Enzyme-like Acceleration for the Hydrolysis of a DNA Model Promoted by a Dinuclear Zn(II) Catalyst in Dilute Aqueous Ethanol
Bibliographic record
Abstract
The rates and products of cleavage of methyl (2-chloro-4-nitrophenyl) phosphate ( 2 ) promoted by a dinuclear Zn(II) complex ( 3 ) of 1,3- bis - N, N ′(1,5,9-triazacyclododecyl)propane along with 1 equiv of ethoxide were investigated in ethanol solution containing small amounts of water (8 mM ≤ [H 2 O] ≤ 2.1 M) at 25 °C and s s pH 7.9. The kinetics of decomposition of 5 × 10 −5 M 2 in the presence of varying [ 3 ] (0.03 mM ≤ [ 3 ] ≤ 0.12 mM) in ethanol containing 28 mM water show very strong saturation binding which is analyzed to give fitted values for the complex dissociation constant ( K d ) and maximum catalytic rate constant ( k cat max ) of 3.2 × 10 −8 M and 1.47 × 10 −3 s −1 . Product analysis indicates that the reaction in ethanol containing 28 mM and 2.1 M water produces 46% and 93% of the hydrolysis product (methyl phosphoric acid), with the remainder being ethanolysis product (ethyl methyl phosphate). Analysis of the kinetics of the reaction at 28 mM water indicates that second order rate constant for the catalytic reaction, given as k cat max / K d, is 4.6 × 10 4 M −1 s −1, is a factor of 8.4 × 10 10 larger than the second order rate constant ( k 2 EtO ) for the ethoxide promoted reaction of 2 in ethanol (5.5 ± 0.3) × 10 −7 M −1 s −1 . A more detailed analysis that considers the relative acidities of water and ethanol in ethanol solvent indicates that at s s pH 7.9, the ethanolysis is accelerated by 2.3 × 10 14 times relative to the computed ethoxide reaction at that s s pH, while the hydrolysis is accelerated by ≥1.6 × 10 17 times relative to the background hydroxide reaction, suggesting that complex 3 promotes the hydrolysis at least 1000 times more effectively than ethanolysis.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".