Two 3d-4f heterometallic one-dimensional chains with neutral 4,4＇-bipyridine ligands as linkers and[Cu2Ln2] clusters （Ln = Gd for 1, Dy for 2） as nodes have been hydrothermally synthesized and structurally characterized. Magnetic studies indicate that complex 1 exhibits a relatively large magnetocaloric effect, with an entropy change -△Smax m= 24.8 J kg 1 K^-1, whilst, complex 2 features slow magnetic relaxation at low temperature.
The self-assembly of polyalcohol ligand 1,1,1-tris（hydroxymethyl）ethane with Dy（NO3）3· 6H2 O and Cr3O-Bzo-t-Bu precursor in the presence of triethylamine step-by-step generated a heterometallic 3d–4f chain. Magnetic investigation of the complex indicates typical slow relaxation of the magnetization at low temperature.
Mei-Hui YuXue JiangSong-De HanQing-Lun WangXian-He Bu
