Crystal structure, spectroscopic studies, and nonlinear optical (NLO) properties of Schiff base metal complexes containing an N, S donor ligand
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Bibliographic record
Abstract
A new ligand, 4-dipropylaminobenzaldehyde thiosemicarbazone (abbreviated as HL), and its complexes ML 2 (M = Ni, Pd, and Cu) have been synthesized and fully characterized by elemental analyses, EI-MS, IR and UVvis spectroscopy, and photoluminescence measurements. All of the compounds exhibit a bluegreen color with dual fluorescence in DMF solution. The quantum yield ratio (Φ′(CT)/Φ(LE)) decreases in the order NiL 2 > HL > PdL 2 > CuL 2 . The ligand HL crystallizes in the monoclinic system, space group P2 1 /n, with a = 15.1680, b = 8.5573, and c = 25.3920 Å, β = 100.3457°, and V = 3242.2 Å 3 . The nickel complex (NiL 2 ) crystallizes in the triclinic system, space group Pī, with a = 8.3093, b = 9.7540, and c = 10.2802 Å, α = 101.383°, β = 107.693°, γ = 96.703°, and V = 764.12 Å 3 . In these complexes, HL has lost a proton from its tautometric thiol form and acts as a single negatively charged bidentate ligand coordinating to the nickel ion via the mercapto sulfur and β-nitrogen atoms. The geometry around Ni(II) is almost square-planar with two equivalent NiN and two equivalent NiS bonds. The monomeric structure of HL or NiL 2 is extended into an infinite two-dimensional network via hydrogen bonds. The two-photon absorption of HL and ML 2 solutions (in DMF) was measured at 532 nm by the open-aperture Z-scan technique. Key words: crystal structure, metal complex, dual fluorescence, NLO.
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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 | 0.000 | 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) | 0.000 | 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 it