Ferrocenylimines of general formula [Fe(η⁵-C₅H₅)(η⁵-C₅H₄CRNR′)](R = Me, R′= Ph 1a, C₆H₄Me-2 1b, C₆H₄Me-4 1c, CH₂Ph 1d, CH₂C₆H₄Me-2 1e, CH₂C₆H₄Cl-2 1f, CH₂CH₂Ph 1g or 1-C₁₀H₇1h; R = H, R′= Ph 1i, C₆H₄Me-2 1j, C₆H₄Me-4 1k, CH₂C₆H₄Me-2 1l, CH₂C₆H₄Cl-2 1m or 1-C₁₀H₇1n) have been prepared and characterized. Addition of these ligands to methanolic solutions of Na₂[PdCl₄], and sodium acetate trihydrate in a 1 : 1 molar ratio, results in the formation of the di-µ-chloro bridged cyclopalladated complex [{[graphic omitted]R′)](µ-Cl)}₂]2a–2n. Reaction of compounds 2a–2n with triphenylphosphine in benzene yields more soluble monocyclopalladated derivatives [[graphic omitted]R′)}Cl(PPh₃)]3a–3n. Proton, ¹³C and ³¹P NMR spectroscopic studies on these complexes reveal that cyclopalladation occurs on the ferrocenyl moiety, thus producing five-membered metallacycles containing the CN bond (endo-type structures). The crystal structures of compounds 1a, 1i and 3g have been determined. Complex 1a is triclinic, space group P with a= 10.152(3), b= 12.169(3), c= 12.239(3)Å, α= 90.45(2), β= 100.56(2) and γ= 102.72(2)°. Compound 1i is monoclinic, space group Cc, with a= 5.876(3), b= 37.298(9), c= 12.640(4)Å and β= 103.26(4)°. The complex [[graphic omitted]CH₂CH₂Ph)}Cl(PPh₃)]·CH₂Cl₂3g is monoclinic, space group P2₁/n with a= 20.343(2), b= 9.133(1), c= 19.714(2)Å and β= 97.17(1)°, and its crystal structure confirms the formation of a five-membered palladocycle fused with the ferrocenyl moiety. The influence of the substituents R (H or Me) and R′ upon the spectroscopic and structural properties of the free ligands and the cyclopalladated complexes is also discussed.

The study of the reactivity of three 1-(2-dimethylaminoethyl)-1H-pyrazole derivatives of general formula [1-(CH(2))(2)NMe(2)}-3,5-R(2)-pzol] {where pzol represents pyrazole and R=H (1a), Me (1b) or Ph (1c)} with [MCl(2)(DMSO)(2)] (M=Pt or Pd) under different experimental conditions allowed us to isolate and characterize cis-[M{κ(2)-N,N'-{[1-(CH(2))(2)NMe(2)}-3,5-R(2)-pzol])}Cl(2)] {MM=PtPt (2a-2c) or Pd (3a-3c)} and two cyclometallated complexes [M{κ(3)-C,N,N'-{[1-(CH(2))(2)NMe(2)}-3-(C(5)H(4))-5-Ph-pzol])}Cl] {M=Pt(II) (4c) or Pd(II) (5c)}. Compounds 4c and 5c arise from the orthometallation of the 3-phenyl ring of ligand 1c. Complex 2a has been further characterized by X-ray crystallography. Ligands and complexes were evaluated for their in vitro antimalarial against Plasmodium falciparum and cytotoxic activities against lung (A549) and breast (MDA MB231 and MCF7) cancer cellular lines. Complexes 2a-2c and 5c exhibited only moderate antimalarial activities against two P. falciparum strains (3D7 and W2). Interestingly, cytotoxicity assays revealed that the platinacycle 4c exhibits a higher toxicity than cisplatin in the three human cell lines and that the complex 2a presents a remarkable cytotoxicity and selectivity in lung (IC(50)=3 μM) versus breast cancer cell lines (IC(50)>20 μM). Thus, complexes 2c and 4c appear to be promising leads, creating a novel family of anticancer agents. Electrophoretic DNA migration studies in presence of the synthesized compounds have been performed, in order to get further insights into their mechanism of action.

Reactions of ferrocenylimines of general formula [Fe(η⁵-C₅H₅){η⁵-C₅H₄CHN(CH₂)_nPh}](n= 1 1a or 2 1b) with palladium(II) salts have been studied. The dimeric cyclopalladated complexes [{[graphic omitted](CH₂)_nPh}]Cl}₂]2a and 2b were obtained when the reactions were carried out in the presence of sodium acetate and using Na₂[PdCl₄] as starting material. Addition of phosphine ligands PR₃(R = Ph or Et) or 1,2-bis(diphenylphosphino)ethane (dppe) to acetone suspensions of these dinuclear compounds produced the more soluble mononuclear complexes [[graphic omitted](CH₂)_nPh]}Cl(PR₃)] with R = Ph (3a and 3b) and Et (4a and 4b) and [[graphic omitted](CH₂)_nPh]}(dppe)]Cl (5a and 5b). Proton and ³¹P NMR spectroscopic studies on these compounds confirm the formations of endo five-membered metallocycles. Mössbauer spectra of compounds 1b–5b have also been recorded. The first crystal structure of a cyclopalladated complex derived from ferrocenylimines has been determined. The compound [[graphic omitted]CH₂CH₂Ph)}Cl(PEt₃)]4b is monoclinic, space group P2₁/a, with a= 15.944(3), b= 12.425(2), c= 12.682(2)Å, β= 100.19(2)° and Z= 4. The structure confirms the formation of an endo five-membered metallocycle on the ferrocene moiety.