Design, XRD/HSA-interactions, spectral, thermal, Solvatochromism and DNA-binding of two [Cu(phen)(triene)]Br2 complexes: Experimental and DFT/TD-DFT investigations

Abstract Two dicationic Cu(II) complexes of [Cu(phen)(NNN)]Br2 (1-2) general formula [phen = 1,10-phenanthroline, NNN = diethelenetriamine (dien) (1) and dipropylenetriamine (dipn)(2)], have been synthesized in very good yields. The two complexes were characterized via UV-vis., CHN-EA, MS, FT-IR, thermal, and X-ray crystallographic techniques. XRD data for 1 showed a distorted square pyramidal Cu(II) ions geometry center with three uncoordinated water molecules. TGA were performed to evaluate the interactions strength and found to support the XRD molecular interactions results. The time-dependent density functional theory (TD-DFT) and electron transfer processes were modeled, and consequently the absorption maxima around 610 and 280 nm were attributed to d–d and Phen(π)→Phen(π٭) transitions. Positive Gutmann's solvatochromism behavior of both complexes have been recorded. Furthermore, the ability of the two complexes for DNA binding was evaluated via absorption studies in the visible region showing high Kb constant values.