Synthesis, structure and a nucleophilic coordination reaction of Germanetellurones

Article abstract of DOI:10.1039/c4dt00937a

β-Diketiminato cyclopentadienyl and ferrocenylethynyl germylenes LGeR (L = HC[C(Me)N-2,6-iPr₂C₆H₃]₂, R = Cp (1) and CCFc (2)) were prepared and utilized to synthesize the GeTe bond species. Reactions of 1, 2, and LGeCCPh (3) with an excess of Te powder proceeded in toluene under reflux successfully yielded germanetellurone L(R)GeTe (R = Cp (4), CCFc (5), and CCPh (6)). Further reaction of 4 with GeCl ₂·dioxane at -78 °C resulted in L(Cp)GeTe(GeCl ₂) (7), the first example of a germylene germanetellurone adduct. Both compounds 4 and 7 contain two isomers that are generated by the simultaneous 1,2-H- and 1,3-H-shifts over the Cp ring at the Ge atom. The reactions of L(Me)GeE with AuC₆F₅·SC ₄H₈ at room temperature led to pentafluorophenyl gold(i) germanethione and germaneselone compounds L(Me)GeE(AuC₆F₅) (E = S (8) and Se (9)). The formation of compounds 7-9 exhibits a rare nucleophilic coordination reaction pathway by the GeE (E = S, Se, Te) bond towards the metal-containing Lewis acidic species. The structures of compounds 1, 2, and 4-9 are studied by the NMR and/or IR spectroscopy and X-ray crystallography. This journal is the Partner Organisations 2014.

Full text of DOI:10.1039/c4dt00937a

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Synthesis, structure and a nucleophilic
coordination reaction of Germanetellurones†
Cite this: Dalton Trans., 2014, 43,
12100
Bin Li,a Yan Li,a Na Zhao,a Yuefei Chen,a Yujue Chen,a Gang Fu,a Hongping Zhu*a
and Yuqiang Ding*b
β-Diketiminato cyclopentadienyl and ferrocenylethynyl germylenes LGeR (L = HC[C(Me)N-2,6-iPr2C6H3]2,
R = Cp (1) and CuCFc (2)) were prepared and utilized to synthesize the GevTe bond species. Reactions
of 1, 2, and LGeCuCPh (3) with an excess of Te powder proceeded in toluene under reflux successfully
yielded germanetellurone L(R)GeTe (R = Cp (4), CuCFc (5), and CuCPh (6)). Further reaction of 4 with
GeCl2·dioxane at −78 °C resulted in L(Cp)GeTe(GeCl2) (7), the first example of a germylene germanetel-
lurone adduct. Both compounds 4 and 7 contain two isomers that are generated by the simultaneous
1,2-H- and 1,3-H-shifts over the Cp ring at the Ge atom. The reactions of L(Me)GeE with AuC6F5·SC4H8 at
room temperature led to pentafluorophenyl gold(I) germanethione and germaneselone compounds
L(Me)GeE(AuC6F5) (E = S (8) and Se (9)). The formation of compounds 7–9 exhibits a rare nucleophilic
coordination reaction pathway by the GevE (E = S, Se, Te) bond towards the metal-containing Lewis
acidic species. The structures of compounds 1, 2, and 4–9 are studied by the NMR and/or IR
spectroscopy and X-ray crystallography.
Received 30th March 2014,
Accepted 21st May 2014
DOI: 10.1039/c4dt00937a
www.rsc.org/dalton
PhSiH3 and CO2 to the corresponding novel addition pro-
ducts,5 consistent with that for the charge-separated species.
Introduction
The chemistry of the heavier group 14 analogues of aldehydes The heavier congeners have been previously synthesized and
and ketones and their heavier congeners has been intensively the charge-separated character of the GevE bond (E = S, Se,
studied in the last two decades, which reveals a general strat- Te) has also been studied.2b,6,7 In comparison, the reactivity of
egy for synthesizing these compounds by taking advantage of these compounds has been investigated in a lesser extent,
the sterically demanding group protection and/or additional which is probably suppressed by the steric protection of the
donor stabilization due to the high reactivity of the MvE bond group(s) at the Ge atom.1g Strikingly, the GevTe complexes
(M = Si, Ge, Sn, Pb; E = O, S, Se, Te).1,2 Recently, the GevO appear fewer in number than those with the GevS or GevSe
species L′Ge(D)vO (L′ = HC[C(Me)N-2,6-iPr2C6H3][C(CH2)-N- bonds.2b Synthesis of the GevTe complexes often requires more
2,6-iPr2C6H3], D = N-heterocyclic carbene3 or 4-dimetylamino- complex conditions, for example the presence of trialkylphosphine
pyridine (DMAP)4) and (Eind)2GevO (Eind = 1,1,3,3,5,5,7,7- as the catalyst,7a or a longer reaction time in the absence of light7b
octaethyl-s-hydrindacen-4-yl)5 have been successfully prepared or upon heat treatment,7c compared to those of their GevS and
by means of this strategy. Meanwhile, the reactivity of these GevSe congeners. The bulky β-diketiminato ligand stabilized
compounds has also been examined by the reaction of L′Ge- L(Cl)GeE (L = HC[C(Me)N-2,6-iPr2C6H3]2, E = S or Se) and the
(DMAP)vO with AlMe3 to L′Ge(Me)OAlMe2(DMAP)4 and the derivatives have been synthesized by Roesky and coworkers.6a–d
reactions of (Eind)2GevO with LiAlH4, MeLi, H2O, Me2CO, However, the related tellurium compound has not yet been pre-
pared although the reaction of LGeCl with Te has been attempted.8
We recently reported on the use of LGeR (R = Me, CuCPh,
C(SiMe3)N2) for the donor–acceptor reaction with organo-
coinage metal(I) species, in which the GeM (M = Cu, Ag, Au)
complexes were formed yielding varied aggregates when the R
aState Key Laboratory of Physical Chemistry of Solid Surfaces, National Engineering
Laboratory for Green Chemical Productions of Alcohols-Ethers-Esters, College of
Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005,
China. E-mail: hpzhu@xmu.edu.cn
bSchool of Chemical and Material Engineering, Jiangnan University, Wuxi,
group was altered.9 This shows the influence of the R group on
the donor reactivity by the lone pair of electrons at the Ge
center. We then became interested in tuning the R group to
promote the reducing reactivity of this pair to approach the
L(R)GeTe species. In this regard the cyclopentadienyl and
ferrocenylethynyl germylene compounds LGeR (R = Cp (1) and
Jiangsu 224161, China. E-mail: yding@jiangnan.edu.cn
†Electronic supplementary information (ESI) available: tables of crystal data col-
lection and structure refinements details, molecular structures of 4a, 4b, 7a and
7b and CIF data of compounds 1, 2 and 4–9. CCDC 982310–982317. For ESI and
crystallographic data in CIF or other electronic format see DOI: 10.1039/
c4dt00937a
12100 | Dalton Trans., 2014, 43, 12100–12108
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CuCFc (2)) were prepared. The reactions of 1, 2, and
LGeCuCPh (3)9b,10 with Te were carried out and germanetel-
lurones L(R)GeTe (R = Cp (4), CuCFc (5), and CuCPh (6))
were successfully formed. The Cp and alkynyl groups are
electron-rich, which probably facilitate the reactions of 1–3 by
the Ge(II) lone pair with Te. Compounds 4–6 exhibit a new type
of heavier ketones containing the cyclopentadienyl or alkynyl
group at Ge. We further investigated the reaction of 4 with
GeCl2·dioxane11 and obtained compound L(Cp)GeTe(GeCl2)
(7), the first example of a germylene germanetellurone adduct.
