Compartment compounds as secondary building units
for the preparation of 3d–4f coordination polymers: Preparation,
structures, and properties of [NiLn(L)(NO3)2(4-pyp)(EtOH)]
(Ln = Nd, Eu; H2L = 1,3-bis((3-methoxysalicylidene)amino)propane;
4-Hpyp = 4-pyridinepropionic acid)