Photosensitized samarium(III) and erbium(III) complexes of planar N,N-donor heterocyclic bases: crystal structures and evaluation of biological activity

摘要: Samarium(III) and erbium(III) complexes, namely [Sm(dpq)(DMF)2(H2O)Cl3] (1), [Sm(dppz)(DMF)2(H2O)Cl3] (2), [Er(dpq)(DMF)2Cl3] (3) [Er(dppz)2Cl3] (4) (dipyrido[3,2-d:2′,3′-f]quinoxaline (dpq in 1 3), dipyrido[3,2-a:2′,3′-c]phenazine (dppz 2 4), N,N′-dimethylformamide (DMF) water (H2O)), have been synthesized structurally characterized. The X-ray crystal structures of complexes 1–4 show discrete mononuclear Ln(III)-based structures. Sm(III) (1) (2) adopts an eight-coordinated distorted square antiprism structure with a bidentate N,N-donor dpq/dppz ligand, three Cl− anions, two DMF molecules one molecule. Er(III) (4), seven-coordinated monocapped octahedral where is coordinated to anions. lattices the intermolecular π–π stacking interactions between planar dpq dppz ligands. Considering planarity photosensitizing ability ligands, were studied for their binding interaction DNA proteins photo-induced cleavage activity. They display significant propensity CT-DNA (Kb ∼ 104 M−1) order: 2, 4 (dppz) > 1, 3 (dpq). Complexes bind through groove partial intercalation. All also (KBSA 105 bovine serum albumin (BSA) protein. efficiently cleave supercoiled (SC) ds-DNA its nicked circular (NC) form upon exposure UV-A light 365 nm via formation singlet oxygen (1O2) hydroxyl radical (HO˙) as reactive species photoredox pathway.