The formation of 7 exhibits a rare example of the nucleophilic
coordination reaction pathway. Furthermore, reactions of
12
L(Me)GeE6a with AuC6F5·SC4H8
were explored, producing
pentafluorophenyl gold(I) germanethione and germaneselone
compounds L(Me)GeE(AuC6F5) (E = S (8), Se (9)).
Fig. 1 Crystal structures of 1 and 2 with thermal ellipsoids at 50% prob-
ability level. The hydrogen atoms are omitted for clarity. Selected bond
lengths (Å) and angles (°) for 1: Ge(1)–N(1) 2.046(1), Ge(1)–N(2) 2.047(1),
Ge(1)–C(9) 2.167(2), Ge(1)⋯C(10) 2.659, Ge(1)⋯C(8) 2.663, Ge(1)⋯C(6)
3.160, Ge(1)⋯C(7) 3.164, Ge(1)⋯CCp(centroid) 2.520, C(6)–C(7) 1.411(3),
C(7)–C(8) 1.365(3), C(8)–C(9) 1.438(3), C(9)–C(10) 1.441(3), C(10)–C(6)
1.355(3); N(1)–Ge(1)–N(2) 86.26(5). For 2 (the data in the square bracket
is for another independent molecule): Ge(1)–N(1) 2.000(2) [2.007(5)],
Ge(1)–N(2) 1.999(1) [2.009(3)], Ge(1)–C(6) 2.008(3) [1.997(3)], C(6)–C(7)
1.203(4) [1.201(3)]; N(2)–Ge(1)–N(1) 90.38(8) [90.54(8)], N(2)–Ge(1)–C(6)
91.46(9) [92.21(9)], N(1)–Ge(1)–C(6) 92.41(9) [93.42(9)], Ge(1)–C(7)–C(6)
173.7(2) [176.7(2)].
Results and discussion
Synthesis of LGeR (R = Cp (1) and CuCFc (2)) and reactions of
1, 2, and LGeCuCPh (3) with Te powder
β-Diketiminato cyclopentadienyl and ferrocenylethynyl germy-
lene compounds LGeR (R = Cp (1) and CuCFc (2)) were pre-
pared by the reaction of the in situ generated LGeCl with the
respective CpNa and FcCuCLi in
a consecutive route
(Scheme 1). This pathway proves efficient by its high yield pro-
duction of 1 (87%) and 2 (81%) when compared to other path-
ways for the preparation of similar compounds using
separated LGeCl as the precursor.6a–d Compound 1 is orange
colored while 2 is deep red. They were characterized by NMR
and/or IR spectroscopy and elemental analysis.
(Fc) part. In the 13C spectrum of 2, the C5H4 carbon atoms
resonate at δ 68.10, 68.64 and 71.31 ppm while the C5H5
carbon atoms resonate at δ 70.06 ppm. These resonance data
are characteristic for Fc-containing compounds.15 The ferroce-
nylethynyl CuC functionality in 2 is revealed from the 13C
NMR (δ 100.28 and 108.26 ppm) and IR (˜ν 2124 cm−1) spectra.
X-ray single-crystal diffraction studies further confirmed the
structures of 1 and 2, in agreement with those analyzed by the
NMR and/or IR spectroscopy. The crystal structures of 1 and 2
are shown in Fig. 1, which reveal a linkage of the L ligand and
Cp in 1 and that of the L and CuCFc in 2 both at the Ge atom.
The Ge–Cp bonding in 1 can be better ascribed in an η1-mode
rather than the η5 one. The Ge(1)–C(9) bond length is found to
be 2.167(2) Å, which is significantly shorter than those of the
other Ge(1)⋯CCp bonds (2.520 to 3.164 Å). The Ge⋯CCp(centroid)
distance is 2.520 Å. The Ge(1)–C(9) bond length in 1 is shorter
but the related Ge⋯CCp(centroid) distance is longer when com-
pared with those in the η5-bonding complex (η5-Cp*)2Ge
1H NMR spectra show the characteristic septet and doublet
resonances for the CHMe2 and CHMe2 of the L ligand con-
1
tained in both 1 and 2. A singlet at δ 5.68 ppm in the H NMR
spectrum and the resonance at δ 113.64 ppm in the 13C NMR
spectrum of 1 correspond to the Cp proton and carbon atoms.
These NMR resonances suggest that the Cp ring in 1 is fluxio-
nal.13 The most similar resonance pattern is found in
[N(SiMe3)C(Ph)C(SiMe3)(C5H4N-2)]GeCp (δ1H 6.07 and δ13C
1
113.54 ppm).14 In the H NMR spectrum of 2, two multiplets
(δ 3.95 and 4.39 ppm) are assigned to the C5H4 and one singlet
(δ 4.15 ppm) to the C5H5, which are both from the ferrocenyl
(Ge–CCp*
,
2.403(4)–2.646(4); Ge⋯CCp*(centroid)
,
2.209 and
2.231 Å).16 The sum of the peripheral angle around the Ge
atom is 285.36°, which is a little wider than that observed in 2
(274.25°) for the three-coordinate Ge center in a triangular
pyramidal geometry. This indicates the presence of a lone pair
of electrons at the Ge center, which greatly influences the
geometric array of the Cp ring.
DFT calculations were performed to pin point the location
of the lone pair at the molecular orbitals (MO) of the Ge atom,
which were run by using the Gaussian 09 program with geo-
metry optimization for 1 and simplified for 2, LGeCuCH on
B3LYP/6-31+G(d). The natural bond orbital (NBO) analysis
Scheme 1 Synthesis of compounds 1 and 2.
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Scheme 3 Two possible structures caused by the distinguishable 1,2-
Scheme 2 Reactions of 1–3 with Te to form germanetellurones 4–6.
H- and 1,3-H-shifts over the Cp ring.
indicates that the Ge atom carries the positive charge of 1.047
for 1 and 0.983 for LGeCuCH, respectively, with 1.967 and
1.943 electrons occupied mainly in the s orbital of each Ge
center (for the HOMO picture see Fig. 7s in the ESI†). UV-vis
spectra recorded in toluene exhibit a weak peak at λ 366 nm
for 1 while a moderate peak at λ 344 nm for 2 (see the ESI†).
This may imply that an electronic interaction occurred
between the Ge(II) lone pair and the adjacent Cp or CuCFc
group. The latter interaction appears stronger.
