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The chemistry of cationic polyphosphorus cages--syntheses, structure and reactivity.

Holthausen MH, Weigand JJ - Chem Soc Rev (2014)

Bottom Line: The aim of this review is to provide a comprehensive view of the chemistry of cationic polyphosphorus cages.The synthetic protocols established for their preparation, which are all based on the functionalization of P4, and their intriguing follow-up chemistry are highlighted.In addition, this review intends to foster the interest of the inorganic, organic, catalytic and material oriented chemical communities in the versatile field of polyphosphorus cage compounds.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Toronto, Toronto, Canada. m.holthausen@utoronto.ca.

ABSTRACT
The aim of this review is to provide a comprehensive view of the chemistry of cationic polyphosphorus cages. The synthetic protocols established for their preparation, which are all based on the functionalization of P4, and their intriguing follow-up chemistry are highlighted. In addition, this review intends to foster the interest of the inorganic, organic, catalytic and material oriented chemical communities in the versatile field of polyphosphorus cage compounds. In the long term, this is envisioned to contribute to the development of new synthetic procedures for the functionalization of P4 and its transformation into (organo-)phosphorus compounds and materials of added value.

No MeSH data available.


Related in: MedlinePlus

Stepwise synthesis of N2P10-cage compound 47[Ga2Cl7]2via insertion of phosphenium ions generated in situ by the reaction of diphosphadiazane 44 with GaCl3.
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sch13: Stepwise synthesis of N2P10-cage compound 47[Ga2Cl7]2via insertion of phosphenium ions generated in situ by the reaction of diphosphadiazane 44 with GaCl3.

Mentions: Cyclic diaminohalophosphanes are important precursors for the preparation of cyclic phosphenium ions via halide abstraction.55 Within this class of compounds, phosphazanes, like the diphosphadiazane 44, are of particular interest (Scheme 13). These compounds feature two chloro-substituted P moieties and, thus, offer a versatile reactivity.56 The diphosphadiazenium ion 45+ is generated from 44 upon chloride abstraction with GaCl3. Solutions of 45+ are characterized by a bright red colour and the 31P NMR spectrum shows a broad resonance at characteristic low field (δ = 242.3 ppm) indicating the formation of a di-coordinated P moiety. Subsequent addition of P4 to this solution leads to discolouration and quantitative formation of the P5+-cage compound 46[GaCl4].57 The molecular structure of cation 46+ shows a planar four-membered (NP)2 ring and an almost orthogonal oriented P–Cl bond (Scheme 13). This arrangement is also reflected by the A2MVXZ spin system observed in the 31P NMR spectrum of CS-symmetric cation 46+. Interestingly, the P5+-cage does not couple with the chloro-substituted P atom resulting in the observation of a singlet resonance for the latter. This P–Cl functionality was used for the in situ generation of a phosphenium ion upon addition of three equivalents of GaCl3 to the reaction mixture. The resulting dicationic intermediate was not detected. However, upon addition of P4, the formation of the corresponding insertion product 472+ is observed. The 31P NMR spectrum of 472+ shows an A2MX2 spin system which is consistent with two C2V-symmtric P5+-cages bridged by two imido-groups. The dication can be isolated as heptachlorodigallate salt 47[Ga2Cl7]2 and the molecular structure of the N2P10-cage was confirmed by single crystal structure determination (Scheme 13). This illustrates that the stepwise insertion of the disguised bifunctional Lewis acid [DippNP]22+ into P–P bonds of two P4 tetrahedra can be mediated by the Lewis acidity of the reaction mixture. The utilization of an excess of GaCl3 allows for the preparation of the more electrophilic, higher charged species 472+, similar to the reaction sequence yielding 433+ (Scheme 12).


The chemistry of cationic polyphosphorus cages--syntheses, structure and reactivity.

Holthausen MH, Weigand JJ - Chem Soc Rev (2014)

Stepwise synthesis of N2P10-cage compound 47[Ga2Cl7]2via insertion of phosphenium ions generated in situ by the reaction of diphosphadiazane 44 with GaCl3.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4288811&req=5

sch13: Stepwise synthesis of N2P10-cage compound 47[Ga2Cl7]2via insertion of phosphenium ions generated in situ by the reaction of diphosphadiazane 44 with GaCl3.
Mentions: Cyclic diaminohalophosphanes are important precursors for the preparation of cyclic phosphenium ions via halide abstraction.55 Within this class of compounds, phosphazanes, like the diphosphadiazane 44, are of particular interest (Scheme 13). These compounds feature two chloro-substituted P moieties and, thus, offer a versatile reactivity.56 The diphosphadiazenium ion 45+ is generated from 44 upon chloride abstraction with GaCl3. Solutions of 45+ are characterized by a bright red colour and the 31P NMR spectrum shows a broad resonance at characteristic low field (δ = 242.3 ppm) indicating the formation of a di-coordinated P moiety. Subsequent addition of P4 to this solution leads to discolouration and quantitative formation of the P5+-cage compound 46[GaCl4].57 The molecular structure of cation 46+ shows a planar four-membered (NP)2 ring and an almost orthogonal oriented P–Cl bond (Scheme 13). This arrangement is also reflected by the A2MVXZ spin system observed in the 31P NMR spectrum of CS-symmetric cation 46+. Interestingly, the P5+-cage does not couple with the chloro-substituted P atom resulting in the observation of a singlet resonance for the latter. This P–Cl functionality was used for the in situ generation of a phosphenium ion upon addition of three equivalents of GaCl3 to the reaction mixture. The resulting dicationic intermediate was not detected. However, upon addition of P4, the formation of the corresponding insertion product 472+ is observed. The 31P NMR spectrum of 472+ shows an A2MX2 spin system which is consistent with two C2V-symmtric P5+-cages bridged by two imido-groups. The dication can be isolated as heptachlorodigallate salt 47[Ga2Cl7]2 and the molecular structure of the N2P10-cage was confirmed by single crystal structure determination (Scheme 13). This illustrates that the stepwise insertion of the disguised bifunctional Lewis acid [DippNP]22+ into P–P bonds of two P4 tetrahedra can be mediated by the Lewis acidity of the reaction mixture. The utilization of an excess of GaCl3 allows for the preparation of the more electrophilic, higher charged species 472+, similar to the reaction sequence yielding 433+ (Scheme 12).

Bottom Line: The aim of this review is to provide a comprehensive view of the chemistry of cationic polyphosphorus cages.The synthetic protocols established for their preparation, which are all based on the functionalization of P4, and their intriguing follow-up chemistry are highlighted.In addition, this review intends to foster the interest of the inorganic, organic, catalytic and material oriented chemical communities in the versatile field of polyphosphorus cage compounds.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Toronto, Toronto, Canada. m.holthausen@utoronto.ca.

ABSTRACT
The aim of this review is to provide a comprehensive view of the chemistry of cationic polyphosphorus cages. The synthetic protocols established for their preparation, which are all based on the functionalization of P4, and their intriguing follow-up chemistry are highlighted. In addition, this review intends to foster the interest of the inorganic, organic, catalytic and material oriented chemical communities in the versatile field of polyphosphorus cage compounds. In the long term, this is envisioned to contribute to the development of new synthetic procedures for the functionalization of P4 and its transformation into (organo-)phosphorus compounds and materials of added value.

No MeSH data available.


Related in: MedlinePlus