Crystal Structures and Selected Properties of CoII Containing Thiostannates prepared by a New Room Temperature Route

The room temperature reaction of Na₄Sn₂S₆ · 5H₂O with CoCl₂ · 6H₂O and 2-(aminomethyl)pyridine (2-AMP) or trans-1,2-diamino-cyclohexane (DACH) leads to crystallization of two compounds with the compositions Co(2-(aminomethyl)pyridine)₃]₂ Sn₂S₆ · 10H₂O ( 1 ) and Co(trans-1,2-diaminocyclohexane)₃]₂Sn₂S₆ · 8H₂O ( 2 ). In both compounds Sn₂S₆]^4– anions are present that are charge balanced each by two Co²⁺ centered complexes. Each of the two Co^II cations are sixfold coordinated by six N atoms of three 2-AMP or DACH ligands within slightly distorted octahedra. In compound 1 , the two complexes are linked by one Sn₂S₆]^4– anion via strong N–H ··· S hydrogen bonds into centrosymmetric charge neutral trimeric units, that are further linked by weak C–H ··· S and N–H ··· S hydrogen bonds into chains that are directed along the a axis. These chains are further joined by N–H ··· O and O–H ··· O hydrogen bonds into a 3D network, with the H₂O molecules forming chains along the b axis. The crystal structure of 2 is similar to that of 1 featuring trimeric units which are also linked into chains. Between the chains water molecules are embedded that link the chains into a 3D network. Upon heating 2 in a thermobalance the water and ligand molecules are removed in discrete steps, indicating that compounds with more condensed thiostannate networks will form.