In this work we present 16 new 3d-4f metal-organic comounds,
which are synthesized by a one-pot method with one uncommon polytopic
N,O-donor ligand formed in situ. All these compounds are characterized
by single crystal X-ray diffraction, which reveals isomorphism for
them and a special heterometallic trinuclear structure in a perfect
linear arrangement. Within this trinuclear unit, the metal(3d)-O-metal(4f)
angle and metal(3d)-to-metal(4f) distance is exceptionally small,
to our best knowledge, which should present the smallest one in the
literature. Moreover, the magnetic properties of partial compounds
are explored, revealing that at high temperature paramagnetic behavior
is observed and the slow decrease is mainly due to a crystal field
effect, at the low temperature antiferromagnetic interaction or magnetic
anisotropy operates.