Synthesis and characterization of some organo-all-tin dendrimers with different peripheral substituents

Article abstract of DOI:10.1016/j.jorganchem.2005.11.012

The synthesis of the first all-tin-dendrimer Sn[(CH₂) ₄SnPh₃]₄ (2) results from complete hydrostannation of tetra(but-3-enyl)stannane (1) with triphenyltin hydride. Selective cleavage of one phenyl group from ea

Full text of DOI:10.1016/j.jorganchem.2005.11.012

Journal of Organometallic Chemistry 691 (2006) 1703–1712
www.elsevier.com/locate/jorganchem
Synthesis and characterization of some organo-all-tin dendrimers
with different peripheral substituents
*
Herbert Schumann , Yilmaz Aksu, Birgit C. Wassermann
Institut fu¨r Chemie, Technische Universita¨t Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
Received 5 November 2005; accepted 7 November 2005
Available online 20 December 2005
Abstract
The synthesis of the first all-tin-dendrimer Sn[(CH2)4SnPh3]4 (2) results from complete hydrostannation of tetra(but-3-enyl)stann-
ane (1) with triphenyltin hydride. Selective cleavage of one phenyl group from each dendron of 2 with anhydrous HCl results
in Sn[(CH2)4Sn(Cl)Ph2]4 (3), which on treatment with LiAlH4 yields the corresponding hydride derivative Sn[(CH2)4Sn(H)Ph2]4
(4) containing four reactive Sn–H bonds. The cyclopentadienyl derivative Sn[(CH2)4Sn(C5H5)Ph2]4 (5) as well as the transition metal
substituted derivatives Sn[(CH2)4Sn{Co(CO)4}Ph2]4 (6), Sn[(CH2)4Sn{Fe(CO)2C5H5}Ph2]4 (7), and Sn[(CH2)4Sn{Mn(CO)5}Ph2]4 (8)
have been prepared by coupling of 3 with the appropriate Grignard or sodium derivatives of the transition metal moieties. The new
compounds were characterized by elemental analyses, IR, 1H-, 13C- and 119Sn NMR spectroscopy and MALDI-TOF mass
spectrometry.
ꢀ 2005 Elsevier B.V. All rights reserved.
Keywords: Organotin compounds; Dendrimers; Organotin hydride; Iron; Cobalt; Manganese
1. Introduction
nation in the core or to the surface. Metallodendrimers
containing main group metals, exclusively those, in which
the metal atoms are able to occupy all branching positions
in the structure, attracted considerable interest and have
also been subject of several publications [14,15]. Although
a few triorganotin derivatives which can be classified as
dendrimers have already been described, they have not
been prepared under the perspective of dendrimer synthe-
sis, but studied in relation to multinuclear NMR spectro-
scopic investigations [16]. In preceding papers [17,18] we
reported on the synthesis of tin containing metallodendri-
mers and their functionalization with water-soluble ligands
with regard to application as X-ray contrast agents.
Continuing our interest in organotin dendrimers we report
here the synthesis and spectroscopic characterization of
dendrimers with tin atoms as branching units, which can
be used as suitable starting materials for new dendritic
organotin macromolecules with reactive units on the
periphery because they permit multiple possibilities for
derivatization.
One of the most remarkable classes of organic com-
pounds developed in recent years is that of dendrimers
[1–3]. Due to their attractive and unique properties [4–6],
as well as their diverse and promising applications for
example in catalysis [7], medicine [8,9], material sciences
[10], or host–guest chemistry [11], interest in this new area
of chemistry increased rapidly. A rising demand for mate-
rials with novel properties forced researchers to incorpo-
rate metal atoms into different sites of the dendritic
structure, creating a new class of compounds, the so-called
metallodendrimers. As a result, several new dendritic sys-
tems based on metal atoms have been described during
recent years [12]. Most of them consist of transition metal
as well as lanthanide [13] complexes linked through coordi-
*
Corresponding author. Tel.: +49 30 314 23984; fax: +49 30 314 22168.
E-mail address: Schumann@chem.tu-berlin.de (H. Schumann).
0022-328X/$ - see front matter ꢀ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.11.012

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H. Schumann et al. / Journal of Organometallic Chemistry 691 (2006) 1703–1712
2. Results and discussion
split bonds between tin and aromatic hydrocarbon ligands
preferably to bonds between tin and aliphatic ligands, con-
verting organotin compounds into their corresponding halo-
gen derivatives [23], treatment of 2 neither with Br2 nor with
excess amounts of gaseous HCl in diethyl ether did not result
in a complete transformation of 2 into Sn(CH2CH2CH2-
CH2SnX3)4. The resulting mixture of compounds containing
all sorts of –SnPh3ÀnCln peripheral substituents could not be
separated. But reaction of 2 in CH2Cl2 at À78 ꢁC with a little
bit more than four equivalents of gaseous HCl dissolved in
2.1. Synthesis of dendritic organotin compounds 2, 3, 4 and 5
Treatment of tetravinylstannane with an excess of tri-
phenylstannane in the presence of azo-isobutyronitrile,
AIBN, provided after workup of the very viscous reaction
mixture with pentane a light yellow solid, whose constitu-
tion did not match that of the desired tetrakis(2-triphenyl-
ethyl)stannane, but that of 1,2-bis(triphenylstannyl)ethane
[19] (Scheme 1). Variation of the reaction conditions, such
as lower or higher reaction temperature, use of different
solvents, changing the stoichiometry or activation by other
catalysts, did not result in the formation of even traces of
the dendrimer. The formation of Ph3SnCH2CH2SnPh3
results obviously from the reaction of triphenyltin hydride
with the intermediate triphenylvinyltin already formed by
vinyl/hydrogen exchange. A similar ligand redistribution
process has previously been observed for the hydrostanna-
tion of diphenyldivinylstannane [20].
Tetraallylstannane reacts in the same way, forming
1,3-bis(triphenylstannyl)propane [21] and not the desired
tetrakis(3-triphenylpropyl)stannane. In contrast, hydro-
stannation of tetrabutenylstannane (1) [22] succeeded,
resulting in the formation of tetrakis(4-triphenylstannylbu-
tyl)stannane (2), which could be isolated after 24 h stirring
of a mixture of 1 and a fourfold amount of Ph3SnH in 94%
yield (Scheme 1).
diethyl
ether
yields
tetrakis[4-(chlorodiphenylstan-
nyl)butyl]stannane (3) as a light yellow oil in nearly quanti-
tative yield (Scheme 2). Crystallization of 3 was not
possible, even after careful recrystallization experiments.
Due to their high reactivity, organotin hydrides represent
a very important category of compounds. Treatment of 3
with LiAlH4 in diethyl ether at 0 ꢁC afforded after hydroly-
sis of the reaction mixture with water and subsequent
workup with aqueous ammonium chloride, the hydride
derivative tetrakis[4-(hydridodiphenylstannyl)butyl]stann-
ane (4) as a colorless, viscous oil in 93% yield (Scheme 2).
The substitution of Cl by H increased the solubility of 3
in diethyl ether in comparison to that of 1 and 2, but the
stability against water and air decreased in the same direc-
tion. Compound 4 is a powerful reagent to convert alkyl
halides to the corresponding alkanes, which could be dem-
onstrated by the NMR-monitored rapid reaction with
CHCl3 yielding CH2Cl2 and 3 within a few minutes.
