Triaryltechnetium(III) and Related Complexes

Ernst, Moritz Johannes; Jungfer, Maximilian Roca; Hagenbach, Adelheid; Abram, Ulrich

doi:10.1021/acs.organomet.2c00101

Cited by 5 publications

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“…26 For the closest chemical analogue of technetium, rhenium, there are six known compounds, in the crystal structure of which thiourea is coordinated directly with the metal. 27−32 In the compounds, rhenium is predominantly in odd oxidation states I, III, and V. 22,33,34 For the rhenium compounds, an exchange of thiourea molecules in the internal coordination sphere is observed with the formation of stable complex compounds: [ReTu 6 ] 3+ , 31 [Re(CO) 3 Tu 3 ] + , 30 [ReOCl 2 Tu 2 (H 2 O)] + , 28 and [ReCl 5 Tu] − , 27 which approves Omori's data. 12 The present work analyzes the reduction reaction of ammonium pertechnetate with thiourea in an aqueous alcoholic medium in the presence of Cl − and Br − .…”

Section: Introductionmentioning

confidence: 99%

“…To date, the existence of several complexes of technetium and thiourea with an established crystal structure is known: [TcTu 6 ]Cl 3 ·4H 2 O, [Tc(MeTu) 6 ](PF 6 ) 3 ·H 2 O, [Tc(Me 2 Tu) 6 ](PF 6 ) 3 , and {TcN(Tu)} 4 (EDTA) 2 ·6H 2 O . For the closest chemical analogue of technetium, rhenium, there are six known compounds, in the crystal structure of which thiourea is coordinated directly with the metal. − In the compounds, rhenium is predominantly in odd oxidation states I, III, and V. ,, For the rhenium compounds, an exchange of thiourea molecules in the internal coordination sphere is observed with the formation of stable complex compounds: [ReTu 6 ] 3+ , [Re(CO) 3 Tu 3 ] + , [ReOCl 2 Tu 2 (H 2 O)] + , and [ReCl 5 Tu] − , which approves Omori’s data …”

Section: Introductionmentioning

confidence: 99%

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Thiourea as a Stabilizer of Reduced Forms of Technetium─Tc(III) and Tc(IV): Experimental and Theoretical Studies of Complexes

et al. 2022

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This paper presents synthetic methods for the preparation of Tc(III) and Tc(IV) coordination compounds with thiourea. We have shown that the main product of the synthesis is the complex [TcTu 5 X]X 2 , (Tu = (NH 2 ) 2 CS, X = Cl, Br) and not [TcTu 6 ]Cl 3 • 4H 2 O, as previously thought. Tu 2 [TcX 6 ]X 2 •3H 2 O is the main technetium-containing byproduct of the reaction. All reaction products, including byproducts, were characterized by X-ray diffraction analysis. We also measured the solubility for the obtained Tc(III) complexes. This research work considers the process of thermolysis of the obtained Tc(III) complexes and shows that the presence of sulfur atoms in the coordination sphere can inhibit the process of metal formation in an argon−hydrogen medium. The analysis of nonvalent interactions in Tc(III) complexes showed that the main contribution is made by van der Waals interactions of the H•••H type (40.8−42.3%) and hydrogen bonds Hal•••H/H•••Hal and H•••S/S•••H, which are 41.6−44.5% in total. As the temperature decreases, the proportion of H•••H contacts and H bonds decreases, and when the halogen (Cl by Br) is replaced, the proportion of H bonds increases and the proportion of van der Waals interactions decreases.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thiourea as a Stabilizer of Reduced Forms of Technetium─Tc(III) and Tc(IV): Experimental and Theoretical Studies of Complexes

et al. 2022

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“…The observed bonding features, particularly the linear ReÀ NÀ C unit, [48][49][50][51][52][53][54][55][56][57][58][59][60] strongly favor the assignment of compound 4 a as an azavinylidene over an interpretation as an amido complex, which would require a bent unit. [61] Recently, we observed the formation of a similar product as result of a nucleophilic attack of a fluorinated aryl lithium reagent, [62] where the obtained azavinylidene complex shows similar geometric features as discussed for 4 a.…”

Section: Chemistry-a European Journalmentioning

confidence: 61%

“…Since the previously reported azavinylidene complexes of iron, osmium, technetium and rhenium appear to be much more stable than complexes 4, [60][61][62][63][64][65] we performed a natural bonding orbital (NBO) analysis on the electronic situation in 4 a combined with a Laplacian of the electron density ~(ρ) and electron localization function (ELF) mapping of the HÀ ReÀ N=CÀ H plane. The results are visualized in Figure 5.…”

