Low-coordinate 3H-1,2,3,4-triazaphospholes are aromatic 6π-electron phosphorus heterocycles which show usually weak s-donor, but considerable π-donor properties.[1,2] In 1984, Regitz et al. demonstrated that these phosphorus derivatives of triazoles could be obtained in a regioselective way by a 1,3-dipolar cycloaddition reaction starting from organic azides and phosphaalkynes.[3] Herein, we report on the synthesis of novel polydentate triazaphospholes which are suitable to perform coordination reactions with several transition-metal precursors.[4]
We could show that benzyl- and pyridyl-based azides underwent facile [3+2]-cycloaddtion reactions with SiMe3-, tBu-, Mes*-substituted phosphaalkynes under formation of the triazaphospholes. These unprecedented derivatives have been characterized spectroscopically and, in the cases of 2, 3 and 5, structural information could be obtained by means of X-ray crystallography. First coordination experiments with Cu(I)-precursors were performed and have shown a rare coordination via the phosphorus atom for the chelating P,N‑hybrid ligand 4. Up to this point only one other example is known in literature where a P-coordination could be achieved.[5]
References:
[1] (a) L. Nyulászi, T. Vesprémi, J. Réffy, B. Burkhardt, M. Regitz, J. Am. Chem. Soc. 1992, 114, 9080−9084. (b) L. Nyulászi, Chem. Rev. 2001, 101, 1229−1246.
[2] (a) J. A. W. Sklorz, S. Hoof, M. G. Sommer, F. Weißer, M. Weber, J. Wiecko, B. Sarkar, C. Müller, Organometallics 2014, 33, 511−516. (b) C. Müller, J. A. W. Sklorz, I. de Krom, A. Loibl, M. Habicht, M. Bruce, G. Pfeifer, J. Wiecko, Chem. Lett. 2014, 43, 1390–1404.
[3] W. Rösch, M. Regitz, Angew. Chem., Int. Ed. 1984, 23, 900.
[4] J. A. W. Sklorz, S. Hoof, N. Rades, N. De Rycke, L. Könczöl, D. Szieberth, M. Weber, J. Wiecko, L. Nyulászi, M. Hissler, C. Müller, Chem. Eur. J. 2015, 21, 11096-11109.
[5] S. L. Choong, C. Jones, A. Stasch, Dalton. Trans. 2010, 39, 5774–5776.
P - Advanced synthesis and characterization , P - General aspects of inorganic chemistry
