Tl Complexes Research Articles

Highly Fluorinated Aryl-Substituted Tris(indazolyl)borate Thallium Complexes: Diverse Regiochemistry at the B–N Bond

The synthesis and characterization (mainly by (19)F NMR and X-ray diffraction) of highly fluorinated aryl-4,5,6,7-tetrafluoroindazoles and their corresponding thallium hydrotris(indazolyl)borate complexes are reported [aryl = phenyl, pentafluorophenyl, 3,5-dimethylphenyl, 3,5-bis(trifluoromethyl)phenyl]. Thanks to N-H···N hydrogen bonds, the indazoles crystallize as dimers that pack differently depending on the nature of the aryl group. The thallium hydrotris(indazolyl)borate complexes Tl[Fn-Tp(4Bo,3aryl)] resulting from the reaction of aryl-4,5,6,7-tetrafluoroindazoles [aryl = phenyl, 3,5-dimethylphenyl, 3,5-bis(trifluoromethyl)phenyl] with thallium borohydride adopt overall C(3v) symmetry with the indazolyl groups bound to boron via their N-1 nitrogen in a conventional manner. When the perfluorinated pentaphenyl-4,5,6,7-tetrafluoroindazole is reacted with thallium borohydride, a single regioisomer of C(s) symmetry having one indazolyl ring bound to boron via its N-2 nitrogen, TlHB(3-pentafluorophenyl-4,5,6,7-tetrafluoroindazol-1-yl)(2)(3-pentafluorophenyl-4,5,6,7-tetrafluoroindazol-2-yl) Tl[F27-Tp((4Bo,3C6F5)*)], is obtained for the first time. Surprisingly, the perfluorinated dihydrobis(indazolyl)borate complex Tl[F(18)-Bp(3Bo,3C6F5)], an intermediate on the way to the hydrotris(indazolyl)borate complex, has C(s) symmetry with two indazolyl rings bound to boron via N-2. The distortion of the coordination sphere around Tl and the arrangement of the complexes in the crystal are discussed.

Homoleptic, heteroleptic and mixed-valent thallium and indium complexes of multidentate chalcogen-centred PCP-bridged ligands

The metathetical reaction of [Li(TMEDA)][HC(PPh(2)Se)(2)] ([Li(TMEDA)]1) with TlOEt in a 1:1 molar ratio afforded a homoleptic Tl(I) complex as an adduct with LiOEt, Tl[HC(PPh(2)Se)(2)]·LiOEt (7), which undergoes selenium-proton exchange upon mild heating (60 °C) to give the mixed-valent Tl(I)/Tl(III) complex {[Tl][Tl{(Se)C(PPh(2)Se)(2)}(2)]}(∞) (8). Treatment of TlOEt with [Li(TMEDA)](2)[(SPh(2)P)(2)CE'E'C(PPh(2)S)(2)] (3b, E' = S; 3c, E' = Se) in a 2:1 molar ratio produced the binuclear Tl(i)/Tl(i) complexes Tl(2)[(SPh(2)P)(2)CE'E'C(PPh(2)S)(2)] (9b, E' = S; 9c, E' = Se), respectively. Selenium-proton exchange also occurred upon addition of [Li(TMEDA)]1 to InCl(3) to yield the heteroleptic complex (TMEDA)InCl[(Se)C(PPh(2)Se)(2)] (10a). Other examples of this class of In(III) complex, (TMEDA)InCl[(E')C(PPh(2)E)(2)] (10b, E = E' = S; 10c, E = S, E' = Se) were obtained via metathesis of InCl(3) with [Li(TMEDA)](2)[(E')C(PPh(2)E)(2)] (2b, E = E' = S; 2c, E = S, E' = Se, respectively). All new compounds have been characterized in solution by (1)H and (31)P NMR spectroscopy and the solid-state structures have been determined for 8, 9c and 10a-c by single-crystal X-ray crystallography. Complex 8 is comprised of Tl(+) ions that are weakly coordinated to octahedral [Tl{(Se)C(PPh(2)Se)(2)}(2)](-) anions to give a one-dimensional polymer. The complex 9c is comprised of two four-coordinate Tl(+) ions that are each S,S',S'',Se bonded to the hexadentate [(SPh(2)P)(2)CSeSeC(PPh(2)S)(2)](2-) ligand in which d(Se-Se) = 2.531(2) Å. The six-coordinate In(III) centres in the distorted octahedral complexes 10a-c are connected to a tridentate [(E')C(PPh(2)E)(2)](2-) dianion, a chloride ion and a neutral bidentate TMEDA ligand.

