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1
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Ernst MJ, Abdulkader A, Hagenbach A, Claude G, Roca Jungfer M, Abram U. [Tc(NO)(Cp)(PPh 3)Cl] and [Tc(NO)(Cp)(PPh 3)(NCCH 3)](PF 6), and Their Reactions with Pyridine and Chalcogen Donors. Molecules 2024; 29:1114. [PMID: 38474627 DOI: 10.3390/molecules29051114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 02/25/2024] [Accepted: 02/27/2024] [Indexed: 03/14/2024] Open
Abstract
Reactions of the technetium(I) nitrosyl complex [Tc(NO)(Cp)(PPh3)Cl] with triphenylphosphine chalcogenides EPPh3 (E = O, S, Se), and Ag(PF6) in a CH2Cl2/MeOH mixture (v/v, 2/1) result in an exchange of the chlorido ligand and the formation of [Tc(NO)(Cp)(PPh3)(EPPh3)](PF6) compounds. The cationic acetonitrile complex [Tc(NO)(Cp)(PPh3)(NCCH3)]+ is formed when the reaction is conducted in NCCH3 without additional ligands. During the isolation of the corresponding PF6- salt a gradual decomposition of the anion was detected in the solvent mixture applied. The yields and the purity of the product increase when the BF4- salt is used instead. The acetonitrile ligand is bound remarkably strongly to technetium and exchange reactions readily proceed only with strong donors, such as pyridine or ligands with 'soft' donor atoms, such as the thioether thioxane. Substitutions on the cyclopentadienyl ring do not significantly influence the ligand exchange behavior of the starting material. 99Tc NMR spectroscopy is a valuable tool for the evaluation of reactions of the complexes of the present study. The extremely large chemical shift range of this method allows the ready detection of corresponding ligand exchange reactions. The observed 99Tc chemical shifts depend on the donor properties of the ligands. DFT calculations support the discussions about the experimental results and provide explanations for some of the unusual findings.
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Affiliation(s)
- Moritz Johannes Ernst
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 34/36, D-14195 Berlin, Germany
| | - Abdullah Abdulkader
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 34/36, D-14195 Berlin, Germany
| | - Adelheid Hagenbach
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 34/36, D-14195 Berlin, Germany
| | - Guilhem Claude
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 34/36, D-14195 Berlin, Germany
| | | | - Ulrich Abram
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 34/36, D-14195 Berlin, Germany
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2
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Besmer ML, Schwitter F, Battistin F, Braband H, Fox T, Spingler B, Alberto R. Induced fac- mer rearrangements in {M(CO) 3} + complexes (M = Re, 99(m)Tc) by a PNP ligand. Dalton Trans 2024; 53:1434-1438. [PMID: 38189151 DOI: 10.1039/d3dt03992g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The fac-mer rearrangements in [MX3(CO)3]2- (M = Re, 99Tc) induced by a pincer-type ligand (PNP) and a "halide scavenger" are reported. The reactions of fac-[99mTc(CO)3(OH2)3]+ or [99mTcO4]- in saline both yield mer-[99mTc(PNP)(CO)3]+, the first example of a mer-{99mTc(CO)3}+ type complex. In contrast, reactions with terpyridine (terpy) only gave the facial κ2-terpy complexes with Re and 99Tc.
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Affiliation(s)
- Manuel Luca Besmer
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
| | - Flurina Schwitter
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
| | - Federica Battistin
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
| | - Henrik Braband
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
| | - Thomas Fox
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
| | - Bernhard Spingler
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
| | - Roger Alberto
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
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Sidorenko GV, Miroslavov AE, Tyupina MY. Technetium(I) carbonyl complexes for nuclear medicine: Coordination-chemical aspect. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Jungfer MR, Abram U. [ReH 3 (PPh 3 ) 4 ] - A Key Compound in the Rhenium Hydride Chemistry. Chemistry 2023; 29:e202203317. [PMID: 36628556 DOI: 10.1002/chem.202203317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/06/2023] [Accepted: 01/10/2023] [Indexed: 01/12/2023]
Abstract
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 CH3 CN 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 HOC6 H3 (CH3 )2 and thiourea after prolonged heating in toluene and characterized by IR spectroscopy and X-ray diffraction.
