metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
In an attempt to elucidate the mechanism by which the
AFA complexes are formed and, more specifically, to under-
stand better the effect that the isocyanide substituent has on
the insertion reaction, we investigated a series of reactions
between the complex [(ꢁ5-C5H5)Cu(CNtBu)] and varying
amounts of alkyl and aryl isocyanides. The reaction of both
[(ꢁ5-C5H5)Cu(CNtBu)] and [(ꢁ5-C5H5)Cu(CNPh)] with an
excess of the alkyl isocyanide, CNtBu (ca 4 equivalents) was
studied, but 1H NMR spectroscopic studies failed to establish
any evidence of reaction. However, the analogous reaction of
[(ꢁ5-C5H5)Cu(CNtBu)] (Kruck et al., 1993) with an excess
(4 equivalents) of CNPh has been shown to produce the AFA
complex, [(Ph2-AFA)Cu(CNPh)2], as evidenced by the
appearance of indicative resonances for the ligand system in
the 1H NMR spectra, and provides an alternative route for the
synthesis of the complex (Johnson et al., 2009). We previously
noted that the reaction of [(ꢁ5-C5H5)Cu(CNtBu)] with the
electron-withdrawing isocyanides CN(p-C6H4F) and CN(p-
C6H4NO2) shows a much more rapid production of AFA
complexes (<< 12 h), indicating that the electronic nature of
the isocyanide is a significant factor in the migratory insertion
of isocyanides into C—H bonds of the Cu–C5H5 systems
(Johnson et al., 2009).
ISSN 0108-2701
Bis(tert-butyl isocyanide-jC)[4-fluoro-
N-({2-[N-(4-fluorophenyl)carbox-
imidoyl]cyclopenta-2,4-dien-1-yl-
idene}methyl)anilinido-j2N,N0]-
copper(I)
Alexander M. Willcocks,a Andrew L. Johnson,a* Paul R.
Raithby,a Stefanie Schiffersa and John E. Warrenb
aDepartment of Chemistry, University of Bath, Bath BA2 7AY, England, and bSTFC
Daresbury Laboratory, Warrington WA4 4AD, England
Correspondence e-mail: a.l.johnson@bath.ac.uk
Received 17 April 2011
Accepted 24 May 2011
Online 4 June 2011
The solid-state structure of the title compound, [Cu(C19H13-
F2N2)(C5H9N)2], shows that the CuI centre adopts a distorted
tetrahedral coordination geometry, being coordinated by two
N atoms of the 6-aminofulvene-2-aldimine (AFA) chelating
ligand and by the bridgehead C atoms of the two isocyanide
ligands. The cyclopentadienyl and imine components of the
AFA ligand are approximately coplanar, with an angle
between the planes of 5.00 (3)ꢀ. The Cu atom lies
˚
0.6460 (3) A above the imine plane defined by the N and C
atoms of the seven-membered metallocycle. There is also an
uncommon C—Hꢁ ꢁ ꢁCu anagostic interaction, with an intra-
˚
molecular Cuꢁ ꢁ ꢁH distance of 2.67 A, which is less than the
The title complex, (I), was formed by the reaction of
4-fluorophenyl isocyanide with [(ꢁ5-C5H5)Cu(CNtBu)] in
tetrahydrofuran in a copper-mediated insertion of two
equivalents of CN(4-C6H4F) into two vicinal C—H bonds of
the cyclopentadienyl moiety of the complex [(ꢁ5-C5H5)-
Cu(CNtBu)].
Complex (I) crystallizes in the monoclinic space group
P21/n (Fig. 1) and an examination of the crystal packing shows
no abnormally short intermolecular contacts. The shortest
sum of the van der Waals radii.
Comment
The diimine-substituted cyclopentadienyl 6-aminofulvene-2-
aldimines (AFAs) have recently attracted attention as ligands
for a variety of metals because of both their similarity to well
established ligand systems, such as ꢀ-diketiminate, amino-
troponiminate or anilidoiminate ligands (Willcocks et al., 2011;
Bailey et al., 2003, 2007, 2010), and their ability to bind to
metal centres via the diimine donor groups or via the cyclo-
pentadienyl unit (Bailey et al., 2003, 2007).
As part of a wider study into the coordination chemistry of
CuI complexes, we have recently reported the double migra-
tory insertion of phenyl isocyanide (Ph—NC) into two vicinal
sp2 C—H bonds of the ꢁ5-coordinated cyclopentadienyl group
in the complex [(ꢁ5-C5H5)Cu(CNPh)], resulting in the
formation and isolation of the AFA complexes [(Ph2-
AFA)Cu(CNPh)] and [(Ph2-AFA)Cu(CNPh)2] (Johnson et al.,
2009).
˚
intermolecular interaction is 2.29 A between atoms F1 and
1
H20(x + 12, ꢂy + , z + 12).
2
The molecular structure of (I) (Fig. 1) shows the CuI centre
to be coordinated by the two N atoms of the AFA ligand and
the two divalent C atoms of the isocyanide ligands (Table 1),
which are comparable with the CuI–AFA and CuI–isocyanide
interactions in related complexes (Willcocks et al., 2011),
resulting in a coordination environment about the CuI centre
that is best described as approximately tetrahedral. The
cyclopentadienyl and imine portions of the AFA ligand are
approximately coplanar. The dihedral angle between the C7–
C11 and N2/C6/C7/C11/C12/N3 planes is 5.00 (3)ꢀ. The CuI
Acta Cryst. (2011). C67, m215–m217
doi:10.1107/S010827011101972X
# 2011 International Union of Crystallography m215