Triazaphospholes versus Triazoles: An Investigation of the Differences between “Click”-Derived Chelating Phosphorus- and Nitrogen-Containing Heterocycles

• Published in: Organometallics 2014-01, Vol.33 (2), p.511-516
• Main Authors: Sklorz, Julian A. W, Hoof, Santina, Sommer, Michael G, Weißer, Fritz, Weber, Manuela, Wiecko, Jelena, Sarkar, Biprajit, Müller, Christian
• Format: Article
• Language: English
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om4010077

A new class of pyridyl-functionalized triazaphospholes bearing either t Bu or SiMe3 substituents at the 5-position of the N3PC heterocycle have been prepared via the “click” reaction starting from 2-(azidomethyl)pyridine and the corresponding phosphaalkynes. In order to investigate the electronic structure and donor–acceptor properties of such novel chelating and low-coordinate phosphorus heterocycles, calculations at the DFT level have been carried out. Moreover, cyclic voltammetry measurements were performed and the results were compared with those for the structurally related triazole-based systems, demonstrating a significant influence of the phosphorus atom as well as the substitution pattern on the electronic properties of the novel compounds. The P,N hybrid ligands form Re(I) complexes of the type [(N∧ mN)Re(CO)3Br] via coordination of the nitrogen atom N2 to the metal center rather than via the phosphorus atom, as verified crystallographically.