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Affiliation(s)
- Maximilian Roca Jungfer
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 34/36, 14195, Berlin, Germany
- University of Heidelberg, Im Neuenheimer Feld 584, 69120, Heidelberg, Germany
| | - Ulrich Abram
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 34/36, 14195, Berlin, Germany
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Claude G, Zeh L, Roca Jungfer M, Hagenbach A, Figueroa JS, Abram U. The Chemistry of Phenylimidotechnetium(V) Complexes with Isocyanides: Steric and Electronic Factors. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238546. [PMID: 36500639 PMCID: PMC9736260 DOI: 10.3390/molecules27238546] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/21/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
Organometallic approaches are of ongoing interest for the development of novel functional 99mTc radiopharmaceuticals, while the basic organotechnetium chemistry seems frequently to be little explored. Thus, structural and reactivity studies with the long-lived isotope 99Tc are of permanent interest as the foundation for further progress in the related radiopharmaceutical research with this artificial element. Particularly the knowledge about the organometallic chemistry of high-valent technetium compounds is scarcely developed. Here, phenylimido complexes of technetium(V) with different isocyanides are introduced. They have been synthesized by ligand-exchange procedures starting from [Tc(NPh)Cl3(PPh3)2]. Different reactivity patterns and products have been obtained depending on the steric and electronic properties of the individual ligands. This involves the formation of 1:1 and 1:2 exchange products of Tc(V) with the general formulae [Tc(NPh)Cl3(PPh3)(isocyanide)], cis- or trans-[Tc(NPh)Cl3(isocyanide)2], but also the reduction in the metal and the formation of cationic technetium(I) complex of the formula [Tc(isocyanide)6]+ when p-fluorophenyl isocyanide is used. The products have been studied by single-crystal X-ray diffraction and spectroscopic methods, including IR and multinuclear NMR spectroscopy. DFT calculations on the different isocyanides allow the prediction of their reactivity towards electron-rich and electron-deficient metal centers by means of the empirical SADAP parameter, which has been derived from the potential energy surface of the electron density on their potentially coordinating carbon atoms.
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Affiliation(s)
- Guilhem Claude
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 34/36, 14195 Berlin, Germany
| | - Laura Zeh
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 34/36, 14195 Berlin, Germany
| | - Maximilian Roca Jungfer
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 34/36, 14195 Berlin, Germany
| | - Adelheid Hagenbach
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 34/36, 14195 Berlin, Germany
| | - Joshua S. Figueroa
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA
- Correspondence: (J.S.F.); (U.A.)
| | - Ulrich Abram
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 34/36, 14195 Berlin, Germany
- Correspondence: (J.S.F.); (U.A.)
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6
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Roca Jungfer M, Abram U. Unlocking Air- and Water-Stable Technetium Acetylides and Other Organometallic Complexes. Inorg Chem 2022; 61:7765-7779. [PMID: 35548933 DOI: 10.1021/acs.inorgchem.2c00070] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The first technetium complexes containing anionic alkynido ligands in an end-on coordination mode have been prepared by using the nonprotic, cationic precursor mer,trans-[Tc(SMe2)(CO)3(PPh3)2]+. This cation acts as a functional analogue of the highly reactive 16-electron metallo Lewis acid {Tc(CO)3(PPh3)2}+ in reactions with alkynes, acetylides, and other organometallic reagents. Such reactions give a variety of organometallic technetium complexes in excellent yields and enable the preparation of [Tc(CH3)(CO)3(PPh3)2], [Tc(Ph)(CO)3(PPh3)2], [Tc(Cp)(CO)2(PPh3)], [Tc(═CCH2CH2CH2O)(CO)3(PPh3)2]+, [Tc(═CCH2CH2CH2CH2O)(CO)3(PPh3)2]+, [Tc(C≡C-H)(CO)3(PPh3)2], [Tc(C≡C-Ph)(CO)3(PPh3)2], [Tc(C≡C-tBu)(CO)3(PPh3)2], [Tc(C≡C-nBu)(CO)3(PPh3)2], [Tc(C≡C-SiMe3)(CO)3(PPh3)2], and [Tc{C≡C-C6H3(CF3)2}(CO)3(PPh3)2]. The bonding situation in the alkynyl complexes is compared to that in corresponding alkyl- and arylnitrile and -isonitrile complexes. [Tc(N≡C-Ph)(CO)3(PPh3)2](BF4), [Tc(C≡N-Ph)(CO)3(PPh3)2](BF4), [Tc(N≡C-tBu)(CO)3(PPh3)2](BF4), and [Tc(C≡N-tBu)(CO)3(PPh3)2](BF4) were prepared in high yields by ligand exchange reactions starting from mer,trans-[Tc(OH2)(CO)3(PPh3)2](BF4). The novel complexes were characterized by single-crystal X-ray diffraction and spectroscopic methods. In particular, 99Tc nuclear magnetic resonance spectroscopy proved to be an invaluable and sensitive tool for the characterization of the complexes. Density functional theory calculations strongly suggest similar bonding situations for the related alkynyl, nitrile, and isonitrile complexes of technetium.
