Chemistry of 2,4,6-trimercapto-1,3,5-triazine (TMT): Acid dissociation constants and group 2 complexes

The acid dissociation constants of 2,4,6-trimercaptotriazine (H3TMT, 1) wer e determined and now can be employed in the preparation of complexes having specific M-TMT (M = divalent metal; TMT = 2,4,6-trimereapto-1,3,5-triazini de, C3N3S33-) ratios. For example, the combination of H3TMT (1) with Mg(OH) (2) at pH 7.1 leads to the crystallization of Mg(H2TMT)(2). 6H(2)O (4). Wit h the appropriate pH adjustment, the contiguous series of compounds Ba-3(TM T)(2). 8H(2)O (3), Ba(H2TMT)(2). 7H(2)O (5), and BaHTMT . 3H(2)O (6) can be isolated. The compounds were characterized by mp, IR, TGA, elemental analy sis, and, in the cases of 4, 5, and 6, crystallography. The comparison of 4 with 5 and 6 offers an interesting view of the difference in hard and soft bonding with TMT. In the saltlike Mg structure of 4, there is extensive hy drogen bonding, but in the Ba structures, 5 and 6, covalent Ba-S bonding do minates.