The addition reaction exclusively follows the anti-Mark-
ownikow rule forming exclusively Sn[(CH2)4SnPh3]4 (2) as
a white solid, which is stable against moisture and air in the
solid state as well as in solution. All attempts failed to get it
in a crystalline state, useful for X-ray diffraction studies.
Compound 2 melts at 151 ꢁC without decomposition, and
it is soluble in aromatic hydrocarbons and CHCl3, but
insoluble in diethyl ether and aliphatic hydrocarbons.
Substitution of all phenyl groups in 2 by halogens should
open the way to the synthesis of second generation tin cen-
tered dendrimers. But in contrast to the well known fact, that
halogens, hydrogen halides as well as some metal halides
Compound 3 reacts with four equivalents of NaC5H5 in
toluene with formation of tetrakis[4-(cyclopentadienyldi-
phenylstannyl)butyl]stannane (5) in 72% yield as a viscous
yellow–green oil (Scheme 2), which decomposed rapidly at
room temperature. However, it is considerably stable
below 0 ꢁC and can be used as a starting material for novel
transition metal containing organotin dendrimers.
2.2. NMR and MALDI-TOF spectra of 2, 3, 4, and 5
1
Low intensities and overlapping of the broad H NMR
signals in the spectra of 2, 3 and 4 prevented in most cases
Scheme 1.

H. Schumann et al. / Journal of Organometallic Chemistry 691 (2006) 1703–1712
1705
Scheme 2.
the recognition of the tin hydrogen coupling constants. The
1H NMR spectrum of 2 shows two clearly separated signal
ranges, two multiplets of the phenyl groups in the aromatic
region and three multiplet signals between 0.45 and
1.76 ppm for the remaining aliphatic hydrogens of the
butyl chain. The absence of any peaks in the olefinic region
reveals the successful and complete hydrostannation. Com-
pounds 3 and 4 exhibit similar signal patterns to 2; the
chlorine substituents in 3 shift the signals for the aliphatic
protons slightly downfield, the hydrido ligands in 4 cause a
weak upfield shift of those resonances. Compound 4 shows
an intense singlet signal at d 6.37 ppm for the Sn–H reso-
nance. The large coupling constant 1J(1H117/119Sn) of
1723.17/1803.76 Hz corresponds to that of Ph3SnH [24].
ligands. Consequently, for each of these carbon atoms two
coupling constants 2J(13C117/119Sn) and 3J(13C117/119Sn)
were determined. Since aryl substituted organotin com-
pounds cause larger J(13C,Sn) coupling constants then those
of alkyl substituted compounds, the signal at d = 31.77 ppm
3
with J(13C119Sn) = 63.22 Hz indicates a c-position for the
phenyl substituted peripheral tin atoms and allows an
assignment of this signal to the carbon atom in c-position
to the phenyl substituted tin atom. The resonance at
31.36 ppm (3J(13C119Sn) = 57.77 Hz) belongs to the remain-
ing carbon atom. The resonances detected for 3 range from 8
to 140 ppm. The butyl carbon atoms bonded to the periph-
eral tin atoms are influenced particularly by the replacement
of one phenyl group by chlorine in each dendron, which
is reflected by a strong deshielded resonance at d =
17.01 ppm. On the other hand, a reversed but smaller effect
is observed for the b and c carbon atoms of the butyl chain,
which appear with a slight upfield shift at d = 30.02 and
30.98 ppm. The presence of the electron rich chlorine
increases the s-character of the hybrid orbitals, participating
in the Sn–C bond confirmed by an enlargement of the corre-
sponding coupling constants 1J(13C117/119Sn) = 405.99/
424.52 Hz by 28 Hz. The 13C- {1H} NMR spectra of 4 and
5 differ only slightly from that of 2. The exchange of chlorine
by hydrogen in 4 and by C5H5 in 5 causes an upfield shift of
the signals of the butyl carbon atoms bonded to the periph-
eral tin atoms from d = 17.01 ppm in 3 to 10.24 ppm in 4
and 9.72 ppm in 5. The 13C/Sn coupling constants diminish
and show values close to those of 2.
1
The H NMR spectrum of 5 shows only one sharp singlet
with satellites caused by the coupling with 117/119Sn
(2J = 22.60/23.64 Hz) for the cyclopentadienyl protons at
6.28 ppm, illustrating the non-rigid behavior of the cyclo-
pentadienyl group bonded to tin [25].
The 13C{1H} NMR spectra of 2, 3, 4 and 5 display
distinguishable signals surrounded with Sn satellites for
each carbon atom and confirm the 1H NMR results.
Neither traces of olefinic resonances nor doubled signals
due to non-equivalence of the dendritic branches could be
observed. The 13C{1H} NMR spectrum of 2 shows eight
well separated singlets; four for the aromatic and four for
the aliphatic carbon atoms. In principle, the relation
1J > 3J > 2J > 4J valid for the tin carbon coupling constants
of most alkyl and aryl substituted tin compounds [26] per-
mits an exact assignment of all signals. Thus, the two upfield
resonances at 8.32 and 10.69 ppm have been assigned to the
directly tin bonded aliphatic carbon atoms. The bonds of the
sp2-hybridized phenyl carbon atoms to the peripheral tin
atoms cause an s orbital influence to the Sn–Cbutyl
(d = 10.69 ppm) bond formation and thus an enlargement
of the coupling constant 1J(13C117/119Sn) from 295.91/
309.81 to 377.38/394.82 Hz. The smaller coupling constant
1J(13C117/119Sn) (295.91/309.81 Hz) of the signal at
8.32 ppm is significant for tetraalkyltin compounds and
for that reason is assigned to the carbon atoms bonded to
the central tin atom. The signals of the b and c carbon atoms
of the butyl chain lie very close together at d = 31.66 and
31.77 ppm. The presence of two non-equivalent tin centers
at both ends of the butyl chain gives rise to couplings with
two tin atoms, each coordinated by different organic
The 119Sn{1H} NMR spectra of 2 to 4 display for the
two non-equivalent tin atoms two resonances with differ-
ent intensities (Fig. 1). While the central tin atom is not
much affected, the peripheral tin atoms display signals
dependent upon the electronegativity of the different third
ligand at tin at À136.65 ppm (4), À99.36 ppm (2) and
+17.50 ppm (3).
The constitution of compounds 2–4, has been certified
also by MALDI-TOF mass spectrometric investigations.
For all dendrimers the appropriate molecular ion could
be detected as peak with the highest m/z value (2: m/z
1766.42 (Fig. 2), 3: m/z 1599.13 and 4: m/z 1462.39). The
spectra indicate no signals assignable to impurities with
imperfectly branched dendrimers or incomplete substitu-
tion reactions. The molecular ion peaks, which appear
with the appropriate tin isotope ratios agreed very closely

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H. Schumann et al. / Journal of Organometallic Chemistry 691 (2006) 1703–1712
Fig. 1. 119Sn NMR spectra (149.21 MHz) of 2, 3 in CDCl3 and 4 in C6D6.
Fig. 2. MALDI-TOF mass spectrum of 2.
with the calculated values. The MALDI-TOF mass spec-
trum of 3 exhibits a lower mass peak arising from the loss
of two chlorine groups at m/z 1530.33 [M À 2Cl + Na]+.
