  Artificial nanostructures, fabricated by placing building blocks such as
atoms or molecules in well-defined positions, are a powerful platform in which
quantum effects can be studied and exploited on the atomic scale. Here, we
report a strategy to significantly reduce the electron-electron coupling
between a large planar aromatic molecule and the underlying metallic substrate.
To this end, we use the manipulation capabilities of a scanning tunneling
microscope (STM) and lift the molecule into a metastable upright geometry on a
pedestal of two metal atoms. Measurements at millikelvin temperatures and
magnetic fields reveal that the bottom-up assembled standing metal-molecule
nanostructure has an $S = \frac{1}{2}$ spin which is screened by the substrate
electrons, resulting in a Kondo temperature of only $291 \pm 13$ mK. We extract
the Land\'e $g$-factor of the molecule and the exchange coupling $J\rho$ to the
substrate by modeling the differential conductance spectra using a third-order
perturbation theory in the weak coupling and high-field regimes. Furthermore,
we show that the interaction between the STM tip and the molecule can tune the
exchange coupling to the substrate, which suggests that the bond between the
standing metal-molecule nanostructure and the surface is mechanically soft.
