Group 2 Complexes of 2,4,6-Trimercaptotriazine (TMT)

The 2,4,6-trimercaptotriazine (TMT) ligand system is currently being used as a complexing agent for divalent metals although little is known about its chemistry. This report entails a description of the syntheses and structures of TMT complexes having the formula M(TMTH₂)₂·nH₂O (M = Ca (1), Sr (2), and Ba (3), where n = 11, 11, and 4.5, respectively). In 1 and 2, the structures consist of alternating layers of hydrated metal cations and π-stacked TMT groups. A wide range of hydrogen-bonding interactions connect these layers. Compound 3 forms as a polymeric molecule with covalent bonds between the Ba atoms and TMT ligands. Each of the compounds was structurally characterized. X-ray data: 1, C₂₄H₁₀₄Ca₄N₂₄O₄₄S ₂₄, triclinic, P1, a = 12.9622(7)Å, b = 15.9874(9) Å, c = 24.516(1) Å, α = 81.191(1)°, β= 89.560(1)°, γ = 72.433(1)°, Z = 2; 2, C₆H₂₆N₆O₁₁S₆-Sr, triclinic P1̄, a = 8.7454(5) Å, b = 11.7545(6) Å, c = 13.7292(7) Å, α = 66.529(1)°, β= 73.201(1)°, γ = 77.034(1)°, Z = 2; 3, C₁₂H₁₈Ba₂N₁₂O₉S ₁₂, monoclinic, P2₁/c, a = 8.5576(4) Å, b = 21.028(1) Å, c = 20.276(1) Å, β= 96.440(1)°, Z = 2.