C. Elschenbroich et al., METAL-COMPLEXES OF HETEROARENES .6. HEXAK IS-(ETA(1)-PHOSPHININE) CHROMIUM - SYNTHESIS, STRUCTURE AND REDOX BEHAVIOR, Journal of organometallic chemistry, 459(1-2), 1993, pp. 157-167
Two alternative pathways, metal-atom ligand-vapor cocondensation and l
igand substitution at bis(2,4-dimethyl-eta5-pentadienyl)chromium, lead
to hexakis(eta1-phosphinine)chromium(0), 10. According to an X-ray cr
ystal structure determination the CrP6 core represents an almost ideal
octahedron, the bond lengths d(CT-P) 226.5 pm being particularly shor
t. Whereas the intraligand bond-lengths experience only minor changes
upon eta1-coordination of phosphinine, the changes in the H-1-, C-13-
and P-31 parameters are substantial. Compared with hexakis(eta1-phenyl
isocyanide)chromium, the UV/VIS spectrum of 10 displays a bathochromic
shift in the MLCT region which attests to a stronger pi-acceptor char
acter of phosphinine. The attendant propensity of this ligand to stabi
lize the oxidation state Cro manifests itself in the redox potentials
for the couples CrL+/0 which are increasingly anodic according to the
sequence Cr(bpy)3 < Cr(PhNC)6 < Cr(C5H5P), < Cr(CO)6.