Understanding and Designing of Bent Aromatic Heterometallabenzenes

As a significant member of benzene-like aromatic compounds,
heterocyclic
aromatic compounds have significantly broadened the aromatic family
and exhibited wide applications in catalysis, functional materials,
and biopharmaceuticals. Introducing a heteroatom in metalla-aromatic
compounds thus offers an opportunity to create new aromatic functional
materials. Intriguingly, heterometallabenzenes often display bent
geometries that differ from their heterobenzene counterparts. We herein
reveal that the unexpected geometric bending in heterometallabenzenes
can be well rationalized by our previously proposed σ-dominated
scheme, which has demonstrated its validity in metallabenzenes and
fused-ring metallabenzenes. More interestingly, our calculations suggest
that introducing an isolobal heteroatom in the C5 ring
could lead to a more significant bending in heterometallabenzenes
than that in their corresponding metallabenzenes, and the aromaticity
is even enhanced with the geometric bending. Overall, our investigation
extends the validity of the σ-dominated scheme and provides
an approach for the rational designing of organometallic-based functional
materials with fascinating aromaticity.