Several salicylatocopper(II) complexes with diethylnicotinamide: Preparation, structure, spectral properties and Hirshfeld surface analysis

Abstract The little change of the reaction conditions led to formation four monomeric copper (II) complexes of different hydrate formula [Cu(XSal) 2 (dena) 2 (H 2 O) x ] (where x = 0 for XSal = 3,5-dichlorosalicylate; x = 1 for XSal = 5-methylsalicylate or x = 2 for XSal = 4-chlorosalicylate resp. 3,5-dichlorosalicylate; dena = N,N-diethylnicotinamide) and two anhydrous polymeric complexes [Cu(XSal) 2 (dena) 2 ] n (where XSal = 5-bromosalicylate or XSal = 4-methoxysalicylate). The monomeric complexes build up 1D chains and/or 2D supramolecular network. The polymeric ones constitute 1D coordination polymers. The intermolecular interactions were studied by Hirshfeld surface analysis. Four different coordination modes of anion were observed in compounds and they are in good relation to their spectral information. The EPR spectra of all the complexes were measured at room temperature. The g -factor values evaluated from the axially symmetric Cu(II) EPR spectra fulfilled an usual relation of g //  >  g ┴  > 2.0023, which is consistent with d x 2 - y 2 ground electronic state and which indicates the coordination sphere of the distorted tetragonal symmetry for copper (II) ions.