Crystal Structures of Spiroborates Derived from 2,2′-Dihydroxybiphenyl
Bibliographic record
Abstract
Salts of bis[[1,1′-biphenyl]-2,2′-diolato- O,O ′] borate ( 4 ) were prepared by the reaction of boric acid with 2,2′-dihydroxybiphenyl in the presence of various cations. Ten salts were crystallized, and their structures were solved by X-ray diffraction. In all cases examined, spiroborate 4 favors enantiomeric ( R,R ) and ( S,S ) structures with a flattened D 2 geometry. Moreover, the crystals analyzed all incorporate the two enantiomers in a 1:1 ratio, even when the cations themselves are chiral and enantiomerically pure. In crystals of certain salts (NH 4 +, NH 2 Me 2 +, NMe 4 +, PPh 4 +, and MBA + ), the packing of spiroborate 4 can be considered to define homochiral layers; in other salts, however, the organization of the anions is helical (NMe 4 + ), columnar (NPr 4 + ), or can be described as either layered or columnar (NBu 4 + and NPent 4 + ). These variations presumably arise because neighboring anions are not positioned reliably by strong directional interactions between them. Derivatives of spiroborate 4 that can engage in such interactions are expected to have well-defined molecular geometries and to serve as effective subunits for engineering crystals and other ordered materials with predetermined structures and properties.
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".