Structural Evidence for an Unusual Conformation and Weak Interligand Interactions in Two Copper Chelates with (<i>o</i>‐Nitrophenyl)ethylenediaminediacetic Acid
Bibliographic record
Abstract
Abstract Two mixed‐ligand copper(II) complexes, [Cu(L1)(H2O)]·H2O (1) and [Cu(L1)(bipy)]·2H2O (2), containing the title N‐substituted iminodiacetate (IDA) derivative (L12–) as primary ligand with and without 2,2′‐bipyridine as auxiliary ligand, have been synthesised. Both have been fully characterised by means of IR spectroscopy, mass spectrometry, elemental analysis and conductimetry, as well as X‐ray crystallography. The dominant structural feature of these complexes is the presence of a flexible coordinating arm on the IDA skeleton which controls the conformation of the resulting complexes. The CuII centre in complex 1 exhibits a distorted square‐pyramidal [4+1] coordination in which the apical site is unexpectedly occupied by the N(2) atom of the coordinating arm instead of a water molecule. The IDA skeleton adopts a tridentate mer‐O2N arrangement in 1, whereas in 2 it exhibits an unusual fac‐O2N(apical) configuration, which is observed for the first time for a tridentate IDA unit bearing a flexible arm containing a coordinating atom. The o‐nitro aromatic group in the flexible arm gives rise to different inter‐ and/or intramolecular stacking interactions. Classic intermolecular “nitrophenyl‐nitrophenyl” π‐π stacking interactions are observed between pairs of complex molecules in crystals of 1, whereas intramolecular “nitrophenyl‐pyridyl” interactions alternate with unprecedented interligand π‐π “nitrophenyl–metal chelate ring” interactions in crystals of 2.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
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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 | 0.001 | 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".