UNUSUAL BONDING PATTERN FOR FORMALLY DIVALENT HGPPH(3) FRAGMENT IN A TRIANGULAR HGRE2 CLUSTER COMPOUND (PH EQUALS PHENYL)

The crystal structures of (PPh(3))HgRe2 (mu-acPh) (mu-PCy(2))(CO)(6) 1 and (PPh(3))HgRe2(mu-PCy(2)) Cl(CO)(7) 2 (Cy = cyclohexyl) exhibit bo th a HgRe2 triangular metal core with an exocyclic PPh, ligand attache d to HE. 1 crystallizes in space group P (1) over bar with a = 9.703(2 ) Angstrom, b = 10.484(3) Angstrom, c = 21.526(6) Angstrom, alpha = 86 .46(2)degrees, beta = 84.26(2)degrees, gamma = 81.65(2)degrees, V = 21 53(1) Angstrom(3). The metal-metal bond lengths are Re-Re 3.060(1) Ang strom, Hg-Re 2.757(1) Angstrom, and Hg-Re 2.765(1) Angstrom. Compound 2 crystallizes in space group P2(1)/n with a = 15.134(4) Angstrom, b = 9.623(4) Angstrom, c = 27.273(9) Angstrom, beta = 92.42(2)degrees, V = 3967(2) Angstrom(3). Bond lengths are Re - Re 3.254(1) Angstrom, Hg - Re 2.770(1) Angstrom and Hg - Re 2.786(1) Angstrom.