A Novel N,P,C Cage Complex Formed by Rearrangement of a Tricyclic Phosphirane Complex: On the Importance of Non‐covalent Interactions

Abstract

The reaction of Li/Cl P-CPh3 phosphinidenoid tungsten(0) complex 2 with dimethylcyanamide afforded tricyclic phosphirane complex 4, an unprecedented rearrangement of which led to the novel N,P,C cage complex 6. On the basis of DFT calculations, formation and intramolecular [3+2] cycloaddition of the transient nitrilium phosphane ylide complex 3 to a phenyl ring of the triphenylmethyl substituent to give 4 is proposed. Furthermore, theoretical evidence for terminal N-amidinophosphinidene complex 7, formed by [2+1] cycloelimination from 4, is provided, and the role of the electronic structure and non-covalent interactions of intermediate 7 discussed.

Activation of a 1‐Chlorophosphirane Complex by Aluminum Trichloride: Generation and Trapping of [Fc‐P‐W(CO)5] (Fc = Ferrocenyl)

“…The HOMO–LUMO gap at 2.51 eV is larger than that for [MeP‐W(CO) 5 ] at 2.34 eV. From this standpoint, 7 lies between the C‐substituted phosphinidene complex and the less‐electrophilic N‐substituted phosphinidene complex 15. From another standpoint, it is quite interesting to compare the reactions of the 1‐chlorophosphirane and 1‐chlorophosphirene complexes with AlCl 3 .…”

Unprecedented Ring–Ring Interconversion of N,P,C‐Cage Ligands

“…Usually, electrophilic terminal phosphinidene complexes with π‐acidic co‐ligands11b, 22 belong to a well‐known class of highly reactive intermediates5 and, therefore, it is worth mentioning the surprisingly low energy of complexes 10 Cr . This is even more impressive when compared with the energy of the azaphosphiridine precursors 9 Cr , which are stable, easily manipulated and storable compounds.…”

“…The other two are weaker and are channels for alleviating the excess electron density at the otherwise too‐electron‐enriched phosphorus atom into 1) the corresponding π*(CC) orbital at Cp* (stabilisation E SOPT =0.67 kcal mol −1 ; see HOMO‐4 in Figure 3d) and 2) the σ*(CH) orbital of one of the ortho positions of the aryl substituent by the formation of a P⋅⋅⋅HC hydrogen bond ( d P⋅⋅⋅H =2.661 Å, ρ ( r )=1.38×10 −2 e/a 0 3 , WBI=0.012, LBO=0.071, angle P⋅⋅⋅HC 126.6°, stabilisation E SOPT =1.42 kcal mol −1 ). Furthermore, NBO deletion calculations11b, 28 provide an additional approach to the quantification of the above‐mentioned main stabilising interactions, the associated binding energies of which are in good agreement with the reported E SOPT : through‐bond N→P donation, 67.4 kcal mol −1 ; through‐bond N←P back‐donation, 0.4 kcal mol −1 ; through‐space P←π(CC) transfer, 8.0 kcal mol −1 ; through‐space P→π*(CC) transfer, 1.3 kcal mol −1 ; through‐space P→σ*(P⋅⋅⋅HC) transfer, 5.1 kcal mol −1 .…”

Isomerization of Secondary Phosphirane into Terminal Phosphinidene Complexes: An Analogy between Monovalent Phosphorus and Transition Metals

“…[8] As ingle example concerns the rearrangement of an azaphosphiridine into aphosphinidene complex in which some stabilization is gained by interaction with af uran lone pair and ad istant C=Cb ond. [8] As ingle example concerns the rearrangement of an azaphosphiridine into aphosphinidene complex in which some stabilization is gained by interaction with af uran lone pair and ad istant C=Cb ond.…”