Synthesis, spectroscopic and structural characterization of bis[N,N′-3-azapentane-1,5-diyl-bis(salicylideneiminato)]-dicobalt(III)

•The distance between Co3 + ions in [Co2(salen)2] could be interpreted as a single Co–Co σ bond.•UV-Vis/IR spectra features of [Co2(salen)2].2DMSO reflect the Co(III) coordination.•NMR spectra of [Co2(salen)2].2DMSO show the long-range coupling.•ESR and NMR spectra are consistent with low-spin configuration for Co3+ in agreement with the X-ray structure.•The optical refractive index of a DMSO solution of [Co2(salen)2].2DMSO is modified by light absorption.

In this work, we explore the synthesis, spectroscopic and structural characterization of a robust neutral homodinuclear Co(III) complex, namely bis[N,N′-3-azapentane-1,5-diyl-bis(salicylideneiminato)]-dicobalt(III), which was crystallized as a dimethyl sulfoxide disolvate. The main ligand is a derivative of the double Schiff base N1,N3-bis(salicylideneimino)diethylenetriamine, H3salen. Compound [Co2(salen)2]·2DMSO was synthesized by direct synthesis, and its composition and identity were inferred from mass spectrum (FAB +), FT-IR, UV–Vis, and NMR spectroscopy. Single crystal X-ray diffraction indicates that each anion (salen)3 − behaves as a pentadentate ligand, with the central N atom bridging the metal centers. As a result, the local geometry of the cobalt ions is close to octahedral, and the metal…metal separation is rather short, 2.8541(8) Å. We also studied linear and nonlinear optical properties of this compound, and the results of Z-scan measurements are discussed.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide