The [NEt
4]
+ (
1a), [NHMe
3]
+ (
1b), and [N(PPh
3)
2]
+ (
1c) salts of the monoanion [Fe(CO)
3(
5-7-CB
10H
11)]
- have been prepared via the reaction between [Fe
3(CO)
12] and [NHMe
3][
nido-7-CB
10H
13] in THF (tetrahydrofuran). The complexes [N(PPh
3)
2][Fe(CO)
2(L)(
5-7-CB
10H
11)](L = PPh
3 (
2), CNBu
t (
3)) were obtained by treating
1c in THF with PPh
3 and CNBu
t,respectively, in the presence of Me
3NO. The compound [N(PPh
3)
2][Mo(CO)
4(
5-7-CB
10H
11)](
4) has been synthesized from [Na]
3[
nido-7-CB
10H
11] and [Mo(CO)
3(NCMe)
3] in the presenceof CO and with addition of HBF
4·Et
2O and [N(PPh
3)
2]Cl. An X-ray diffraction studyestablished that in the anion of
4 the Mo atom is coordinated on one side by the four COmolecules and on the other by a
nido-7-CB
10H
11 carborane in a
5 manner. In reactions withPPh
3 and CNBu
t, the salt
4 gives the species [N(PPh
3)
2][Mo(CO)
3(L)(
5-7-CB
10H
11)] (L =PPh
3 (
5a), CNBu
t (
6)). Salts of the anions [Fe(CO)
3(
5-7-CB
10H
11)]
- and [Mo(CO)
3(PPh
3)(
5-7-CB
10H
11)]
- react with donor molecules (THF, OEt
2, SMe
2) in the presence of acids andother hydride abstracting reagents to give zwitterionic complexes: [Fe(CO)
3(
5-9-L-7-CB
10H
10)] (L = O(CH
2)
4 (
7), OEt
2 (
8), SMe
2 (
9)) and [Mo(CO)
3(PPh
3)(
5-9-L-7-CB
10H
10)] (L =O(CH
2)
4 (
10), OEt
2 (
11)), formed as single isomers. That the donor molecules L are bondedto a boron atom which lies in a
![](/images/gifchars/beta2.gif)
-site with respect to the carbon in the
CBBBB ring ligatingthe metal was established by X-ray diffraction studies on
7 and
10. In the latter the PPh
3molecule is transoid to the BO(CH
2)
4 group, presumably for steric reasons. Alkyne-molybdenum complexes [N(PPh
3)
2][Mo(CO)
2(Bu
tC
![](/images/entities/tbd1.gif)
CH)(
5-7-CB
10H
11)] (
13) and [N(PPh
3)
2][Mo(CO)
2(PhC
![](/images/entities/tbd1.gif)
CR)(
5-7-CB
10H
11)] (R = H (
14), Ph (
15)) have also been prepared.