(NBu4)[Cp(η4-COD)Os(μ-H)(μ-Cl)2OsCl(η4-COD)]. The latter is
suggested to undergo both the 1,2-H- and 1,3-H-shifts over the
Cp ring during the formation of this compound.17 Thus, we
assume that the two structures (4a and 4b) are generated when
the GevTe bond forms during the reaction (Scheme 3). The
1
elevated temperature (25–80 °C) H NMR spectral studies were
performed to see a possible exchange of these two structures.
However, almost no change of such a resonance pattern was
observed (see the ESI†). This implies an occurrence of the dis-
tinguishable 1,2-H- and 1,3-H-shifts over the Cp ring, which is
significantly different from those fluxionally dynamic solution
behaviors observed in compounds [N(SiMe3)C(Ph)C(SiMe3)-
(C5H4N-2)]GeCp14 and 1. In the latter two complexes, only one
signal is observed for the Cp ring protons by undergoing a
series of fast 1,2-H- or 1,3-H-shifts.13
To obtain detailed insight into the structures of these
germanetellurones, X-ray single crystal diffraction studies of
4–6 were carried out. The structural analysis clearly reveals a
formation of the GevTe bond in these three compounds. The
molecular structures of 4–6 are shown in Fig. 2 and 3. The Ge
atoms in 4–6 are all four-coordinate adopting a tetrahedral
geometry. The Ge–Te bond lengths are 2.424(2) in 4, 2.416(9)
[2.411(7)] in 5 and 2.410(8) Å in 6, respectively. These distances
Reactions of compounds 1, 2, and LGeCuCPh (3) with Te
powder were treated upon reflux in toluene, readily affording
germanetellurone L(R)GeTe (R = Cp (4), CuCFc (5), and
CuCPh (6)) (Scheme 2). Compounds 4–6 were isolated as
orange, dark red, and red crystals, respectively, in moderate
yields (59% for 4, 55% for 5, and 66% for 6). These com-
pounds are air and moisture sensitive. Melting point measure-
ments indicate that these compounds can tolerate elevated
temperature treatments (241 for 4, 296 for 5, and 265 °C for 6).
When exceeding these temperatures decomposition of the
related compound occurs, as indicated by a change in color. All
of these compounds are soluble in solvents like toluene, THF
and CH2Cl2, but sparingly soluble in n-hexane. The 1H NMR
spectrum of 5 exhibits two multiplets (δ 3.93 and 4.39 ppm)
corresponding to the C5H4 (Fc) and one singlet (δ 4.13 ppm)
corresponding to the C5H5 (Fc). The 13C NMR spectrum of 5 dis-
plays three resonances (δ 64.76, 69.05 and 71.75 ppm) and one
resonance (δ 70.18 ppm) for the C5H4 and C5H5, respectively.
These data are similar by either the chemical shifts or the
resonance pattern to those for 2. The ferrocenylethynyl CuC
carbon resonances (δ 124.42 and 124.83 ppm), however, change
a lot when compared with those for 2. This implies the dis-
appearance of the electronic influence of the lone pair elec-
trons at the Ge center on the CuC part when the GevTe bond
forms.
1
The H and 13C NMR spectra of 4 are complex and present
two sets of the resonance data as typically indicated by the
observance of two resonances for either the γ-CH proton
(δ 4.90 and 4.92 ppm) or carbon (δ 98.96 and 99.45 ppm)
atoms in the L ligand backbone. Also of note are the eight
signals at δ 2.63 (2 H), 3.25 (2 H), 6.38 (1 H), 6.48 (1 H), 6.59
(1 H), 7.02 (1 H), 7.22 (1 H) and 7.41 (1 H) ppm in the 1H NMR
spectrum of 4, which are assigned to the Cp ring proton reson-
ances. A similar resonance pattern is only observed for that of
the σ-bonded Cp ring in the 1H NMR spectrum of
Fig. 2 Crystal structure of 4 with thermal ellipsoids at 50% probability
level. The hydrogen atoms are omitted for clarity. Selected bond lengths
(Å) and angles (°): Ge(1)–N(1) 1.927(7), Ge(1)–N(2) 1.959(7), Ge(1)–Te(1)
2.424(2), Ge(1)–C(6) 1.922(4), C(6)–C(7) 1.482(5), C(7)–C(8) 1.414(6),
C(8)–C(9) 1.419(9), C(9)–C(10) 1.485(7), C(10)–C(6) 1.357(5); N(1)–Ge(1)–
N(2) 94.59(1), Te(1)–Ge(1)–C(6) 114.46(1).
12102 | Dalton Trans., 2014, 43, 12100–12108
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convergence by both two hydrogen addition treatments (see
the ESI†).
It is also interesting to find that the planarity of the
Ge(1)C(6)C(7)C(8)C(9)C(10) can be extended to the Te atom
(ΔTe(1)Ge(1)C(6)C(7)C(8)C(9)C(10) = 0.0381 Å), which implies a prob-
able electronic conjugation between the GevTe bond and the
CvC bond of Cp. Then, by means of the DFT calculations for
isomers 4a, 4b, and a presumed L(η1-Cp)GeTe (4c), the energy
difference was found by −2.5 for 4a and −1.0 for 4b relative to
the 0.0 kcal mol−1 for 4c. Isomers 4a and 4b appear more
stable than 4c (see the ESI†). Reasonably,
a co-planar
rearrangement of the GevTe bond and the Cp ring rendered
by the electronic conjugation interaction may be responsible
for driving the 1,2-H- and 1,3-H-shifts over Cp.
Reactions of 4–6 with GeCl2·dioxane and of L(Me)GeE (E = S
and Se) with AuC6F5·SC4H8
Fig. 3 Crystal structures of 5 and 6 with thermal ellipsoids at 50% prob-
ability level. The hydrogen atoms are omitted for clarity. Selected bond
lengths (Å) and angles (°) for 5 (the data in the square bracket is for
another independent molecule): Ge(1)–Te(1) 2.416(9) [2.411(7)], Ge(1)–N
(1) 1.915(4) [1.917(4)], Ge(1)–N(2) 1.914(4) [1.912(4)], Ge(1)–C(6) 1.911(6)
[1.905(5)], C(6)–C(7) 1.192(7)[1.195(6)]; N(1)–Ge(1)–N(2) 95.21(2) [95.33
(18)], C(6)–Ge(1)–Te(1) 118.16(2) [118.40(2)], Ge(1)–C(6)–C(7) 171.2(5)
[173.4(5)]. For 6: Ge(1)–N(1) 1.928(4), Ge(1)–N(2) 1.921(4), Ge(1)–C(31)
1.914(6), Ge(1)–Te(1) 2.415(2), C(31)–C(32) 1.204(8); N(1)–Ge(1)–N(2)
96.22(2), Te(1)–Ge(1)–C(31) 119.59(2), Ge(1)–C(31)–C(32) 173.5(5).
