Reactions of Ln(BH
4)
3(THF)
3 (Ln = Nd, Ce) and M
2dddt (M = Na, K; dddt = 5,6-dihydro-1,4-dithiine-2,3-dithiolate)in THF or pyridine gave, after addition of 18c6 (18-crown-6), several crystalline compounds which all contain thetris(dithiolene) Ln(dddt)
3 unit. Crystals of [Na(18c6)(py)
2]
2[Na(18c6)(py)][Nd(dddt)
3(py)]·3py (
1·3py) are built up fromdiscrete mononuclear cationic and anionic species whereas crystals of {[Na(18c6)(py)
2]
0.5[Na(18c6)(py)
1.5][Na
1.5Nd(dddt)
3]}
![](/images/entities/infin.gif)
(
2) are composed of discrete [Na(18c6)(py)
x]
+ cations and polymeric anionic two-dimensional layersin which the Nd(dddt)
3 units are linked to three neighbors by sodium atoms to form a honeycomb network. Analysisof the temperature dependence of the molar magnetic susceptibility of
2 shows that
MT decreases from 1.63 cm
3K mol
-1 at 300 K down to 0.6 cm
3 K mol
-1 at 5 K, due to the crystal-field splitting of the
4I
9/2 free-ion state.Complexes {[Na
3(18c6)
1.5Nd(dddt)
3(THF)]·3THF}
![](/images/entities/infin.gif)
(
3·3THF) and {[K
3(18c6)
1.5Nd(dddt)
3(py)]·3py}
![](/images/entities/infin.gif)
(
4·3py) exhibitneutral polymeric layers with the Nd(dddt)
3 units linked by M
2(18c6) fragments. In the cerium compound{[Na
2(18c6)Na(py)
2Ce(dddt)
3(py)]·3py}
![](/images/entities/infin.gif)
(
5·3py), each Ce(dddt)
3 unit is linked to two neighbors only by Na
2(18c6)moieties, giving infinite zigzag chains.