Mercury Thiolato Complexes: Syntheses, Crystal Structures, and Decomposition Pathways

Complexes of the general formula ClHgSR (R = benzyl, neopentyl, isopropyl) and the mercury bis(thiolate) compound [Hg(SBz) 2 ] ∞ each have been prepared and characterized by single crystal X-ray diffraction. ClHgSBz·TMEDA crystallizes in the triclinic space group P 1̄ with cell constants a = 8.136(2) Å, b = 9.958(7) Å, c = 11.834(3) Å, α = 108.71(2)°, β = 92.93(2)°, γ = 109.05(2)°, and Z = 2. Refinement of 2534 observed reflections yields R = 0.050 and R w = 0.056. [ClHgS-iso-Pr] ∞ crystallizes in the monoclinic space group C 2 with cell constants a = 21.430(7) Å, b = 4.678(2) Å, c = 6.724(2) Å, β = 90.43(2)°, and Z = 2. Refinement of 528 observed reflections yields R = 0.039 and R w = 0.033. [ClHg(S-neo-Pent)·0.5Py] ∞ crystallizes in the monoclinic space group C 2 with cell constants a = 16.732(2) Å, b = 11.200(1) Å, c = 11.929(2) Å, β = 104.21(1)°, and Z = 4. Refinement of 2561 observed reflections yields R = 0.035 and wR 2 = 0.081. [Hg(SBz) 2 ] ∞ crystallizes in the monoclinic space group C 2/ c with cell constants a = 22.599(4) Å, b = 4.334(1) Å, c = 29.566(5) Å, β = 106.76(1)°, and Z = 8. Refinement of 1264 observed reflections yields R = 0.036 and wR 2 = 0.116. The solid-state thermal decompositions of the chloromercury thiolate compounds have been studied and the XRPD patterns of the resultant solid-state materials were obtained. The formation of Hg 2 Cl 2 is observed upon thermolysis of [ClHg(S-neo-Pent)·0.5 Py] ∞ or [ClHgS-iso-Pr] ∞ at 200 °C, whereas ClHgSBz·TMEDA produces HgS under identical conditions. Upon mixing equimolar quantities of HgCl 2 and Ph 3 CSH in EtOH, moderately crystalline HgS is produced at ambient temperature. The volatile products liberated during the thermal decomposition have been isolated and characterized by GC/MS techniques. For the cases involving the production of HgS from ClHgSR (R = Bz, Ph 3 C), the reaction coproduct was identified as RCl. In the instances where Hg 2 Cl 2 was synthesized from ClHgSR (R = iso-Pr, neo-Pent), R−(S) n −R ( n = 2, 3, 4) have been identified. The decomposition pathways of the various chloromercurythiolate compounds are discussed, and mechanisms consistent with the observed reaction products are presented.