The charge-separated nature of the GevE (E = O, S, Se, Te)
bond with the electronic resonance structures has been theor-
etically19 and experimentally1k,4,6a–c discussed. Owing to this
property, complexes with the GevE bond can be used as a
donor molecule. However, the donor reactivity of these com-
plexes is rarely investigated. Driess and coworkers have
reported on the reaction of germanone L′Ge(DMAP)vO with
AlMe3 to L′Ge(Me)OAlMe2(DMAP)4 where L′Ge(DMAP)vO
(AlMe3) was thought to be an intermediate and the transfer of
the Me group to the Ge center easily occurred. Herein we
report on the investigation of such donor reactivity by altering
the acceptor molecules.
are intermediate between those in three-coordinate Tbt(Dis)-
GeTe (Tbt = 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, Dis =
bis(trimethylsilyl)methyl,
2.384(2)
Å),7c
five-coordinate
Me8taaGeTe (Me8taa = tetramethyldibenzotetra-aza(14)azulene,
2.466(1) Å)7a and [(C5H4N)C(SiMe3)2]2GeTe (2.479(1) Å)
compounds.7b
By using compounds 4–6 as the precursors, we screened the
reactions of these compounds with several Lewis acidic
species, such as AlCl3, GeCl2·dioxane and AuC6F5·SC4H8.20
However, only the reaction of 4 with GeCl2·dioxane gave com-
pound L(Cp)GeTe(GeCl2) (7). The other reactions are complex,
as indicated by the 1H NMR analysis. Isolation of the pure
compounds was not successful. Compound 7 was prepared by
the addition of a THF solution of GeCl2·dioxane to a toluene
solution of 4 from −78 °C to room temperature (Scheme 4). In
an attempt to explore the donor reactivity of the related sulfur
and selenium congeners, we prepared Roesky’s compounds
L(Me)GeE (E = S, Se),6a–c and accomplished the reactions with
AuC6F5·SC4H8 in toluene at room temperature. Compounds
L(Me)GeE(AuC6F5) (E = S (8), Se (9)) were readily obtained
(Scheme 5).
Compound 7 was isolated as an off-white solid in a low
yield (29%). It is extremely air and moisture sensitive and
Clearly, in comparison with the structure of 1, the Cp ring
in 4 adopts a σ-bonding fashion to the Ge (the least-square
plane ΔGe(1)C(6)C(7)C(8)C(9)C(10) = 0.0359 Å). The Ge–CCp bond
length is 1.922(4) Å and is comparable to that observed in the
similarly σ-bonded Ge(IV) compound Me2Ge(C7H6)(C5H4)Ti
(1.969(2) Å).18a However, the formation pathways of the Ge–CCp
σ-bonding of these two compounds are completely different.
The latter is generated via the further deprotonation of the
C5H5 group commonly observed. The former is a result of
the rearrangement of the hydrogen atoms over the C5H5 ring
when the GevTe bond forms, and represents, to the best of
our knowledge, the first example among the cyclopentadienyl
germanium compounds and the derivatives.14,16,18b–h Within
the Cp ring, the C–C bond lengths are 1.357(5) for C(6)–C(10),
1.414(6) for C(7)–C(8), 1.419(9) for C(8)–C(9), 1.482(5) for C(6)–
C(7), and 1.485(7) Å for C(9)–C(10), respectively. The C(6)–
C(10) is of a double bond character while the C(6)–C(7) and
C(9)–C(10) are the single bonds. However, the C(7)–C(8)–C(9) is
prone to be in an allylic arrangement. As a consequence, the
addition of the two H atoms at C(7) corresponds to struc-
ture 4a via the 1,2-H-shift, while structure 4b is formed by
the addition at C(9) via a 1,3-H-shift. These two structural
features are in good agreement with those analyzed by the
NMR spectrum. The final structural refinements gave a perfect
12
Scheme 4 Reaction of 4 and GeCl2·dioxane to form compound 7.
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Scheme 5 Reactions of L(Me)GeE (E = S, Se) with AuC6F5·SC4H8 to
yield compounds 8 and 9.
thermally unstable (163 °C (dec.)). Even when kept at room
temperature in an inert atmosphere (Ar or N2) compound 7
gradually changed color to grey after 2 d. Compound 8 was iso-
lated as colorless crystals in a yield of 72% while 9 as light-
yellow crystals in a yield of 56%. Unlike 7, these two com-
Fig. 4 Crystal structure of 7 with thermal ellipsoids of 50% probability
level. The hydrogen atoms are omitted for clarity. Selected bond lengths
(Å) and angles (°): Ge(1)–N(1) 1.894(6), Ge(1)–N(2) 1.911(6), Ge(1)–Te(1)
2.461(7), Ge(2)–Te(1) 2.750(1), Ge(2)–Cl(1) 2.266(3), Ge(2)–Cl(2) 2.308(3),
pounds can bear elevated temperature treatments and decom- Ge(1)–C(6) 1.909(8), C(6)–C(7) 1.361(9), C(7)–C(8) 1.477(1), C(8)–C(9)
1.416(1), C(9)–C(10) 1.380(1), C(10)–C(6) 1.481(1); N(1)–Ge(1)–N(2) 97.9
(3), Te(1)–Ge(1)–C(6) 116.7(2), Ge(1)–Te(1)–Ge(2) 93.9(2).
pose at temperatures higher than 238 °C for 8 and 260 °C for 9.
Compounds 8 and 9 are soluble in toluene, THF and
CH2Cl2. They have been characterized by multinuclear NMR
(1H, 13C and 19F) spectroscopy. In contrast, compound 7 is not
well soluble in the solvents mentioned above and only the
1H NMR spectral data was obtained in either C6D6 or D8-THF.
1
The H NMR spectrum of 7 in D8-THF exhibits a resonance
mode similar to that of 4, in which two signals (δ 5.50 and
5.63 ppm) for the γ-CH of the L ligand backbone are observed.
Eight resonances at δ 2.58 (2 H), 2.98 (2 H), 6.56 (1 H), 6.70
(1 H), 6.78 (1 H), 7.02 (1 H), 7.10 (1 H) and 7.26 (1 H) ppm
correspond to the Cp protons, indicative of a retaining of the
1
σ-bonded Cp group at the Ge atom. The H NMR spectra of 8
and 9 in C6D6 show the respective singlet resonances at δ 0.22
and 0.38 ppm for the GeMe. The 19F spectra display the reson-
ances at δ −162.92 (m-F), −161.36 (p-F) and −115.12 (o-F) for 8
and δ −162.72 (m-F), −161.28 (p-F) and −114.90 (o-F) for 9 with
an integral intensity ratio of 2 : 1 : 2, both corresponding to the
C6F5 group attached to the Au atom.
