B12tasot

B12tasot is a fictional cobalt-containing organometallic complex described in speculative chemistry and science fiction as an analogue of vitamin B12. The name combines the real B12 motif with a hypothetical class of ligands called tasots, invoked to explore how axial ligands might influence reactivity in cobalt centers.

In the imagined structure, B12tasot centers on a cobalt ion coordinated by a corrin-like macrocycle similar to cobalamin, with an axial tasot ligand and optional co-ligands. The tasot group is described as tuning redox properties and stabilizing key organometallic intermediates, enabling uncommon bond-forming steps while preserving a B12-like electronic framework.

The fictional synthesis of B12tasot involves metallation of a preformed corrin precursor with cobalt(II), followed by introduction of the tasot ligand through sulfur- or phosphorus-based linkers. Reduction to a lower oxidation state such as Co(I) is described as a prerequisite for enabling methyl transfer and other nucleophilic attack steps central to the proposed reactivity.

Proposed reactivity includes reversible methyl transfer between B12tasot and organic or inorganic acceptors, as well as activation of small molecules under mild conditions. The key intermediate often highlighted is a Co–CH3 species that mirrors the methylcob(III) state postulated for natural B12 enzymes in these imagined scenarios.

In its fictional context, B12tasot is used as a teaching and storytelling device to illustrate principles of organometallic catalysis, electron transfer, and the influence of ligand environment on cobalt chemistry. As a constructed entry, it is not recognized as an established chemical compound in real-world chemistry. See also cobalamin and organometallic catalysis.