The first [1]mol
ybdarenophanes were s
ynthesized and structurall
y characterized. The aluminumand gallium compounds [(Me
2Ntsi)Al(
6-C
6H
5)
2Mo] (
2a) and [(Me
2Ntsi)Ga(
6-C
6H
5)
2Mo] (
2b) [Me
2Ntsi =C(SiMe
3)
2(SiMe
2NMe
2)] were obtained from [Mo(LiC
6H
5)
2]·TMEDA and (Me
2Ntsi)ECl
2 [E = Al, Ga] inanal
ytical pure form with isolated
yields of 74% (
2a) and 52% (
2b). The silicon-bridged species [Ph
2Si(
6-C
6H
5)
2Mo] (
2c) was s
ynthesized from [Mo(LiC
6H
5)
2]·TMEDA and Ph
2SiCl
2. Compound
2c was isolatedas a cr
ystalline material in an approximatel
y 90% overall purit
y, from which a single cr
ystal was used forX-ra
y anal
ysis. The molecular structures of all three [1]mol
ybdarenophanes
2a-
c were determined b
y single-cr
ystal X-ra
y anal
ysis. The ring-tilt angle
![](/images/gifchars/alpha.gif)
was found to be 18.28(17), 21.24(10), and 20.23(29)
![](/images/entities/deg.gif)
for
2a,
2b, and
2c, respectivel
y. Variable temperature NMR measurements of
2a and
2b (-80 to 80
![](/images/entities/deg.gif)
C; 500MHz) showed a d
ynamic behavior of the gallium species
2b but not of compound
2a. The d
ynamic behaviorof
2b was rationalized b
y assuming that the Ga-N donor bond breaks, inversion at the nitrogen atomoccurs, and a rotation of the Me
2Ntsi ligand takes place followed b
y a re-formation of the Ga-N bond onthe other side of the gallium atom. The anal
ysis of the signals of meta and ortho protons of
2b gaveapproximate values of
G![](/images/entities/ne.gif)
of 59.6 and 59.1 kJ mol
-1, respectivel
y. Compound
2b reacted with [Pt(PEt
3)
3]to give the ring-open product [(
6-C
6H
6)Mo{
6-C
6H
5[GaPh(Me
2Ntsi)]}] (
3b). The molecular structure of
3bwas deduced from a single-cr
ystal X-ra
y determination. The formation of the unexpected platinum-freeproduct
3b can be rationalized b
y assuming that benzene reacted with
2b in a 1:1 ratio. Through aseries of
1H NMR experiments with
2b it was shown that small amounts of donor molecules (e.g., THF) inbenzene are needed to form
3b; in the absence of a donor molecule,
2b is thermall
y stable.