Simple Ligand-Field Theory of <i>d</i><sup>4</sup> and <i>d</i><sup>6</sup> Transition Metal Complexes with a <i>C</i><sub>3</sub> Symmetry Axis
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
There have been a number of recent studies reporting high-spin d(4,6) complexes with three- and four-coordinate geometry, which exhibit roughly trigonal symmetry. These include complexes of Fe(II) with general formula L(3)FeX, where L = thioether or dialkylphosphine donors of a tripodal chelating ligand and X is a monodentate ligand on the C(3) axis. In these systems, there is unquenched orbital angular momentum, which has significant consequences on the electronic/magnetic properties of the complexes, including magnetic susceptibility, EPR spectra, and magnetic Mössbauer spectra. We describe here a simple model using a description of the d orbitals with trigonal symmetry that along with the application of the spin-orbit interaction successfully explains the magnetic properties of such systems. These d orbitals with 3-fold symmetry are complex orbitals with a parameter, a, that is determined by the bond angle, α, of LFeX. We demonstrate that the E symmetry states in such systems with S > 1/2 cannot be properly "simulated by" or be "represented by" the Zeeman and second-order zero-field spin Hamiltonian alone because by definition the parameters D and E are second-order terms. One must include the first-order spin-orbit interaction. We also find these systems to be very anisotropic in all their magnetic properties. For example, the perpendicular values of g and the hyperfine interaction parameter are essentially zero for the ground-state doublet. For illustrative purposes, the discussion focuses primarily on two specific Fe(II) complexes: one with the bond angle α greater than tetrahedral and another with the bond angle α less than tetrahedral. The nature of the EPR spectra and hyperfine interaction of (57)Fe are discussed.
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.
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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