Isolating rare arylhalodiphosphene P=P–X bonds
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.
Source
Isolation of arylhalodiphosphenes: periodic trends in R-P[double bond, length as m-dash]P-X bonding (X = Cl, Br, I)
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.
What they did
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.
What they found
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*.
The limits
What it doesn't show
A free diphosphadiazonium salt is still not isolated; halide abstraction gives mixtures, and 31P spectra retain trace impurities after recrystallization.
Key terms
- Diphosphene
- RP=PR′ analogue of an alkene with a P=P double bond.
- Arylhalodiphosphene
- Ar–P=P–X species (X = Cl, Br, I) isolated here as monomers.
- 1JPP
- One-bond 31P–31P coupling; 574 Hz supports P=P in 8.
- E/Z isomerism
- Geometry about P=P; both isomers appear in the crystal.
- Masked diphosphadiazonium
- The PPCl unit as a heavier analogue of an aryldiazonium chloride.
Flashcards
0 of 11 answers reviewed
Research intelligence for this paper
See its role on concept claims, tensions it is part of, placement history, and related discoveries.
Quiz yourself
Compound 8 is best described as:
Common questions
What new motif was isolated?
A monomeric aryl-PPCl diphosphene, 8·(Et2O)2.
What 31P signature indicates P=P?
Downfield doublets at 433 and 502 ppm with 1JPP = 574 Hz.
How are Br and I analogues made?
Heat 8 with TMSBr or TMSI at 100 °C.
Does halide abstraction work?
AlCl3/GaCl3 decompose 8; AgOTf gives a coordination complex instead.
More on Organic synthesis