Synthesis and Crystal Structure of a New Type of Ionic Technetium(V) Dioxo Phosphine Complexes, [Tc(O)2(PR3)3]+. Reactions with Pyridine and Crystal Structures of trans,cis,cis-[Tc(O)2(PR3)2(py)2]+ Compounds

Rochon, Fernande D.; Melanson, R.; Kong, Pi-Chang

doi:10.1021/ic970573l

Cited by 16 publications

(7 citation statements)

References 22 publications

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“…This suggests that a main decomposition pathway starts with the hydrolysis of the imido ligand and subsequent reduction of the intermediately formed oxidotechnetium(V) product (see Scheme ). This is plausible keeping in mind that an unexpected hydrolysis of phenylimidotechnetium(V) complexes is not without precedent, and oxidotechnetium(V) complexes with triphenylphosphine are not stable and readily form Tc(IV) and/or Tc(III) complexes . For the corresponding rhenium compounds, such a decomposition is not observed.…”

Section: Results and Discussionmentioning

confidence: 95%

Complexes of Technetium(V) and Rhenium(V) with β-Diketonates

et al. 2019

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Reactions of (NBu4)[MOCl4] complexes (M = Tc or Re) with an excess of hexafluoroacetylacetone (Hhfac) give products with a composition of (NBu4)[MOCl3(hfac)] as bright yellow (Tc) or red (Re) solids. The products are stable as solids but rapidly decompose in solution. A number of related phenylimidorhenium(V) complexes were synthesized starting from [Re(NPhF)Cl3(PPh3)2], where (NPhF)2– is a para-fluorinated phenylimido ligand. Products with compositions of [Re(NPhF)Cl2(PPh3)(acac)], [Re(NPhF)Cl2(PPh3)(hfac)], [Re(NPhF)Cl2(PPh3)(tfac)], [Re(NPhF)Cl2(PPh3)(naphtfac)], and [Re(NPhF)Cl2(PPh3)(tbutfac)] (Hacac = acetylacetone, Htfac = trifluoroacetylacetone, Hnaphtfac = naphthoyltrifluoroacetylmethane, and Htbutfac = tert-butyroyltrifluoroacetylmethane) were isolated from reactions of the quite soluble [Re(NPhF)Cl3(PPh3)2] with the corresponding β-diketones and studied spectroscopically and by X-ray diffraction. The β-diketonates are coordinated in a meridional arrangement with the phenylimide. The formation of two isomers was detected for nonsymmetric β-diketones with a preference for the “equatorial” position for the more bulky substituents. Products with more than one chelating ligand were not obtained. The technetium complexes [Tc(NPhX)Cl3(PPh3)2] (X = p-F or p-CF3) were prepared from reactions of pertechnetate, PPh3, HCl, and substituted arylacetylhydrazines and isolated as green solids. They are sufficiently stable as solid but rapidly decompose in moist solvents upon hydrolysis of the Tc–N bonds. From reactions of [Tc(NPh)Cl3(PPh3)2] or [Tc(NPhF)Cl3(PPh3)2] in dry solvents, the complexes [Tc(NPh)Cl2(PPh3)(hfac)] and [Tc(NPhF)Cl2(PPh3)(hfac)] were prepared and isolated in crystalline form. An X-ray diffraction study shows that fluorination of the para position of the phenylimido ligand results in a slight lengthening of all bonds in the coordination sphere of technetium.

