DNA-like nanoarchitectonics and hypersensitivity to dioxygen of supermolecules of vitamin B12 nucleotide-free analogue.

Recently, we have described the first supermolecular nanoentities of vitamin B12 analogues, i.e., monocyano forms of heptabutyl cobyrinate, which are unique nanoparticles with emerging optical and catalytic properties and rapid response to gaseous toxins highly dangerous to humans. However, the following questions remain: why do all the studied properties change dramatically in supermolecules, and can their structures provide an answer to this question? Herein, we present the first evidence obtained from X-ray diffraction analysis of supermolecules of organometallic compounds. They were created by a nanoarchitectonic approach using directed self-assembly of vitamin B12 derivatives in layers at the air-water interface in a confined space at the nanolevel. The Bragg peaks indicated that two types of supermolecular structures can be formed in Langmuir-Schaefer (LS) films: molecular stacks twisted into a circular helix and supercoiled ones. They were stabilized by interactions similar to those in DNA-stacking, hydrogen bonds, and hydrophobic interactions. The advantages of the supermolecules as an active layer of ITO electrodes were demonstrated. They exhibited hypersensitivity to dioxygen (ca. 1 μM), exceeding that of drop-coating films and earlier prepared corrin-based sensors (ca. tenfold). ITO glass substrates with immobilized LS films consisting of a single supermolecular layer are recommended for use as a highly sensitive nanomaterial in medical and industrial testing systems for sensing dissolved O2 in aqueous solutions, including biological liquids.