Synthesis and spectroscopic characterization of cobalt(III)-alkyl amine complexes showing surface affinity: Single crystal X-ray structure determinations

Structurally integrated cobalt(III) complexes showing interesting surface affinity in the interfacial electron transfer reactions were synthesized by incorporating alkyl amines into the coordination sphere of cis-[CoIII(en)2(RNH2)Cl]Cl2; (where RNH2 = MeNH2 (1), EtNH2 (2), PrnNH2 (3), BunNH2 (4), BuiNH2 (5), PennNH2 (6), HexnNH2 (7) and BzNH2 (8)) through a modified synthetic route. Such complexes are playing important role as electron acceptors in the interfacial electron transfer reactions taking place between metal complex and nanosized semiconductor particles in energy conversion schemes. The complexes were characterized by spectral, 1H NMR and 13C NMR techniques, which indicate the 1,2-diamino ethane site angles are closely similar forming five membered gauche configuration. Single crystal X-ray refinements were made to explore the structures of five complexes (2)–(5) and (7). The complexes under study crystallize either in monoclinic or orthorhombic structure and the space consists; (2) P21/n, (3) P212121, (4) Pbca, (5) P21 and (7) P21/n. The Co(III) ion does not have an electronic preference, however, the structures reflect the conformational preference of RNH2 ligand.

► Synthesis of cobalt(III)-alkyl amine complexes showing surface affinity. ► Single crystal X-ray structure refinement of cobalt(III) complexes. ► Electron acceptor complexes for interfacial electron transfer reactions. ► Structural features of complexes can imply their surface affinity.