The structures of 7–9 were determined by the X-ray single
crystal diffractions. The structural analysis of 7 confirms a
Fig. 5 Crystal structures of 8 and 9 with thermal ellipsoids at 50%
probability level. The hydrogen atoms are omitted for clarity. Selected
bonding of GeCl2 at the Te atom (Fig. 4). This bonding fashion
can be compared to those found for SivO→B(C6F5)3,21
SivO→AlX3 (X = Me,22a Cl22b) and AlvO→B(C6F5)3.23 Com-
pound 7 represents the first example of a germylene germane-
tellurone adduct. The Ge(1) atom is four-coordinate in a
tetrahedral geometry while the Ge(2) is three-coordinate adopt-
ing a triangular pyramidal geometry. The Ge(2)–Te(1) bond
length (2.750(1) Å) is longer than that of the Ge(1)–Te(1)
(2.461(7) Å), and also longer than those in the Ge–Te single
bond compounds 4-CH3C6H4C(O)TeGePh3 (2.574(2) Å),24
[(Me3SiNvPPh2)2CvGe(μ-Te)]2 (2.585(4) and 2.577(4) Å),25 and
[((Me3Si)2N2)Ge]2(μ-Te)2 (2.595(2), 2.596(2) Å).26 This implies a
probably weak coordinative L(Cp)GevTe→GeCl2 bonding.
Moreover, the Ge(1)–Te(1) bond length is in between those of
the double bond in 4 and the single bond in the above-men-
tioned complexes.24–26 All of these probably imply a partial
charge transfer from the Ge(1) center to the Ge(2) atom
(Scheme 4). The Cp group in 7 remains a σ-bonding mode to
bond lengths (Å) and angles (°) for 8: Ge(1)–N(1) 1.892(6), Ge(1)–N(2)
1.905(6), Ge(1)–C(6) 1.922(8), Ge(1)–S(1) 2.135(4), Au(1)–S(1) 2.308(2);
N(1)–Ge(1)–N(2) 97.3(3), C(6)–Ge(1)–S(1) 115.0(2), Ge(1)–S(1)–Au(1)
105.7(8), S(1)–Au(1)–C(31) 171.7(2). For 9: Ge(1)–N(1) 1.890(1), Ge(1)–N(2)
1.914(2), Ge(1)–C(30) 1.888(2), Ge(1)–Se(1) 2.272(3), Au(1)–Se(1) 2.414(3);
N(1)–Ge(1)–N(2) 96.3(3), C(30)–Ge(1)–Se(1) 113.4(6), Ge(1)–Se(1)–Au(1)
103.20(1), Se(1)–Au(1)–C(31) 172.4(5).
the Ge(1) (the least-square plane ΔTe(1)Ge(1)C(6)C(7)C(8)C(9)C(10)
=
0.0473 Å). The C–C bond lengths (1.361(9) for C(6)–C(7),
1.380(1) for C(9)–C(10) and 1.416(1) for C(8)–C(9), and 1.477(1)
for C(7)–C(8) and 1.481(1) Å for C(6)–C(10)) over the Cp ring
are similar to those in 4.
The X-ray structural analysis of 8 and 9 confirms a bonding
of AuC6F5 at the E atom of L(Me)GeE (E = S, Se) (Fig. 5). The
Ge atoms adopt the tetrahedral geometry while the Au atoms
are in an almost linear geometry (E(1)–Au(1)–C(31), E = S,
171.7(2); Se, 172.4(5)°). The S–Au bond length (2.308(2) Å) in 8
12104 | Dalton Trans., 2014, 43, 12100–12108
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is slightly shorter than those in AuC6F5·SC4H8 (2.317(3) and GeCl2·dioxane11 and AuC6F5·SC4H8 were prepared according
12
2.320(3) Å).27 The Se–Au bond distance (2.414(3) Å) in 9 is to the literature.
shorter than that in AuC6F5·SePPh2Me (2.4353(11) Å).28 These
L(Cp)Ge (1). At −30 °C, nBuLi (2 mL 2.5 M solution in
data suggest a strongly coordinative interaction between L(Me)- n-hexane, 5 mmol) was added to a solution of LH (2.091 g,
GeE and AuC6F5 by the charge transfer from the Ge center 5 mmol) in toluene (50 mL). The mixture was warmed to room
to the Au atom (Scheme 5), which is probably responsible temperature and stirred for 12 h to produce a lithium salt LLi.
for the higher thermal stability of 8 and 9 than that of 7. By cooling again to −30 °C, a precooled (−30 °C) suspension
The Ge–S and Ge–Se bond lengths are ranged between those of GeCl2·dioxane (1.160 g, 5 mmol) in toluene (30 mL) was
of the non-coordinated double bond6 and single bond added. The mixture was warmed to room temperature and
complexes.6f,h,7b,25
stirred for 12 h to give LGeCl in an orange-yellow color.
Without isolation, LGeCl was cooled to −30 °C and to it CpNa
(2.5 mL 2 M THF solution, 5 mmol) was added. The mixture
was warmed to room temperature and stirred for 20 h. All vola-
tiles were removed under reduced pressure and the residue
was extracted with toluene. The extract was evaporated to
dryness under reduced pressure and the residue was washed
with cold n-hexane (8 mL) to give an orange crystalline solid of
1 (2.06 g). The n-hexane washing solution was stored at −20 °C
for three days to give X-ray quality single crystals of 1 (0.35 g).
Total yield: 2.41 g, 87%. Mp: 205 °C. 1H NMR (400 MHz, C6D6,
Conclusion
In summary, by using β-diketiminato cyclopentadienyl and
alkynyl germylenes, germanetellurones L(R)GeTe (R = Cp (4),
CuCFc (5), and CuCPh (6)) were successfully prepared.
However, when LGeCl was employed as the precursor, no reac-
tion occurred with Te even upon reflux or other treatments,8
although the reactions of LGeCl with S or Se successfully led
to the formation of L(Cl)GeE (E = S, Se).6a–c The chloride at the
Ge center is more electron-withdrawing than the cyclopenta-
dienyl and ferrocenylethynyl groups, which affects a reduction
of the Te element by the lone pair of the electrons at the Ge.
The formation of the GevTe bond in 4 resulted in a change of
the Ge–Cp bond from an η1-mode in 1 to a σ-bonding one by
the simultaneous 1,2-H- and 1,3-H-shifts over the Cp ring,
exhibiting a novel Ge–Cp bonding fashion.14,16,18 The reaction
of 4 with GeCl2·dioxane to L(Cp)GeTe(GeCl2) (7) and reactions
of L(Me)GeE with AuC6F5·SC4H8 to L(Me)GeE(AuC6F5) (E = S (8),
Se (9)) all show a nucleophilic coordination reaction way.
It reflects a donor reactivity of the heavier ketones by the
charge-separated GevE (E = S, Se, Te) bond.
