Soluble Ring‐Unsubstituted Phthalocyanine Zirconium(IV) and Niobium(V) <i>cis</i> ‐Alkoxides and Their Catalytic Activity Toward the Ring‐Opening Polymerization of <i>rac‐</i> Lactide
Bibliographic record
Abstract
Abstract A series of soluble ring‐unsubstituted early‐transition metallophthalocyanine (PcM) alkoxides with zirconium(IV) and niobium(V) metal centers was prepared via salt metathesis with PcM chlorides and a range of lithium or sodium alkoxides (NaOMe, NaOEt, LiO i Pr, and NaO t Bu); several examples were structurally characterized. Given their large ionic size, the metal centers protrude out of the Pc cavity, engendering cis ‐axial ligation of the alkoxides and thereby generating substantially improved solubility relative to the starting PcM chlorides. Seven‐coordinate PcM(OR) 3 ‐type coordination spheres were typically observed, with lithium‐ or sodium‐balanced “ ate ” species PcZr(O i Pr) 3 Li(THF) and PcZr(O t Bu) 3 Na(THF) isolated for PcZr(IV), compared to the neutral PcNb(O i Pr) 3 . With the highly steric R = t Bu the neutral six‐coordinate PcZr(O t Bu) 2 was also structurally characterized. The catalytic activity of the PcZr(IV) and PcNb(V) alkoxides was probed toward the ring‐opening polymerization (ROP) of rac ‐lactide, with PcZr(O i Pr) 3 Li(THF) being the most active, while the PcNb(V) systems were either inactive or yielded oligomers.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".