Unique Anionic Eight-Connected Net with 3⁶4¹⁸5³6 Topology Derived from a Rare Co₆(μ₃-OH)₂(μ-H₂O)(CO₂)₁₂ Building Block

[(CH3)2NH2]2[Co6(μ3-OH)2(μ-H2O)(ip)6]·2.5H2O (1), where ip2− is the 1,3-benzenedicarboxylate dianion, has been prepared by the solvothermal self-assembly of CoCl2 and H2ip in N,N′-dimethylformamide. Complex 1 contains a rare Co6(μ3-OH)2(μ-H2O)(CO2)12 building block with six crystallographically distinct cobalt(II) ions, one with a trigonal bipyramidal, two with a pseudotetrahedral, and three with a pseudooctahedral coordination environment; the bridging ip2− dianions serve as spacers to yield a unique anionic eight-connected net with 36418536 topology. The magnetic properties of 1 indicate that the six cobalt(II) ions are paramagnetic with, at most, very weak intramolecular antiferromagnetic exchange coupling.