Unexpected Ring Expansion of a Four-Membered Cyclophosphazane

Abstract

Nucleophilic substitution reactions of the N(R),N(R)-spiro-bridged octachlorobis(cyclotriphosphazene), N3P3Cl4[N(CH2)5CH3]2N3P3Cl4 (1), with sodium salts of alcohols (1,3-propanediol, 2,2,3,3,4,4-hexafluoro-1,5-pentanediol, and phenol) give ansa products (2-4) via an unexpected rearrangement. These products were characterized by elemental analysis, mass spectrometry, and (1)H and (31)P NMR spectroscopy. The molecular structures of compounds 3 and 4 were also established by X-ray crystallography. This new class of phosphazene structures consists of three fused P3N3 rings that arise from expansion of the four-membered phosphazane ring in 1 to a six-membered N3P3 ring during alcoholysis reactions.

2-Naphthylthio Cyclotriphosphazene Derivatives: Synthesis, Characterization, Crystallographic and Fluorescence Properties

“…Also, they can be used as ligand in coordination chemistry and organometallic chemistry (10)(11)(12)(13)(14). Six-membered trimer (P3N3) is more preferred and studied than eight-membered tetramer (P4N4) because it is planar, stable, rigid, and its product range is less than tetramer (17)(18)(19)(20). Thus, an easily functionalized platform is created for the preparation of compounds suitable for different and new application areas such as biologically active materials, liquid crystallinity, anticancer agents, fluorescent chemosensors and organic light emitting diodes (21)(22)(23)(24)(25)(26).…”

New Synthetic Approach to Molecular Rods Using Cyclophosphazene-Based Oligospiranes

“…Recently, deprotonation reactions were used to form fused cyclophosphazene rings joined by a phosphazene or phosphazane ring. The new types of molecular structures that were synthesized via these routes were found to be very stable and promising as potential building blocks for larger structures . These results prompted us to build up new types of molecular rods by combining the two strategies described above.…”