Electrochemical studies of Mn3HgM (M = Mo, W, Mn, Fe or Co) and Mn3Au cluster anions

Iron−Gold (or −Mercury) Carbide Clusters Derived from [Fe6C(CO)16]2-. X-ray Crystal Structures of (NEt4)[Fe6C{AuPPh3}(CO)16] and [Fe4C{AuPPh3}(CO)11(NO)]

“…These data indicate that fast Hg-M bond cleavage occurs during the electrochemical reduction of complexes 2-4, and we propose the mechanism shown in Scheme 1. This mechanism agrees well with those reported for other Hg cluster compounds: m 2 Hg, 32 (PPh 4 )[Fe 3 {Hg(m)}(CO) 11 ], 7 (PPh 4 )[Mn 3 {Hg(m)}(CO) 12 -(H)], 33 and [Ru 3 {Hg(m)}(CO) 9 (µ 3 -η 2 -CdC t Bu)]. 34 For all the compounds studied the oxidation step appeared irreversible at 0.1 V s -1 and also at higher scan rates (2000 V s -1 ).…”

“…The additional wave at more cathodic potential as well as the shift in the cathodic direction of the reduction wave of 5 compared to 2 − 4 may arise from the different environment around the Hg atom or, more probably, from the different charge over these clusters. The latter is reinforced by the finding that the complexes [{Ru 3 (CO) 9 (μ 3 -η 2 -CC t Bu)} 2 (μ 4 -Hg)] and [Ru 3 {HgMo(CO) 3 Cp}(CO) 9 (μ 3 -η 2 -CC t Bu)], both neutral, show similar electrochemical reduction values 34 whereas the oxidation and reduction potentials of the similar but dianionic compound (PPh 4 ) 2 [{Mn 3 (CO) 12 (H)} 2 (μ 4 -Hg)] are shifted to less anodic potential values compared to the monoanionic compounds (PPh 4 )[Mn 3 {Hg(m)}(CO) 12 (H)] …”

“…The latter is reinforced by the finding that the complexes [{Ru 3 (CO) 9 (µ 3 -η 2 -CdC t Bu)} 2 (µ 4 -Hg)] and [Ru 3 {HgMo(CO) 3 Cp}(CO) 9 (µ 3 -η 2 -CdC t Bu)], both neutral, show similar electrochemical reduction values 34 whereas the oxidation and reduction potentials of the similar but dianionic compound (PPh 4 ) 2 [{Mn 3 (CO) 12 -(H)} 2 (µ 4 -Hg)] are shifted to less anodic potential values compared to the monoanionic compounds (PPh 4 )[Mn 3 -{Hg(m)}(CO) 12 (H)]. 33 Molecular Orbital Study. Fe 4 C Butterfly Compounds.…”

Electrophilic Additions of Mercury and Gold Species to the Anion Carbide Cluster [Fe5C(CO)14]2-. X-ray Crystal Structures of (NEt4)[Fe5C(CO)14{μ-HgW(CO)3Cp}] and (NEt4)2[μ4-Hg{Fe5C(CO)14}2]

“…These data indicate the ease with which the Hg−M bond cleavage occurs during the electrochemical reduction, as found for the following mercury clusters: M 2 Hg, (PPh 4 )[Fe 3 (CO) 11 {μ-HgM}], (PPh 4 )[Mn 3 (CO) 12 (H){μ-HgM}], [Ru 3 (CO) 9 {μ-HgMo(CO) 3 Cp}(μ 3 -η 2 -C C t Bu)], (NEt 4 )[Fe 6 C(CO) 16 {μ-HgM}], and (PPh 4 )[Fe 4 C(CO) 12 {μ-HgM}] …”

Cobalt/Mercury Carbide Clusters Based on Trigonal-Prismatic or Octahedral Co6C Skeletons − X-ray Crystal Structure of (NEt4)2[Co6C(CO)12{HgW(CO)3Cp}2]

“…Treatment of (NEt 4 ) 2 [Co 6 C(CO) 15 ] (1) with ClHgM in CH 2 Cl 2 at Ϫ12 °C in the presence of a thallium salt as a halide abstractor gave the brown cluster complexes (NEt 4 )[Co 6 C(CO) 15 {HgM}] [M ϭ W(CO) 3 Cp (3a), Mo(C-O) 3 Cp (3b), Fe(CO) 2 Cp (3c), Co(CO) 4 (3d), Mn(CO) 5 (3e)]. Only compound 3a could be isolated as a crystalline solid; the other mercury derivatives were recovered as oily materials.…”