylphenol – Ammonium Sulfate System

Nonionic ethoxylated surfactants, including ethoxylated nonylphenols, can be considered as neutral oxygen-containing extraction reagents, the formation of delamination systems with which is possible when salting-out with inorganic salts. In this work, the distribution of halide and thiocyanate acid complexes of thallium (III), iron (III), indium and gallium in the water – ethoxylated nonylphenol (neonol AF 9-12) – ammonium sulfate system at 25°C was investigated. It is established that thallium (III) is quantitatively extracted in the form of tetrahalidetallate-ion with an acidity of more than 0.1 mol/l, extraction of other metals is not quantitative. Among the thiocyanate acid complexes, zinc, cobalt and copper (II) are quantitatively concentrated, which can be used for group concentration of these metals or their extraction-spectrophotometric determination methods

Extraction of chloride acido complexes of triply charged metal cations in water–oxyethylated nonylphenol–salting-out agent systems

The characteristic features of extraction of chloride acido complexes of iron(III), thallium(III), indium, and gallium in water–oxyethylated nonylphenol (neonol AF-9-12)–salting-out agent systems are studied. The role of temperature, nature of the salting-out agent, and its salting-out ability is shown.

Development of a Chemosensor for the In Situ Monitoring of Thallium in the Water Network

Thallium is an emerging contaminant, which can be retained in scale encrustation within the pipeline and then released to drinking water. It is included in the Priority Pollutant List of the U.S. EPA. In this study, a sample from the water pipeline of Pietrasanta (Italy), affected by the contamination of thallium, is characterized by SEM-EDS, TGA, and FT-IR. Fluorescence spectroscopy is then proposed as the optimal technique for the detection of the contaminant. The functionality of a previously reported fluorescent calix[4]arene-based chemosensor is verified first on a standard solution of thallium nitrate and then on the sample under investigation. The quenching of the fluorescence of the sensor during the complexation of thallium is confirmed, identifying an ON-OFF sensor with high sensitivity, able to detect concentrations as low as 10−6 M and with high potential of development for the in situ and fast monitoring of the pollutant in the water network.

Bis- and Tris(2-oxobenzimidazolyl)hydroborato Complexes of Sodium and Thallium: New Classes of Bidentate and Tridentate Oxygen Donor Ligands.

A series of bis- and tris(oxobenzimidazolyl)hydroborato compounds, namely, [BoRBenz]Na and [ToRBenz]-Na (R = Me, But, Ad), which feature uncommon sterically demanding LX [O2] and L2X [O3] donor ligands, have been obtained via the reactions of NaBH4 with 1-R-1,3-dihydro-2H-benzimidazol-2-ones. Evidence that the alkyl substituents are suitably located to have a significant impact on the coordination environment is provided by the observation that the methyl derivative [ToMeBenz]Na(κ3-diglyme) exhibits κ3-coordination of the diglyme, whereas the t-butyl and adamantyl derivatives, [ToButBenz]Na(κ2-diglyme) and [ToAdBenz]Na(κ2-diglyme), exhibit κ2-coordination. The [BoRBenz] and [ToRBenz] ligands also allow for isolation of discrete mononuclear thallium compounds, [BoRBenz]Tl and [ToRBenz]Tl, for which the steric demands of the ligands have been quantified in terms of both cone angle and buried volume concepts.

Three-Dimensional Polymeric Thallium(I) Morpholinedithiocarbamate [Tl2{S2CN(CH2)4O}2] n and Its Capability of Binding Gold(III) from Solutions: Chemisorption Synthesis of a Heteronuclear Gold(III)–Thallium(III) Complex of the Ionic Type, ([Au{S2CN(CH2)4O}2][TlCl4]) n , the Role of Secondary Interactions Tl…O, Tl…S, and Au…S in the Supramolecular Self-Organization, 13C MAS NMR, and Thermal Behavior

Crystalline polymeric thallium(I) morpholinedithiocarbamate [Tl2{S2CN(CH2)4O}2]n (I) and the heteronuclear ion–polymeric gold(III)–thalium(III) complex ([Au{S2CN(CH2)4O}2][TlCl4])n (II) are prepara ...

Electrospray ionization mass spectrometric study of thallium complexes with nucleosides.

The complexes between Tl+, K+, and nucleosides were studied by using electrospray ionization mass spectrometry. It was found that for complexes of 1:1 stoichiometry, thallium complexes with cytidine were the most abundant and thallium complexes with guanosine were the second most abundant ones. The relative abundances of cytidine-Tl+ to cytidine-K+ complexes depended on stoichiometry (at higher stoichiometry the potassium complexes were more abundant). In other words, the relative affinity of Tl+ and K+ to form cytidine complexes depends on the stoichiometry of the formed complexes. Guanosine-Tl+ complexes were more abundant than guanosine-K+ complexes, irrespective of stoichiometry. Both guanosine tetramer and mixed cytidine/guanosine tetramer were more abundant when they were stabilized by thallium than potassium. Therefore, Tl+ may affect the K+ stabilization of these tetramers.