3
3
298 K, ppm): δ = 1.16 (d, JHH = 6.8 Hz, 12 H), 1.40 (d, JHH
=
6.8 Hz, 12 H) (CHMe2), 1.52 (s, 6 H, CMe), 3.49 (br, 4 H,
CHMe2), 4.68 (s, 1 H, γ-CH), 5.68 (s, 5 H, Cp-H), 7.13–7.19 (m,
6 H, C6H3). 13C NMR (100 MHz, C6D6, 298 K, ppm): δ = 23.03,
24.96, 28.59 (CMe, CHMe2), 95.91 (γ-C), 113.64 (Cp-C), 124.47,
127.01, 141.27, 144.60 (C6H3), 164.00 (CN). UV-vis (nm): λ =
320, 366. Anal. Calcd (%) for C34H46GeN2 (Mr = 555.38): C,
73.53; H, 8.35; N, 5.04. Found: C, 73.50; H, 8.09; N, 5.23.
LGeCuCFc (2, Fc = C5H4FeC5H5). LGeCl (5 mmol) was pre-
pared in a similar manner to that for synthesizing 1 and used
directly for reaction without isolation. FcCuCLi was freshly
prepared from the reaction of FcCuCH (1.05 g, 5 mmol) with
nBuLi (2 mL 2.5 M n-hexane solution, 5 mmol) in toluene
(20 mL) from −30 °C to room temperature within 3 h, and
added drop by drop to the in situ generated LGeCl at −30 °C.
The mixture was warmed to room temperature and stirred for
20 h. The insoluble solid was removed by filtration, and the
filtrate was evaporated to dryness under reduced pressure to
give a deep red crystalline solid of 2. Yield: 2.82 g, 81%. Mp:
Experimental section
Materials and methods
All manipulations were carried out under dry argon or nitro- 221 °C. 1H NMR (400 MHz, C6D6, 298 K, ppm): δ = 1.13 (d,
gen atmosphere by using Schlenk line and glovebox tech- 3JHH = 6.8 Hz, 6 H), 1.30 (d, JHH = 6.8 Hz, 6 H), 1.42 (d, JHH
=
3
3
3
niques. Solvents toluene, n-hexanes and tetrahydrofuran were 6.8 Hz, 6 H), 1.52 (d, JHH = 6.8 Hz, 6 H) (CHMe2), 1.62 (s, 6 H,
3
3
dried by refluxing with sodium/potassium benzophenone CMe), 3.44 (sept, JHH = 6.8 Hz, 2 H), 4.12 (sept, JHH = 6.8 Hz,
under N2 prior to use. The NMR (1H, 13C, and/or 19F) spectra 2 H) (CHMe2), 3.95 (m, 2 H), 4.39 (m, 2 H) (C5H4), 4.15 (s, 5 H,
were recorded on a Bruker Avance II 400 or 500 MHz spectro- C5H5), 5.08 (s, 1 H, γ-CH), 7.11–7.24 (m, 6 H, C6H3). 13C NMR
meter. Infrared spectra were obtained on a Nicolet FT-IR (100 MHz, C6D6, 298 K, ppm): δ = 23.28, 23.91, 24.44, 24.69,
330 spectrometer. Melting points of the compounds were 28.06, 28.21, 28.98 (CMe, CHMe2), 68.10, 68.64, 71.31 (C5H4),
measured in a sealed glass tube using a Büchi-540 instrument. 70.06 (C5H5), 99.94 (γ-C), 100.28, 108.26 (CuC), 123.98, 124.75,
UV-vis spectra were measured on a Shimadzu UV-2550 spectro- 127.25, 141.56, 143.56, 146.65 (C6H3), 165.70 (CN). IR (KBr
photometer with solution samples in toluene (2 mL) at con- plate, cm−1): ˜ν = 2124 (CuC). UV-vis (nm): λ = 284, 377. Anal.
centrations of 1.0 × 10−5 mol L−1 and a slit width (D2 lamp) of Calcd (%) for C41H50GeFeN2 (Mr = 699.33): C, 70.42; H, 7.21;
2.0 nm was used with a slow scan speed. Elemental analysis N, 4.01. Found: C, 70.21; H, 7.09; N, 4.19. X-ray quality single
was performed on a Thermo Quest Italia SPA EA 1110 instru- crystals of 2 were obtained by recrystallization from n-hexane–
ment. Commercial reagents were purchased from Aldrich, toluene solvent mixture at −20 °C.
Acros, or Alfa-Aesar Chemical Co. and used as received. Com-
L(Cp)GeTe (4). A mixture of 1 (0.278 g, 0.5 mmol) and Te
pounds LGeCuCPh (3),9b LGeCl,29 L(Me)GevE (E = S, Se),6a powder (0.128 g, 1.0 mmol) in toluene (20 mL) was refluxed
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3
for 12 h. After cooling to room temperature, the unreacted Te 7.0 Hz, 6 H), 1.60 (d, JHH = 7.5 Hz, 6 H) (CHMe2), 3.39 (sept,
3
powder was filtered off. The filtrate was concentrated (to 3JHH = 7.0 Hz, 2 H), 3.80 (sept, JHH = 7.0 Hz, 2 H) (CHMe2),
ca. 8 mL) and n-hexane (2 mL) layered on the top. After storing 5.02 (s, 1 H, γ-CH), 6.95–7.46 (m, 11 H, C6H3 and C6H5).
at −20 °C for two days, the orange crystals of 4 were 13C NMR (125 MHz, C6D6, 298 K, ppm): 24.27, 24.55, 24.63,
1
formed (0.20 g, 59%). Mp: 241 °C (dec.). The H and 13C NMR 25.08, 27.67, 29.18, 29.43 (CMe and CHMe2), 97.25, 101.45
spectral analyses indicate the presence of two sets of the reson- (CuC), 100.35 (γ-C), 124.64, 125.12, 128.66, 128.89, 132.15,
ance data corresponding to two isomeric structures, 4a and 4b, 138.12, 144.59, 146.87 (C6H3 and C6H5), 169.60 (CN). IR (KBr
due to a slight structural difference over the Cp ring (Scheme 3). plate, cm−1): ˜ν 2151 (CuC). Anal. Calcd (%) for C40H53GeN2Te
However, a clear assignment was not possible. The resonances (6·0.5n-hexane, Mr = 762.10): C, 63.04; H, 7.01; N, 3.68. Found:
for each same functional group of both 4a and 4b are described C, 62.99; H, 6.84; N, 3.79.
