The reaction of tha
llium ethoxide with [H(OEt
2)
2][H
2N{B(C
6F
5)
3}
2] in diethy
l ether afforded [T
l(OEt
2)
3][H
2N{B(C
6F
5)
3}
2] (
2a), [T
l(OEt
2)
4][H
2N{B(C
6F
5)
3}
2] (
2b), or [T
l(OEt
2)
2][H
2N{B(C
6F
5)
3}
2]·CH
2C
l2 (
2c),depending on the reaction conditions. The dication in the hydro
lysis product [T
l4(
3-OH)
2][H
2N{B(C
6F
5)
3}
2]
2·4CH
2C
l2 consists of two bridging and two termina
l T
l+ ions bound to trip
ly bridging hydroxides. HeatingEt
2O comp
lexes in to
luene afforded [T
l(
6-to
luene)
n][H
2N{B(C
6F
5)
3}
2] (
4,
n = 2, 3), whi
le C
6Me
6 additiongave the first tha
llium-C
6Me
6 adduct, [T
l(
6-C
6Me
6)
2][H
2N{B(C
6F
5)
3}
2]·1.5CH
2C
l2 (
5a), a bent sandwichcomp
lex with very short T
l···centroid distances. These arene comp
lexes show no c
lose contacts betweencations and anions. Disp
lacement of to
luene
ligands by ferrocene gave [T
l2(FeCp
2)
3][H
2N{B(C
6F
5)
3}
2]
2·5CH
2C
l2 (
6) which contains the mu
ltidecker cations [T
l(FeCp
2)]
+ and [T
l(FeCp
2)
2]
+ in a 1:1 ratio. By contrast,decamethy
lferrocene
leads to e
lectron transfer; the iso
lab
le tha
llium-ferrocene comp
lexes may thereforebe viewed as precursor comp
lexes for this redox step. With 18-crown-6 the comp
lexes [T
l(18-crown-6)
2][H
2N{B(C
6F
5)
3}
2] (
11a) and [T
l(18-crown-6)][H
2N{B(C
6F
5)
3}
2]·2CH
2C
l2 (
11b) were iso
lated. The structureof the
latter shows an eight-coordinate tha
llium ion, where the coordination to the six oxygen donors inequatoria
l positions is comp
leted by axia
l contacts to two F atoms of the counter anions. The bondingbetween tha
llium(I) and arenes was exp
lored by density-functiona
l theory (DFT) ca
lcu
lations. The optimizedgeometry of [T
l(to
l)
3]
+ converged to a structure very simi
lar to that obtained experimenta
lly. Ca
lcu
lationson [T
l(C
6Me
6)
2]
+ (
5b) to estab
lish whether a
linear or bent geometry is the most stab
le revea
led a very f
latpotentia
l-energy surface for distortions of the Ctr(3)-T
l-Ctr(4) ang
le. Overa
ll, there is very
litt
le energeticpreference for one particu
lar geometry over another above about 140
![](/images/entities/deg.gif)
, in good agreement with thecrysta
llographic geometry. The ca
lcu
lated T
l-arene interaction energies increase from 73.7 kJ mo
l-1 forto
luene to 121.7 kJ mo
l-1 for C
6Me
6.