Solvothermal synthesis of two new thioantimonates with transition-metal complexes [Co(dien)2]4[CoSb6S14] and [Co(dien)2]2[Sb4S9]

► The majority of solvothermal reactions carried out in the presence of d-block TM ions result in the formation of isolated SbxSym- frameworks combined with TM complex cations as counterions, but whole d-block TM ion encapsulated within the thioantimonate anion was relatively rare, 1 is the only example of two [SbIII3S7] units sharing two edges with one CoS4 tetrahedran. ► Moreover, the coexistence of SbIII and SbV in a thioantimonate anion was less observed. ► 2 is characterized a new 1-D mixed-valent thioantimonate anion [Sb4S94-]n based on the combination of the [SbIII3S7] units and the SbVS4 tetrahedra.