The delicate regulation of structural phase transition
can provide
advanced approaches for fabricating desired and well-organized nanoarchitectures
on surfaces. Introduction of metal ions into pure organic systems
can facilitate the phase transition from hydrogen-bonded structures
to metal–organic structures by coordinating with organic molecules.
However, it remains a challenge to attain a phase transition dominated
by variable metal coordination configurations through adjustment of
the metal ion concentration. Herein, we report the phase transitions
of naphthalene-2,3-carbonitride (2,3-DCN) molecules on highly oriented
pyrolytic graphite (HOPG) under varying solvents and Cu2+ ion concentrations. By integrating data from scanning tunneling
microscopy imaging and density functional theory calculations, it
is demonstrated that phase transitions of 2,3-DCN occur through forming
diverse coordination configurations where Cu2+ ions can
coordinate with 2,3-DCN and 1-nonanoic acid or Cl– ions to form different ligand components with a coordination number
of 4 when varying the molar ratios of 2,3-DCN to Cu2+ ion
in the 1-nonanoic acid solvent. However, in the case of 1-heptanoic
acid as a solvent, the self-assembly structure of 2,3-DCN only changes
via the alteration of hydrogen bonding sites and Cu2+ ions
do not coordinate with 2,3-DCN molecules. These findings provide valuable
insights into the coordination behavior of metal ions in different
solvents.