title: Long-range intramolecular electronic communication in bis(ferrocenylethynyl) complexes incorporating conjugated heterocyclic spacers: synthesis, crystallography, and electrochemistry.
abstract: A new series of bis(ferrocenylethynyl) complexes, 3-7, and a mono(ferrocenylethynyl) complex, 8, have been synthesized incorporating conjugated heterocyclic spacer groups, with the ethynyl group facilitating an effective long-range intramolecular interaction. The complexes were characterized by NMR, IR, and UV-vis spectroscopy as well as X-ray crystallography. The redox properties of these complexes were investigated using cyclic voltammetry and spectroelectrochemistry. Although there is a large separation of ∼14 Å between the two redox centers, ΔE(1/2) values in this series of complexes ranged from 50 to 110 mV. The appearance of intervalance charge-transfer bands in the UV-vis-near-IR region for the monocationic complexes further confirmed effective intramolecular electronic communication. Computational studies are presented that show the degree of delocalization across the Fc-C≡C-C≡C-Fc (Fc = C5H5FeC5H4) highest occupied molecular orbital.
authors.affiliation: Department of Chemistry, Sultan Qaboos University, P.O. Box 36, Al-Khodh 123, Sultanate of Oman.
authors.forename: Hakikulla H
authors.initials: HH
authors.lastname: Shah
authors.forename: Rayya A
authors.initials: RA
authors.lastname: Al-Balushi
authors.forename: Mohammed K
authors.initials: MK
authors.lastname: Al-Suti
authors.forename: Muhammad S
authors.initials: MS
authors.lastname: Khan
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Woodall
authors.forename: Kieran C
authors.initials: KC
authors.lastname: Molloy
authors.forename: Paul R
authors.initials: PR
authors.lastname: Raithby
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Robinson
authors.forename: Sara E C
authors.initials: SE
authors.lastname: Dale
authors.forename: Frank
authors.initials: F
authors.lastname: Marken