Highly Active Ethene Polymerization Catalysts with Unusual Imine Ligands - Late Transition Metal Polymerization Catalysis - page 74

Fig. 3.6 Molecular structure of iron complex
61a ; hydrogen atoms and solvent molecules
are omitted for clarity. Selected bond lengths
(pm): Fe(1)-N(1) =220.2(4), Fe(1)-N(3)=
222.2(4), Fe(1)-N(5) =207.9(5), Fe(1)-Cl(1)=
230.9(2), Fe(1)-Cl(2) =225.9(2), N(1)-N(2) =
140.3(6), N(3)-N(4) =141.8(6). Selected an-

gles ( ): N(1)-Fe(1)-N(5)=73.5(2), N(3)-
Fe(1)-N(5) =73.0(2), N(1)-Fe(1)-N(3)=
143.1(2), N(5)-Fe(1)-Cl(1) =96.69(12), N(3)-
Fe(1)-Cl(1)=100.12(12), N(1)-Fe(1)-Cl(1) =
98.56(12), N(5)-Fe(1)-Cl(2) =138.67(12),
N(3)-Fe(1)-Cl(2)=95.66(13), N(1)-Fe(1)-
Cl(2)=99.47(13).

The metal is coordinated in a distorted trigonal bipyramidal geometry to the
three nitrogens N(1), N(3), N(5) of the bis(imino)pyridyl ligand and to two chlo-
rines; furthermore the metal is clearly displaced from the [N,N,N] ligand plane by
40.6(4) pm. The bond distance of the pyridyl nitrogen is significantly shorter than
the distances of both imino nitrogens and the two chlorine substituents have
more or less similar metal-chlorine bond lengths. The planes of the sterically
shielding N-carbazolyl groups are roughly orthogonal to the plane of the [N,N,N]
bis(imino)pyridyl ligand backbone [78.5(3)

] and the N-carbazolyl moi-
eties are planar in accordance with the sp 2 hybridization of the nitrogens N(2), N(4)
in these N-heterocycles. All these structural features of 61a are quite similar to those
of Gibson's N-aryl bis(imino)pyridyl complexes [13], again indicating only subtle
structural differences between N-azolyl and N-aryl bis(imino)pyridyl metal halide
precatalysts.

and 75.1(2)