Bibliographic record
Abstract
The synthesis, spectroscopic and redox properties of new metallophthalocyanines (PcM) are active areas of research. The rings of PcM complexes can be successively reduced using chemical, electrochemical, or photochemical methods to give rise to species containing ring-reduced Pc(3-), Pc(4-) or Pc(5-) ligands ; in the other direction, both ring-oxidized Pc(-1) and Pc(0)-containing systems can be accessed. These species are usually generated and characterized in situ and have only recently begun to be isolated and structurally characterized. In particular, there are few examples of phthalocyanines with early-transition and f-block metals - despite the rich organometallic-type reactivity of these metals - and thus we targeted new PcM complexes in this underdeveloped area of the periodic table. Given their larger ionic size, the unusual structural feature of the metal centre protruding far out of the Pc cavity is observed. Hence, the exposure of the coordination sphere of these Lewis-acidic (often d0) metals makes these PcM complexes attractive catalysts; this cis-oriented axial ligation also drastically improves the solubility, despite the Pc-ring remaining unsubstituted. In this presentation the isolation and structural characterization of new PcM materials with M = scandium, zirconium, niobium and (time-permitting) molybdenum will be described, along with rare structurally characterized examples of their reduced Pc(4-) and Pc(3-)complexes. Their electronic structure and electrochemical behaviour will be discussed using a combination of spectroscopic and structural techniques. A series of moisture-sensitive, soluble PcZr(IV) and PcNb(V) alkoxides were prepared, characterized, and their catalytic activity towards the ring-opening polymerization of rac-lactide was studied and will be detailed. Reaction of PcScCl with LiO i Pr and NaO t Bu yielded two hydroxide complexes containing the PcScOH unit, obtained from the hydrolysis of the putative PcSc-alkoxide intermediate. The two structurally characterized systems have a tilted “butterfly” shape structure, reminiscent of bent metallocenes. The solubility of these early transition-metal based complexes present new opportunities for the advancement of this underdeveloped area of PcM chemistry. Time permitting, our related work on organometallic PcLnX complexes will also be described. References Zhou, D.B. Leznoff, Chem. Commun., 2018, 54, 1829-1832. W. Zhou, J.R. Thompson, C.C. Leznoff, D.B. Leznoff, Chem. Eur. J., 2017, 23, 2323-2331; R. Platel, W. Zhou, T.T. Tasso, T. Furuyama, N. Kobayashi, D.B. Leznoff, Chem. Commun., 2015, 5986-89; D. McKearney, W. Zhou, V.E. Williams, D.B. Leznoff, Chem. Commun., 2019, 55, 6696-6699; Y. Ganga-Sah, E. Tajbakhsh, R.H. Platel, W. Zhou, D.B. Leznoff, J. Porph. Phthalocyanines, 2019, 23, 1592-1602; W. Zhou, D. McKearney, D.B. Leznoff, Chem. Eur. J., 2020, 26, 1027-31.
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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".