Phosphazenes

Abstract

Phosphazenes are compounds containing the [P═N] motif. Three broad classes of compounds fall in this category: (a) acyclic phosphazenes, also known as iminophosphoranes, (b) cyclophosphazenes and (c) polyphosphazenes. There has been a growing tendency in the literature to bunch all polymeric compounds containing the phosphazene motif in the category of polyphosphazenes. While we would be dealing all polymeric compounds in the subsection on polyphosphazenes, the distinction between the various types needs to be appreciated. Polyphosphazenes are those that contain a [P═N] backbone with substituents on phosphorus. Other forms of polymers could be regarded as hybrid polymers which often contain an organic backbone with phosphazene pendant groups or cross-linked polymers containing interconnected cyclophosphazene units. This chapter summarizes the literature on phosphazenes that was published in the calendar year 2020.

Phosphorus–nitrogen compounds: part 70. Syntheses of tetraaminomono/bis(4-fluorobenzyl)spiro(N/N)cyclotriphosphazenes: structural characterization, Hirshfeld surface analysis and comparative evaluation of esterase activities of hCA I and hCA II isoenzymes

“…For many years, hexachlorocyclotriphosphazene, N 3 P 3 Cl 6 (HCCP; trimer), a member of cyclic inorganic systems containing phosphorus and nitrogen atoms linked together by successive PN units, has been widely used as the starting cyclic compound in the syntheses of numerous newly substituted cyclotriphosphazene derivatives. 1,2 The displacement reactions of HCCP, which has six highly reactive Cl atoms, with monodentate, bidentate and multidentate ligands continue to be broadly studied in the field of phosphazene chemistry. 3,4 It has been stated in the literature that various products such as spiro, ansa, spiro-ansa (sa), dispiro (cis/trans), spiro-ansa-spiro (sas) and spiro-bino-spiro (sbs) type structures have occurred as a result of these reactions.…”

Phosphorus–nitrogen compounds: part 71. Novel unsymmetrically-substituted dispiro-cyclotriphosphazenes: synthesis, characterization, antituberculosis activity, and phototunable charge storage studies

“…In recent years, there has been an increasing interest in phosphazene chemistry. [1][2][3][4][5][6] This can be attributed to the following reasons: a large number of phosphazene derivatives can be prepared, some of them are ligands for transition metal cations, and their ability to polymerize. [7][8][9][10][11] The studies are mainly focused on cyclophosphazenes, especially hexachlorocyclotriphosphazene (N 3 P 3 Cl 6 , trimer, and HCCP).…”