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Affiliation(s)
- Maximilian Roca Jungfer
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstrasse 34/36, D-14195 Berlin, Germany
| | - Ulrich Abram
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstrasse 34/36, D-14195 Berlin, Germany
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Ernst MJ, Roca Jungfer M, Hagenbach A, Abram U. Triaryltechnetium(III) and Related Complexes. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Moritz Johannes Ernst
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Fabeckstrasse 34/36, D-14195 Berlin, Germany
| | - Maximilian Roca Jungfer
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Fabeckstrasse 34/36, D-14195 Berlin, Germany
| | - Adelheid Hagenbach
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Fabeckstrasse 34/36, D-14195 Berlin, Germany
| | - Ulrich Abram
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Fabeckstrasse 34/36, D-14195 Berlin, Germany
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Roca Jungfer M, Elsholz L, Abram U. Technetium(I) Carbonyl Chemistry with Small Inorganic Ligands. Inorg Chem 2022; 61:2980-2997. [PMID: 35108005 DOI: 10.1021/acs.inorgchem.1c03919] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
[Tc(OH2)(CO)3(PPh3)2](BF4) has been used as a synthon for reactions with small inorganic ligands with relevance for the treatment of nuclear waste solutions such as nitrate, nitrite, pseudohalides, permetalates (M = Mn, Tc, Re), and BH4-. The formation of bond isomers and/or a distinct reactivity has been observed for most of the products. [Tc(NCO)(CO)3(PPh3)2], [Tc(NCS)(CO)3(PPh3)2], [Tc(CN)(CO)3(PPh3)2], [Tc(N3)(CO)3(PPh3)2], [Tc(NCO)(OH2)(CO)2(PPh3)2], [Tc(η2-OON)(CO)2(PPh3)2], [Tc(η1-NO2)(CO)3(PPh3)2], [Tc(η2-OONO)(CO)2(PPh3)2], [Tc(η1-ONO2)(CO)3(PPh3)2], [Tc(η2-OO(CCH3))(CO)2(PPh3)2], [Tc(η2-SSC(SCH3))(CO)2(PPh3)2], [Tc(η2-SSC(OCH3))(CO)2(PPh3)2], [Tc(η2-SSC(CH3))(CO)2(PPh3)2], [Tc(η2-SS(CH))(CO)2(PPh3)2], [Tc(OTcO3)(acetone)(CO)2(PPh3)2], [Tc(OTcO3)(CO)3(PPh3)2], and [Tc(η2-HHBH2)(CO)2(PPh3)2] have been isolated in crystalline form and studied by X-ray crystallography. Additionally, the typical reactivity patterns (isomerization, thermal decomposition, hydrolysis, or decarbonylation) of the products have been studied by spectroscopic methods. 99Tc NMR spectroscopy has proved to be a particularly useful tool for the evaluation of such reactions of the diamagnetic technetium(I) compounds in solution.
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Affiliation(s)
- Maximilian Roca Jungfer
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstraße 34/36, D-14195 Berlin, Germany
| | - Laura Elsholz
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstraße 34/36, D-14195 Berlin, Germany
| | - Ulrich Abram
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstraße 34/36, D-14195 Berlin, Germany
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Roca Jungfer M, Abram U. [Tc(OH 2)(CO) 3(PPh 3) 2] +: A Synthon for Tc(I) Complexes and Its Reactions with Neutral Ligands. Inorg Chem 2021; 60:16734-16753. [PMID: 34657434 DOI: 10.1021/acs.inorgchem.1c02599] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A scalable synthesis of the novel and highly reactive [Tc(OH2)(CO)3(PPh3)2]+ cation is described. The ligand-exchange chemistry of this compound with neutral ligands coordinating through C, N, O, S, Se, and Te has been explored systematically. The complexes either retain the original mer-trans tricarbonyl core under exclusive exchange of the aqua ligand or form dicarbonyl complexes by thermal decarbonylation. Ligand exchange reactions starting from [Tc(OH2)(CO)3(PPh3)2]+ proceed under mild conditions and are generally almost quantitative. Some of the formed complexes are remarkably stable and inert, while others provide products with one labile ligand for further reactions. The derived complexes of the type [Tc(L)(CO)3(PPh3)2]+ and [Tc(L)2(CO)2(PPh3)2]+ represent an interesting opportunity for the development of 99mTc complexes with potential use in radiopharmacy. The ready displacement of the aqua ligand highlights the synthetic value of [Tc(OH2)(CO)3(PPh3)2]+ as a reactive entry point for further studies in the little explored field of the organometallic chemistry of technetium.
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Affiliation(s)
- Maximilian Roca Jungfer
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstrasse 34/36, D-14195 Berlin, Germany
| | - Ulrich Abram
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstrasse 34/36, D-14195 Berlin, Germany
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