Synthesis and characterization of diorganotin compounds containing silicon and germanium and crystal structure of precursor carboxy-ethyltrichlorogermanium

Full text of DOI:10.1081/SIM-100002047

Synthesis and Reactivity in Inorganic and Metal-Organic
Chemistry
ISSN: 0094-5714 (Print) 1532-2440 (Online) Journal homepage: http://www.tandfonline.com/loi/lsrt19
SYNTHESIS AND CHARACTERIZATION OF
DIORGANOTIN COMPOUNDS CONTAINING
SILICON AND GERMANIUM AND CRYSTAL
STRUCTURE OF PRECURSOR CARBOXY-
ETHYLTRICHLOROGERMANIUM
M. Aziz Choudhary , M. Mazhar , U. Salma , S. Ali , X. Qinglan & K. C. Molloy
To cite this article: M. Aziz Choudhary , M. Mazhar , U. Salma , S. Ali , X. Qinglan & K. C.
Molloy (2001) SYNTHESIS AND CHARACTERIZATION OF DIORGANOTIN COMPOUNDS
CONTAINING SILICON AND GERMANIUM AND CRYSTAL STRUCTURE OF PRECURSOR CARBOXY-
ETHYLTRICHLOROGERMANIUM, Synthesis and Reactivity in Inorganic and Metal-Organic
Chemistry, 31:2, 277-295, DOI: 10.1081/SIM-100002047
To link to this article: http://dx.doi.org/10.1081/SIM-100002047
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SYNTH. REACT. INORG. MET.-ORG. CHEM., 31(2), 277–295 (2001)
SYNTHESIS AND CHARACTERIZATION
OF DIORGANOTIN COMPOUNDS
CONTAINING SILICON AND GERMANIUM
AND CRYSTAL STRUCTURE
OF PRECURSOR CARBOXY-
ETHYLTRICHLOROGERMANIUM
M. Aziz Choudhary,1 M. Mazhar,1,∗ U. Salma,1 S. Ali,1
X. Qinglan,2 and K. C. Molloy3
1Department of Chemistry, Quaid-i-Azam University,
Islamabad-45320, Pakistan
2Key National Laboratory of Elemento-organic Chemistry,
Nankai University, Tianjin-300071,
People’s Republic of China
3Department of Chemistry, University of Bath,
Claverton Down, Bath BA2 7AY, U.K.
ABSTRACT
Eight compounds of general formula [R1(CH3)2SiCH2]2Sn-
[O2CCH2(R2)CHGeR3 ] [R1 = CH3, C2H5; R2 = C6H5,
3 2
C6H4OMe-3/4, R3 = CH3, N(CH2CH2O)3] have been synthesised
from [R1 (CH3)2SiCH2]2SnCl2 and R3 GeCH(R2)CH2CO2H in the
3
presenceoftriethylamine. (Me3CCH2)3SnO2CCH2(R1)CHGe(R2)3
[R1 = C6H5, C6H4OMe-3; R2 = N(CH2CH2O)3] have been syn-
thesised similarly from (Me3CCH2)3SnCl. The compounds have
∗Address correspondence to M. Mazhar.
277
Copyright ꢀ 2001 by Marcel Dekker, Inc.
www.dekker.com
C

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CHOUDHARY ET AL.
been characterised by 1H, 13C, 29Si and 119Sn NMR. The structure
of a precursor, Cl3GeCH(Ph)CH2CO2H, has been re-determined
and shown to be a hydrogen-bonded dimer rather than a monomer
as previously described.
INTRODUCTION
Recently, organotin compounds of various ligands containing nitrogen,
oxygen and sulphur have been tested for their possible use in cancer chemotherapy
(1,2). These ligands include ketones, thiols, metallocenes, thiocarbazides, proteins,
amino acids, purines, lipids, hormones, vitamins, sugar and other ligands (3–8).
Complexes of Sn(IV) have been found to have positive activity in vivo against
tumors. The dialkyltin compounds have the lowest mammalian toxicity (9) and
exhibit greater antitumor activity than the corresponding, mono-, tri- and tetraalkyl
derivatives. In order to explore the biological activity of diorganotin compounds
we have prepared a new series of diorganotin carboxylates containing silicon in
the alkyl group bonded to tin and germanium as part of the carboxyl ligand. The
introduction of silicon and germanium in diorganotin carboxylate is primarily an
attempt to achieve lower toxicity, high biological activity and strengthen the body
immune system (10–13). These compounds have been characterized by elemental
analyses, IR and multinuclear NMR. Results of their biological activity will be
reported elsewhere.
EXPERIMENTAL
All reactions were carried out in solvents dried over sodium benzophe-
none under an atmosphere of argon. IR spectra were recorded in KBr discs on a
1
Hitachi model 270–50 IR spectrophotometer. H, 13C, 29Si, 119Sn NMR spectra
were recorded on a Bruker Am 500 MHz spectrometer in CDCl3. Chemical shifts
are reported with reference to TMS or tetramethyltin for 1H, 13C, 29Si and 119Sn,
respectively.
Preparation of Precursors
Bis(trimethylsilylmethyl)tin Dichloride
This compound was synthesized by the following procedure. Mg (2.65 g,
0.11 mol) was heated to 100◦C in a 500 mL (without solvent) three-necked flask
fitted with a reflux condenser and magnetic stirrer under an argon atmosphere.