The effect of a 3-benzyl group on the coordination chemistry of homoscorpionate ligands.

New homoscorpionate ligands containing a 3-benzyl substituent, hydrotris(3-benzyl-5-methylpyrazol-1-yl)borate, Tp(Bn,Me), and hydrotris(3-benzyl-4-phenylpyrazol-1-yl)borate, Tp(Bn,4Ph), have been synthesized, and the dynamic behavior of a number of metal complexes was studied by NMR. Structures of the complexes Tl[Tp(Bn,Me)], 1, Tl[Tp(Bn,4Ph)], 2, Co[Tp(Bn,Me)][Tp(Np)], 3, Mo[Tp(Bn,Me)](CO)(2)NO, 4, Co[Tp(Bn,4Ph)][Tp], 5, and Mo[Tp(Bn,Me)](CO)(2)(eta(3)-methallyl), 6, were determined by X-ray crystallography. In the Tp(Bn,Me) ligand, the benzyl group is freely rotating and provides less steric hindrance to the coordinated metal than a neopentyl group, but steric hindrance is increased in the Tp(Bn,4Ph) ligand, where the rotation of the benzyl substituent is restricted by the 4-phenyl substituent.

Homoscorpionate Ligands Based on 3-(Cyclobutyl)pyrazole and 3-(Cyclopentyl)pyrazole

The novel scorpionate ligands hydrotris[3-(cyclobutyl)pyrazol-1-yl]borate (TpCbu), hydrotris[3-(cyclopentyl)pyrazol-1-yl]borate (TpCpe), tetrakis[3-(cyclobutyl)pyrazol-1-yl]borate (pzoTpCbu), tetrakis[3-(cyclopentyl)pyrazol-1-yl]borate (pzoTpCpe), have been synthesized, converted into a variety of homo- and heteroleptic complexes, and studied by NMR spectroscopy. The complexes Tl[TpCbu] (1), Tl[TpCpe] (2), Co[TpCbu]2 (3), Co[TpCpe*]2 (4), Co[TpCpe][Tp] (5), Co[pzoTpCbu]2 (6), and Co[pzoTpCpe]2 (7) have been structurally characterized by X-ray crystallography. The coordination behavior of TpCpe is similar to that of TpCy or TpiPr in producing stable tetrahedral TpCpeMX complexes, but octahedral homoleptic complexes only with ligand rearrangement, yielding M[TpCpe*]2. By contrast, TpCbu is unusual in forming both tetrahedral TpCbuMX, and homoleptic M[TpCbu]2 complexes, without rearrangement. The complex 6 is tetrahedral in solution but octahedral in the crystal, while complex 7 is tetrahedral in solution and in the crystal. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Equilibrium Dynamics in the Thallium(III)-Cyanide System in Aqueous Solution.

