Spectroelectrochemistry of alternating ambipolar copolymers of 4,4′- and 2,2′-bipyridine isomers and quaterthiophene

Abstract

of alternating ambipolar copolymers of 4,4 -and 2,2 -bipyridine isomers and quaterthiophene, Electrochimica Acta http://dx.doi.org/10. 1016/j.electacta.2017.01.076 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Functionalized 4,4′-Bipyridines: Synthesis and 2D Organization on Highly Oriented Pyrolytic Graphite

“…Compounds 2, 8, 9, 19, 22, and 24 were expected to be good candidates for surface patterning, keeping in mind that 4,4′-bipys are often used as connectors in 1D/2D/3D self-assembled molecular architectures. To confirm the ability of 2,2′ and 2,2′,6,6′ or 3,3′ functionalized 4,4′-bipys to physisorb and organize on surfaces into ordered supramolecular structures, scanning tunneling STM experiments revealed that 2,2′-substituted 4,4′-bipys (2, 8, 9) are more prone to self-assemble into ordered patterns than 3,3′-substituted bipys (19,22,24). As shown in Figure 3, compounds 2, 8, and 9 formed highly ordered 2D supramolecular assemblies stabilized via van der Waals interactions between the molecules and the underlying HOPG surface.…”

“…The nucleophilic addition of a Grignard reagent with a long alkyl chain (ClMgC 18 H 37 ) also failed, and these methods were not pursued any further. In a less direct synthesis inspired by work of Fürstner et al., a Kumada coupling reaction of 2,2′-dichloro-4,4′-bipyridine ( 1 ) with ClMgC 18 H 37 in the presence of 10 mol % Fe­(acac) 3 gave the dialkyl product 2 in 34% yield (Scheme ). In addition, 4,4′-bipy, resulting from dehalogenation, was recovered in 10% yield from a mixture containing other side products.…”

“…Compounds 1 , 5 , 10 , 14 , and 15 were prepared according to literature procedures. Octadecylmagnesium chloride solution (0.5 M in THF) was purchased from Aldrich (394262).…”

“…An octadecyl-magnesium chloride solution (20 mL, 10 mmol, 0.5 mol/L) was added to 2,2′-dichloro-4,4′-bipyridine 1 (0.5 g, 2.22 mmol) and tris­(acetylacetonato)­iron­(III) (78 mg, 0.22 mmol) in degassed THF (60 mL) at 0 °C. The orange mixture immediately became dark purple.…”

“…18 Two functional groups can be efficiently added by first activating the 2,2′ positions of 4,4′-bipy. N-Oxides have proven to be useful intermediates to introduce chloro 19 or nitrile groups. 20 In addition, fluoride activation using acetyl hypofluorite 21 leads to the addition of two acetoxy groups to 4,4′-bipy in excellent yield.…”