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279
Chloromethyltrimethylsilane (12.25 g, 0.10 mol) in ether (60 mL) was added
dropwise at room temperature. The reaction mixture was then cooled to 0◦C in
an ice bath and stirred for another hour. Tin tetrachloride (6.5 g, 0.025 mol) in
toluene (120 mL) was added dropwise keeping the temperature at 0◦C. On com-
pletion of the addition and further eight hours at reflux, the reaction mixture was
cooled in an ice bath and hydrolysed with 5% aqueous HCl (50 mL). The or-
ganic layer was separated and the aqueous layer extracted three times with di-
ethyl ether. All washings were combined and dried over anhydrous Na2SO4. The
solvent was removed under vacuum, and the remaining thick liquid distilled at
35◦C/10 mm Hg to yield tetrakis(trimethylsilylmethyl)tin(IV). Anal.: calc. for
C16H44Si4Sn (466): C, 41.14; H, 9.42%. Found: C, 41.1; H, 9.30%. Yield, 9.3 g
(80%).
To a two-necked flask fitted with a reflux condenser and magnetic stir-
rer was added tetrakis(trimethylsilylmethyl)tin(IV) (4.66 g, 0.01 mol) and SnCl4
(2.61 g, 0.01 mol) and the mixture stirred at 220◦C for 1.5 hours. The reaction
mixture was cooled in an ice bath for half an hour, heated again to 220◦C for
another 1.5 hours. The resultant mixture was distilled at 77◦C at 0.025 mm Hg
to yield bis(trimethylsilylmethyl)tin(IV)-dichloride; C8H22Cl2Si2Sn (363.69),
Yield, 3.0 g (70%). 1H NMR: 0.05 (s, 18H, SiCH3), 0.5 (s, 4H, SiCH2Sn),
2
2
J(Si H) = 18.9 Hz, J(Sn-H) = 26.9 Hz]; 29Si: 2.70 ppm, 119Sn: 146.6 ppm.
–
Similarly, bis(ethyldimethylsilylmethyl)tin dichloride was synthesized. 1H NMR:
0.45 (s, 4H, SiCH2Sn); 0.52 (q, 4H, SiCH2 J = 6 Hz.), 0.92 (t, 6H, CH3CH2Si J =
5.5 Hz). Yield, 4.0 g (68%), b.p. 110◦C at 0.025 mm Hg.
3-Phenyl-3-trichlorogermylpropionic Acid, Cl3GeCH(Ph)CH2CO2H
This compound was synthesised by a literature method (14–17), m.p. 105–
107◦C. Yield 12.5 g, (85%): Anal.: calc. for C9H9O2Cl3Ge (328), C, 33.0;−H1,
==
–
2.72%. Found: C, 32.9; H, 2.72%. IR ν(C O) = 1710, 400; ν(Ge Cl) = 482 cm
;
1H NMR: 3.17 (d, 2H, CH2, J = 7 Hz), 3.93 (t, 1H, CH; J = 7Hz), 7.35 (m, 5H,
phenyl), 8.37 (s, 1H, COOH). 3-(4-Methoxy)phenyl-3-trichlorogermylpropionic
acid was synthesized by the above method.
3-Phenyl-3-germaniumsesquioxidepropionic Acid
This compound was synthesized as follows: Distilled water (20 mL) was
added dropwise to 3-phenyl-3-trichlorogermyl-propionic acid (6.26 g, 0.019 mol)
in ether (20 mL) in a 250 mL conical flask. The mixture was stirred vigorously
to form the solid sesquioxide which was filtered and washed with water, ether
and dried at reduced pressure. Yield, 4.43 g (95%): Anal.: calc. for C9H9GeO3.5