For all dendrimers no significant fragmentation could be
observed.
2.3. Dendrimers with peripheral transition metal complexes
Dendrimer 3 containing four chlorine atoms bonded to
the four peripheral tin atoms is a promising starting
material for the synthesis of transition metal containing

H. Schumann et al. / Journal of Organometallic Chemistry 691 (2006) 1703–1712
1707
Scheme 3.
dendrimers with a stable organotin core and four transition
metals at the periphery potentially useful for homogeneous
catalysis. To investigate this possibility, we treated 3 with a
slight excess (4.1 equiv) of NaCo(CO)4 in diethyl ether and
BrMgFe(CO)2C5H5, as well as BrMgMn(CO)5 in THF.
The new dendrimers Sn[(CH2)4Sn{Co(CO)4}Ph2]4 (6),
Sn[(CH2)4Sn{Fe(CO)2C5H5}Ph2]4 (7), and Sn[(CH2)4Sn-
{Mn(CO)5}Ph2]4 (8), respectively, are formed as a green vis-
cous oil (6), as a brown viscous oil (7), and as a yellowish oil
(8), respectively, and are isolated after repeated extraction
with cold diethyl ether/pentane mixtures in satisfying yields
(Scheme 3). They are soluble in aromatic hydrocarbons and
THF, but insoluble in alkanes and diethyl ether. They are
air sensitive and decompose on contact with atmospheric
oxygen within a few hours accompanied by discoloration
and solidification. On the other hand, 6–8 are stable on
exposure to degassed water. This resistance allows removal
of excess Grignard reagents by hydrolysis and isolation of
the products in high purity.
The 13C{1H} NMR spectra of compounds 6–8 show just
one signal for each carbon atom, demonstrating the purity
of the derivatives and the consistence with the proposed
structures. The replacement of the chlorine atoms at the
surface of the dendrimer 2 by the fragments Co(CO)4 in
6 and Mn(CO)5 in 8 produced a diminution of the coupling
constants, confirmed specifically by a strong downfield
shift of the d-carbon atom of the butenyl chain, whereas
the remaining carbon atoms of this chain are less affected
and maintain their original positions with only very light
deviations. For 7 the Sn/C-coupling constants could not
be observed. Even long-time measurements afforded no
detection. The spectrum of 6 displays a slightly upfield
shifted d-carbon atom (d = 17.94 ppm) with a reduced cou-
1
pling constant of J(13C117/119Sn) = 320.16/335.15 Hz. The
introduction of [Fe(CO)2C5H5] units in 7 exerts similarly a
large upfield shift of the d-carbon atoms to d = 15.41 ppm.
The [Mn(CO)5] ligands in 8 cause a further and stronger
upfield shift to d = 14.46 ppm and a more intense reduction
of the appropriate coupling constant 1J(13C117/119Sn)
(280.11/292.37 Hz). The characteristic carbonyl groups
can be detected likewise in the expected region, as singlets
at d = 199.46 ppm (6), 214.89 ppm (7), and 213.87 ppm (8).
The 119Sn{1H} NMR spectra of compounds 5–8 show
only two signals each for the two different kinds of tin atoms
and reflect the successful conversion of 3 and preclude the
formation of uncompleted substitution products (Fig. 3).
Due to the drastic shifts of the appropriate 119Sn{1H}
NMR resonances, the effect of the cyclopentadienyl groups
and the transition metal ligands on the peripheral tin atoms
can be pursued more simply and significantly than with the
13C{1H} NMR data. The extreme downfield location of the
119Sn NMR signals is remarkable. While the cyclopentadie-
nyl groups cause an upfield shift of the terminal tin atom res-
onances from d = 17.50 ppm for 3 to À70.65 ppm in 5, the
conversion of 3 to 6 and 7 accompanies simultaneous and
The 1H NMR spectra of 6–8 show strongly widened sig-
nals, presumably as a result of the broadening effect arising
from the presence of transition metal containing ligands,
whose interference prevent a determination of the hydro-
gen tin couplings. In contrast the resemblance to the spec-
tra of the dendrimers 2–4, and the good concordance of the
relative intensities of the signals with the theoretical values
1
makes a correct location possible. All H NMR spectra
exhibit the expected number of signals and could be ana-
lyzed without exception. For all transition metal deriva-
tives the resonances for the SnaCH2 protons and the
protons of the phenyl ligands were identified with almost
identical chemical shift values as in the parent compound
2. Differences were observed for the b, c, and d protons
of the butenyl chains, which experience a slightly downfield
shift caused by the presence of the new transition metal
complex units.

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H. Schumann et al. / Journal of Organometallic Chemistry 691 (2006) 1703–1712
Fig. 3. 119Sn NMR spectra (149.21 MHz) of 5 and 6 in C6D6 and 7 and 8 in CDCl3.
differentiated downfield shifts to 58.39 (6) and 88.65 ppm
(7), respectively. In contrast 8 shows an upfield shifted reso-
nance at d = 5.61 ppm for the same tin atoms. A correlation
between these 119Sn NMR data and the magnitude of the
corresponding 13C117/119Sn coupling constants is not pro-
ducible. Obviously not only the electronic character of the
peripheral tin atoms plays a role in these effects.
The IR spectra of 6–8 recorded in CHCl3 show the pre-
dominant m(C@O) absorption bands in the typical regions
of comparably modified organotin compounds [27].
Despite the application of different ionization methods,
significant mass spectra could not be obtained for 5 and 6.
The thermolability and air sensibility of these compounds
prevented a sufficient characterization by mass spectrome-
try. For dendrimers 7 and 8 the corresponding sodium ion
adduct peaks m/z 2165.39 [M7 + Na]+ and m/z 2235.08
[M8 + Na]+ were detected satisfyingly with MALDI-TOF
mass spectrometry.
atmosphere of nitrogen using standard Schlenk techniques.
Melting points were measured in sealed capillaries with a
Buchi 510 melting point determination apparatus and are
¨
uncorrected. Elemental analyses were performed on a Per-
kin–Elmer Series II CHNS/O Analyzer 2400. The NMR
spectra were recorded on Bruker ARX 200 (1H,
200 MHz; 13C, 50 MHz) and ARX 400 (1H, 400 MHz;
13C, 100.64 MHz; 119Sn, 149.21 MHz) spectrometers at
ambient temperature. Chemical shifts are reported in
1
ppm and referenced to the H and 13C residues of the deu-
terated solvents. Chemical shifts for 119Sn measurements
are given relative to (CH3)4Sn. IR spectra were obtained
on a Nicolet Magna System 750 spectrometer. Mass spec-
tra (EI, 70 eV) were recorded on a Varian MAT 311
A/AMD instrument. Only characteristic fragments con-
taining the isotopes of the highest abundance are listed.
Relative intensities are given in parentheses.
