First iron and cobalt(ii) hexabromoclathrochelates: structural, magnetic, redox, and electrocatalytic behavior?

Dalton Transactions Pub Date: 2015-01-05 DOI: 10.1039/C4DT03082F

Abstract

Template condensation of dibromoglyoxime with n-butylboronic acid on the corresponding metal ion as a matrix under vigorous reaction conditions afforded iron and cobalt(II) hexabromoclathrochelates. The paramagnetic cobalt clathrochelate was found to be a low-spin complex at temperatures below 100 K, with a gradual increase in the effective magnetic moment at higher temperatures due to the temperature 1/2?3/2 spin crossover and a gap caused by the structure phase transition. The multitemperature X-ray and DSC studies of this complex and its iron(II)-containing analog also showed temperature structural transitions. The variation of an encapsulated metal ion's radius, electronic structure and spin state caused substantial differences in the geometry of its coordination polyhedron; these differences increase with the decrease in temperature due to Jahn–Teller distortion of the encapsulated cobalt(II) ion with an electronic configuration d7. As follows from CV and GC data, these cage iron and cobalt complexes undergo both oxidation and reduction quasireversibly, and showed an electrocatalytic activity for hydrogen production in different producing systems.

Graphical abstract: First iron and cobalt(ii) hexabromoclathrochelates: structural, magnetic, redox, and electrocatalytic behavior
Recommended Literature