Ligand exchange reactions of thallium(III) cyano complexes, Tl(CN)(n)()(3)(-)(n)(), have been systematically studied in aqueous solution containing 4 M ionic medium {[ClO(4)(-)](tot) = 4 M, [Na(+)](tot) = 1 M, [Li(+)](tot) + [H(+)](tot) = 3 M}, at 25 degrees C, using (205)Tl and (13)C NMR one-dimensional inversion transfer techniques. Rate constants for all dominating exchange pathways were determined and compared to the previously studied thallium(III) halide complexes. Also in the case of cyanide ligands the ligand exchange is dominated by the rare type of reactions occurring via a direct encounter of two complexes (self-exchange reactions), e.g. Tl(CN)(3) + Tl(CN)(2)(+) right harpoon over left harpoon Tl(CN)(2)(+) + Tl(CN)(3) (k(32), k(23)) or Tl(CN)(2)(+) + Tl(CN)(4)(-) right harpoon over left harpoon 2Tl(CN)(3) (k(24), k(33)). The determined cyanide exchange rate constants between complexes Tl(CN)(m)()(3)(-)(m)() and Tl(CN)(n)()(3)(-)(n)(), for the rate-determining step have all similar values, about 100-1000 s(-)(1), that are 5 orders of magnitude smaller than for the corresponding halide exchange processes. This indicates the presence of a common rate-determining step for the self-exchange reactions of the cyanide ligand, proposed to be the breaking of the thermodynamically very stable Tl-CN bond. This is in contrast to the Tl(III)-halide systems, where the breaking of the Tl-OH(2) bond was proposed to determine the reaction rate. The second type of cyanide exchange, namely anation, has been found only in two cases: Tl(CN)(2)(+) + CN(-) right harpoon over left harpoon Tl(CN)(3) (k'(23), k'(32)); and Tl(CN)(3) + CN(-) right harpoon over left harpoon Tl(CN)(4)(-) (k'(34), k'(43)). These reactions are very fast, k'(mn)() approximately 10(9) M(-)(1) s(-)(1), and are proposed to proceed through an associative interchange mechanism, where the rate-determining step is a water dissociation mediated by the incoming ligand, i.e. similarly as for the corresponding halide complexes. The third type of cyanide exchange reactions was possible to study due to the presence of an NMR-active nucleus ((13)C) in the ligand. Only the following ligand substitution reaction was observed: Tl(CN)(2)(+) + HCN right harpoon over left harpoon Tl(CN)(2)(+) + HCN The reason for the dominant role of the self-exchange reactions is the very low concentration of free CN(-) and the inertness of the HCN species in the ligand exchange reactions. The obtained dynamic information is discussed and compared to the corresponding data for the thallium(III) halide complexes.

Equilibrium Dynamics in the Thallium(III)−Cyanide System in Aqueous Solution

Ligand exchange reactions of thallium(III) cyano complexes, Tl(CN)(n)()(3)(-)(n)(), have been systematically studied in aqueous solution containing 4 M ionic medium {[ClO(4)(-)](tot) = 4 M, [Na(+)](tot) = 1 M, [Li(+)](tot) + [H(+)](tot) = 3 M}, at 25 degrees C, using (205)Tl and (13)C NMR one-dimensional inversion transfer techniques. Rate constants for all dominating exchange pathways were determined and compared to the previously studied thallium(III) halide complexes. Also in the case of cyanide ligands the ligand exchange is dominated by the rare type of reactions occurring via a direct encounter of two complexes (self-exchange reactions), e.g. Tl(CN)(3) + Tl(CN)(2)(+) right harpoon over left harpoon Tl(CN)(2)(+) + Tl(CN)(3) (k(32), k(23)) or Tl(CN)(2)(+) + Tl(CN)(4)(-) right harpoon over left harpoon 2Tl(CN)(3) (k(24), k(33)). The determined cyanide exchange rate constants between complexes Tl(CN)(m)()(3)(-)(m)() and Tl(CN)(n)()(3)(-)(n)(), for the rate-determining step have all similar values, about 100-1000 s(-)(1), that are 5 orders of magnitude smaller than for the corresponding halide exchange processes. This indicates the presence of a common rate-determining step for the self-exchange reactions of the cyanide ligand, proposed to be the breaking of the thermodynamically very stable Tl-CN bond. This is in contrast to the Tl(III)-halide systems, where the breaking of the Tl-OH(2) bond was proposed to determine the reaction rate. The second type of cyanide exchange, namely anation, has been found only in two cases: Tl(CN)(2)(+) + CN(-) right harpoon over left harpoon Tl(CN)(3) (k'(23), k'(32)); and Tl(CN)(3) + CN(-) right harpoon over left harpoon Tl(CN)(4)(-) (k'(34), k'(43)). These reactions are very fast, k'(mn)() approximately 10(9) M(-)(1) s(-)(1), and are proposed to proceed through an associative interchange mechanism, where the rate-determining step is a water dissociation mediated by the incoming ligand, i.e. similarly as for the corresponding halide complexes. The third type of cyanide exchange reactions was possible to study due to the presence of an NMR-active nucleus ((13)C) in the ligand. Only the following ligand substitution reaction was observed: Tl(CN)(2)(+) + HCN right harpoon over left harpoon Tl(CN)(2)(+) + HCN The reason for the dominant role of the self-exchange reactions is the very low concentration of free CN(-) and the inertness of the HCN species in the ligand exchange reactions. The obtained dynamic information is discussed and compared to the corresponding data for the thallium(III) halide complexes.

