Modulation of Electronic Communication between Two Equivalent Ferrocenyl Groups Mediated Through Tricarbonylcyclobutadieneiron

Abstract

Three sets of 1,3- and 1,2- derivatives of tricarbonylcyclobutadieneiron, [Fe(CO)3-η4-CbFc2R2] [Cb =cyclobutadiene, Fc = ferrocenyl, R = –CHO: 1a (1,3-isomer), 1b (1,2-isomer); R = –CHNOH: 2a (1,3-isomer), 2b (1,2-isomer); R = –CN: 3a (1,3-isomer), 3b (1,2-isomer)] have been synthesized under facile reaction conditions starting from FcC≡C-CHO and Fe(CO)5. Effect of changing electronic nature of tricarbonylcyclobutadieneiron, arising from substituent variation and their relative position, has been correlated with the extent of electronic communication between two ferrocenyl groups by cyclic voltammetry and differential pulse voltammetry studies and also supported by density functional calculations. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim