Synthesis of Diferrocenyl Hydrazone–Enone Receptor Molecules – Electronic Communication, Metal Binding, and DFT Study

Abstract

Four new diferrocenyl hydrazone–enone compounds were obtained through a two-step reaction process involving 1,1′-diacetylferrocene, hydrazides, and ferrocenecarboxaldehyde. The structural characterization of two compounds, 6 and 7, through single-crystal X-ray diffraction showed the presence of a stable eclipsed conformation with the two ferrocenyl moieties oriented in trans geometries. The electrochemical and metal-ion sensing properties of the diferrocenyl-bifunctionalized compounds were explored to understand their potential in electronic communication and as receptor molecules. Compounds 1,1′-[(η5-C5H5)Fe(η5-C5H4)CH=CHC(O)(η5-C5H4)Fe{(η5-C5H4)C(CH3)=N–N(H)C(O)–R}] [R = C6H4OH (6), C6H4N-p (7)], showed selective interactions with Pb2+ cations and distinct binding interactions with bovine serum albumin (BSA) protein. The mode of the metal–receptor interaction was established through DFT studies. The redox properties of the diferrocenyl compounds with variable end groups revealed distinct electronic communication between the two electroactive groups. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim