Carbidohexarhenate Cluster Cores Bicapped by Mercury with Acetate or Thiolate Ligands

Abstract

The reaction of [PPh4]3[Re7C(CO)21] (1) with 1 or more equiv of Hg(OAc)2 in dichloromethane provides the monomercury derivative [PPh4]2[Re7C(CO)21HgOAc] (2) in high yield. However, in the presence of methanol the reaction of 1 with 2 equiv of Hg(OAc)2 yields the dimercury hexarhenium cluster compound [PPh4]2[Re6C(CO)18(HgOAc)2] (3) together with the dirhenium complex [PPh4][Re2(CO)6(mu-OMe)2(mu-OAc)] (4). The dimercury compound 3 reacts with various thiols HS-Z to form thiolate-substituted derivatives [PPh4]2[Re6C(CO)18(HgSZ)2] [Z = C6H4Br (5); C5H4N (6); C2H4COOH (7)]. All new compounds have been characterized by a combination of analytical and spectroscopic data, and the molecular structures of compounds 3-6 have been determined by X-ray crystallography.

Carbidoheptarhenate Cluster Complexes of Cadmium and Zinc Units: The Structure of [PPh4]2[Re7C(CO)21(μ3-ZnCl)]

“…It contains an octahedron of rhenium atoms, centered on an interstitial carbon atom, with rhenium tricarbonyl and zinc chloride units capping trans (1,4) faces. This is the characteristic geometry found previously for carbidoheptarhenate complexes, , in particular, the mercury-capped dervivatives. − The average Re−Re distances for the zinc-capped face in 2 are ca. 0.05 Å longer than those for the uncapped faces, which average 2.98 Å.…”

“…2.88 Å in the corresponding mercury derivatives. [1][2][3] The implied difference in covalent radius is similar to that suggested by comparing M-N distances in four-coordinate (11) This characteristic IR band of carbidoheptarhenate complexes is extremely intense. The molar absorption coefficient directly determined for the HgCl complex is 7.0 × 10 4 cm -1 M -1 , and the analogous best fit parameter for the ZnCl complex 2 is 5.3 × 10 pyrazolylborate complexes of mercury (ca.…”

“…The molecular structure of the cluster anion in 2 is depicted in Figure 2. It contains an octahedron of rhenium atoms, centered on an interstitial carbon atom, with rhenium tricarbonyl and zinc chloride units capping trans (1,4) faces. This is the characteristic geometry found previously for carbidoheptarhenate complexes, 15,16 in particular, the mercury-capped dervivatives.…”

“…This is the characteristic geometry found previously for carbidoheptarhenate complexes, 15,16 in particular, the mercury-capped dervivatives. [1][2][3] The average Re-Re distances for the zinc-capped face in 2 are ca. 0.05 Å longer than those for the uncapped faces, which average 2.98 Å.…”

“…As part of our investigation of carbidoheptarhenate cluster complexes of mercury units, with the general formula [Re 7 C-(CO) 21 (µ 3 -HgX)] 2-, [1][2][3][4] we became interested in extending this chemistry to include the lighter group 12 congeners, namely, cadmium and zinc. A recent discussion of cluster complexes with various bonds between transition elements and zinc, cadmium, or mercury is available.…”