“…The distance of the hydrogen−hydrogen interaction is 1.800 Å, and the dihedral angle between the two rings is only 12.6°. These values compare well with those of a similar cis structure also with very little helical character but with sp 3 carbons at C(1) and C(10) which was determined earlier by us …”
Section: Resultssupporting
confidence: 89%
“…In our earlier reports, we described the synthesis of a tetralithium complex, the dimeric {Li 2 (THF) 2 [η 5 :η 5 ,η 5 -C 24 H 12 ](SiMe 3 ) 2 } 2 ( 2 ). Structural studies of compound 2 showed that two of the four lithium atoms were bound on the same side of each ligand in a cis fashion with each sandwiched between two Cp rings.…”
The oxidation of the substituted-fulvalene dianion with group 13
metal halides yields dark
green crystals of the stable π-conjugated fulvalene
C24H12(SiMe3)2.
Reaction of the fulvalene
monoanion with the metal halides results in the oxidative coupling of
the ligand to give the
dimer
[C24H13(SiMe3)2]2.
These compounds, obtained rather unexpectedly during efforts
to
synthesize metal complexes of the fulvalene-type ligand, have been
characterized by X-ray
crystallography.
“…The distance of the hydrogen−hydrogen interaction is 1.800 Å, and the dihedral angle between the two rings is only 12.6°. These values compare well with those of a similar cis structure also with very little helical character but with sp 3 carbons at C(1) and C(10) which was determined earlier by us …”
Section: Resultssupporting
confidence: 89%
“…In our earlier reports, we described the synthesis of a tetralithium complex, the dimeric {Li 2 (THF) 2 [η 5 :η 5 ,η 5 -C 24 H 12 ](SiMe 3 ) 2 } 2 ( 2 ). Structural studies of compound 2 showed that two of the four lithium atoms were bound on the same side of each ligand in a cis fashion with each sandwiched between two Cp rings.…”
The oxidation of the substituted-fulvalene dianion with group 13
metal halides yields dark
green crystals of the stable π-conjugated fulvalene
C24H12(SiMe3)2.
Reaction of the fulvalene
monoanion with the metal halides results in the oxidative coupling of
the ligand to give the
dimer
[C24H13(SiMe3)2]2.
These compounds, obtained rather unexpectedly during efforts
to
synthesize metal complexes of the fulvalene-type ligand, have been
characterized by X-ray
crystallography.
“…We attribute this to the occurrence of anharmonic displacements. This distance ®ts well in the range of distances from 1.79 (Jutzi et al, 1985) to 2.09 A Ê (Malaba et al, 1992) reported for other lithium cyclopentadienide complexes. The positions of the H atoms are not given.…”
The crystal structure of pentamethylcyclopentadienyllithium, [Li(C(10)H(15))] (LiCp*), has been determined from a high-resolution powder pattern by modelling and the maximum entropy method (MEM). The compound crystallizes in space group R3m with lattice parameters a = b = 14.7711 (5), c = 3.82206 (6) Å and V = 722.19 (4) Å(3) (Z = 3). LiCp* forms polymeric 'multidecker' chains along the c axis. The pentamethylcyclopentadienyl anions are coplanar with each other and show threefold rotational disorder. The MEM calculations did not only confirm the structural model and the type of disorder, but also discovered additional symmetry compared with the Rietveld analysis. This is the first solid-state structure of a Lewis-base-free alkali metal Cp* compound.
“…As expected for mainly ionic compounds, Li(η 5 -C 5 Bz 5 ) dimerizes in a head-to-tail manner, whereas in the above-mentioned dimeric η 5 -C 5 Bz 5 compounds of In I and Tl I the metal atoms point towards each other. Li(η 5 -C 5 Bz 5 ) exhibits two differently coordinated Li atoms, very similar to the dimeric [Li 2 {C 24 H 14 (SiMe 3 ) 2 }]·2THF, which contains two Li atoms sandwiched between the Cp rings of two polycyclic dianions and two further THF-solvated Li atoms situated on the outside of the sandwich units (Figure ). 2 Schematic representation of dimeric [Li 2 {C 24 H 14 (SiMe 3 ) 2 }]·2THF …”
(Pentabenzylcyclopentadienyl)lithium
(Li(η5-C5Bz5)) has been
prepared by lithiation of
pentabenzylcyclopentadiene with tert-butyllithium in toluene
or benzene. This compound,
which is the nonisolated starting material for most of the known
pentabenzylcyclopentadienides, has been characterized by NMR and mass spectroscopy. The
molecular structure of
the benzene adduct of dimeric
Li(η5-C5Bz5) has been
determined by X-ray diffraction studies.
A triple-decker-like structure,
(η5-C5Bz5)Li(η5-C5Bz5)Li(η2-C6H6),
results. The reaction of
Li(η5-C5Bz5) with
Al(η5-C5Me5) leads to
Al(η5-C5Bz5) and
Li(η5-C5Me5), with
[Li(η5-C5Bz5)2][Al(η5-C5Me5)2] as a side product.
The molecular structure of the last-named compound
consists
of the separated sandwich ions
[Li(η5-C5Bz5)2]-
and
[Al(η5-C5Me5)2]+.
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