Nitrogen-15 NMR of cis-diamine-platinum(II) complexes in aqueous solution

Alei, Mohammed; Vergamini, Phillip J.; Wageman, William E.

doi:10.1021/ja00512a052

Cited by 33 publications

(12 citation statements)

References 2 publications

(2 reference statements)

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“…The large upfield shift of the 15 N 3 resonance (ca. 90 ppm, compared to δ ( 15 N 3 ) of free 1‐methylimidazole at 221.08 ppm) observed for all the new 1‐methylimidazole species is consistent with coordination of 1‐methylimidazole to platinum taking place through the N 3 atom 25. The possible coordination of phosphates from the buffer was also ruled out, as in the 1D 31 P{ 1 H} NMR spectrum only one peak was detected at 3.84 ppm, arising from the PBS solution itself.…”

Section: Resultssupporting

confidence: 80%

A robust methodology for kinetic model parameter estimation for biocatalytic reactions

Al-Haque

Santacoloma

Neto

et al. 2012

Biotechnology Progress

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Effective estimation of parameters in biocatalytic reaction kinetic expressions are very important when building process models to enable evaluation of process technology options and alternative biocatalysts. The kinetic models used to describe enzyme-catalyzed reactions generally include several parameters, which are strongly correlated with each other. State-of-the-art methodologies such as nonlinear regression (using progress curves) or graphical analysis (using initial rate data, for example, the Lineweaver-Burke plot, Hanes plot or Dixon plot) often incorporate errors in the estimates and rarely lead to globally optimized parameter values. In this article, a robust methodology to estimate parameters for biocatalytic reaction kinetic expressions is proposed. The methodology determines the parameters in a systematic manner by exploiting the best features of several of the current approaches. The parameter estimation problem is decomposed into five hierarchical steps, where the solution of each of the steps becomes the input for the subsequent step to achieve the final model with the corresponding regressed parameters. The model is further used for validating its performance and determining the correlation of the parameters. The final model with the fitted parameters is able to describe both initial rate and dynamic experiments. Application of the methodology is illustrated with a case study using the ω-transaminase catalyzed synthesis of 1-phenylethylamine from acetophenone and 2-propylamine.

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Section: Resultssupporting

confidence: 80%

A robust methodology for kinetic model parameter estimation for biocatalytic reactions

Al-Haque

Santacoloma

Neto

et al. 2012

Biotechnology Progress

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show abstract

“…90 ppm, compared to δ ( 15 N 3 ) of free 1-methylimidazole at 221.08 ppm) observed for all the new 1-methylimidazole species is consistent with coordination of 1-methylimidazole to platinum taking place via the N 3 atom. [25] The possible coordination of phosphates from the buffer was also ruled out, as in the 1D 31 P{ 1 H} NMR spectrum only one peak was detected at 3.84 ppm, arising from the PBS solution itself.…”

Section: Resultsmentioning

confidence: 99%

Photoinduced Reactions of cis,trans,cis‐[Pt^IV(N₃)₂(OH)₂(NH₃)₂] with 1‐Methylimidazole

Phillips¹,

Ronconi²,

Sadler³

2009

Chemistry A European J

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The photodecomposition of cis,trans,cis-[Pt IV (N 3 ) 2 (OH) 2 (NH 3 ) 2 ] in phosphate buffered saline (PBS), as well as in the presence of 1-methylimidazole (1-MeIm), induced by UVA light (centered at λ = 365 nm) has been studied by multinuclear NMR spectroscopy. We show that photoreduction, photoisomerisation and trans-labilization pathways are involved. The photodecomposition pathway in PBS which involves azide release, as detected by 14 N NMR spectroscopy, appears to differ from that in acidic aqueous conditions, where N 2 is a product. A number of trans-{N-Pt II -NH 3 } species were also observed as photoproducts, as well as the release of free ammonia with a corresponding increase in pH. Oxygen was also detected as a product in solution. In the presence of 1-methylimidazole, surprisingly the major photoproduct was the tetrasubstituted Pt II complex [Pt II (1-MeIm-N 3 ) 4 ] 2+ (structure confirmed by crystallography), even at a Pt:1-MeIm molar ratio of 1:1, together with cis-and trans-[Pt II (NH 3 ) 2 (1-MeIm-N 3 ) 2 ] 2+ as minor products. In these photoinduced 1-MeIm reactions, free ammonia, azide and oxygen were also detected. The results from this study illustrate that photoinduced reactions of platinum complexes can lead to novel reaction pathways, and therefore to new cytotoxic mechanisms in cancer cells.

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“…The Divalent Compounds. As has been previously shown, adjustment of the pH of the solution containing the complex cation [ci5-PtII(15NH3)2(H20)2]2+ to ~7 results in the formation of dinuclear and trinuclear Pt(II) compounds containing µbridges.26, [15][16][17][18] The oligomerization process appears to be initiated by deprotonation of one of the coordinated water molecules of the mononuclear species, which in turn reacts with a second complex to initially yield an "open ring" µ--bridged dinuclear compound. This compound either reacts via water displacement with itself to yield a dinuclear Pt(II) complex possessing a rO, four-membered Pt Pt ring, referred to as the dimer, or reacts with OJ an additional mononuclear complex, referred to as the monomer, via water displacement with itself and ring closure to produce a trinuclear species, the trimer.…”

Section: Resultsmentioning

confidence: 99%

Oxidation of a dinuclear platinum(II) complex with hydrogen peroxide

Al-Baker¹,

Dabrowiak²

1987

Inorg. Chem.

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Nitrogen-15 NMR of cis-diamine-platinum(II) complexes in aqueous solution

Cited by 33 publications

References 2 publications

A robust methodology for kinetic model parameter estimation for biocatalytic reactions

A robust methodology for kinetic model parameter estimation for biocatalytic reactions

Photoinduced Reactions of cis,trans,cis‐[Pt^IV(N₃)₂(OH)₂(NH₃)₂] with 1‐Methylimidazole

Oxidation of a dinuclear platinum(II) complex with hydrogen peroxide

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Nitrogen-15 NMR of cis-diamine-platinum(II) complexes in aqueous solution

Cited by 33 publications

References 2 publications

A robust methodology for kinetic model parameter estimation for biocatalytic reactions

A robust methodology for kinetic model parameter estimation for biocatalytic reactions

Photoinduced Reactions of cis,trans,cis‐[PtIV(N3)2(OH)2(NH3)2] with 1‐Methylimidazole

Oxidation of a dinuclear platinum(II) complex with hydrogen peroxide

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Photoinduced Reactions of cis,trans,cis‐[Pt^IV(N₃)₂(OH)₂(NH₃)₂] with 1‐Methylimidazole