Structural characterization of bis(pyrazolyl)hydroborato thallium complexes: monomeric “two-coordinate” thallium derivatives supplemented by [Tl…H-B] interactions

The syntheses and structural characterization of a series of mononuclear bis(pyrazolyl)hydroborato thallium complexes Tl[Bp Bu t R] (R = Me, Pr ii , Bu t ) are described. In each case, the two-coorinate Tl( I) centers of Tl[Bp Bu t,R ] are supplemented by secondary [Tl…H-B] interactions.

Structure of Thallium(III) Chloride, Bromide, and Cyanide Complexes in Aqueous Solution

The structures of the hydrated thallium(III) halide and pseudohalide complexes, [TlX(n)(OH2)(m)]((3-n)+), X = Cl, Br, CN, in aqueous solution have been studied by a combination of X-ray absorption fine structure spectroscopy (XAFS), large-angle X-ray scattering (LAXS), and vibrational spectroscopic (Raman and IR) techniques including far-infrared studies of aqueous solutions and some solid phases with known structures. The vibrational Tl-X frequencies of all complexes are reported, force constants are calculated using normal coordinate analysis, and assignments are given. The structural results are consistent with octahedral six-coordination for the cationic complexes Tl(OH2)(6)(3+), TlX(OH2)(5)(2+), and trans-TlX(2)(OH2)(4+). The coordination geometry changes to trigonal bipyramidal for the neutral TlBr3(OH2)(2) complex and possibly also for TlC3(OH2)(2). The TlX(4)(-) complexes are all tetrahedral. Higher chloride complexes, TlCl5(OH2)(2-) and TlCl63-, are formed and have again Octahedral coordination geometry. For the first and second halide complexes, TlX(OH2)(5)(2+) and TlX(2)(OH2)(4+), no lengthening was found of the Tl-X bonds, with Tl-Br distances of 2.50(2) and 2.49(2) Angstrom, respectively, and Tl-Cl distances of 2.37(2) Angstrom for both complexes. The mean Tl-O bond distances increase slightly, approximate to 0.04 Angstrom, from that of the Tl(OH2)(6)(3+) ion, at the formation of the first thallium(m) halide complexes. A further, more pronounced lengthening of about 0.1 Angstrom occurs when the second complex forms, and it can be related to the relatively high bond strength in the trans-XTlX entity, which also is manifested through the Tl-X stretching force constants. For the recently established Tl-3(CN)(n)((3-n)+) complexes with no previously available structural information, the Tl-C distances were determined to be 2.11(2), 2.15(2), and 2.19(2) Angstrom for n = 2, 3, and 4, respectively. The Tl(CN)(2)+ complex has a linear structure, and the Tl(CN)(4)(-) complex is tetrahedral with the CN- ligands linearly coordinated. The lower complexes (n = 1-3) are hydrated, although the coordination numbers could not be unambiguously determined. A well-defined second coordination sphere corresponding to at least eight water molecules at a Tl-O-II distance of approximate to 4.3 Angstrom was found around the second complex, probably trans-Tl(CN)(2)(OH2)(4+). The third cyano complex is probably pseudotetrahedral, Tl(CN)(3)(OH2). The bonding in the hexahydrated Tl3+ and Hg2+ ions is discussed, and differences in the mean M-O bond lengths, determined by the LAXS and EXAFS techniques, are interpreted as being due to an occurrence of two different sets of M-O distances in the first hydration shell. (Less)