Matrix-assisted laser desorption ionization time-of-
flight (MALDI-TOF) mass spectrometry was performed
in the reflection mode on an Applied Biosystems Voy-
agerꢂ-Elite mass spectrometer equipped with a nitrogen
laser emitting at 337 nm. The acceleration voltage was set
to 20 and 25 kV, respectively, with positive or negative ion-
3. Experimental
All manipulations involving air sensitive compounds
were carried out in dry, oxygen-free solvents under an inert

H. Schumann et al. / Journal of Organometallic Chemistry 691 (2006) 1703–1712
1709
ization. The mass spectrometer was externally calibrated
with a mix of three peptides with different masses. Trans-
indolacrylicacid (IAA) was used as MALDI matrix at a
concentration of 0.2 M and 10 mM in THF/CH3CN
(3:1), respectively. Sample solutions were prepared with
an approximate concentration of 1 mM in THF or CH2Cl2.
Solutions containing 2 mM of CH3CO2Na, KCl or AgI
were used as ionization agents. Sonification was applied
to speed up mixing. One microlitre of the sample was
mixed with 1 lL of the matrix solution and 1 lL of the
resulting mixture was deposited on a stainless-steel flat
plate and allowed to dry at room temperature. CH2@CH-
CH2CH2Br, anhydrous HCl(g), LiAlH4, SnCl4, Ph3SnCl,
Sn(CH@CH2)4, Sn(CH2CH@CH2)4, Mn2(CO)10, and
[Fe(CO)2-g5-C5H5]2 were used as purchased. Ph3SnH
[28], NaC5H5 [25], Na[Co(CO)4] [29], BrMg[Fe(CO)2-g5-
C5H5] [30], and BrMg[Mn(CO)5] [30] were prepared
according to published procedures.
18H, Ph–Hm/p). 13C{1H} NMR (50.32 MHz, CDCl3): d
8.17 [1J(13C117/119Sn) = 296.22/309.83 Hz, CH2CH2SnPh3],
30.20 [2J(13CSn) = 43.31/45.30 Hz, CH2CH2SnPh3], 128.77
[3J(13C117/119Sn) = 137.73/140.07 Hz, Ph–Cm], 129.15 [4J(13C-
117/119Sn) = 11.1/11.64 Hz, Ph–Cp], 137.54 [1J(13C117/119Sn) =
455.53/476.48 Hz, Ph–Cipso], 137.87 [2J(13C117/119Sn) =
45.51/47.60 Hz, Ph–Co]. MS (203 ꢁC): m/z (%): 743 (0.03)
[M]+, 701 (1) [M À C3H6]+, 624 (3) [M À C3H6 À C6H5]+,
547 (1) [M À C3H6 À 2C6H5]+, 352 (99) [M À C3H6 À Sn-
(C6H5)3]+, 120 (24) [Sn]+. Anal. Calc. for C39H36Sn2
(742.09 g/mol): C, 63.12; H, 4.89. Found: C, 63.09; H, 5.27%.
3.3. Synthesis of Sn(CH2CH2CH@CH2)4 (1)
A solution of CH2@CHCH2CH2MgBr in THF (100 ml),
prepared from CH2@CHCH2CH2Br (20 g, 148 mmol) with
excess magnesium turnings (4.0 g, 165 mmol) was placed in
a 250 ml flask and cooled to 0 ꢁC, before freshly distilled
SnCl4 (9.6 g, 37 mmol) was added cautiously within 1 h.
The solution was stirred for 0.5 h at 0 ꢁC and subsequently
for 5 h at ambient temperature. After cooling to 0 ꢁC, the
reaction mixture was hydrolyzed slowly with water. The
organic fraction was extracted with Et2O, washed several
times with saturated NH4Cl solution and dried over
Na2SO4. After the removal of all volatiles, 1 was obtained
as a light yellow oil.
3.1. Hydrostannation of tetravinylstannane
Freshly distilled Ph3SnH (11 g, 31.5 mmol) and AIBN
(5 mol%, 0.3 g, 1.5 mmol) were placed in a 50 ml flask
and stirred for 0.5 h at room temperature. Then Sn(CH@
CH2)4 (1.43 g, 6.3 mmol) was added slowly within 0.5 h.
After stirring the reaction mixture overnight at ambient
temperature, pentane was added to the viscous crude prod-
uct to precipitate a solid. Filtration, subsequent washing of
the residue three times with a mixture of Et2O/pentane
(50:50) and removal of the solvents in vacuum (10À2 mbar)
yielded (Ph3SnCH2)2 as a light yellow solid.
Yield 9.50 g (76%), b.p. 60–64 ꢁC/0.06 mbar (Lit.
78–82 ꢁC/0.04 mmHg [22]). IR (KBr/film): m(C@C)
1639 cmÀ1(s). 1H NMR (200.13 MHz, CDCl3): d 0.96
[m, 2J(1H117/119Sn) = 46.85/48.79 Hz, 8H, SnCH2], 2.29
(m, 8H, SnCH2CH2), 4.97 (m, 8H, @CH2), 5.90 (m,
Yield: 1.97 g (2.7 mmol), m.p. 204–205 ꢁC (Lit.: 205–
4H, CH). 13C{1H} NMR (50.32 MHz, CDCl3):
d
1
207 ꢁC [19]). H NMR (200.13 MHz, CDCl3): d 1.94 (m,
8.46 [1J(13C117/119Sn) = 300.27/314.17 Hz, SnCH2], 30.78
[2J(13C119Sn) = 17.98 Hz, SnCH2C], 112.99 (@CH2),
141.79 [3J(13CSn) = 50.14 Hz, CH]. 119Sn{1H} NMR
(149.21 MHz, CDCl3): d À5.6. MS (110 ꢁC): m/z (%):
285 (8) [M À C4H7]+, 230 (7) [M À 2C4H7]+, 175 (11)
[M À 3C4H7]+, 120 (6) [Sn]+. Anal. Calc. for C16H28Sn
(339.1 g/mol): C, 56.67; H, 8.32. Found: C, 56.59; H,
8.29%.
4H, CH2SnPh3), 7.33–8.03 (m, 12H, Ph–Ho), 7.57–7.81
(m, 18H, Ph–Hm/p). 13C{1H} NMR (50.32 MHz, CDCl3):
d 8.20 [1J(13C117/119Sn) = 297.32/311.10 Hz, CH2SnPh3],
128.97
[3J(13C117/119Sn) = 136.37/142.64 Hz,
Ph–Cm],
129.34 [4J(13C117/119Sn) = 10.97/11.48 Hz, Ph–Cp], 137.25
[1J(13C117/119Sn) = 456.75/477.76 Hz, Ph–Cipso], 137.70
[2J(13C117/119Sn) = 44.62/46.67 Hz, Ph–Co]. MS (192 ꢁC):
m/z (%): 728.6 (0.02) [M]+, 659 (2) [M À C2H4]+, 582 (1)
[M À C2H4 À C6H5]+, 505 (3) [M À C2H4 À 2C6H5]+, 352
(99) [M À C2H4 À Sn(C6H5)3]+, 120 (24) [Sn]+. Anal. Calc.
for C38H34Sn2 (728.07 g/mol): C, 62.69; H, 4.71. Found: C,
62.39; H, 4.39%.
3.4. Synthesis of Sn[CH2CH2CH2CH2Sn(C6H5)3]4 (2)
Freshly distilled Ph3SnH (22.1 g, 63 mmol) was treated
with AIBN (0.50 g, 5 mol%, 3 mmol) and stirred at room
temperature for 0.5 h. Then 1 (5.33 g, 15.7 mmol) was
added slowly within 0.5 h. Stirring of the mixture was con-
tinued for 12 h at ambient temperature, during which the
reaction solution solidified. The resulting viscous mixture
was dissolved in 10 ml of toluene and stirred for additional
12 h. Addition of pentane (25 ml) to the light yellow solu-
tion resulted in the formation of a white precipitate. The
yellow supernatant was filtered off and the product was
washed several times with a mixture of pentane/Et2O
(50:50, 25 ml). Removal of the solvents in a vacuum
(10À2 mbar) remained white solid 2.
3.2. Hydrostannation of tetraallylstannane
In analogy with the hydrostannation of Sn(CH@CH2)4,
Sn(CH2CH@CH2)4 (1.37 g, 4.84 mmol) was added slowly
at room temperature to a mixture of Ph3SnH (8.5 g,
24.2 mmol) and AIBN (5 mol%, 0.2 g, 1.2 mmol). After
the reaction and workup (Ph3SnCH2)2CH2 [21] was
obtained as a yellow powder.
Yield: 0.47 g (1.7 mmol). 1H NMR (200.13 MHz,
CDCl3): d 1.39 (m, 4H, CH2SnPh3), 1.49–1.80 (m, 2H,
CH2CH2SnPh3), 7.23–8.11 (m, 12H, Ph–Ho), 7.65–7.93 (m,

1710
H. Schumann et al. / Journal of Organometallic Chemistry 691 (2006) 1703–1712
Yield: 25.7 g (94%), m.p. 109 ꢁC. 1H NMR
suspension. A solution of 3 (7.9 g, 5 mmol) in 100 ml of
Et2O was syringed into the addition funnel and added
dropwise at 0 ꢁC within 1 h. The resulting brown solution
was stirred for 1 h at this temperature and 5 h at room tem-
perature, before it was hydrolyzed carefully with water
(0.1 g, 5.5 mmol) in 20 ml of dioxane at 0 ꢁC. After stirring
for 0.5 h at room temperature, the reaction mixture was fil-
tered and extracted three times with Et2O (25 ml). The
combined organic fractions were washed twice with a satu-
rated solution of NH4Cl (20 ml) and twice with a saturated
solution of NaCl (20 ml) in water. After drying with
Na2SO4 and evaporation of the solvents in vacuum (10À2
mbar), 4 was isolated as a colorless viscous oil.
(200.13 MHz, CDCl3): d 0.45–0.80 (m, 8H, SnCH2),
1.32–1.58 (m, 16H, SnCH2CH2 and SnCH2CH2CH2),
1.58–1.76 (m, 8H, Ph3SnCH2), 7.30–7.42 (m, 36H,
Ph–Hm/p), 7.51–7.62 (m, 24H, Ph–Ho). 13C{1H} NMR
(50.32 MHz, CDCl3): d 8.32 [1J(13C117/119Sn) = 295.91/
309.81 Hz, SnCH2], 10.69 [1J(13C117/119Sn) = 377.38/
394.82 Hz, Ph3SnCH2], 31.36 [3J(13CSn) = 57.77 Hz,
2J(13CSn) = 22.07 Hz, SnCH2CH2C], 31.77 [2J(13CSn) =
18.23 Hz,
3J(13CSn) = 63.22 Hz,
SnCH2C],
128.42
[2J(13CSn) = 46.87 Hz, Ph–Cm], 128.76 [4J(13CSn) =
12.26 Hz, Ph–Cp], 137.01 [3J(13CSn) = 35.42 Hz, Ph–Co],
139.11 [1J(13C117/119Sn) = 458.58/479.83 Hz, Ph–Cipso].
119Sn{1H} NMR (149.21 MHz, CDCl3): d À11.45 (SnC4),
À99.36 (SnPh3). MS-MALDI-TOF (IAA, thf): m/z (calc.)
1766.42 (1766.22) [M + Na]+, 1874.36 (1874.09)
[M + Na + Ag]+. Anal. Calc. for C88H92Sn5 (1743.15
g/mol): C, 60.64; H, 5.32. Found: C, 60.42; H, 5.30%.
Yield: 6.69 g (93%). IR (KBr/Film): m(Sn–H) 1829 cmÀ1
(s). 1H NMR (200.13 MHz, C6D6): d 0.57–0.98 (m,
8H, SnCH2), 1.04–1.40 (m, 8H, Ph2SnCH2), 1.41–1.80
(m, 16H, SnCH2CH2 and SnCH2CH2CH2), 6.37 [s,
1J(1H117/119Sn) = 1723.17/1803.76Hz, 4H, SnH], 7.05–7.28
(m, 36H, Ph–Hm/p), 7.35–7.71 (m, 24H, Ph–Ho). 13C{1H}
NMR (50.32 MHz, C6D6): d 8.82 [1J(13C117/119Sn) =
295.64/309.26 Hz, SnCH2], 10.24 [1J(13C117/119Sn) =
376.57/394.56 Hz, Ph2SnCH2], 31.84 [3J(13CSn) = 59.67
Hz, 2J(13CSn) = 19.35 Hz, SnCH2CH2], 32.17 [2J-
(13CSn) = 22.62 Hz, 3J(13CSn) = 52.861 Hz, SnCH2CH2-
CH2], 128.83 [4J(13CSn) = 10.89 Hz, Ph–Cp], 129.05
[2J(13C117/119Sn) = 47.68 Hz, Ph–Cm], 137.51 [3J(13C-
117/119Sn) = 36.24 Hz, Ph–Co], 138.30 [1J(13C117/119Sn) =
465.67/487.46 Hz, Ph–Cipso]. 119Sn{1H} NMR (149.21
MHz, C6D6,): d À11.58 (SnC4), À136.65 (SnPh2). MS-
MALDI-TOF (IAA, thf): m/z (calc.): 1462.39 (1461.84)
[M + Na]+. Anal. Calc. for C64H76Sn5 (1438.76 g/mol):
C, 53.43; H, 5.32. Found: C, 53.14; H, 5.11%.
3.5. Synthesis of Sn[CH2CH2CH2CH2SnCl(C6H5)2]4 (3)
A 50 ml flask equipped with an additional funnel con-
taining a colorless solution of 2 (10.5 g, 6 mmol) in 30 ml
of CH2Cl2 was cooled to À78 ꢁC. The additional funnel
was charged with a 4 M solution of anhydrous HCl(g) in
Et2O (6 ml, 24 mmol), which was added dropwise to the
vigorously stirred solution of 2 within 0.5 h. After 5 h at
À78 ꢁC, the reaction mixture was gradually warmed to
room temperature and stirred for additional 12 h. The
resulting benzene and the solvents were evacuated under
vacuum (10À2 mbar). 3 was obtained as a light yellow vis-
cous oil.
1
Yield: 8.67 g (92%). H NMR (200.13 MHz, CDCl3): d
0.80–1.02 (m, 8H, SnCH2), 1.60–1.80 (m, 8H, Ph2SnCH2),
1.82–2.06 (m, 16H, SnCH2CH2 and SnCH2CH2CH2),
7.47–7.68 (m, 36H, Ph–Hm/p), 7.71–7.88 (m, 24H, Ph–
3.7. Synthesis of Sn[CH2CH2CH2CH2Sn(C5H5)-
(C6H5)2]4 (5)
Ho). 13C{1H} NMR (50.32 MHz, CDCl3):
d
8.32
A solution of 3 (4.0 g, 2.54 mmol) in toluene (25 ml) was
placed in a 50 ml flask equipped with an addition funnel,
and cooled to 0 ꢁC. A suspension of NaC5H5 (1.35 g,
15.30 mmol) in toluene (25 ml) was syringed into the addi-
tion funnel, and added slowly to the solution. The light yel-
low solution was stirred for 48 h at room temperature. After
cooling to 0 ꢁC the reaction mixture was filtered and the
clear yellow solution concentrated under vacuum (10À2
mbar). The product was further purified by repeated extrac-
tion with cold toluene. After removal of the solvents in vac-
uum (10À2 mbar) 5 was obtained as a viscous yellow oil.
[1J(13C117/119Sn) = 295.91/309.81 Hz, SnCH2], 17.01 [1J
(13C117/119Sn) = 405.99/424.52 Hz,
Ph2SnCH2],
30.02
3
[2J(13CSn) = 27.79 Hz, J(13CSn) = 58.04 Hz, SnCH2CH2-
C], 30.98 [3J(13CSn) = 69.210 Hz, 2J(13CSn) = 19.35 Hz,
SnCH2C], 128.84 [2J(13C117/119Sn) = 46.32/47.96 Hz, Ph–
Co], 130.00 [4J(13CSn) = 12.53 Hz, Ph–Cp], 135.64
[3J(13C117/119Sn) = 56.68/58.86 Hz, Ph–Cm], 138.89 [1J
(13C117/119Sn) = 512.80/536.78 Hz, Ph–Cipso]. 119Sn{1H}
NMR (149.21 MHz, CDCl3): d À10.46 (SnC4), 17.50
(SnPh2). MS-MALDI-TOF (IAA, thf): m/z (calc.)
1576.95 (1576.62) [M]+, 1599.13 (1599.62) [M + Na]+,
1638.93 (1638.62) [M + Na + K]+, 1530.33 [M À 2Cl +
Na]+. Anal. Calc. for C64H72Cl4Sn5 (1576.54 g/mol): C,
48.76; H, 4.60. Found: C, 48.42; H, 4.30%.
1
Yield: 3.05 g (71%). H NMR (200.13 MHz, C6D6,): d
0.48–0.81 (m, 8H, SnCH2), 0.85–1.15 (m, 8H, Ph2SnCH2),
1.22–1.67 (m, 16H, SnCH2CH2 and SnCH2CH2CH2), 6.28
2
(s, J(1HSn) = 22.60/23.64 Hz, 20H, Cp-H), 7.05–7.30 (m,
36H, Ph–Hm/p), 7.37–7.68 (m, 24H, Ph–Ho). 13C{1H}
NMR (50.32 MHz, C6D6): d 8.75 [1J(13C117/119Sn) =
284.46/297.55 Hz, SnCH2], 9.72 [1J(13C117/119Sn) =
385.28/405.72 Hz, Ph2SnCH2], 31.74 [2J(13CSn) = 27.80
Hz, 3J(13CSn) = 56.13 Hz, SnCH2CH2CH2], 32.06 [3J
(13CSn) = 68.12 Hz, 2J(13CSn) = 19.35 Hz, SnCH2CH2],
3.6. Synthesis of Sn[CH2CH2CH2CH2SnH(C6H5)2]4 (4)
LiAlH4 (0.19 g, 5 mmol) was placed in a 250 ml three-
necked flask equipped with reflux condenser and addition
funnel and dissolved in 100 ml of Et2O to give a dark grey

H. Schumann et al. / Journal of Organometallic Chemistry 691 (2006) 1703–1712
1711
113.64 (Cp-C), 128.48 [3J(13C117/119Sn) = 52.86 Hz, Ph–
Cm], 129.32 [4J(13CSn) = 10.90 Hz, Ph–Cp], 136.84
[2J(13CSn) = 35.42 Hz, Ph–Co], 140.21 [1J(13C117/119Sn) =
438.96/459.40 Hz, Ph–Cipso]. 119Sn{1H} NMR (149.21
MHz, C6D6,): d À12.36 (SnC4), À70.65 (SnPh2). MS-
MALDI-TOF (IAA, thf): m/z: no signal. Anal. Calc. for
C84H92Sn5 (1695.10 g/mol): C, 59.52; H, 5.47. Found: C,
59.01; H, 5.13%.
ther purification of the product was achieved by dissolving
the residue several times in CH2Cl2 and precipitating it by
adding Et2O/pentane (50:50). Evaporation of volatiles and
drying in a vacuum (10À2 mbar) gave 7 as viscous brown oil.
Yield: 0.96 g (88%). IR (KBr/film): m(C”O) 1932 (s),
1985 cmÀ1(s). 1H NMR (400.13 MHz, CDCl3): d 0.56–
0.84 (m, 8H, SnCH2), 1.12–1.78 (m, 16H, SnCH2CH2
and SnCH2CH2CH2), 1.82–2.09 (m, 8H, Ph2SnCH2),
4.40–5.10 (m, 20H, Cp-H), 6.98–7.51 (m, 36H, Ph–Hm/p),
7.51–7.90 (m, 24H, Ph–Ho). 13C{1H} NMR (100.61 MHz,
CDCl3,): d 8.23 (SnCH2), 15.41 (Ph2SnCH2), 31.74
(SnCH2CH2), 32.23 (SnCH2CH2CH2), 81.95 (Cp–C),
127.81 (Ph–Cp), 128.01 (Ph–Cm), 136.33 (Ph–Co), 144.77
(Ph–Cipso), 214.89 (CO). 119Sn{1H} NMR (149.21 MHz,
CDCl3,): d À11.68 (Sn), 88.65 (Ph2Sn). MS-MALDI-
TOF (ACCA, thf): m/z (calc.): 2165.39 (2165.64)
[M + Na]+, 2271.54 (2273.51) [M + Na + Ag]+, 2056.20
[M À CO]+. Anal. Calc. for C92H92O8Fe4Sn5 (2142.58
g/mol): C, 51.57; H, 4.33. Found: C, 51.09; H, 4.17%.
3.8. Synthesis of Sn{CH2CH2CH2CH2Sn[Co(CO)4]-
(C6H5)2}4 (6)
NaCo(CO)4 (2.72 g, 14 mmol) dissolved in THF (20 ml)
was put into a 50 ml flask with an addition funnel and
cooled to À78 ꢁC. A solution of 3 (5.4 g, 3.4 mmol) in
20 ml of THF was added dropwise under vigorous stirring.
The clear light brown reaction mixture was stirred 3 h at this
temperature and overnight at room temperature. The pre-
cipitated NaCl was removed by filtration and volatiles were
evaporated in vacuum (10À2 mbar). Repeated dissolving of
the remaining crude product in toluene and precipitating it
again with cold CH3OH gave 6 as a viscous green oil.
Yield: 5.83 g (81%). IR (KBr/film): m(C”O) 2084 (s), 2020
3.10. Synthesis of Sn{CH2CH2CH2CH2Sn[Mn(CO)5]-
(C6H5)2}4 (8)
1
(s), 2002 cmÀ1(s). H NMR (200.13 MHz, C6D6): d 0.48–
In analogy to 7, a solution of 3 (0.8 g, 0.5 mmol) in
25 ml of THF was reacted at room temperature with a dark
red solution of BrMgMn(CO)5, prepared from [Mn(CO)5]2
(0.43 g, 1.1 mmol), BrCH2CH2Br (0.20 g, 1.1 mmol), and
Mg (0.12 g, 5 mmol) in 50 ml of THF. After stirring for
5 h at room temperature and workup, 8 was obtained as
a viscous orange oil.
