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Metallaphosphinidene Coupling with a Phosphorus Ylide to Form a Phosphavinyl [P═CH2]− Ligand

Tan, Mattias LU ; Sandoval-Pauker, Christian ; Takacs, Zoltan LU and Reinholdt, Anders LU (2026) In Journal of the American Chemical Society 148(24). p.25096-25106
Abstract

Metallaphosphinidenes, [M–P], contain open-shell single-atomic phosphorus but typically display uncontrollable reactivity, preventing their utilization to selectively construct elusive functional groups. Here, we report an iridium phosphaethynolate complex, [(PCP)Ir(PCO)] (2), in a halide metathesis with Na(OCP). Photolysis of 2 leads to a bimetallic, side-on bound {P2} motif, [{(PCP)(OC)Ir}2(η2,η2;μ2-P2)] (3), via the intermediacy of a putative, triplet iridium phosphinidene, [(PCP)Ir(P)(CO)] (A), probed computationally. When 2 is instead photolyzed in the presence of a phosphorus ylide, PhMe2PCH2, the photointermediate is intercepted, leading to a... (More)

Metallaphosphinidenes, [M–P], contain open-shell single-atomic phosphorus but typically display uncontrollable reactivity, preventing their utilization to selectively construct elusive functional groups. Here, we report an iridium phosphaethynolate complex, [(PCP)Ir(PCO)] (2), in a halide metathesis with Na(OCP). Photolysis of 2 leads to a bimetallic, side-on bound {P2} motif, [{(PCP)(OC)Ir}2(η2,η2;μ2-P2)] (3), via the intermediacy of a putative, triplet iridium phosphinidene, [(PCP)Ir(P)(CO)] (A), probed computationally. When 2 is instead photolyzed in the presence of a phosphorus ylide, PhMe2PCH2, the photointermediate is intercepted, leading to a unique phosphavinyl complex, [(PCP)Ir(P═CH2)] (4), in 60% spectroscopic yield. Complex 2 also reacts thermally with PhMe2PCH2 to form 4. Tracking of the extruded CO fragment uncovers a divergent reactivity landscape; in the photolytic pathway, a carbonyl complex, [(PCP)Ir(CO)](PCO), forms, whereas in the thermal pathway, one CO and two CH2 groups couple to a [C3] fragment in a new ylide, PhMe2PCHCOCH3. Structural characterization, isotopic labeling, and IR and NMR spectroscopic studies, along with quantum simulations, unveil a rigid, π-bonded [P═CH2]− moiety in 4, having magnetically inequivalent hydrogens at room temperature. Complex 4 comprises a deprotonated ligand form of the elusive phosphaethylene molecule (HP═CH2) but possesses a much lower isomerization barrier (15.9(5) kcal mol–1) than classical phosphaalkenes (>40 kcal mol–1), owing to an interplay between the [(PCP)Ir]+ and [P═CH2]− fragments, leading to a linear {Ir═P═CH2} transition geometry for this molecular switch. Lastly, we utilize the phosphavinyl ligand to form other rare π-constructs with an organic azide.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of the American Chemical Society
volume
148
issue
24
pages
11 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • pmid:42257848
  • scopus:105042608877
ISSN
0002-7863
DOI
10.1021/jacs.6c06304
language
English
LU publication?
yes
id
78c6a7a7-6f57-4deb-9d49-e6e0ab4aea61
date added to LUP
2026-08-13 13:10:11
date last changed
2026-09-10 14:58:53
@article{78c6a7a7-6f57-4deb-9d49-e6e0ab4aea61,
  abstract     = {{<p>Metallaphosphinidenes, [M–P], contain open-shell single-atomic phosphorus but typically display uncontrollable reactivity, preventing their utilization to selectively construct elusive functional groups. Here, we report an iridium phosphaethynolate complex, [(PCP)Ir(PCO)] (2), in a halide metathesis with Na(OCP). Photolysis of 2 leads to a bimetallic, side-on bound {P<sub>2</sub>} motif, [{(PCP)(OC)Ir}<sub>2</sub>(η<sup>2</sup>,η<sup>2</sup>;μ<sub>2</sub>-P<sub>2</sub>)] (3), via the intermediacy of a putative, triplet iridium phosphinidene, [(PCP)Ir(P)(CO)] (A), probed computationally. When 2 is instead photolyzed in the presence of a phosphorus ylide, PhMe<sub>2</sub>PCH<sub>2</sub>, the photointermediate is intercepted, leading to a unique phosphavinyl complex, [(PCP)Ir(P═CH<sub>2</sub>)] (4), in 60% spectroscopic yield. Complex 2 also reacts thermally with PhMe<sub>2</sub>PCH<sub>2</sub> to form 4. Tracking of the extruded CO fragment uncovers a divergent reactivity landscape; in the photolytic pathway, a carbonyl complex, [(PCP)Ir(CO)](PCO), forms, whereas in the thermal pathway, one CO and two CH<sub>2</sub> groups couple to a [C<sub>3</sub>] fragment in a new ylide, PhMe<sub>2</sub>PCHCOCH<sub>3</sub>. Structural characterization, isotopic labeling, and IR and NMR spectroscopic studies, along with quantum simulations, unveil a rigid, π-bonded [P═CH<sub>2</sub>]<sup>−</sup> moiety in 4, having magnetically inequivalent hydrogens at room temperature. Complex 4 comprises a deprotonated ligand form of the elusive phosphaethylene molecule (HP═CH<sub>2</sub>) but possesses a much lower isomerization barrier (15.9(5) kcal mol<sup>–1</sup>) than classical phosphaalkenes (&gt;40 kcal mol<sup>–1</sup>), owing to an interplay between the [(PCP)Ir]<sup>+</sup> and [P═CH<sub>2</sub>]<sup>−</sup> fragments, leading to a linear {Ir═P═CH<sub>2</sub>} transition geometry for this molecular switch. Lastly, we utilize the phosphavinyl ligand to form other rare π-constructs with an organic azide.</p>}},
  author       = {{Tan, Mattias and Sandoval-Pauker, Christian and Takacs, Zoltan and Reinholdt, Anders}},
  issn         = {{0002-7863}},
  language     = {{eng}},
  month        = {{06}},
  number       = {{24}},
  pages        = {{25096--25106}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Journal of the American Chemical Society}},
  title        = {{Metallaphosphinidene Coupling with a Phosphorus Ylide to Form a Phosphavinyl [P═CH<sub>2</sub>]<sup>−</sup> Ligand}},
  url          = {{http://dx.doi.org/10.1021/jacs.6c06304}},
  doi          = {{10.1021/jacs.6c06304}},
  volume       = {{148}},
  year         = {{2026}},
}