Abstract
C
(Cage)-substituted cyclohexylamino-carborane trianionic ligand coordinated Zr and Ti complexes and polymer supported analogues were synthesized and structurally investigated by NMR, IR spectroscopy, and, in the case of polymer supported compounds, by DSC–TGA analysis. The polymerization of vinyl chloride and ethylene catalyzed by the new complexes is discussed.
In situ reaction of Li[
closo-1-Ph-1,2-C
2B
10H
10] with 7-azabicyclo [4.1.0] heptane results in the formation of the disubstituted carborane,
closo-1-Ph-2-(2′-aminocyclohexyl)-1,2-C
2B
10H
10 (
1), in 63% yield. Decapitation of
(1) with potassium hydroxide in refluxing ethanol produces the cage-opened
nido-carborane, K[
nido-7-Ph-8-(2′-aminocyclohexyl)-7,8-C
2B
9H
10]
− (
2), in 80% yield. Deprotonation of the above monoanion with two equivalents of
n-butyllithium followed by reaction with anhydrous MCl
4
·
2THF (M
=
Zr, Ti) provides
d
0-half-sandwich metallocarboranes,
closo-1-M(Cl)-2-Ph-3-(2′-
σ-(H)
N-cyclohexyl)-2,3-
η
5-C
2B
9H
9 (
3 M
=
Zr;
4 M
=
Ti) in 53% and 42% yields, respectively. The reaction of Li[
closo-1,2-C
2B
10H
11] with 7-azabicyclo [4.1.0] heptane in THF affords
closo-1-(2′-aminocyclohexyl)-1,2-C
2B
10H
10 (
5) in 59% yield. Immobilization of the carboranyl amino ligand (
1) to an organic support, Merrifield’s peptide resin (1%), has been achieved by the reaction of the sodium salt of
(5) with polystyryl chloride in THF to produce
closo-1-(2′-aminocyclohexyl)-2-polystyryl-1,2-C
2B
10H
10 (
6) in 87% yield. Further reaction of the dianion derived from (
6) with anhydrous ZrCl
4
·
2THF led to the formation of the organic polystyryl supported
d
0-half-sandwich metallocarborane,
closo-1-Zr(Cl)-2-(2′-
σ-(H)
N-cyclohexyl)-3-polystyryl-2,3-η
5-C
2B
9H
9 (
7), in 38% yield. These new compounds have been characterized by elemental analyses, NMR, and IR spectra. Polymerizations of both ethylene and vinyl chloride with
(3) and (
7) have been performed in toluene using MMAO-7 (13% ISOPAR-E) as the co-catalyst. Molecular weights up to 32.8
×
10
3 (
M
w/
M
n
=
1.8) and 9.5
×
10
3 (
M
w/
M
n
=
2.1) were obtained for PE and PVC, respectively.