3,3-Bis(3,5-dimethylpyrazol-1-yl)propionic acid: A tripodal N,N,O ligand for manganese and rhenium complexes – Syntheses and structures

The tripodal N,N,O ligands 3,3-bis(3,5-dimethylpyrazol-1-yl)propionic acid (Hbdmpzp) (1) and 3,3-bis(pyrazol-1-yl)propionic acid (Hbpzp) (2) form the “missing link” between the well-known bis(pyrazol-1-yl)acetic acids and related ligands with a longer “carboxylate arm”. To illustrate the reactivity of this ligand, manganese and rhenium complexes bearing the ligand bdmpzp are reported. The complexes are compared to related compounds bearing other tripod ligands such as bis(3,5-dimethylpyrazol-1-yl)acetate (bdmpza) and 3,3-bis(1-methylimidazol-2-yl)propionate (bmip). Spectroscopic and structural data are used as a basis for comparison, as well as DFT calculations. Both ligands 1 and 2 and the complexes fac-[Mn(bdmpzp)(CO)3] (3) and fac-[Re(bdmpzp)(CO)3] (4) were characterised by X-ray crystallography.

Graphical abstractThe N,N,O ligand 3,3-bis(3,5-dimethylpyrazol-1-yl)propionic acid forms the “missing link” between the well-known bis(pyrazol-1-yl)acetic acids and related ligands with a longer “carboxylate arm”. New manganese and rhenium complexes bearing this ligand were synthesised to elucidate the reactivity of this ligand. Its coordination properties are discussed by means of spectroscopic and structural data and by DFT calculations.Figure optionsDownload full-size imageDownload as PowerPoint slide