“…To this end, we have designed novel derivatives of nitrogen-chelating pyrazolyl–pyridine ligands with CC (L′) and CN (L) junctions, to study their in vitro individual anticancer activities with particular emphasis on their complexes of Co, Fe, Ni, and Mn. This led us to prepare diethyl 2,2′-(pyridine-2,6-diylbis(5-methyl-1 H -pyrazole-3,1-diyl)) diacetate (L′) 30 and diethyl 1,1′-(pyridine-2,6-diyl) bis(5-methyl-1 H -pyrazole-3-carboxylate) (L) ( Scheme 1 ). Metal complexes [CoL 2 ](ClO 4 ) 2 (1), [FeL 2 ](ClO 4 ) 2 (2), [NiL 2 ](ClO 4 ) 2 (3), [MnLCl 2 ] (4), [MnL′Cl 2 ] (1′) and [CdL′Cl 2 ] (2′) were also investigated.…”