ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Dicobaloxime/organodicobaloximes bridged by different axial groups: synthesis, characterization, spectroscopy, and catalysis

Ahmet Kilic, Hamza Fırat, Emine Aytar, Mustafa Durgun, Aysegul Kutluay Baytak, Mehmet Aslanoglu, and Mahmut Ulusoy

Department of Chemistry, Faculty of Arts and Sciences, Harran University, Şanlıurfa, Turkey

E-mail: kilica63@harran.edu.tr

Abstract: In this study, the various ligands axially coordinated to two cobalt center bound to the N₄-oxime core in 12 new dicobaloxime/organodicobaloxime (1–12) complexes have been synthesized and characterized by NMR (¹H and ¹³C), UV–Visible, FT-IR, LC–MS, molar conductivity analysis, melting point, and magnetic susceptibility experiments with elemental analysis. These spectroscopic results indicate that the formation of new dicobaloxime/organodicobaloxime (1–12) complexes. The (C=N–OH) peaks disappeared in the ¹H-NMR spectrum of dicobaloxime/organodicobaloxime (1–12) complexes, while new peaks were observed at range 20.18–18.33 ppm, indicating that the groups of ligands have been transformed to intramolecular H-bridge (O–H⋯O). The dicobaloxime (1–6) species give a better cyclic voltammogram as compared to its organodicobaloxime derivatives (7–12) due to cyclic voltammograms of the organodicobaloximes (7–12) were poor. This is possibly due to the enhanced σ donation by R groups in the organocobaloximes which are substantially stabilized. The organodicobaloxime (10) showed much better catalytic activity compared to the other cobaoxime complexes.

Keywords: Co(III) complexes; Dicobaloxime; Organodicobaloxime; Cyclic voltammetry; Cyclic carbonates; CO₂ fixation; Reaction parameters

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-017-0165-0

Chemical Papers 71 (9) 1705–1720 (2017)