Six Lanthanide-Coordination Polymers Based on 2-Fluoroisonicotinic Acid: Synthesis, Structure, Luminescence and Magnetic Properties
Bibliographic record
Abstract
Abatract: Six new 1D lanthanide-based coordination polymer helical chains with formulas of {[Ln(FINA)3(H2 O)2 ]· H2 O}n(Ln=Pr(1), Nd(2), Eu(3), Gd(4)), {[Dy(FINA)3(H2 O)2 ]}n(5), and {[Gd(FINA)2(phen)(OH)]}n(6)(HFINA=2-Fluoroisonicotinic acid, phen=1,10-phenthroline), were synthesized and structurally characterized. It is the first time that 2-Fluoroisonicotinic acid is employed in producing coordination polymers. Carboxylate moieties of the ligand in these compounds exhibit two types of coordination modes because of the lanthanide contraction effect. Ln3+ion is coordinated by eight donor atoms in a distorted bicapped trigonal-prismatic arrangement in 1~4 while in distorted dodecahedron geometry in 5~6. All of helical chains are further extended via the intermolecular π… π interactions, strong O-H … O/N hydrogen bonds and C-H … F hydrogen bonds into a 3D supramolecular structures. Interestingly, in 1~4, there is a small 1D solvent channel along the b-axis, where water molecules are located. The luminescence properties of 3 and 4 have been investigated and the result indicate that compound 3 displays intense red luminescence and exhibits the characteristic transition of the Eu3+ion with a decay lifetime of 333.81 μs, while 4 would be attributed to the intraligand fluorescence, based on the emission spectrum of the free ligand. The magnetic properties of 2 ~6 reveal the weak antiferromagnetic characters. Additionally, the thermal analyses suggest the high thermal stability of compounds 1~6. CCDC: 977317, 1; 977318, 2; 977319, 3; 977320, 4; 977321, 5; 977322, 6.
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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".