Ligand exchange and complex formation kinetics studied by NMR exemplified on fac-[(CO)3M(H2O)]+ (M=Mn, Tc, Re)

Helm, Lothar

doi:10.1016/j.ccr.2008.01.009

Cited by 33 publications

(31 citation statements)

References 62 publications

(153 reference statements)

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“…In the series, the only exceptions comprised complex 1 (X = H 2 O) and complex 2 (X = cisc), in which the base peak corresponded to the water‐detached ion in five‐coordinated [Re(CO) 3 (PO) + H] + at m/z 549 (Figure ), and the isonitrile‐inserted in seven‐coordinated [Re(CO) 3 (PO)(cisc) 2 + H] + at m/z 767 (bottom trace, Figure S1, supporting information), respectively. The release of water observed in complex 1 is in agreement with the property of this complex to act as labile precursor for the synthesis of other Re‐tricarbonyl compounds . In the same way, the possibility to increase the coordination sphere toward low‐valent, seven‐coordinated species is a recognized property of rhenium compounds, especially in the presence of phosphine ligands …”

Section: Discussionsupporting

confidence: 74%

“…The release of water observed in complex 1 is in agreement with the property of this complex to act as labile precursor for the synthesis of other Re-tricarbonyl compounds. 21,22 In the same way, the possibility to increase the coordination sphere toward low-valent, seven-coordinated species is a recognized property of rhenium compounds, especially in the presence of phosphine ligands. 23 Under ESI(+) conditions, neutral [Re(CO) 3 (PO)(X)] complexes had to undergo protonation in the ion trap, a process that could modify their biological behavior.…”

Section: Complexes With X = Phosphine: [Re(co) 3 (Po)(poh)] 6 and mentioning

confidence: 99%

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Electrospray ionization study of tricarbonyl fac‐[Re(CO)₃(PO)(X)]‐type complexes: influence of ancillary co‐ligands in the release of carbon monoxide

Tisato

Porchia

Shegani

et al. 2018

Rapid Comm Mass Spectrometry

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The nature of the co-ligand X drives the primary loss in the MS processes of [Re(CO) (PO)(X) + H] compounds. When X = solvent, the energetics of these decompositions follow the trend H O < MeOH < CO. In each case, loss of CO is a favored fragmentation route with associated energies following the trend: N-py ≤ P-phosphine < C-isonitrile. Overall, MS pathways indicate that [Re(PO)] (Re with chelated PO phosphine) constitutes the residual moiety. This behavior indicates that the presence of a functionalized phosphine is essential for a sequential, controlled release of CO.

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Section: Discussionsupporting

confidence: 74%

Section: Complexes With X = Phosphine: [Re(co) 3 (Po)(poh)] 6 and mentioning

confidence: 99%

Electrospray ionization study of tricarbonyl fac‐[Re(CO)₃(PO)(X)]‐type complexes: influence of ancillary co‐ligands in the release of carbon monoxide

Tisato

Porchia

Shegani

et al. 2018

Rapid Comm Mass Spectrometry

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“…+ are known to be rapidly exchangeable with solution water molecules and exchange much more rapidly than do the carbon monoxide ligands (Helm, 2008). So if a suitable (likely tridentate) molecule such as gluconate or perhaps aminocarboxylates are present (and are represented above as "complex"), the rapidly exchangeable ligand sites are blocked and reoxidation of this n-Tc species occurs slowly, as has been reported previously.…”

Section: Discussionmentioning

confidence: 77%

“…Furthermore, recent research has shown that such substitutions for the water molecules in the Tc(I) tricarbonyl moiety can be a facile process (Lukens et al 2006a;Seifert et al 2000;Lukens et al 2004;Alberto et al 1998;Helm 2008). It is worth noting here that the possibility of replacing a carbonyl with a linear nitrosyl ligand to generate the neutral complex [(NO)(CO) 2 Tc(H 2 O) 3 ] or a similar derivative such as noted above is also a plausible candidate based on the available technetium XANES and EXAFS data.…”

Section: Sy 103mentioning

confidence: 99%

Development of a Chemistry-Based, Predictive Method for Determining the Amount of Non-Pertechnetate Technetium in the Hanford Tanks: FY 2012 Progress Report

