TY - JOUR
T1 - Homoleptic Diphosphacyclobutadiene Complexes [M(η4-P2C2R2)2]x- (M=Fe, Co; x=0, 1)
AU - Wolf, Robert
AU - Ehlers, A.W.
AU - Khusniyarov, M.M.
AU - Hartl, F.
AU - de Bruin, B.
AU - Long, G.J.
AU - Grandjean, F.
AU - Schappacher, F.M.
AU - Pöttgen, R.
AU - Slootweg, J.C.
AU - Lutz, M.
AU - Spek, A.L.
AU - Lammertsma, K.
PY - 2011
Y1 - 2011
N2 - The preparation and comprehensive
characterization of a series of
homoleptic sandwich complexes containing
diphosphacyclobutadiene ligands
are reported. Compounds
[K([18]crown-6)ACHTUNGTRENUNG(thf)2][Fe(η4-
P2C2tBu2)2] (K1), [K([18]crown-6)-
ACHTUNGTRENUNG(thf)2][Co(h4-P2C2tBu2)2] (K2), and
[K([18]crown-6)ACHTUNGTRENUNG(thf)2][Co(η4-
P2C2Ad2)2] (K3, Ad=adamantyl) were
obtained from reactions of
[K([18]crown-6)ACHTUNGTRENUNG(thf)2][M(η4-C14H10)2]
(M=Fe, Co) with tBuC P (1, 2), or
with AdC P (3). Neutral sandwiches
[M(h4-P2C2tBu2)2] (4: M=Fe 5: M=
Co) were obtained by oxidizing 1 and 2
with [Cp2Fe]PF6. Cyclic voltammetry
and spectro-electrochemistry indicate
that the two [M(η4-P2C2tBu2)2] /[M(η4-
P2C2tBu2)2] moieties can be reversibly
interconverted by one electron oxidation
and reduction, respectively. Complexes
1–5 were characterized by multinuclear
NMR, EPR (1 and 5), UV/Vis,
and Mçssbauer spectroscopies (1 and
4), mass spectrometry (4 and 5), and
microanalysis (1–3). The molecular
structures of 1–5 were determined by
using X-ray crystallography. Essentially
D2d-symmetric structures were found
for all five complexes, which show the
two 1,3-diphosphacyclobutadiene rings
in a staggered orientation. Density
functional theory calculations revealed
the importance of covalent metal–
ligand p bonding in 1–5. Possible oxidation
state assignments for the metal
ions are discussed.
AB - The preparation and comprehensive
characterization of a series of
homoleptic sandwich complexes containing
diphosphacyclobutadiene ligands
are reported. Compounds
[K([18]crown-6)ACHTUNGTRENUNG(thf)2][Fe(η4-
P2C2tBu2)2] (K1), [K([18]crown-6)-
ACHTUNGTRENUNG(thf)2][Co(h4-P2C2tBu2)2] (K2), and
[K([18]crown-6)ACHTUNGTRENUNG(thf)2][Co(η4-
P2C2Ad2)2] (K3, Ad=adamantyl) were
obtained from reactions of
[K([18]crown-6)ACHTUNGTRENUNG(thf)2][M(η4-C14H10)2]
(M=Fe, Co) with tBuC P (1, 2), or
with AdC P (3). Neutral sandwiches
[M(h4-P2C2tBu2)2] (4: M=Fe 5: M=
Co) were obtained by oxidizing 1 and 2
with [Cp2Fe]PF6. Cyclic voltammetry
and spectro-electrochemistry indicate
that the two [M(η4-P2C2tBu2)2] /[M(η4-
P2C2tBu2)2] moieties can be reversibly
interconverted by one electron oxidation
and reduction, respectively. Complexes
1–5 were characterized by multinuclear
NMR, EPR (1 and 5), UV/Vis,
and Mçssbauer spectroscopies (1 and
4), mass spectrometry (4 and 5), and
microanalysis (1–3). The molecular
structures of 1–5 were determined by
using X-ray crystallography. Essentially
D2d-symmetric structures were found
for all five complexes, which show the
two 1,3-diphosphacyclobutadiene rings
in a staggered orientation. Density
functional theory calculations revealed
the importance of covalent metal–
ligand p bonding in 1–5. Possible oxidation
state assignments for the metal
ions are discussed.
U2 - 10.1002/chem.201001913
DO - 10.1002/chem.201001913
M3 - Article
SN - 0947-6539
VL - 16
SP - 14322
EP - 14334
JO - Chemistry-A European Journal
JF - Chemistry-A European Journal
IS - 48
ER -