0.90 (m, 8H, SnCH2), 1.43–1.65 (m, 8H, Ph2SnCH2), 1.63–
1.99 (m, 16H, SnCH2CH2 and SnCH2CH2CH2), 6.97–7.34
(m, 36H, Ph–Hm/p), 7.39–7.87 (m, 24H, Ph–Ho). 13C{1H}
NMR (50.32 MHz, C6D6,): d 8.55 [1J (13C117/119Sn) =
295.34/308.99 Hz, SnCH2], 17.94 [1J (13C117/119Sn) =
320.16/335.15 Hz, Ph2SnCH2], 31.78 [3J(13CSn) = 73.30
Hz, 2J(13CSn) = 18.26 Hz, SnCH2CH2], 32.19 [2J
(13CSn) = 25.07 Hz, 3J(13CSn) = 56.95 Hz, SnCH2CH2-
CH2], 129.10 [2J(13C117/119Sn) = 58.86 Hz, Ph–Cm], 129.57
[4J(13CSn) = 11.44 Hz, Ph–Cp], 136.30 [3J(13C117/119Sn) =
39.51 Hz, Ph–Co], 141.26 [1J(13C117/119Sn) = 394.23/
412.53 Hz, Ph–Cipso], 199.46 (CO). 119Sn{1H} NMR
(149.21 MHz, C6D6,): d À12.35 (Sn), 58.39 (SnPh2). MS-
MALDI-TOF (IAA, thf): m/z no signal. Anal. Calc. for
C80H72O16Co4Sn5 (2118.62 g/mol): C, 45.35; H, 3.43.
Found: C, 44.92; H, 3.45%.
Yield: 0.87 g (79%). IR (KBr/film): m(C„O) 1987 (s),
1
2005 (s), 2090 cmÀ1(s). H NMR (200.13 MHz, CDCl3,):
d 0.33–0.91 (m, 8H, SnCH2), 1.33–1.50 (m, 8H, Ph2Sn-
CH2), 1.51–1.70 (m, 16H, SnCH2CH2 and SnCH2-
CH2CH2), 7.26–7.52 (m, 36H, Ph–Hm/p), 7.54–7.81 (m,
24H, Ph–Ho). 13C{1H} NMR (50.32 MHz, CDCl3): d
8.20 [1J(13C117/119Sn) = 295.64/308.99 Hz, SnC4], 14.46
[1J(13C117/119Sn) = 280.11/292.37 Hz, Ph2SnCH2], 31.78
[3J(13CSn) = 73.30 Hz, 2J(13CSn) = 18.26 Hz, SnCH2CH2],
32.19 [2J(13CSn) = 25.07 Hz, 3J(13CSn) = 56.95 Hz, Sn-
CH2CH2CH2], 128.28 [4J(13CSn) = 11.99 Hz, Ph–Cp],
128.29 [2J(13C117/119Sn) = 43.87 Hz, Ph–Cm], 136.36
[3J(13C117/119Sn) = 34.84 Hz, Ph–Co], 141.49 [1J(13C117/119Sn)
= 334.06/350.14 Hz, Ph–Cipso], 213.87 (CO). 119Sn{1H}
NMR (149.21 MHz, CDCl3,): d À11.54 (Sn); 5.61 (Ph2Sn).
MS-MALDI-TOF (IAA, thf): m/z (calc.): 2235.08
(2237.76) [M + Na]+, 2257.73 (2260.76) [M + 2Na]+. Anal.
Calc. for C84H72O20Mn4Sn5 (2214.69 g/mol): C, 45.56; H,
3.28. Found: C, 45.44; H, 3.30%.
3.9. Synthesis of Sn{CH2CH2CH2CH2Sn[Fe(CO)2)-
(C5H5)](C6H5)2}4 (7)
A solution of 3 (0.8 g, 0.51 mmol) in THF (25 ml) was
dropped slowly within 1 h at room temperature to a dark
red solution of BrMgFe(CO)2(C5H5), prepared from
[Fe(CO)2C5H5]2 (0.39 g, 1.1 mmol), BrCH2CH2Br (0.19 g,
1.1 mmol), and Mg turnings (0.12 g, 5 mmol) in 50 ml of
THF. After 5 h stirring at ambient temperature the reaction
mixture was cooled to 0 ꢁC, hydrolyzed carefully with
degassed and nitrogen saturated water, then extracted three
times with Et2O (25 ml). The combined organic fractions
were washed with a saturated solution of NH4Cl in degassed
water (50 ml), three times with a saturated solution of NaCl
(50 ml) in degassed water, and dried over Na2SO4. The sol-
vents were removed at reduced pressure (10À2 mbar). Fur-
Acknowledgments
The authors thank the Fonds der Chemischen Industrie,
the Deutsche Forschungsgemeinschaft (Graduiertenkolleg
‘‘Synthetische, mechanistische und reaktionstechnische As-
pekte von Metallkatalysatoren’’), the Bundesministerium
fur Bildung, Forschung und Technologie (grant no. 03 D
¨

1712
H. Schumann et al. / Journal of Organometallic Chemistry 691 (2006) 1703–1712
(d) S. Serroni, S. Campagna, G. Denti, A. Juris, M. Venturi, V.
Balzani, in: G.R. Newkome (Ed.), Advances in Dendritic Macro-
molecules, vol. 3, JAI, London, 1996;
(e) S. Achar, R.J. Puddephatt, Organometallics 14 (1995) 1681;
(f) V. Balzani, S. Campagna, G. Denti, A. Juris, S. Serroni, M.
Venturi, Acc. Chem. Res. 31 (1998) 26.
0057 3) and the Schering A.-G. for financial support. We
¨
are grateful to Dr. Sevil Aksu, Akdeniz Universitesi, Anta-
lya/Turkey, for helpful discussion.
References
[13] M.N. Bochkarev, M.A. Katkova, S.Ya. Khorshev, N.P. Makarenko,
Russ. Chem. Bull. 47 (1998) 349.
[14] J.P. Majoral, A.M. Caminade, Chem. Rev. 99 (1999) 845.
[15] (a) M.N. Bochkarev, M.A. Katkova, Usp. Khim. 64 (1995) 1106;
(b) Yu.D. Semchikov, M.N. Bochkarev, Vysokomol. Soedin, Ser. A i
B 44 (2002) 2293;
[1] P.J. Flory, J. Am. Chem. Soc. 74 (1952) 2718.
[2] (a) G.R. Newkome, C.N. Moorefield, F. Vo¨gtle, Dendritic Molecules:
Concepts, Syntheses, Perspectives, VCH, Weinheim, 1996;
(b) F. Vo¨gtle, Dendrimers II: Architecture, Nanostructure and
Supramolecular Chemistry, Topics in Current Chemistry 210,
Springer, Berlin, 2000.
(c) I.I. Pestova, E.N. Khanov, T.I. Kulikova, Yu.A. Kurskii, S.Ya.
Khorshev, T.G. Mustina, S.D. Zaitsev, Yu.D. Semchikov, M.N.
