Synthesis, Characterization, and Structure of Macrocyclic Mono- and <i>C</i><sub>2</sub>-Symmetric, Binuclear Nickel Calixsalen Complexes
Bibliographic record
Abstract
Mono- (3a,b) and binuclear (4a,b) tetradentate NiII complexes of a series of 26-membered macrocyclic salen dimers, [salen(CH2)]2, are prepared in good yield by solvent-controlled reaction with Ni(OAc)2. The mononuclear complex 3b crystallizes in the trigonal space group 3P1(#144), a = 18.2566(2) A, c = 15.9244(2) A, V = 4596.57(8) A3, and Z = 3. Refinement converged with R = 0.054 and Rw = 0.049 for 6852 reflections with I > 2.003 sigma(I). The NiII in complex 3b coordinates in an approximate square planar geometry to one of the two available tetradentate salen sites. Complex 4b crystallizes in the orthorhombic space group P2(1)2(1)2(1)(#19), a = 19.531(2) A, b = 22.891(3), c = 13.373(1) A, V = 5960(1) A3, and Z = 4. The refinement converged with R = 0.067 and Rw = 0.065 for 3752 reflections with I > 2.003 sigma(I). Complex 4b coordinates two distorted square planar, cofacially oriented NiII-salen units held 7.1 A apart by a rigid, syn-folded macrocyclic structure. The solution spectroscopic data and solid-state crystallographic data of 3b and 4b demonstrate the presence of a molecular-sized cavity which shows host-guest properties. Reaction of the flexible 32-membered disalen macrocycle [salen(OCH2CH2O)]2 with Ni(OAc)2 resulted in formation of a binuclear complex, 5. Complex 5 crystallizes in the triclinic space group P1(#1), a = 10.366(4) A, b = 12.170(3) A, c = 10.021(2) A, alpha = 106.29(2) degrees, beta = 91.69(2) degrees, gamma = 68.63(2) degrees, V = 1126.3(5) A3, and Z = 1. The refinement converged with R = 0.052 and Rw = 0.053 for 2385 reflections with I > 2.003 sigma(I). The binuclear complex 5 contains two cofacially oriented, square planar NiII-salen groups lying 3.5 A apart in an anti-folded macrocyclic structure.
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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".