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Section: Results and Discussionmentioning

confidence: 95%

Complexes of Technetium(V) and Rhenium(V) with β-Diketonates

et al. 2019

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“…Technetium complexes are also of interest in the radiopharmaceutical industry. 234 Owing to the ideal energy of g radiation (140 keV), lack of particulate radiation dose, the small half-life T 1/2 and the fact that 99m Tc is readily accessible, this isotope is a radionuclide of choice for obtaining images in diagnostic nuclear medicine. 235,236…”

Section: Technetium Complexesmentioning

confidence: 99%

“…Phosphine 99m Tc-labelled derivatives can be used for obtaining images of internal organs, for example, heart images. Complexes of the [TcO 2 (PR 3 ) 3 ](BPh 4 ) (R = Et or Pr) type 234 have distorted trigonal-bipyramidal structures with two oxo ligands located in a single plane. Salts of the [TcO 2 (PR 3 ) 3 ] + cations are convenient starting compounds for the synthesis of other complexes with mixed ligands.…”

Section: Complexes With Phosphorus-containing Ligandsmentioning

confidence: 99%

“…The [TcO 2 (PR 3 ) 2 (Py) 2 ] + derivatives are diamagnetic, which is indicative of a noticeable deviation of their geometry from the ideal octahedron. 234 The reactions of pertechnate with derivatives of phosphinocarboxylic acids afforded the TcL 3 complexes [L is 2-(diphenylphosphino)benzoic acid, 3-(diphenylphosphino)propionic acid or (diphenylphosphino)acetic acid]. According to the results of spectroscopic studies and X-ray diffraction analysis, these complexes possess a distorted octahedral geometry with the mer configuration in which the donor atoms of the same type are in trans positions with respect to each other and the phosphorus atom is in the trans position with respect to the oxygen atom.…”

Section: Complexes With Phosphorus-containing Ligandsmentioning

confidence: 99%

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State-of-the-art coordination chemistry of radioactive elements

Kharisov¹,

Méndez‐Rojas²

2001

Russ. Chem. Rev.

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“…Although the CSD nowadays contains well over 2700 entries with triethylphosphine, only 47 (20 compounds) report the existence of phase transitions or multiple polymorphic forms. Of the 47, only three mention conformational changes of the triethylphosphine ligand (Cole et al, 1995;Torabi et al, 2002;Rochon et al, 1998). None of the three studies actually recounts phase transitions between the polymorphs they describe.…”

Section: Introductionmentioning

confidence: 99%

Triethylphosphine as a molecular gear — phase transitions in ferrocenyl–acetylide–gold(I)

Makal

2018

Acta Crystallogr Sect B

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A sequence of two discontinuous phase transitions, occurring just above 125 K and 148 K, has been observed for a ferrocenyl-acetylide-gold(I) complex with triethylphosphine, structure (1), by means of a multi-temperature single-crystal X-ray diffraction technique. Three distinct phases have been identified. The high-temperature and low-temperature phases share the same space group Pbca, whereas the intermediate phase is in the Pb2 1 a subgroup of Pbca. In all phases molecules of (1) form well defined double layers, with PEt 3 groups interlocking in planes perpendicular to c. On the molecular level, both phase transitions involve almost uniquely a conformational change of triethylphosphine: a gear-like rotation around the P-Au axis and concerted flips of the ethyl moieties. The mechanism of these transitions may be imagined as initiated by a rotation of a single PEt 3 group in a double layer (a single gear movement), followed by adjacent phosphines adjusting their conformations as a result of steric strain. The structural changes underlying phase transitions are sequential, occurring layer-wise, the ! transition involving approximately every other layer in the crystal lattice, the ! yielding a total conformation change. The sequence of phase transitions results in a noticeable contraction of the crystal cell volume.

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Synthesis and Crystal Structure of a New Type of Ionic Technetium(V) Dioxo Phosphine Complexes, [Tc(O)₂(PR₃)₃]⁺. Reactions with Pyridine and Crystal Structures of trans,cis,cis-[Tc(O)₂(PR₃)₂(py)₂]⁺ Compounds

Cited by 16 publications

References 22 publications

Complexes of Technetium(V) and Rhenium(V) with β-Diketonates

Complexes of Technetium(V) and Rhenium(V) with β-Diketonates

State-of-the-art coordination chemistry of radioactive elements

Triethylphosphine as a molecular gear — phase transitions in ferrocenyl–acetylide–gold(I)

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