Rearrangements of Metastable Micelles to Different Molecular Bilayers on Planar Graphite, Mica, Silicon, and Hydrocarbon Surfaces

Abstract

Bis(2,2‘-bipyridyl)(dihexadecyl-2-[2,2‘-dipyridylmethylene] malonate) ruthenium(II) dihexafluorophosphate, 1, formed multilayered micelles (denoted C16-micelles) upon sonication of aqueous suspensions. The C16-micelles collapsed upon transfer to gold, mica, and silicon surfaces and rearranged to planar bilayers. These bilayers appeared in different arrangements under the atomic force microscope. On graphite, the ruthenium headgroups and the alkyl chains lay flat and were both in direct contact with the substrate. On mica and silicon wafers, upright-standing interdigitated bilayers were found exclusively. Self-assembly of a dodecylsilane layer containing cracks on the silicon surface induced the formation of irregular double and triple layers of 1. Bulk polyethylene or octadecylthiol layers on gold with smooth surfaces did not disrupt the micelles. C18- and C22-micelles made of the corresponding homologues of 1 were much more stable on most surfaces, C14-micelles were destroyed on all surfaces. The variability of micelle−substrate interactions is discussed qualitatively.

Porphyrinphosphonate Fibers on Mica and Molecular Rows on Graphite

“…No disruption of the fibers and no trace of mono-or bilayer formation were detected. 26 Highly curved micelles of octadecylkanamycinamide were also stable on hydrophobic HOPG and hydrophilic oxidized carbon grids. 26 The interactions between the porphyrins in fibers and of the porphyrin monolayers with mica are obviously dominated by exceedingly strong interactions between strongly hydrated phosphonate groups.…”

Functionalisation of bolaamphiphiles with mononuclear bis(2,2′-bipyridyl)ruthenium(ii) complexes for application in self assembled monolayers

“…The chloroform fractions were combined, dried over magnesium sulphate and evaporated in vacuo to give 2.2 g (86%) of (iii) as a yellow waxy solid. 1 2´] Bipyridinyl-5-carbonyl)-amino]-ethylcarbamoyl}-tridec-12-enoic acid benzyl ester (v) 0.9 g (2 mmol) of the lipid ester (iv) and 0.49 g (1 eq) of the bipyridyl amine (iii) were dissolved in 20 cm 3 of choroform/methanol (1:1) and stirred at room temperature overnight. After removal of the solvent under reduced pressure, the remainder was partitioned between aqueous HCl and chloroform.…”

“…147-150ºC. 1 69 (d, 1H, pyH3), 9.04 (s, 1H, pyH6 After stirring overnight at room temperature, the solvent was removed in vacuo. The residue was taken up in dil.…”

“…[1][2][3][4] The exact nature of the assembly formed is dependent not only on the lipid but also on the conditions employed. Controlling the length of the chain, the nature of the head groups and the environment in which they are to be studied, allows for the formation of highly organised assemblies.…”

“…1 Instrumentation 1 H NMR spectra were recorded on a Perkin Elmer AC250 (250MHz) or a Bruker AC400 (400MHz) NMR Spectrometer. All measurements were carried out in (CD 3 ) 2 SO for ligands and CD 3 CN or (CD 3 ) 2 CO for complexes.…”