Solvent-Induced Structural Diversity and Magnetic Research of Two Cobalt(II) Complexes

The solvent-induced topological and structural diversities of two Co(II) complexes, namely, [Co(L) 2 (SCN) 2 ] ( Co1 ) and [Co 2 (L) 2 (SCN)(OAc) 3 ] ( Co2 ) (L = 8-methoxyquinoline), were comparatively analyzed. Certain proportions of L, Co(OAc) 2 ·4H 2 O, and NaSCN were mixed and dissolved in CH 3 OH at 60 °C to obtain complex Co1 . Complex Co2 , an asymmetric dinuclear compound, was obtained by simply replacing CH 3 OH with CH 3 CN as the solvent. The Co(II) ion in complex Co1 was coordinated by the N 4 O 2 mode provided by two L ligands and two SCN - anions. The two Co(II) ions in Co2 were in the N 2 O 4 and NO 5 coordination environment and were linked by two μ 2 -OAc - bridges and one rare μ 3 -OAc - bridge. Weak interaction analysis revealed that complexes Co1 and Co2 exhibited 6-connected shp and 14-connected fcu nets, respectively. Magnetic studies showed that Co1 demonstrated single-ion magnet behavior under 2000 Oe. These behaviors are indicative of clearly field-induced single-ion magnetic behavior with U eff = 34.7(2) K and τ 0 = 2.7(2) × 10 -7 s under 2000 Oe dc field, respectively. By contrast, Co2 lacked frequency dependence under zero-field conditions. Electrospray ionization mass spectrometry indicated that two complexes were stable in N , N -dimethylformamide.