Tri-, Tetra-, and Hexanuclear Copper(II) Phosphonates Containing <i>N</i>-Donor Chelating Ligands: Synthesis, Structure, Magnetic Properties, and Nuclease Activity
Bibliographic record
Abstract
Reaction of Cu(ClO(4))(2).6H(2)O with cyclopentyl phosphonic acid and 2,2'-bipyridine (bpy) in presence of triethylamine afforded a trinuclear compound [Cu(3)(C(5)H(9)PO(3))(2)(bpy)(3)(MeOH)(H(2)O)](ClO(4))(2) (2). The latter dimerizes to a hexanuclear derivative [Cu(6)(C(5)H(9)PO(3))(4)(bpy)(6)(MeOH)(4)](ClO(4))(4) (1) under prolonged reaction conditions. Reaction of CuCl(2) with cyclopentyl phosphonic acid and 2,2'-bipyridylamine (bpya) affords a tetranuclear derivative [Cu(4)(C(5)H(9)PO(3))(2)(mu-Cl)(2)(bpya)(4)](Cl)(2), (MeOH)(2) (3). Reaction of the latter with NaClO(4) also affords a trinuclear compound [Cu(3)(C(5)H(9)PO(3))(2)(mu-Cl)(bpya)(3)(H(2)O)](ClO(4)) (4). Double and single-bridged hexanuclear species, [{Cu(3)(C(5)H(9)PO(3))(2)(bpy)(3)(bpp)}(MeOH)(2)(H(2)O)(CH(2)Cl(2))(ClO(4))(2)](2) (5), [{Cu(3)(i-PrPO(3))(2)(bpy)(3)(4.4'-bpy)(H(2)O)}(H(2)O)(2)(ClO(4))(2)](2) (6), [{Cu(3)(C(5)H(9)PO(3))(2)(bpya)(3)(4.4'-bpy)(H(2)O)}(MeOH)(H(2)O)(ClO(4))(2)](2) (7), and [Cu(6)(t-BuPO(3))(4)(phen)(6)(4,4'-bpy)(MeOH)(4)](CH(2)Cl(2))(H(2)O)(ClO(4))(4) (8) (phen = 1,10-phenanthroline) were obtained by the reaction of an in situ generated trinuclear complex with appropriate bridging ligands 4,4'-bipyridine (4,4'-bpy) or 1,3-bis(4-pyridyl)propane (bpp). ESI-MS studies of these complexes reveal that 2-4 retain their structures in solution. Molecular structures of 2-8 were determined by X-ray crystallography. All the compounds reveal a capping coordination mode by tridentate phosphonate [RPO(3)](2-) ligands. Detailed magnetic studies on 2 and 4-8 reveal intramolecular antiferromagnetic interactions between Cu(II) S = 1/2 spins. 2 and 4 are excellent artificial nucleases and can convert supercoiled plasmid DNA (pBR322) into its nicked form without the aid of an external oxidant.
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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".