2D NMR exchange spectroscopy with spy nuclei for thallium(III) cyano complexes in aqueous solution

We have used a combination of 13 C and 205 Tl NMR 2D exchange spectroscopy (EXSY) to study cyanide exchange reactions in an aqueous solution containing the recently established complexes Tl( 13 CN) 3 and Tl( 13 CN) 4 - , and H 13 CN. Because of the well-resolved heteronuclear spin-spin couplings (up to 8 kHz), the system was considered to have six exchanging sites for 13 C NMR and nine for 205 Tl NMR. The employed method have an overview of the dynamic processes at chemical equilibrium

Equilibria and dynamics of thallium-EDTA (Tl(edta)X2-) complexes (X = halide, pseudohalide) studied by multinuclear NMR

Equilibria and dynamics in aqueous solutions of mixed complexes Tl(edta)X[sup 2[minus]] containing ionic medium (1 M NaClO[sub 4]) have been studied by means of [sup 205]Tl-, [sup 15]N-, [sup 13]C-, and [sup 1]H-NMR and potentiometry. Individual [sup 205]Tl chemical shifts have been determined for all the investigated complexes (X = H[sub 2]O, OH, Cl, Br, CN, SCN). For the pseudohalide complexes the [sup 15]N- and [sup 13]C-NMR shifts as well as the spin-spin coupling constants J([sup 205]Tl-[sup 15]N) and J([sup 205]Tl-[sup 13]C) have also been determined. The coupling constant [sup 1]J([sup 205]Tl-[sup 13]C) for the complex Tl(edta)CN[sup 2[minus]] is remarkably large, 10 479 Hz, indicating a very strong thallium-carbon bond. The stability constants, K[sub x] = [Tl(edta)X[sup 2[minus]]]/([Tl(edta)[sup [minus]]][X[sup [minus]]]), determined by a combination of [sup 205]Tl- and [sup 13]C-NMR and potentiometry, for X = Cl, CN, and SCN are, respectively: log K[sub x] = 2.6 ([+-] = [sigma]), 8.72 ([+-] 0.03) and 2.70 ([+-] 0.03). In order to facilitate the discussion of reaction mechanisms, the crystal and molecular structure of the compound Na[sub 2][Tl(edta)CN]-3H[sub 2]O has been determined using single-crystal x-ray diffraction. This compound crystallizes in the monoclinic space group P2[sub 1]/c (no. 14) with a = 7.769 (2)more » [angstrom], b = 14.130 (6) [angstrom], c = 17.069 (5) [angstrom], [beta] = 101.44(2)[degree], and Z = 4.« less

Synthesis and dynamic nuclear magnetic resonance studies of pentafluorobenzenethiolate complexes of molybdenum and tungsten. The crystal and molecular structures of [W(SC6F5)3(CO)(η5-C5H5)]·0.5CH2Cl2and [N(PPh3)2][Mo(SC6F5)4(η5-C5H5)

