A. Muhleckerknoepfler et al., SYNTHESIS AND CRYSTAL-STRUCTURE OF THE SUBVALENT MERCURY CLUSTER [TRIANGULO-HG-3(MU-DMPM)(4)][O3SCF3](4) (DMPM=ME2PCH2PME2), Journal of the Chemical Society. Dalton transactions, (9), 1997, pp. 1607-1610
The subvalent mercury cluster [triangulo-Hg-3(mu-dmpm)(4)][O3SCF3](4)
[dmpm = bis(dimethylphosphino)methane], involving the +4/3 oxidation s
tate of mercury, was formed by reaction of [Hg-2](2+) with 2 equivalen
ts of dmpm or by reduction of a mixture of [Hg(Me2SO)(6)][O3SCF3](2) a
nd dmpm in the molar ratio 2:4 with elemental Hg. The cation consists
of a Hg, triangle [Hg-Hg 276.68(14), 280.99(14) and 295,53(14) pm] in
which two edges are bridged by one dmpm ligand and the third edge is d
oubly bridged by a pair of dmpm ligands. The three Hg atoms and the ph
osphorus atoms of the singly bridging dmpm ligands are nearly in a pla
ne. The dihedral angles of the Hg, triangle and the mean planes formed
by the doubly bridged Hg atoms and the phosphorus atoms of the two br
idging dmpm ligands respectively are 61 and 46 degrees. The complex is
fluxional on the P-31 NMR time-scale at 81 MHz at ambient temperature
due to intramolecular exchange between the two different types of dmp
m ligands.