Synthesis and characterization of the pentadentate macrobicyclic ligand, 14-thia-1,4,8,11-tetraazabicyclo[9.5.3]nonadecane (L1) and its nickel(II) complexes. X-ray crystal structure of [Ni(L1)(ClO<sub>4</sub>)](ClO<sub>4</sub>)·2[Ni(L1)(OH<sub>2</sub>)](ClO<sub>4</sub>)<sub>2</sub>·6H<sub>2</sub>O
Bibliographic record
Abstract
The pentadentate macrobicycle,14-thia-1,4,8,11-tetraazabicyclo[9.5.3]nonadecane (L1), has been synthesized by high dilution cyclization of 1-thia-4,8-diazacyclododecane ([10]aneN 2 S) (2) with N,N'-bis(α-chloro acetamido) propane (3) and subsequent reduction of the di-oxo intermediate. The structure of the [Ni(L1)(ClO 4 )](ClO 4 )·2[Ni(L1)(OH 2 )](ClO 4 ) 2 ·6H 2 O complex (monoclinic, P2 1 /c, a = 13.9261(4) Å, b = 30.279(2) Å, c = 17.1248(3) Å, β = 94.5065(3)°) at R = 0.039 (R w = 0.034) for 911 parameters using 18 266 reflections with I > 3σI has been determined. The ligand adopts a trans-III configuration. The Ni(II) ion is pseudooctahedral with Ni-S = 2.3896(10) Å in [Ni(L1)(ClO 4 )] + and 2.4193(10) Å, 2.4225(10) Å, in the two [Ni(L1)(H 2 O)] 2+ cations. Both nickel(II) and nickel(III) complexes are six-coordinate in solution. Oxidation of the [Ni(L1)(OH 2 )] 2+ complex with K 2 S 2 O 8 in aqueous solution yielded an ESR active Ni(III) species and the frozen solution spectrum displayed axial symmetry with g [Formula: see text] = 2.159 and g || = 2.024. In CH 3 CN, the [Ni(L1)(solv)] 2+ complex showed two reversible redox waves corresponding to the Ni 2+/+ couple at E 1/2 = -1.807 V vs. Fc +/0 and Ni 3+/2+ couple at E 1/2 = 0.715 V vs. Fc +/0 .Key words: synthesis, structure, polydentate macrobicycle, nickel(II).
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.003 | 0.003 |
| Meta-epidemiology (broad) | 0.005 | 0.002 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.000 | 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; both teacher heads agree on what is shown here.
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".