The reaction between [WBr3(CO)2(η5-C5H5)] and excess of Tl(SC6F5)(CH2Cl2, 20 °C) affords Tl[W(SC6F5)4(η5-C5H5)](2b) as the major product and [W(SC6F5)3(CO)(η5-C5H5)](3) as the minor product. Complex (3) has been structurally characterised as its 0.5 CH2Cl2 solvate by X-ray diffraction. Chiral molecules of [W(SC6F5)3(CO)(η5-C5H5)] adopt a distorted square-based ‘piano-stool’ geometry with the trans W–S bond [2.443 6(15)A] longer than the cis W–S bonds (mean 2.358 A). The SC6F5 ligands lie with S–C bonds approximately in the plane of the square base and, all C6F5 groups have the same rotational orientation about the central W atom. However, dynamic 19F n.m.r. studies of (3) reveal that two isomeric forms exist at low temperature due to different orientations of the SC6F5 ligands but these undergo exchange at ambient temperature as a result of rotation about the W–SC6F5 bonds or inversion at sulphur. Similar studies of complex (2b) established that apparent rotation of the SC6F5 groups is solvent dependent and occurs in conjunction with ionic dissociation into Tl+ and [W(SC6F5)4(η5-C5H5)]–. The TlI in (2b) and related complexes Tl[Mo(SC6F5)4(η5-C5H5)] and Tl[Mo(SC6F5)2(CO)2(η5-C5H5)] can be replaced by non-co-ordinating cations to give X+[M(SC6F5)4(η5-C5H5)]–[M = Mo, X = NBun4(4a) or N(PPh3)2(4b); M = W, X = NMe4] and N(PPh3)2+[Mo(SC6F5)2(CO)2(η5-C5H5)]– which also exhibit fluxional behaviour according to 19F n.m.r. studies. The structure of complex (4b), determined in the solid state by X-ray diffraction, comprises discrete ions [(Ph3P)N(PPh3)]+ and [Mo(SC6F5)]4[(η5-C5H5)]–. The complex anion has a ‘piano-stool’ geometry with a square base defined by four SC6F5 ligands (mean Mo–S 2.420 A) and the C6F5 groups form a ‘swastika-like’ arrangement about the square plane. Reactions of (2b) with tertiary phosphines (L) in CH2Cl2 at 20 °C afford 1:2 adducts Tl[W(SC6F5)4L2(η5-C5H5)][L = PPh3(6b), PMe2Ph (6c), or PEt3(6d)]. Dynamic 19F n.m.r. studies established a different structure for (6b) in solution compared to (6c) and (6d).

Thallium(I) interactions in biological fluids: A potentiometric investigation of thallium(I) complex equilibria with some sulphur-containing amino acids

Formation constants for thallium(I) complexes of L-cysteine (CysH 2), DL-penicillamine (PenH 2), N-acetyl-L-cysteine (AcyH 2), and N-acetyl-DL-penicillamine (ApeH 2) in aqueous solution have been determined in 150 mmol dm −3 NaCl medium at 37°C by potentiometric titrations using a glass electrode. Glycine has been used as a model for simple amino acids. The experimental data may be explained by the formation of the complexes Tl(Cys) −, Tl(Cys)H, Tl(Pen) −, Tl(Pen)H, Tl(Acy) −, and Tl(Ape) − with log formation constants 3.26, 11.28, 3.60, 12.05, 2.27, and 2.45, respectively. Analysis of the results obtained and comparison of thallium(I) complexing ability with that of dimethylthallium(III) seem to indicate that thallium(I) toxicity does not directly stem from its interference with the metabolism of sulphur-containing compounds.

Electromigration of Carrier-Free Radionuclides. 6. Iodide and Bromide Complexes of Carrier-Free 201Tl(I) in Aqueous Solutions

Individual ion mobility of 201Tl(I) = +7.3 (3) X 10−4 cm3 s−1 V−1 was observed at 298.1 ± 0.1 K in aqueous solutions of H(K)ClO4, 1.5 · 10−3 ≦ μ ≦ 0.5 and 0.3 ≦ pH ≦ 6.5. Experimental dependences of 201Tl(I) overall ion mobilities on concentrations of ligand anions in solutions of perchlorate background electrolytes have been used to calculate stability constants of neutral thallium complexes Tl I and Tl Br at 298.1 ± 0.1 K and μ = 0.1. They are 115 ± 25 l · mol−1, and 5.25 ± 0.35 l · mol−1 respectively.

