The facile assembly of bis-, tris- and poly(triazaphosphole) systems using “click” chemistry

Abstract

Uncatalysed 1,3-dipolar cycloaddition reactions between two phosphaalkynes, P≡CR (R = But or Me), and a series of di-, tri- and poly-azido precursor compounds have given very high yields of a range of triazaphosphole substituted systems. These comprise the 1,1′-bis(triazaphosphole)ferrocenes, [Fe(C5H4(N3PCR))2], the tris(triazaphosphole)cyclohexane, cis-1,3,5-C6H9(N3PCBut)3, and the poly(allyltriazaphosphole)s, (C3H5(N3PCR))∞. Electrochemical studies on the 1,1′-bis(triazaphosphole)ferrocenes reveal the compounds to undergo reversible 1-electron oxidation processes, at significantly more positive potentials than ferrocene itself. Attempts to chemically oxidise one 1,1′-bis(triazaphosphole)ferrocene with a silver salt, Ag[Al(OC(CF3)3)4] were not successful, and led to the formation of a silver coordination complex, [(Fe[μ-C5H4(N3PCBut)]2(μ-Ag))2][Al(OC(CF3)3)4]2, thereby demonstrating the potential the reported triazaphosphole substituted systems possess as novel ligands in coordination chemistry. © 2013 The Royal Society of Chemistry.