Exploring the electrical and biological aspects of newly synthesized samarium-based macrocyclic complexes with Isatin ligand and it′s derivatives

Herein, the electrochemical, luminescent and potential biological properties of a newly synthesized series of macrocyclic complexes of samarium(III) metal ion are described. Macrocycles, Schiff bases and their complexes with metals display several structural and electronic features that allow their vast applications in diverse research fields especially, in medicinal science. The synthesis of luminescent and electrically active complexes containing (1E,15Z)-3,4,6,7,9,10,12,13,14,16-decahydro-2H-[1, 4, 7]trioxa [11, 14]diaza-cycloheptadecino[12, 13-b]indole scaffold is done via template route using isatin or its derivatives i.e., 5-chloroisatin and 5-bromoisatin, and 1,13-diamino-4,7,10-trioxatri-dacane ligand precursors in the presence of Sm(III)nitrate hexa-hydrate salt. The synthesized complexes are found thermally stable up to ~ 230^oC and after that started to decompose. The structural characterization is done by the ¹H-NMR, electrospray ionization mass, Fourier transform, and ultraviolet-visible spectroscopy. The proposed structure of these complexes was well-matched by the data. Crystalline nature of the reported complexes is confirmed by the existence of sharp narrow peaks in the X-ray diffraction (XRD). The complexes also found electrically active as the cyclic voltammetry conductivity measured by using DMSO solvent. The complexes displayed characteristic luminescence peaks of Sm(III) at ~ 563, ~602 & ~644 nm assigned to ⁴G_5/2 →⁶H_5/2, ⁴G_5/2→ ⁶H_7/2, ⁴G_5/2→ ⁶H_9/2 transitions respectively. The biological studies results indicate the remarkable potential of these complexes as antimicrobial and antioxidant agent which may lead the use of these complexes in pharmaceutical field.