Unusual Ring Systems Containing Indium. Synthesis and Structure of the First Mercuraindacycles

The mercuraindacycles
bis(μ-1,8-naphthalenediyl)mercury(II)(bis(tetrahydrofuran)chloroindium(III))
(5) and bis(μ-1,8-naphthalenediyl)mercury(II)(bis(tetrahydrofuran)bromoindium(III))
(7) are the products of the reaction of
indium(I) halides with
1,8-naphthalenediylbis(mercury(II) halides). Their
formation involves a partial transmetalation followed by a spontaneous ring closure. Compounds
5 and 7 have been characterized by
1H, 13C, and
199Hg NMR spectroscopy. The X-ray crystal
structures of
5·(InCl3(THF)3) and
7 have been determined. Compound
5 crystallizes as an
InCl3(THF)3 adduct in the monoclinic space
group P21/c with a =
17.529(2) Å, b = 8.954(1)
Å, c = 27.704(1) Å, β = 107.02(1)°,
V = 4157.8(7) Å3, and Z =
4. Compound 7 crystallizes in the
orthorhombic
space group P212121 with
a = 8.368(1) Å, b = 15.357(1) Å,
c = 19.446(1) Å, V = 2499.0(4)
Å3, and Z = 4. In
both structures, the eight-membered dimetallacycles adopt a twisted
conformation with conspicuously short In···
Hg transannular distances. Finally, the X-ray crystal
structure of the diindacycle
bis(μ-1,8-naphthalenediyl)bis(bis(tetrahydrofuran)chloroindium(III)) (8) is
reported. This compound is isolated as a low-yield side product
in
the synthesis of 5. Compound 8 crystallizes
in the tetragonal space group P4/n with
a = 19.492(1) Å, c =
10.432 Å, V = 3963.5(5) Å3, and
Z = 4.