Hydrothermal synthesis and characterization of a novel crystal containing [Co4O4]4+ cubane core: [Co4O4(dpaH)4(CH3COO)2]2V4O12 · 5H2O

The hydrothermal reaction of Co(CH 3 COO) 2  · 4H 2 O, NaVO 3 , 2,2′-dipyridylamine (dpaH) and H 2 O yielded a novel crystal [Co 4 O 4 (dpaH) 4 (CH 3 COO) 2 ] 2 V 4 O 12  · 5H 2 O, which was characterized by X-ray structure analysis. The crystal structure is composed of an isolated molecular unit [V 4 O 12 ] 4− and two [Co 4 O 4 (dpaH) 4 (CH 3 COO) 2 ] 2+ moieties. The cobalt atoms and the bridging-oxygen atoms are introduced as structure-directing components and form the [Co 4 O 4 ] cubane core. As the N Co N bond angles increase, the O Co O bond angles of the acetate-bridged top and bottom faces decrease and the four-membered cobalt–oxygen rings are more distorted.