Synthesis, thermoanalytical and spectroscopic characterization of newly synthesized macrocyclic complexes of thallium(III) and tin(IV)

Spectroscopic, thermal and fluorescence properties of various thallium and tin complexes, X-Tl(III)t(4-Y)PP and X-Sn(IV)t(4-Y)PP where X = 5-SO3H-2-OHOC6H4,(5-SSA); 5-Cl-2-OHOC6H4,(5-CSA); and 5-NH2-2-OHOC6H4,(5-NSA) and Y = –Cl, –OCH3, are investigated in detail. Analysis of the spectral data [IR, UV–Vis and NMR (1H and 119Sn)] of complexes suggests that the two trans-axial ligands are strongly bound in a symmetric manner at the tin center in these complexes. Whereas the absorption and emission studies of thallium complexes characterized the sitting-Atop (SAT) feature of the complexes, the fluorescence lifetime of the tin complexes is found to be higher than thallium complexes. The structure and morphology of complexes were studied by X-ray powdered diffraction analysis. From the X-ray diffractograms, it could be revealed that the complexes are crystallized in mixed crystalline forms. Thermal studies of these porphyrins were carried out in an argon atmosphere from room temperature to 800 °C using thermal analyzer. Evaluation of the thermal analysis of the two metal complexes reveals that the tin(IV) porphyrin complexes are more stable than thallium(III) complexes. Some of the synthesized complexes of thallium and tin have been screened for biological activity against B. subtilis, M. luteus, S. aureus, P. florescens and E. coli by agar well diffusion methods that were found to be inactive against bacterial strains.

Synthesis, Characterization and Antibacterial Studies of N-(Benzothiazol-2-yl)-4-chlorobenzenesulphonamide and Its Neodymium(III) and Thallium(III) Complexes.

N-(Benzothiazol-2-yl)-4-chlorobenzenesulphonamide (NBTCS) was synthesized by condensation reaction of 4-chlorobenzenesulphonyl chloride and 2-aminobenzothiazole in acetone under reflux. Neodymium(III) and thallium(III) complexes of the ligand were also synthesized. Both ligand and metal complexes were characterized using UV-Vis, IR, 1H- and 13C-NMR spectroscopies, elemental analysis and molar conductance measurement. IR studies revealed that the ligand is tridentate and coordinates to the metal ions through nitrogen and oxygen atoms of the sulphonamide group and nitrogen atom attached to benzothiazole ring. The neodymium(III) complex displays a coordination number of eight while thallium(III) complex displays a coordination number of six. The ligand and its complexes were screened in vitro for their antibacterial activities against Escherichia coli strains (E. coli 6 and E. coli 13), Proteus species, Staphylococcus aureus and Pseudomonas aeruginosa using the agar well diffusion technique. The synthesized compounds were found to be more active against the microorganisms screened relative to ciprofloxacin, gentamicin and co-trimoxazole.

PNacPNacE: (E = Ga, In, Tl) - monomeric group 13 metal(i) heterocycles stabilized by a sterically demanding bis(iminophosphoranyl)methanide.

The salt metathesis reaction of the sterically demanding bis(iminophosphoranyl)methanide alkali metal complexes LM (L- = HC(Ph2P[double bond, length as m-dash]NDip)2-, Dip = 2,6-iPr2C6H3; M = Li, Na, K) with "GaI", InBr or TlBr afforded the monomeric group 13 metal(i) complexes LE:, E = Ga (1), In (2) and Tl (3) in moderate yields, and small quantities of LGaI24 in the case of Ga, respectively. The molecular structures of LE: 1-3 from X-ray single crystal diffraction show them to contain puckered six-membered rings with N,N'-chelating methanide ligands and two-coordinated metal(i) centres. Reduction reactions of LAlI25, prepared by iodination of LAlMe2, were not successful and no aluminium(i) congener could be prepared so far. DFT studies on LE:, E = Al-Tl, were carried out and support the formulation as an anionic, N,N'-chelating methanide ligand coordinating to group 13 metal(i) cations. The HOMOs of the molecules for E = Al-In show a dominant contribution from a metal-based lone pair that is high in s-character.

Comparison of thallium(I) complexes with mesityl-substituted tris(pyrazolyl)hydroborate ligands, [Tl{HB(3-Ms-5-Mepz)3}] and [Tl{HB(3-Ms-5-Mepz)2(3-Me-5-Mspz)}

Tris(pyrazolyl)borate (scorpionate) ligands can be considered as the most prolific ligands in contemporary coordination chemistry due to the availability of various steric and electronic substituents at the pyrazolyl rings that allow fine-tuning of the open-coordination site for metal centres. The thallium(I) complexes of anionic tridentate-chelating scorpionate ligands, namely [tris(3-mesityl-5-methyl-1H-pyrazol-1-yl-κN2)hydroborato]thallium(I) monohydrate, [Tl(C39H46BN6)]·H2O, (I), and [bis(3-mesityl-5-methyl-1H-pyrazol-1-yl-κN2)(5-mesityl-3-methyl-1H-pyrazol-1-yl-κN2)hydroborato]thallium(I), [Tl(C39H46BN6)], (II), show a {TlIN3} coordination, with average TlI-N bond lengths of 2.53 and 2.55 Å in (I) and (II), respectively. The overall TlI coordination geometry is distorted trigonal pyramidal, with the average N-TlI-N angle being approximately 73° for both. The dihedral angle between the planes of the pyrazolyl and benzene rings of the mesityl group is 82° in (I), while the corresponding angles in (II) are in the range 64-104°. The structural differences between the two ligands are expected to contribute to the different reactivities of the transition metal coordination complexes towards activation of small molecules such as dioxygen and ethylene.