Organic synthesis
Isolating rare arylhalodiphosphene P=P–X bonds
Open access · cc by · source: Europe PMC
A bulky aryl-PPCl diphosphene is isolated as a monomer, swapped to Br and I, and shown to have a P=P double bond unlike diazonium chlorides.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
This library holds 7 empirical chemistry papers on organic synthesis with isolated findings, rates or spectra rather than reviews.
Evidence for the claim as stated.
A bulky aryl-PPCl diphosphene is isolated as a monomer, swapped to Br and I, and shown to have a P=P double bond unlike diazonium chlorides.
Evidence for the claim as stated.
A high yield on one substrate is not a general method, and many 'new reactions' are still one-pot screens rather than mechanism-complete syntheses.
Evidence for the claim as stated.
For an unusual molecular crystal, SC-XRD reports isomer populations that NMR then names. Arylhalodiphosphene 8·(Et₂O)₂ is 85% E / 15% Z in the solid with E/Z disorder; ³¹P signals at 433 and 502 ppm (¹JPP = 574 Hz) confirm P=P. Computed E-8* is 2.96 kcal mol⁻¹ more stable than Z-8*. Halide abstraction still does not isolate a free diphosphadiazonium salt.
Evidence for the claim as stated.
A powder pattern of a colloid and a single-crystal structure of a molecule are not the same XRD experiment. Fcc Ag peaks at 38.1–77.9° identify a metal phase and roughly a size regime; they do not give a coordination number, a space group of a molecular hydrate, or an E/Z ratio. Quoting 'XRD confirmed the structure' without saying powder versus single-crystal erases that.
Evidence for the claim as stated.
³¹P NMR is often the identity test for unusual phosphorus multiple bonds. Arylhalodiphosphene 8 showed ³¹P signals at 433 and 502 ppm with ¹JPP = 574 Hz; the solid was 85% E / 15% Z. Halide abstraction still did not isolate a free diphosphadiazonium salt.
Evidence for the claim as stated.
Solution NMR, in-cell NMR and solid-state/identity NMR are not the same experiment. Titration Kas in wet DMSO, oocyte SOFAST-HMQC of a labelled oligonucleotide, and ³¹P shifts of a diphosphene answer different questions. A student who says 'we ran NMR' without saying which nuclei and which medium cannot compare those papers.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
A high yield on one substrate is not a general method, and many 'new reactions' are still one-pot screens rather than mechanism-complete syntheses.
A powder pattern of a colloid and a single-crystal structure of a molecule are not the same XRD experiment. Fcc Ag peaks at 38.1–77.9° identify a metal phase and roughly a size regime; they do not give a coordination number, a space group of a molecular hydrate, or an E/Z ratio. Quoting 'XRD confirmed the structure' without saying powder versus single-crystal erases that.
Solution NMR, in-cell NMR and solid-state/identity NMR are not the same experiment. Titration Kas in wet DMSO, oocyte SOFAST-HMQC of a labelled oligonucleotide, and ³¹P shifts of a diphosphene answer different questions. A student who says 'we ran NMR' without saying which nuclei and which medium cannot compare those papers.
Study at a glance
- Design
- Other — Synthesis, SC-XRD, and DFT of thermally robust arylhalodiphosphenes and halide exchanges
- N
- Main-group synthesis/structure study — no sample N
- Population
- Arylhalodiphosphene compounds and silver coordination complexes
- Outcome
- P=P bonding metrics and E/Z preferences across halide series
Structured fields used in claim comparison tables when every cited study has a complete layer.
Inspect source passages
Isolating rare arylhalodiphosphene P=P–X bonds
These passages occur verbatim in the stored paper text. They support the points listed below; they do not verify every statement in the explanation.
31P resonances at 433 and 502 ppm with 1JPP = 574 Hz.
The 31 P NMR resonances of the product are shifted strongly downfield with respect to the precursor at 433 ppm and 502 ppm and exhibit a larger 1 J PP coupling constant of 574 Hz, consistent with an asymmetric diphosphene species with a P–P double bond.
The crystal is 85% E and 15% Z.
Our model features disorder between a major E -isomer with an occupancy of 85% () and a minor Z -isomer with an occupancy of 15% with respect to the asymmetric diphosphene unit.
Key findings
31P signals at 433 and 502 ppm with 1JPP = 574 Hz. The solid is 85% E / 15% Z. TMSBr/TMSI at 100 °C give 9 and 10; GaCl3/AlCl3 decompose 8, while AgOTf gives complex 11. E-8* is 2.96 kcal mol−1 more stable than Z-8*.
Methodology
Authors prepared thermally robust 8·(Et2O)2, confirmed P=P by 31P NMR and SC-XRD (E/Z disorder), exchanged Cl for Br/I with TMSX, coordinated Ag+, and computed E-8*–E-10* at PBE0-D3/def2-TZVPP.
Limitations
A free diphosphadiazonium salt is still not isolated; halide abstraction gives mixtures, and 31P spectra retain trace impurities after recrystallization.
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