An efficient palladium-catalyzed tandem amination approach was developed in one step to afford functionalized 4-quinolones in good to excellent yields from easily accessible o-haloaryl acetylenic ketones and primary amines.

Seven heptacoordinate titanium(IV) complexes were synthesized based on the concept of hetero-bis-chelate stabilization of salan (ONNO) and thiosalan (OSSO) titanium(IV)alkoxides with 2,6-pyridinedicarboxylic acid (dipic) and derivatives thereof. The resulting compounds were investigated in a solid by X-ray diffraction and in solution by NMR spectroscopy. A thiosalan (OSSO) titanium(IV) complex could be isolated and its conformational stabilization by dipic was shown by (1)H NMR spectroscopy to lead to nonfluxional behavior even at room temperature. The stability of selected complexes was assessed at pH 1.9, 6.8, and 12.1 by an UV-vis monitored hydrolysis study with >5 Mio. equivalents of water. Even at pH 12.1 [L(1)Ti(dipic)(1)] showed t1/2 of more than 2 days. The cytotoxicity of all compounds was investigated in two human carcinoma cell lines. IC50-values in the range of cisplatin were achieved by all tested compounds except for [L(4)Ti(dipic)(1)], which was proven to be nontoxic. The functionalization of dipic was thus well tolerated and did neither interfere with the stability nor the cytotoxicity of the heteroleptic complexes.

A simple and efficient palladium-catalyzed amidation-hydrolysis reaction has been developed to afford N-aryl monosubstituted carboxamides in good to excellent yields from easily accessible ketone-derived gem-dihaloolefins and aryl amines.

A series of novel sulfonamide substituted heteroleptic salan titanium(IV)-bis-chelates complexed to 2,6-pyridinedicarboxylic acid were synthesized, structurally characterized and evaluated for their anticancer activity against two human carcinoma cell lines. All cytotoxic complexes showed complete inhibition of cell growth at active concentration, two complexes based on pyrrolidine and azepane substituted sulfonamides displayed IC50 values below 1.7 μM and are more cytotoxic than cisplatin in both tested cell lines. The azepane substituted complex [L3Ti(dipic)] exhibited excellent activity with an IC50 value of 0.5 ± 0.1 μM in Hela S3 and 1.0 ± 0.1 μM in Hep G2.

Four novel bidentate phosphine-Pd complexes coordinated by NiN2S2 metallodithiolate ligands were synthesized and characterized, including XRD analysis; these redox-active complexes are stable in air, and they survive column chromatography on silica gel. The Ni–Pd bimetallic complexes are demonstrated to be precatalyst for Suzuki–Miyaura cross-coupling reactions. The best of these has an overall yield of over 99% under only 1% catalyst loading. The role of NiN2S2 as a stabilizing bidentate ligand that is also oxidizable may account for its efficacy in the support of the catalysis.