Reaction of [Cp(2)''Th(C4H6)] (1) with As-4 in boiling xylene gives th
e dinuclear complex [Cp(2)''Th(mu-eta (2:1:2:1)-As-6)ThCp(2)''] (2), C
p'' = C5H3((t)Bu)(2). The molecular structure of 2 has been determined
by X-ray diffraction (space group P2(1)/n, a = 11.459(3), b = 19.442(
3), c = 26.725(6) Angstrom, beta = 97.82(1)degrees, Z = 4, R = 0.060,
R(w) = 0.059). The As-6 ligand can formally be regarded as open-edged
As-6 benzvalene.