Section: Chemistry-a European Journalmentioning

confidence: 99%

[ReH₃(PPh₃)₄] – A Key Compound in the Rhenium Hydride Chemistry

Jungfer

Abram

2023

Chemistry A European J

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The chemistry of the rhenium trihydrido complex [ReH3(PPh3)4] (1) has been reinvestigated. An improved synthesis and the solid‐state structure of the compound as well as several reactions are reported. The solid‐state structure of 1 is similar to that of [TcH3(PPh3)4] having a capped‐octahedral coordination sphere. The PPh3 ligands surround the Re atom in a trigonal‐pyramidal mode with a short apical Re−P bond (2.300(2) Å) and three longer basal bonds (2.429(2)–2.449(2) Å). Reactions of 1 with monodentate phosphines such as PMe3 or PBu3 give the mono‐substituted complexes [ReH3(PPh3)3(PMe3)] (2) and [ReH3(PPh3)3(PBu3)] (3) under retention of the apical PPh3 ligand and substitution of one of the basal PPh3 ligands. The stability of the phosphine trihydride complexes decreases in the order PPh3>PMe3>PBu3. Treatment of [ReH3(PPh3)4] with trityl hexafluorophosphate in CH3CN does not result in a hydride abstraction, but gives the tetrahydrido cation [ReH4(NCCH3)(PPh3)3]+ (4), while reactions with nitriles give unstable azavinylidene complexes of the composition [ReH2(PPh3)3(NC(H)R)] (5). They are formed by an insertion of the nitrile into a Re−H bond. The solid‐state structure of the methyl derivative [ReH2(PPh3)3(NC(H)CH3)] (5 a) was determined showing a linear Re−N−C unit with rhenium−nitrogen and nitrogen−carbon double bonds, while the N=CH−C bond is clearly bent with an angle of 124°. Two previously unknown polymorphs of [ReH5(PPh3)3] were isolated from reactions of 1 with HOC6H3(CH3)2 and thiourea after prolonged heating in toluene and characterized by IR spectroscopy and X‐ray diffraction.

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“…The tissue retention depends on the membrane potential as has been proven by 99 Tc NMR spectroscopy . It is not surprising that the extraordinary success of 99m Tc-Sestamibi in nuclear medical imaging procedures stimulated the development of the technetium coordination chemistry with isocyanides, and numerous Tc(I) and Tc(III) complexes with such ligands have been synthesized and structurally characterized, − including mixed-ligand compounds with chelating ligands. − …”

Section: Introductionmentioning

confidence: 99%

Technetium Complexes with an Isocyano-alkyne Ligand and Its Reaction Products

Claude,

Puccio,

Roca Jungfer

et al. 2023

Inorg. Chem.

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The attachment of an ethyne substituent in the para position of phenylisocyanide, CNPhpCCH, enables the isocyanide to replace carbonyl ligands in the coordination sphere of common technetium(I) starting materials such as (NBu4)[Tc2(μ-Cl)3(CO)6]. The ligand exchange proceeds under thermal conditions and finally forms the corresponding hexakis(isocyanide)technetium(I) complex. The product undergoes a copper-catalyzed cycloaddition (“Click” reaction), e.g., with benzyl azide, which gives the [Tc(CNPhazole)6]+ cation. The free, uncoordinated “Click” product is obtained from a reaction of the corresponding tetrakis(CNPhazole)copper(I) complex and NaCN. It readily reacts with mer-[Tc(CO)3(tht)(PPh3)2](BF4) (tht = tetrahydrothiophene) under exchange of the thioether ligand. Alternatively, [Cu(CNPhazole)4]+ can be used as a transmetalation reagent for the synthesis of the hexakis(isocyanide)technetium(I) complex, which is the preferable approach for the synthesis of the technetium complex with the short-lived nuclear isomer 99mTc, and a corresponding protocol for [99mTc(CNPhazole)6]+ is reported. The 99Tc and copper complexes have been studied by single-crystal X-ray diffraction and/or spectroscopic methods including IR and multinuclear NMR spectroscopy.

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Triaryltechnetium(III) and Related Complexes

Abstract: Crystallographic tables, bond lengths, angles and ellipsoid plots; spectroscopic data (PDF)Accession Codes CCDC 2151025−2151030 and 2166733 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk

Cited by 5 publications

References 64 publications

Thiourea as a Stabilizer of Reduced Forms of Technetium─Tc(III) and Tc(IV): Experimental and Theoretical Studies of Complexes

Thiourea as a Stabilizer of Reduced Forms of Technetium─Tc(III) and Tc(IV): Experimental and Theoretical Studies of Complexes

[ReH₃(PPh₃)₄] – A Key Compound in the Rhenium Hydride Chemistry

Technetium Complexes with an Isocyano-alkyne Ligand and Its Reaction Products

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Triaryltechnetium(III) and Related Complexes

Abstract: Crystallographic tables, bond lengths, angles and ellipsoid plots; spectroscopic data (PDF)Accession Codes CCDC 2151025−2151030 and 2166733 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk

Cited by 5 publications

References 64 publications

Thiourea as a Stabilizer of Reduced Forms of Technetium─Tc(III) and Tc(IV): Experimental and Theoretical Studies of Complexes

Thiourea as a Stabilizer of Reduced Forms of Technetium─Tc(III) and Tc(IV): Experimental and Theoretical Studies of Complexes

[ReH3(PPh3)4] – A Key Compound in the Rhenium Hydride Chemistry

Technetium Complexes with an Isocyano-alkyne Ligand and Its Reaction Products

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Product

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[ReH₃(PPh₃)₄] – A Key Compound in the Rhenium Hydride Chemistry