Synthesis and Structure of the First Hybrid Borazine—Phosphazene Ring

Main-group-based rings and polymers

“…This allowed us to access the borazine-phosphazene hybrid ring 11, which was well characterized spectroscopically by 11 B, 31 P, 1 H, and 13 C NMR spectroscopy. 26 Significantly, the 11 B NMR spectrum in CH 2 Cl 2 of 11 clearly showed that boron was in a planar 'borazine-like' environment with a broad resonance at δ 31.7 which is similar to that of [ClBNMe] 3 ( 11 B δ 31.2). Conclusive evidence for the abstraction of chlorine at boron was provided by X-ray analysis of colourless crystals obtained from the reaction mixture.…”

“…1) which was synthesised by Binder's route. 26 The structure showed that the BP 2 N 3 ring deviates significantly from planarity with the boron atom substantially removed [by 0.39(1) Å] from the best plane of the other five ring atoms. However, the most interesting features of the structure of 10 involve the environment at the boron atom.…”

Inorganic Benzene Valence Isomers

“…[44] The 31 P NMR resonance of I-BNP1 (δ = 35.5 ppm) is shifted downfield compared to the corresponding precursor (δ = 28.2 ppm) (Scheme 7). [45] The 31 P NMR of phosphazene I-PN1 (δ = 19.3 ppm) is somewhat upfield compared to I-BNP1. The 11 B NMR chemical shifts of phosphaborazines (I-BP2-I-BP6) appear around δ = ppm, which are upfield-shifted with respect to that observed for the antiaromatic system (ThexylBPMes) 2 (Thexyl = tert-hexyl) (δ = 95.1 ppm).…”

“…In 1994, the Manners group reported the synthesis of the first hybrid borazine phosphazene cation I‐BNP1 by the dechlorination of precursor (Scheme ) . The B−N bond length is 1.429(10) Å and the average distance of P−N bond is 1.624(6) Å.…”

“…The 11 B NMR chemical shifts of I‐BN1 (δ=28.5 ppm), I‐BN3 (δ=38.6 ppm, 20.8 ppm), and I‐BNP1 (δ=31.7 ppm) are in the range of the aromatic 1,2‐azaborinine system (δ=20–40 ppm, e. g. 1,2‐dihydro‐1,2‐azaborinine: δ=31.0 ppm) . The 31 P NMR resonance of I‐BNP1 (δ=35.5 ppm) is shifted downfield compared to the corresponding precursor (δ=28.2 ppm) (Scheme ) . The 31 P NMR of phosphazene I‐PN1 (δ=19.3 ppm) is somewhat upfield compared to I‐BNP1 .…”