1
together. H NMR (400 MHz, C6D6, 298 K, ppm): δ = 0.91 (d,
L(Cp)GeTe(GeCl2) (7). GeCl2·dioxane (0.046 g, 0.2 mmol)
was dissolved in THF (15 mL) and added to a solution of 4
3JHH = 6.4 Hz, 6 H), 1.01(d, JHH = 6.4 Hz, 6 H), 1.04 (d, JHH
=
3
3
6.4 Hz, 6 H), 1.08 (d, 3JHH = 6.4 Hz, 6 H), 1.12 (d, 3JHH = 6.4 Hz, (0.136 g, 0.2 mmol) in toluene (15 mL) at −78 °C. After the
3
3
6 H), 1.52 (d, JHH = 6.4 Hz, 6 H), 1.64 (d, JHH = 6.4 Hz, 6 H), mixture was stirred for ca. 0.5 h, an off-white solid of 7 started
1.69 (d, 3JHH = 6.4 Hz, 6 H) (CHMe2), 1.13 (s, 6 H), 1.53 (s, 6 H) to form. After warming to room temperature, all of the white
(CMe), 2.50 (br, 2 H), 2.67 (br, 2 H), 3.48 (br, 2 H), 3.55 (br, solids were collected by filtration and washed with n-hexane
2 H) (CHMe2), 2.63 (br, 2 H), 3.25 (br, 2 H) (Cp-CH2), 4.90 (s, (3 mL). Yield: 0.048 g (29%). The combined filtrate and
1 H), 4.92 (s, 1 H) (γ-CH), 6.38 (br, 1 H), 6.48 (br, 1 H), 6.59 (br, n-hexane washing solution was stored at −20 °C for three days
1 H), 7.02 (overlapped, 1 H), 7.22 (br, 1 H), 7.41 (br, 1 H) (Cp- to give pieces of colorless X-ray quality single-crystals of 7. Mp:
CH), 7.03–7.20 (m, 12 H, C6H3). 13C NMR (100 MHz, C6D6, 163 °C (dec). The solubility of 7 is not good in organic sol-
1
298 K, ppm): δ = 24.13, 24.25, 24.33, 24.39, 24.48, 24.54, 25.00, vents, and only the H NMR spectral data was recorded. Com-
25.31, 25.40, 26.17, 27.80, 29.49, 29.69 (CMe, CHMe2), 40.41, pound 7 also contains two isomers similar to those of 4a and
45.49 (Cp-CH2), 98.96, 99.45 (γ-C), 124.43, 124.48, 124.52, 124. 4b due to the slight structural difference over the Cp ring and
64, 128.35, 131.23, 133.73, 134.52, 137.16, 138.26, 138.42, two sets of the data were found but not separable. 1H NMR
3
144.39, 145.89, 146.01, 150.01, 150.13, 150.88 (C6H3, Cp-CH (500 MHz, d8-THF, 298 K, ppm): δ 0.77 (d, JHH = 6.5 Hz, 6 H),
3
3
and Cp-C), 169.24, 169.49 (CN). Anal. Calcd (%) for 0.88 (d, JHH = 6.5 Hz, 6 H), 0.90 (d, JHH = 6.5 Hz, 6 H), 1.05
3
3
C34H46GeN2Te (Mr = 682.98): C, 59.79; H, 6.79; N, 4.10. Found: (d, JHH = 6.5 Hz, 6 H), 1.13 (d, JHH = 6.5 Hz, 6 H), 1.29 (d,
3
3
C, 59.59; H, 6.74; N, 4.23.
L(FcCuC)GeTe (5). A mixture of 2 (0.675 g, 1.0 mmol) and 6.5 Hz, 6 H) (CHMe2), 1.96 (s, 6 H), 1.97 (s, 6 H) (CMe), 2.48
3JHH = 6.5 Hz, 6 H), 1.43 (d, JHH = 6.5 Hz, 6 H), 1.47 (d, JHH
=
3
3
Te powder (0.256 g, 2.0 mmol) in toluene (30 mL) was refluxed (sept, JHH = 6.5 Hz, 2 H), 2.62 (sept, JHH = 6.5 Hz, 2 H), 3.34
3
3
for 12 h. After cooling to room temperature, the unreacted Te (sept, JHH = 6.5 Hz, 2 H), 3.40 (sept, JHH = 6.5 Hz, 2 H)
powder was filtered off. The filtrate was concentrated to (CHMe2), 2.58 (br, 2 H), 2.98 (br, 2 H) (Cp-CH2), 5.50 (s, 1 H),
ca. 10 mL and n-hexane (2 mL) was added to it. The solution 5.63 (s, 1 H) (γ-CH), 6.56 (br, 1 H), 6.70 (br, 1 H), 6.78 (br, 1 H),
was stored at −20 °C for three days to give dark red crystals of 7.02 (br, 1 H), 7.10 (overlapped, 1 H), 7.26 (br, 1 H) (Cp-CH),
5. Yield: 0.44 g, 55%. Mp: 296 °C (dec.). 1H NMR (400 MHz, 7.12–7.25 (m, 12 H, C6H3). Anal. Calcd (%) for
C6D6, 298 K, ppm): δ 1.07 (d, 3JHH = 6.8 Hz, 6 H), 1.36 (d, 3JHH
=
=
=
C34H46Cl2Ge2N2Te (Mr = 826.53): C, 49.41; H, 5.61; N, 3.39.
Found: C, 49.61; H, 5.87; N, 3.41.
L(Me)GeS(AuC6F5) (8). AuC6F5·SC4H8 (0.136 g, 0.3 mmol)
3
3
6.8 Hz, 6 H), 1.59 (d, JHH = 6.8 Hz, 6 H), 1.66 (d, JHH
3
6.8 Hz, 6 H) (CHMe2), 1.55 (s, 6 H, CMe), 3.38 (sept, JHH
3
6.8 Hz, 2 H), 3.82 (sept, JHH = 6.8 Hz, 2 H) (CHMe2), 3.93 (m, was dissolved in toluene (10 mL) and added to a solution of
2 H), 4.39 (m, 2 H) (C5H4), 4.13 (s, 5 H, C5H5), 4.99 (s, 1 H, L(Me)GevS (0.161 g, 0.3 mmol) in toluene (15 mL) at room
γ-CH), 6.96–7.35 (m, 6 H, C6H3). 13C NMR (100 MHz, C6D6, temperature. An immediate solution color change from orange
298 K, ppm): δ 24.02, 24.29, 24.37, 24.86, 27.68, 28.67, 29.64 to light-yellow was observed. After stirring for 4 h, the solution
(CMe and CHMe2), 64.76, 69.05, 71.75 (C5H4), 70.18 (C5H5), was concentrated to ca. 5 mL and n-hexane (1 mL) layered
100.12 (γ-C), 124.42, 124.83 (CuC), 128.58, 137.73, 144.54, on the top. After storing at −20 °C for five days, almost color-
145.15 (C6H3), 169.40 (CN). IR (KBr plate, cm−1): ˜ν 2150 less crystals of 8 were formed. Yield: 0.194 g, 72%. Mp: 238 °C
1
(CuC). Anal. Calcd (%) for C41H50GeFeN2Te (Mr = 826.93): (dec.). H NMR (400 MHz, C6D6, 298 K, ppm): δ 0.22 (s, 3 H,
C, 59.55; H, 6.09; N, 3.39. Found: C, 59.35; H, 5.99; N, 3.57.
