Magnetic Properties versus Network Dimensionality of Cerium(III) Octacyanotungstate(V) Compounds

The reaction of cerium(III) nitrate, sodium octacyanotungstate(V), and 2,2′-bipyrimidine (bpm) under various conditions leads to the formation of three new compounds: ionic [Ce₂(bpm)(dmf)₆(H₂O)₈][W(CN)₈]₂·3H₂O (1; dmf = N,N-dimethylformamide), tetranuclear molecules [Ce₂(bpm)(dmso)₈(H₂O)₄][W(CN)₈]₂·4H₂O (2; dmso = dimethyl sulfoxide), and a two-dimensional inorganic−organic hybrid coordination polymer {[Ce₂(bpm)(dmf)₈(H₂O)₂][W(CN)₈]₂}_n·2nH₂O (3), all of which contain the subunit [Ce₂(μ-bpm)] within the structure. These systems were characterized by single-crystal X-ray diffractometry, FTIR spectroscopy, and thermogravimetric analysis. Magnetic susceptibility measurements for 1−3 were performed on polycrystalline samples of the compounds. Magnetic behavior was interpreted in terms of the ligand-field splitting parameters and the exchange interaction between lanthanide centers and a d-electron spin carrier. The results confirmed the ferromagnetic cyano-mediated {Ce−NC−W} interaction J_CeW = 1.7 (2) and 1.4(3) cm⁻¹ (3) compared to the antiferromagnetic {Ce−bpm−Ce} interaction J_CeCe = −1.1 cm⁻¹ (1 and 2).