A TTF Derivative Acting as a Chelate Ligand: Structure of |i-[Tetra(niethyIthio)tetrathiafuIvaleneJdi[diodoniercury(II)], (TTM-TTF) (Hgl2)2, and the Structure of a Second Modification of Free TTM-TTF

(TTM -TTF)(HgI2)2 [TTM-TTF = tetra(methylthio)tetrathiafulvalene. C 1(IH 12S8] was obtained as one of the products of the reaction of TTM-TTF with H gl,. It is triclinic, P I , a = 7.667(1), b = 8 .308(2), c = 11.608(3) Ä , a = 81.42(2), ß = 75.15(2), y = 67.06(2)°, V = 657.2 Ä 3, Z = 1, Mr = 1297.53, dc = 3.28 g e m -3, final RK = 0.035 for 2755 reflections and 116 parameters. The donor acts as a bridging chelate ligand by coordination of the S atoms of the -S C H , groups to Hg, with H g S distances o f 3.038(2) and 3.157(3) Ä . Hg I contacts of 3.648(1) and 3.761(1) Ä lead to coordination-polymer like chains of the Hg complexes. TTM-TTF (phase II) is triclinic, P I, a = 5 .141(2). b = 7.565(3), c = 10.950(2) A , a = 72.46(2), ß = 79.03(2), y = 84.87(3)°, V = 398.4 Ä 3, Z = 1, Mr = 388.73, dc = 1.62 g cm 3, final RK = 0.032 for 1876 reflections and 106 parameters. The molecules form sheets of stacks with shorter interstack S S contacts [3.591(1) Ä] than within the same stack [3.720(1) Ä],