Synthesis, structural studies, and oxidation catalysis of the manganese(II), iron(II), and copper(II) complexes of a 2-pyridylmethyl pendant armed side-bridged cyclam

Shircliff, Anthony D.; Wilson, Kevin R.; Cannon-Smith, Desiray J.; Jones, Donald G.; Zhang, Zhan; Chen, Zhuqi; Yin, Guochuan; Prior, Timothy J.; Hubin, Timothy J.

Abstract

Abstract The first 2-pyridylmethyl pendant armed structurally reinforced cyclam ligand has been synthesized and successfully complexed to Mn^{2 +}, Fe^{2 +}, and Cu^{2 +} cations. X-ray crystal structures were obtained for the diprotonated ligand and its Cu^{2 +} complex demonstrating pentadentate binding of the ligand with trans-II configuration of the side-bridged cyclam ring, leaving a potential labile binding site cis to the pyridine donor for interaction of the complex with oxidants and/or substrates. The electronic properties of these complexes were determined by means of solid state magnetic moment, with a low value of μ = 3.10 μ<inf>B</inf> for the Fe^{2 +} complex suggesting that it has a trigonal bipyramidal coordination geometry, matching the crystal structure of the Cu^{2 +} complex, while the μ = 5.52 μ<inf>B</inf> value for the Mn^{2 +} complex suggests that it is high spin octahedral. Cyclic voltammetry in acetonitrile revealed reversible redox processes in all three complexes, suggesting that catalytic reactivity involving electron transfer processes are possible for these complexes. Screening for oxidation catalysis using hydrogen peroxide as the terminal oxidant identified the Fe^{2 +} complex as the oxidation catalysts most worthy of continued development.

Citation

Shircliff, A. D., Wilson, K. R., Cannon-Smith, D. J., Jones, D. G., Zhang, Z., Chen, Z., Yin, G., Prior, T. J., & Hubin, T. J. (2015). Synthesis, structural studies, and oxidation catalysis of the manganese(II), iron(II), and copper(II) complexes of a 2-pyridylmethyl pendant armed side-bridged cyclam. Inorganic Chemistry Communications, 59, 71-75. https://doi.org/10.1016/j.inoche.2015.07.002

• Journal Article Type: Article
• Acceptance Date: Jul 5, 2015
• Online Publication Date: Jul 11, 2015
• Publication Date: 2015-09
• Deposit Date: Apr 1, 2022
• Journal: Inorganic Chemistry Communications
• Print ISSN: 1387-7003
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 59
• Pages: 71-75
• DOI: https://doi.org/10.1016/j.inoche.2015.07.002
• Keywords: Structurally reinforced cyclam; Side-bridged cyclam; Pendant-arm macrocycle; Oxidation catalysis; 2-Pyridylmethyl
• Public URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937565435&doi=10.1016%2fj.inoche.2015.07.002&partnerID=40&md5=212532c0a8db1bb843f644da840e7bf9