Rapko¹,

Bryan²,

Bryant³

et al. 2013

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Executive SummaryThis report describes investigations directed toward understanding the extent of the presence of highly alkaline soluble, non-pertechnetate technetium (n-Tc) in the Hanford Tank supernatants. The goals of this report are to: a) present a review of the available literature relevant to the speciation of technetium in the Hanford tank supernatants, b) attempt to establish a chemically logical correlation between available Hanford tank measurements and the presence of supernatant soluble n-Tc, c) use existing measurement data to estimate the amount of n-Tc in the Hanford tank supernatants, and d) report on any likely, processfriendly methods to eventually sequester soluble n-Tc from Hanford tank supernatants.The work described herein follows on a substantial literature developed in the 1990s and early 2000s that first identified the problem of the presence of n-Tc and led to a tentative identification of the species in at least two Hanford tank waste supernatants. This project attempted to correlate chemically relevant indicators for which quality-valid data exists in the TWINS database suitable for eventual extrapolation to as-yet untested tank supernatants. In addition, two other tangential tasks were undertaken. First, a model was developed that expanded upon a previously published model by Lukens et al. (2001), for the rate of reduction of pertechnetate by radiolysis and inorganic chemical-based processes. Using information obtained from TWINS, this model was applied to the Hanford tank supernatants to identify the rate of pertechnetate reduction in the various Hanford tank supernatants. Second, one proposed species for n-Tc, the complex [(CO) 3 Tc(H 2 O) 3 ] + , was prepared, and initial studies into its spectroscopic signature and chemical stability were performed.From this work, the only acceptable chemically based correlations with data from the TWINS database were that the fraction of n-Tc present negatively correlates with either of two, closely related variables: total dose experienced in the tank, and 137 Cs concentration in the tank supernatants. The observed inverse correlation is counterintuitive, but a possible explanation is discussed. However, the correlation should lend some insight as to which tanks might be tested to further validate and enhance the predictive value of this correlation.As noted above, chemical data, radiolysis constants and known chemical rate constants for the reaction of water radiolysis products with inorganic Hanford tank waste supernatant constituents were used to evaluate the relative rates of pertechnetate reduction in the Hanford tank supernatants. These results are summarized in the report. Interestingly, the reduction rate for pertechnetate is greatest in two tanks, AZ-101 and AZ-102, where the presence of n-Tc is not detected. However, this reduction only concerns the rate of pertechnetate reduction; the speciation of the reduced product is not addressed. Consequently, reduction of pertechnetate to the poorly alkaline-soluble technetium dioxide could ...

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“…Studies of Mn, Tc and Re, with a focus on their kinetic variations, exchange reactions, hydrolysis and stability in a range of alkaline to acidic solutions, have revealed chemical patterns and dependencies. These parameters are important to remember when considering and developing radiopharmaceuticals (Prinz et al, 2004;Botha & Roodt, 2008;Helm, 2008;Grundler et al, 2006). The design of model pharmaceuticals, in particular radiopharmaceuticals, can follow various approaches (Liu, 2004).…”

Section: Introductionmentioning

confidence: 99%

Structural comparison of group 7 tricarbonyl complexes of 2-{[2-(1H-imidazol-4-yl)ethyl]iminomethyl}-5-methylphenolate

et al. 2015

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Two tricarbonyl complexes of rhenium(I) and manganese(I) coordinated by the ligand 2-{[2-(1H-imidazol-4-yl)ethyl]iminomethyl}-5-methylphenolate are reported, viz. fac-tricarbonyl(2-{[2-(1H-imidazol-4-yl-κN(3))ethyl]iminomethyl-κN}-5-methylphenolato-κO)rhenium(I) methanol monosolvate, [Re(C16H14N3O4)(CO)3]·CH3OH, (I), and fac-tricarbonyl(2-{[2-(1H-imidazol-4-yl-κN(3))ethyl]iminomethyl-κN}-5-methylphenolato-κO)manganese(I), fac-[Mn(C16H14N3O4)(CO)3], (II), display facial coordination in a distorted octahedral environment. The crystal structure of (I) is stabilized by O-H···O, N-H···O and C-H···O hydrogen-bond interactions, while that of (II) is stabilized by N-H...O hydrogen-bond interactions only. These interactions result in two-dimensional networks and π-π stacking for both structures.

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Ligand exchange and complex formation kinetics studied by NMR exemplified on fac-[(CO)3M(H2O)]+ (M=Mn, Tc, Re)

Cited by 33 publications

References 62 publications

Electrospray ionization study of tricarbonyl fac‐[Re(CO)₃(PO)(X)]‐type complexes: influence of ancillary co‐ligands in the release of carbon monoxide

Electrospray ionization study of tricarbonyl fac‐[Re(CO)₃(PO)(X)]‐type complexes: influence of ancillary co‐ligands in the release of carbon monoxide

Development of a Chemistry-Based, Predictive Method for Determining the Amount of Non-Pertechnetate Technetium in the Hanford Tanks: FY 2012 Progress Report

Structural comparison of group 7 tricarbonyl complexes of 2-{[2-(1H-imidazol-4-yl)ethyl]iminomethyl}-5-methylphenolate

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Ligand exchange and complex formation kinetics studied by NMR exemplified on fac-[(CO)3M(H2O)]+ (M=Mn, Tc, Re)

Cited by 33 publications

References 62 publications

Electrospray ionization study of tricarbonyl fac‐[Re(CO)3(PO)(X)]‐type complexes: influence of ancillary co‐ligands in the release of carbon monoxide

Electrospray ionization study of tricarbonyl fac‐[Re(CO)3(PO)(X)]‐type complexes: influence of ancillary co‐ligands in the release of carbon monoxide

Development of a Chemistry-Based, Predictive Method for Determining the Amount of Non-Pertechnetate Technetium in the Hanford Tanks: FY 2012 Progress Report

Structural comparison of group 7 tricarbonyl complexes of 2-{[2-(1H-imidazol-4-yl)ethyl]iminomethyl}-5-methylphenolate

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Electrospray ionization study of tricarbonyl fac‐[Re(CO)₃(PO)(X)]‐type complexes: influence of ancillary co‐ligands in the release of carbon monoxide

Electrospray ionization study of tricarbonyl fac‐[Re(CO)₃(PO)(X)]‐type complexes: influence of ancillary co‐ligands in the release of carbon monoxide