The synthesis and reaction chemistry of the mono
(σ-alkynyl) titanocene chlorides [Ti](Cl)(C⋮CR)
{[Ti] = (η5-C5H4SiMe3)2Ti;
2a, R = Ph; 2b, R = SiMe3} is
described. Treatment of compounds 2a and 2b
with ClMgCH2SiMe3 or LiC⋮CR‘ yields
[Ti](CH2SiMe3)(C⋮CSiMe3)
(3) or [Ti](C⋮CR)(C⋮CR‘) (5a, R
= Ph, R‘ = SiMe3;
5b, R = R‘ = Ph; 5c, R = R‘ =
SiMe3), respectively. The reaction of compounds
2a, 2b, or 5a with
polymeric
[CuX]
n
(X = Cl, Br, I) produces the
heterobimetallic titanium−copper complexes
{[Ti](Cl)(C⋮CR)}CuX (6a,
R
= Ph, X = Cl; 6b, R = Ph, X = Br; 6c, R
= Ph, X = I; 7a, R = SiMe3, X = Cl;
7b, R = SiMe3, X = Br) or
{[Ti](C⋮CPh)(C⋮CSiMe3)}CuX
(8a, X = Cl; 8b, X = Br). While
compounds 2a and 2b do not react
with
[AgX]
n
(X = Cl, Br), it is found that the
bis(σ-alkynyl)titanocene 5a is able to break
down the polymeric structure
of [AgX]
n
to produce the heterobimetallic
compounds
{[Ti](C⋮CPh)(C⋮CSiMe3)}AgX
(10a, X = Cl; 10b, X =
Br). Moreover, compound 8a can be synthesized by
treatment of 2a or 2b with
[CuC⋮CR‘]
n
(R‘ = SiMe3,
Ph).
However, when compound 3 is reacted with
[CuCl]
n
under appropriate reaction conditions,
the formation of
{[Ti](C⋮CSiMe3)2}CuCl
(9b),
[CuCH2SiMe3]4,
[Ti](Cl)(CH2SiMe3) (4), and
[Ti]Cl2 (1) is observed; a
reaction
mechanism for the formation of the latter compounds is discussed.
The solid state structures of
[Ti](Cl)(CH2SiMe3) (4) and
{[Ti](Cl)(C⋮CSiMe3)}CuBr
(7b) were determined. Crystals of 4 and
7b are monoclinic, space
group P21/n. 4:
C20H37ClSi3Ti, cell
constants a = 6.812(2) Å, b =
11.298(6) Å, c = 33.16(1) Å, β =
92.25(3)°,
and Z = 4. 7b:
C21H35BrClCuSi3Ti, cell
constants a = 13.257(7) Å, b =
10.470(5) Å, c = 20.39(1) Å, β
=
100.91(3)°, and Z = 4.