Bochkarev, Vysokomol. Soedin. Ser. A i B 46 (2004) 1438;
(d) S.D. Zaitsev, A.A. Turshatov, G.M. Pavlov, Yu.D. Semchikov,
M.N. Bochkarev, O.G. Zakharova, Vysokomol. Soedin. Ser. A i B
46 (2004) 1443.
[3] (a) H.B. Mekelburger, W. Jaworek, F. Vo¨gtle, Angew. Chem. 104
(1992) 1609;
H.B. Mekelburger, W. Jaworek, F. Vo¨gtle, Angew. Chem., Int. Ed.
Engl. 31 (1992) 1571;
(b) J. Issberner, R. Moors, F. Vo¨gtle, Angew. Chem. 106 (1994)
2507;
J. Issberner, R. Moors, F. Vo¨gtle, Angew. Chem., Int. Ed. Engl. 33
(1994).
[16] (a) E. Amberger, E. Mu¨hlhofer, J. Organomet. Chem. 12 (1968) 55;
(b) W. Biffar, T. Gasparis-Ebeling, H. No¨th, W. Storch, B. Wrack-
meyer, J. Magn. Reson. 44 (1981) 54;
[4] G.R. Newkome, Zhong-qi Yao, G.R. Baker, V.K. Gupta, J. Org.
Chem. 50 (1985) 2003.
[5] G.R. Newkome, Zhong-qi Yao, G.R. Baker, V.K. Gupta, P.S.
Russo, M.J. Saunders, J. Am. Chem. Soc. 108 (1986) 849.
[6] U. Stebani, G. Lattermann, M. Wittenberg, J.H. Wendorff, Angew.
Chem. 108 (1996) 1941;
U. Stebani, G. Lattermann, M. Wittenberg, J.H. Wendorff, Angew.
Chem., Int. Ed. Engl. 35 (1996) 1858.
[7] (a) D. Astruc, F. Chardac, Chem. Rev. 101 (2001) 2991;
(b) G.E. Oosterom, J.N.H. Reek, P.C.J. Kamer, P.W.N.M. Leeuwen,
Angew. Chem. 113 (2001) 1879;
(c) T.N. Mitchell, B. Babisch, J. Organomet. Chem. 269 (1984) 249;
(d) B.J.J. van de Heisteeg, G. Schat, O.S. Akkerman, F. Bickelhaupt,
Organometallics 5 (1986) 1749;
(e) T.N. Mitchell, A. Amamria, B. Fabisch, H.G. Kuivila, T.J.
Karol, K. Swami, J. Organomet. Chem. 259 (1989) 157;
(f) R.H. Heyn, T.D. Tilley, Inorg. Chem. 29 (1990) 4051.
[17] H. Schumann, B.C. Wassermann, M. Frackowiak, B. Omotowa, S.
Schutte, J. Velder, S.H. Mu¨hle, W. Krause, J. Organomet. Chem. 609
(2000) 189.
[18] H. Schumann, B.C. Wassermann, S. Schutte, J. Velder, Y. Aksu, W.
Krause, B. Radu¨chel, Organometallics 22 (2003) 2034.
[19] T. Kaufmann, R. Kriegesmann, B. Altpeter, F. Steinseifer, Chem.
Ber. 115 (1982) 1810.
G.E. Oosterom, J.N.H. Reek, P.C.J. Kamer, P.W.N.M. Leeuwen,
Angew. Chem., Int. Ed. Engl. 40 (2001) 1828;
(c) M.T. Reetz, D. Giebel, Angew. Chem. 112 (2000) 2614;
M.T. Reetz, D. Giebel, Angew. Chem., Int. Ed. Engl. 39 (2000)
2498.
[20] C.H. Malcolm, J.G. Noltes, J. Am. Chem. Soc. 82 (1960) 558.
[21] Y. Ducharme, S. Latour, J.D. Wuest, Organometallics 3 (1984) 208.
[22] D.J. Petersen, M.D. Robbins, J.R. Hansen, J. Organomet. Chem. 73
(1974) 237.
[8] W. Krause, N. Hackmann-Schlichter, F.K. Maier, R. Muller,
¨
Dendrimers in Diagnostics, in: F. Vo¨gtle (Ed.), Dendrimers II:
Architecture, Nanostructure and Supramolecular Chemistry, Topics
in Current Chemistry 210, Springer, Berlin, 2000.
[23] (a) H. Schumann, I. Schumann, Gmelin Handbuch der Anorgani-
schen Chemie, Erga¨nzungswerk zur 8. Auflage, Band 29, Zinn-
Organische Verbindungen, Teil 2, Springer, Berlin, 1975;
(b) A.G. Davies, Organotin Chemistry, VCH, Weinheim, 1997.
[24] E. Amberger, H.P. Fritz, C.G. Kreiter, M.R. Kula, Chem. Ber. 96
(1963) 3270.
[9] (a) B. Raduchel, H. Schmitt-Willich, J. Platzek, W. Ebert, T. Frenzel,
¨
B. Misselwitz, H.J. Weinmann, Polym. Mater. Sci. Eng. 79 (1998)
516;
´
[25] H.P. Fritz, C.G. Kreiter, J. Organomet. Chem. 1 (1964) 323.
[26] H. Schumann, I. Schumann, Gmelin handbook of inorganic and
organometallic chemistry, Sn, in: Organotin Compounds, Parts 1–25,
Springer, Berlin, 1975–1997.
(b) M. Kawa, J.M.J. Frechet, Chem. Mater. 10 (1998) 286.
[10] (a) M. Venturi, S. Serroni, A. Juris, S. Campagna, V. Balzani, Top.
Curr. Chem. 197 (1998) 193;
´
(b) S. Hecht, J.M.J. Frechet, Angew. Chem. 113 (2001) 77;
´
[27] (a) H. Schumann, I. Schumann, Gmelin handbook of inorganic and
organometallic chemistry, Sn, in: Organotin Compounds, Part 21,
Springer, Berlin, 1994.;
S. Hecht, J.M.J. Frechet, Angew. Chem., Int. Ed. Engl. 40 (2001) 74.
[11] F. Zeng, S.C. Zimmermann, Chem. Rev. 97 (1997) 1681.
[12] (a) A. Juris, V. Balzani, V. Barigelletti, S. Campagna, P. Belser, A.
von Zelewski, Coord. Chem. Rev. 84 (1988) 85;
(b) H. Schumann, I. Schumann, Gmelin handbook of inorganic and
organometallic chemistry, Sn in: Organotin Compounds, Part 22,
Springer, Berlin, 1995.
(b) K. Kalyanasundaram, Photochemistry of Polypyridine and
Porphyrin Complexes, Academic Press, London, 1992;
(c) G. Denti, S. Campagna, V. Balzani, in: D. Mendenhall, A.
Greensberg, J. Liebman (Eds.), Mesomolecules: from Molecules to
Materials, Chapman and Hall, New York, 1995;
[28] H.G. Kuivila, O.F. Beumel, J. Am. Chem. Soc. 83 (1961) 1246.
[29] E.W. Abel, S. Moorhouse, J. Organomet. Chem. 24 (1970) 687.
[30] J.M. Burlitch, S.W. Ulmer, J. Organomet. Chem. 19 (1969) P21.