  We report on the successful on-surface synthesis of metal-organic covalent
coordination networks with a dense Kagome lattice of metallic centers. In the
case of Mn centers ab-initio calculations show that the adsorbed monolayer on
Ag(111) has all the characteristic features of a strictly two-dimensional (2D)
ferromagnetic Kagome metal. Tetrahydroxyquinone (THQ) and metal atoms (M=Cu or
Mn) are co-deposited on the Ag(111) substrate to build well-ordered 2D lattices
M$_3$C$_6$O$_6$. The surface is studied by scanning tunneling microscopy (STM),
low energy electron diffraction (LEED) and X-ray photoelectron spectroscopy
(XPS) to optimize the growth conditions like fluxes and temperatures. The
details of the atomic, electronic and magnetic structures are clarified by
density functional theory (DFT) calculations. XPS and DFT reveal a Cu$^+$
charge state and no local magnetic moments for the Cu-organic network. For the
Mn-organic network, we find the charge state Mn$^{2+}$ and a local spin S=5/2.
Charge transfer stabilizes the Cu$^+$ and Mn$^{2+}$ charge states. We find two
different modifications of the M$_3$C$_6$O$_6$ lattice. DFT calculations which
neglect the small spin-orbit coupling show a Dirac point, i.e. a band crossing
with linear electron dispersion at the K-point of the Brillouin zone. This
Dirac point is at the Fermi level if there is no charge transfer but drops by
100 meV if electron doping of Cu$_3$C$_6$O$_6$ on Ag(111) surface is
acknowledged. We predict the magnetic couplings of an isolated M$_3$C$_6$O$_6$
monolayer to be short range and antiferromagnetic leading to high frustration
at the Kagome lattice and a tendency towards a spin-liquid ground state. In the
case of hole transfer from the substrates ferromagnetic ordering is introduced,
making M$_3$C$_6$O$_6$ an interesting candidate for the quantum anomalous Hall
effect.
