Reaction of UCl
4 with 3 or 4 mol equiv of Na
2dddt (dddt = 5,6-dihydro-1,4-dithiine-2,3-dithiolate) in THF affordedthe first example of a tetrakis(dithiolene) metal compound, [Na
4(THF)
8U(dddt)
4]
![](/images/entities/infin.gif)
(
1). The red crystals of
1 arecomposed of infinite zigzag chains in which Na
2(
![](/images/entities/mgr.gif)
-THF)
3 fragments ensure the linking of Na
2(THF)
5U(dddt)
4 moieties;the uranium atom is in a dodecahedral environment of eight sulfur atoms. Treatment of UCl
4 with 3 mol equiv ofNa
2dddt in pyridine gave a mixture of tris- and tetrakis(dithiolene) compounds. After addition of 18c6 (18-crown-6),only the tris(dithiolene) complex was obtained and crystallized as orange crystals of [Na(18c6)(py)
2]
2[U(dddt)
3]·2py(
2·2py) in which the isolated [U(dddt)
3]
2- anion adopts a slightly distorted trigonal prismatic configuration. A fewred crystals of the unsolvated complex
2 and the trinuclear anionic compound [Na(18c6)(py)
2]
3[Na{U(dddt)
3}
2] (
3)were also obtained along with orange crystals of
2·2py. All the tris(dithiolene) compounds exhibit large folding ofthe dddt ligand and significant interaction between the C=C double bond and the metal center.