L(PhCuC)GeTe (6). A mixture of 3 (0.591 g, 1.0 mmol) and 1.32 (d, JHH = 6.8 Hz, 6 H), 1.57 (d, JHH = 6.8 Hz, 6 H)
Te powder (0.256 g, 2.0 mmol) in toluene (30 mL) was refluxed (CHMe2), 1.53 (s, 6 H, CMe), 2.86 (sept, JHH = 6.8 Hz, 2 H),
GeMe), 0.82 (d, 3JHH = 6.8 Hz, 6 H), 1.07 (d, 3JHH = 6.8 Hz, 6 H),
3
3
3
3
for 12 h. After cooling to room temperature, the unreacted Te 4.36 (sept, JHH = 6.8 Hz, 2 H) (CHMe2), 5.22 (s, 1 H, γ-CH),
powder was filtered off. The filtrate was concentrated to 6.88–7.15 (m, 6 H, C6H3). 13C NMR (100 MHz, C6D6, 298 K,
ca. 6 mL and n-hexane (2 mL) was added to it. The solution ppm): δ 3.02 (GeMe), 23.24, 23.29, 24.36, 24.72, 27.32, 28.86,
was stored at −20 °C for three days to give red crystals of 29.12 (CMe and CHMe2), 102.17 (γ-C), 123.82, 126.67, 129.23,
1
6·0.5n-hexane. Yield: 0.50 g, 66%. Mp: 263 °C (dec.). H NMR 135.45, 143.41, 148.44 (C6H3 and C6F5), 169.94 (CN). 19F NMR
(500 MHz, C6D6, 298 K, ppm): 1.07 (d, 3JHH = 6.5 Hz, 6 H), 1.21 (376 MHz, C6D6, 298 K, ppm): δ −162.92 (m, 2 F, m-F), −161.36
3
3
(d, JHH = 7.0 Hz, 6 H), 1.54 (s, 6 H, CMe), 1.59 (d, JHH
=
(m, 1 F, p-F), −115.12 (m, 2 F, o-F). Anal. Calcd (%) for
12106 | Dalton Trans., 2014, 43, 12100–12108
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C36H44AuF5GeN2S (Mr = 901.41): C, 47.97; H, 4.92; N, 3.11. invaluable discussions on this manuscript. We also thank the
Found: C, 47.81; H, 4.97; N, 3.09.
reviewers for the helpful discussions during revision.
L(Me)GeSe(AuC6F5) (9). AuC6F5·SC4H8 (0.136 g, 0.3 mmol)
was dissolved in toluene (10 mL) and added to a solution of
L(Me)GevSe (0.175 g, 0.3 mmol) in toluene (15 mL) at room
temperature. An immediate solution color change from orange
to light-yellow was observed. After stirring for 4 h, the solution
was concentrated to ca. 5 mL and n-hexane (1 mL) was added
to it. After storing at −20 °C for three days, light-yellow crystals
of 9 were formed. Yield: 0.160 g, 56%. Mp: 260 °C (dec.).
1H NMR (400 MHz, C6D6, 298 K, ppm): δ 0.38 (s, 3 H, GeMe),
Notes and references
1 (a) T. Tsumuraya, S. A. Batcheller and S. Masamune, Angew.
Chem., Int. Ed. Engl., 1991, 30, 902–930; (b) M. C. Kuchta
and G. Parkin, Coord. Chem. Rev., 1998, 176, 323–372;
(c) N. Tokitoh, Phosphorus, Sulfur Silicon Relat. Elem., 1998,
136, 123–138; (d) J. Escudie and H. Ranaivonjatovo, Adv.
Organomet. Chem., 1999, 44, 113–174; (e) N. Tokitoh,
T. Matsumoto and R. Okazaki, Bull. Chem. Soc. Jpn., 1999,
72, 1665–1684; (f) R. Okazaki and N. Tokitoh, Acc. Chem.
Res., 2000, 33, 625–630; (g) N. Tokitoh and R. Okazaki, Adv.
Organomet. Chem., 2001, 47, 121–166; (h) S. Nagendran and
H. W. Roesky, Organometallics, 2008, 27, 457–492;
(i) S. K. Mandal and H. W. Roesky, Chem. Commun., 2010,
46, 6016–6041; ( j) P. P. Power, Nat. Chem., 2012, 4, 343–
344; (k) Y. Xiong, S. Yao and M. Driess, Angew. Chem., Int.
Ed., 2013, 52, 4302–4311.
3
3
0.83 (d, JHH = 6.8 Hz, 6 H), 1.09 (d, JHH = 6.8 Hz, 6 H), 1.29
3
3
(d, JHH = 6.8 Hz, 6 H), 1.54 (d, JHH = 6.8 Hz, 6 H) (CHMe2),
3
1.50 (s, 6 H, CMe), 2.87 (sept, JHH = 6.8 Hz, 2 H), 4.26 (sept,
3JHH = 6.8 Hz, 2 H) (CHMe2), 5.19 (s, 1 H, γ-CH), 6.88–7.14
(m, 6 H, C6H3). 13C NMR (100 MHz, C6D6, 298 K, ppm): δ 5.38
(GeMe), 23.39, 23.46, 24.42, 24.70, 28.88, 29.06 (CMe and
CHMe2), 102.35 (γ-C), 123.96, 126.61, 129.25, 135.48, 143.69
(C6H3 and C6F5), 169.68 (CN). 19F NMR (376 MHz, C6D6, 298 K,
ppm): δ −162.72 (m, 2 F, m-F), −161.28 (m, 1 F, p-F), −114.90
(m, 2 F, o-F). Anal. Calcd (%) for C36H44AuF5GeN2Se (Mr
948.31): C, 45.60; H, 4.68; N, 2.95. Found: C, 45.45; H, 4.83; N,
2.87.
=
2 (a) P. P. Power, Chem. Rev., 1999, 99, 3463–3504;
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Crystallographic data for compounds 1, 5, 7 and 8 were col-
lected on an Oxford Gemini S Ultra system and for 2, 4, 6 and 9
on a Rigaku R-Axis Spider IP. During measurements graphite-
monochromatic Mo-Kα radiation (λ = 0.71073 Å) was used.
Absorption corrections were applied using the spherical har-
monics program (multi-scan type). All structures were solved
by direct methods (SHELXS-96)30 and refined against F2 using
SHELXL-97.31 In general, the non-hydrogen atoms were
located by difference Fourier synthesis and refined anisotropi-
cally, and hydrogen atoms were included using a riding model
with Uiso tied to the Uiso of the parent atoms unless otherwise
specified. In 2, two independent molecules were disclosed, in
which two C5H5, one C5H4 and one iPr groups were disordered
and treated in a splitting mode by PART method. Carbon
atoms C(15A), C(53A), C(54A) and C(54) were isotropically
refined. In 5, two independent molecules were also disclosed,
and one C5H5 and one iPr groups were disordered and treated
in a splitting mode as well. Carbon atoms C(51A) and C(55A)
were isotropically refined. In 7, one carbon atom C(261) was
isotropically refined. A summary of cell parameters, data col-
lection, and structure solution and refinements is given in
Tables 1s and 2s in the ESI.†
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This work was supported by the 973 Program (2012CB821704),
the National Nature Science Foundation of China (20972129),
and the Innovative Research Team Program (IRT1036 and
J1310024). We greatly thank Dr Prinson P. Samuel at the Insti-
tute of Inorganic Chemistry, University of Goettingen for the
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12108 | Dalton Trans., 2014, 43, 12100–12108
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