Effet des anions sur la vitesse d'oxydation de la cyclohexanedione-1,2 par l'ion thallique

The effect of acetate, chloride, bromide, nitrate, and sulfate anions on thallic ion oxidation of 1,2-cyclohexanedione has been studied. Reactivities of the different complexes Tl(III)–anions have been determined. Generally introduction of a ligand in the internal coordination sphere of thallic ion produces an increase in the rate constant.

A spectroscopic investigation of some complexes of thallium(I) and thallium(III) with nitrogen donor ligands

Some new vibrational spectroscopic data are given for Tl(chelate)X3 where chelate = 2.2′bipyridyl, 1.10 phenanthroline or di-2-pyridylamine and X = Cl or Br. The new complexes Tl(tripyam)X3 (tripyam = tri-2-pyridylamine, X = Cl or Br) are reported together with a new series of compounds [Tl(chelate)X3 D.M.F.] (chelate = as above or bidentate tri-2-pyridylamine, X = Cl or Br, DMF = dimethyl-formamide). Chemical and spectroscopic reasoning lead to a preference for a polymeric as opposed to a dimeric structure for [TI(chelate)X3]. New data (1H n.m.r. and i.r.) are reported for [Tl(phen)2]Y (Y = NO3− or ClO4) and [Tl(bipy)2]ClO4. The stereochemical environment of the thallium(I) cation is considered to be close to ψ tetrahedral.

Organothallium compounds. IV. Carboxylatobis(pentafluorophenyl)thallium(III) compounds and their complexes with 1,10-phenanthroline and 2,3'-bipyridyl

Carboxylatobis(pentafluorophenyl)thallium(III) compounds, Tl(OCOR)(C6F5)2 (R = Ph, Me, or C6F5), have been prepared by a metathesis reaction between bromobis(pentafluorophenyl)thallium(III) and the appropriate sodium or ammonium carboxylate in aqueous ethanol. They are considered to have dimeric structures with bridging carboxylate groups. With 1,10- phenanthroline (phen), the complexes Tl(OCOR)(C6F5)2 phen, which are monomeric in benzene and acetone, are obtained. The complexes, Tl(OCOR)(C6F6)2 bipy (bipy = 2,2'-bipyridyl; R = Ph or Me) can be prepared only by using excess ligand. They decompose to Tl(OCOR)(C6F5)2 compounds on attempted recrystallization, partly dissociate into Tl(OCOR)(C6F5)2 and bipyridyl in benzene and acetone, and undergo ligand exchange with 1,10-phenanthroline to give Tl(OCOR)(C6F5)2 phen complexes. By contrast, Tl(OCOC6F5)-(C6F5)2 bipy has been prepared without using excess ligand and can be recrystallized unchanged. It is monomeric in benzene, but dissociates slightly in acetone. The complexes, Tl(OCOR)(C6F5)2(phen or bipy), are considered to contain five-coordinate thallium.

The far infrared spectra of some co-ordination compounds of the thallium(III) halides

The infrared specta (667–222 cm.–1) of the complexes Ph4AsTIX4, TIX3(1 pyridine)2, TIX3(2,2′-bipyridyl), TIX3(1,10-phenanthroline), TICl3(di-2-pyridylamine), and Tl(ethylenediamine)2X3(X = Cl or Br) have been recorded and the thallium–chlorine stretching vibrations assigned. The TlCl4– ion is considered to be tetrahedral in acetone and methyl cyanide solution. TlCl3(py)2 is shown to exist as Tl(py)4Cl2+ TlCl4– in acetone solution.