The syntheses of the two dicarbonyl complexes [Ru(bdmpza)Cl(CO)2] (3) and [Ru(2,2-bdmpzp)Cl(CO)2] (4), bearing a bis(3,5-dimethylpyrazol-1-yl)acetato (bdmpza) or a 2,2-bis(3,5-dimethylpyrazol-1-yl)propionato (2,2-bdmpzp) scorpionate ligand, are described. Both complexes are obtained by reacting the polymer [RuCl2(CO)2]n with either K[bdmpza] or K[2,2-bdmpzp]. Reaction of the acid Hbdmpza with [Ru3(CO)12] results in the formation of two structural isomers of a hydrido complex, [Ru(bdmpza)H(CO)2] (5a,b). Under aerobic conditions conversion of [Ru(bdmpza)H(CO)2] (5a,b) to form the Ru(I) dimer [Ru(bdmpza)(CO)(μ-CO)]2 (6) seems to be hindered in comparison to the case for the η5-C5H5 (Cp) analogues. Dimer 6 is obtained via a reaction of Hbdmpza with catena-[Ru(OAc)(CO)2]n instead. The molecular structures of 3, 4, and 6 have been obtained by single-crystal X-ray structure determinations. The precatalytic properties of the two dicarbonyl complexes 3 and 4 toward the catalytic oxidation of cyclohexene with different oxidizing agents are discussed as well.

The new N,N,O ligand 2,2-bis(3,5-dimethylpyrazol-1-yl)propionic acid (2,2-Hbdmpzp) (2) and its transition metal complexes [Mn(2,2-bdmpzp)(CO)3] (3), [Re(2,2-bdmpzp)(CO)3] (4), [Cu(2,2-bdmpzp)2] (5), and [Ru(2,2-bdmpzp)Cl(L)(PPh3)] [L = PPh3 (6), N2 (7), CO (8a/b), SO2 (9a/b)] have been synthesized, characterized and compared to analogous complexes bearing a bis(3,5-dimethylpyrazol-1-yl)acetic acid. It was found that the additional methyl group has a remarkable influence on the stability and reactivity of transition metal complexes.

One-pot syntheses of three new enantiopure heteroscorpionate ligands derived from (+)-camphor or (−)-menthone are described. The ligands are obtained by reacting pyrazoles derived from (+)-camphor or (−)-menthone with sodium hydride and thionyl chloride. Subsequent reactions with pyridine and various aldehydes afford the tripod ligands in multi-gram amounts. Especially the menthopyrazole based ligand 6 showed encouraging ee values up to 69% in the Cu(I) catalysed enantioselective cyclopropanation of styrene with ethyl diazoacetate.

Reductive S–S bond cleavage of a disulfide precursor 3 obtained from a pyridine-catalyzed Peterson-type reaction starting from camphorpyrazole 1, thionyl chloride and 2-methyl-2-(methyldithio)propionaldehyde yields 2,2′-bis(camphorpyrazol-1-yl)-2-methylpropane-2-thiol (HSiprbpm3cam, 4); the first zinc complexes bearing this ligand exhibit κ3 coordination of the ligand.

One-pot syntheses of three new enantiopure heteroscorpionate ligands derived from (+)-camphor or (−)-menthone are described. The ligands are obtained by reacting pyrazoles derived from (+)-camphor or (−)-menthone with sodium hydride and thionyl chloride. Subsequent reactions with pyridine and various aldehydes afford the tripod ligands in multi-gram amounts. Especially the menthopyrazole based ligand 6 showed encouraging ee values up to 69% in the Cu(I) catalysed enantioselective cyclopropanation of styrene with ethyl diazoacetate.

Reductive S–S bond cleavage of a disulfide precursor 3 obtained from a pyridine-catalyzed Peterson-type reaction starting from camphorpyrazole 1, thionyl chloride and 2-methyl-2-(methyldithio)propionaldehyde yields 2,2′-bis(camphorpyrazol-1-yl)-2-methylpropane-2-thiol (HSiprbpm3cam, 4); the first zinc complexes bearing this ligand exhibit κ3 coordination of the ligand.

The new N,N,O ligand 2,2-bis(3,5-dimethylpyrazol-1-yl)propionic acid (2,2-Hbdmpzp) (2) and its transition metal complexes [Mn(2,2-bdmpzp)(CO)3] (3), [Re(2,2-bdmpzp)(CO)3] (4), [Cu(2,2-bdmpzp)2] (5), and [Ru(2,2-bdmpzp)Cl(L)(PPh3)] [L = PPh3 (6), N2 (7), CO (8a/b), SO2 (9a/b)] have been synthesized, characterized and compared to analogous complexes bearing a bis(3,5-dimethylpyrazol-1-yl)acetic acid. It was found that the additional methyl group has a remarkable influence on the stability and reactivity of transition metal complexes.