Abstract
[Pd(FLU)
2
X
2
]·
y
H
2
O·
z
CH
3
OH (FLU = flubendazole; X = Cl (
1
),
y
= 0,
z
= 0; X = Br (
2
), NO
3
(
3
),
y
= 2,
z
= 0; X = SCN (
4
),
y
= 2,
z
= 3) were synthesized as potential anticancer complexes, and their structures were elucidated using elemental analysis, TG/DTA, IR,
1
H NMR, UV–vis., and conductivity measurements. FLU interacts with Pd(II) ions as a neutral unidentate ligand via the pyridine-type nitrogen of the benzimidazole ring. Geometry optimization, molecular electrostatic potential maps and natural bond orbital analysis were performed by DFT/B3LYP method. FLU, in comparison to its complexes, was screened for its antibacterial and cytotoxic activity. Complexes
1–4
possess strong anticancer activity with IC
50
values (4.13–3.68 μg ml
−1
) compared with 3.57 μg ml
−1
reported for cis-platin. The cytotoxicity was shown to be affected by the nature of the anion, where the sequence is
3
>
2
>
4
>
1
in case of MCF7 cell line. Structural-activity relationships suggested that
E
HOMO
, energy gap and dipole moment were the most significant descriptors for the correlation with the antitumor activity.