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CHOUDHARY ET AL.
(245.59) : C, 42.5; H, 3.64%. Found: C, 42.5; H, 3.64%. 3(4-Methoxyphenyl)-3-
germaniumsesquioxidepropionic acid was synthesized by the above method.
Synthesis of 3-Phenyl-3-germatranylpropionic Acid
A quantity of 2.45 g (9.9 mmol) 3-phenyl-3-germaniumsesquioxidepropio-
nic acid was added to a 250 mL round bottom flask containing toluene (50 mL) and
fitted with a Dean and Stark apparatus. Triethanolamine (1.49 g, 10.0 mmol) was
added dropwise with stirring. The mixture was refluxed for six hours with constant
removal of water. Toluene was decanted and the product crystallized from 95% hot
ethanol to yield pure 3-phenyl-3-germatranylpropionic acid. Yield, 3.14 g (85%)
m.p. 206◦C. Anal.: calc. for C15H21NO5Ge (367.59) : C, 48.83; H, 5.71; N, 3.80%.
Found: C, 48.9; H, 5.77; N, 3.85%.
3-(Methoxyphenyl)-3-germatranylpropionic Acids
Thesecompoundsweresynthesizedbytheproceduredescribedfor3-phenyl-
3-germatranylpropionic acid. Quantities of the reactants used were 6.2 g
(2.25 mmol) of 3-(3-methoxyphenyl)-3-germaniumsesquioxide-propionic acid,
0.4 g (2.25 mmol) triethanolamine. Yield, 8.03 g (90%). Anal.: calc. for
C16H23NO6Ge, (397) : C, 48.3; H, 5.67; N, 3.48 %. Found: C, 48.3; H, 5.78;
N, 3.52%. 3-(4-Methoxyphenyl)-3-germatranylpropionic acid was synthesized by
the above method.
Synthesis of 3-Phenyl-3-trimethylgermylpropionic Acid
3-Phenyl-3-trichorogermylpropionic acid (6.56 g, 0.02 mol) was dissolved
in THF (7 mL) in a three- necked flask fitted with a reflux condenser, magnetic
stirrer and a dropping funnel. Methylmagnesium bromide in diethyl ether (9.52 g,
0.08 mmol) was added dropwise keeping the temperature below 5◦C over a period
of 30 min with constant stirring. Then the temperature was allowed to rise slowly
andthesolutionsubsequentlyrefluxedfor3hours. Thereactionmixturewascooled
in an ice bath and hydrolysed with 20% HCl (15 mL), extracted with CHCl3, the
extract dried over anhydrous MgSO4, and purified by column chromatography
over a silica column (chloroform:hexane, 1:3) to yield the desired product. Yield,
3.73 g (70%). Anal.: calc. for C12H18O2Ge, (266.6) : C, 53.9; H, 6.78%. Found:
C, 54.0; H, 6.75%. 3-Phenyl-3-triethylgermylpropionic acid was synthesized by
the above method.

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281
Preparation of Compounds
Synthesis of Bis(trimethylsilylmethyl)bis(3-4-methoxyphenyl-
3-trimethylgermyl)tin(IV) Propionate (I)
To a two-necked 100 mL flask fitted with a reflux condenser, dropping funnel
and magnetic stirrer was added 3-(4-methoxyphenyl)-3-trimethylgermylpropionic
acid (1.75 g, 6.5 mmol) dissolved in CHCl3 (20 mL) and triethylamine (0.6 g,
6.0 mmol). Subsequently, bis(trimethylsilylmethyl)tin dichloride (1.27 g,
3.25 mmol) in diethyl ether was added dropwise with constant stirring. After com-
plete addition, the contents were refluxed for six hours, then allowed to cool to
room temperature. The solvent was removed under vacuum and the product ex-
tracted with a CHCl3:hexane mixture (1:3) to yield (I) as a viscous liquid. Yield,
4.5 g (80%). Anal.: calc. for C34H60O6Si2Ge2Sn (883.87): C, 46.0; H, 6.70%.
Found: C, 46.1; H, 6.78%.
Synthesis of Bis(trimethylsilylmethyl)-bis(3-phenyl-
3-trimethylgermyl)tin(IV) Propionate (II)
The Procedure for the synthesis of (II) was the same as described for (I). The
quantitiesusedwereasfollows:0.91g(2.5mmol)bis(trimethylsilylmethyl)tin(IV)
dichloride, 0.5 g (5.0 mmol) triethylamine and 1.40 g (0.005 mol) of 3-phenyl-
3-trimethylgermylpropionic acid. Yield, 3.29 g (80%); viscous liquid. Anal.: calc.
for C32H56O4Si2Ge2Sn (823.87): C, 46.9; H, 6.75%. Found: C, 46.6; H,
6.79%.
Synthesis of Bis(ethyldimethylsilylmethyl)-bis-(3-phenyl-
3-triethylgermyl)tin(IV) Propionate (III)
A quantity of 1.35 g (4.4 mmol) of 3 phenyl-3-triethylgermylpropionic
acid in acetone (20 ml) was placed in a two- necked flask fitted with a reflux
condenser and magnetic stirrer. 0.44 g (4.4 mmol) of triethylamine along with
0.83 g (2.2 mmol) of bis(ethyldimethylsilylmethyl)tin dichloride in acetone
(20 mL) were added dropwise. After complete addition, the reaction mixture
was refluxed for six hours and cooled. Triethylamine hydrochloride was filtered,
the solvent removed under vacuum and (III) purified from a mixture of petro-
leum ether and CHCl3 (3:1). Yield, 2.88 g (70%); viscous liquid. Anal.: calc.
for C40H72O4Si2Ge2Sn (935.87): C, 51.2; H, 7.65%. Found: C, 51.3; H,
7.69%.

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CHOUDHARY ET AL.
Synthesis of Bis(trimethylsilylmethyl)bis(3-3-methoxyphenyl-
3-triethylgermyl)tin(IV) Propionate (IV)
Compound (IV) was synthesized by the method described for (III). Quanti-
ties used were: 0.8 g (2.0 mmol) of bis(trimethylsilylmethyl)tin dichloride,
1.35 g (4.0 mmol) of 3-(3-methoxyphenyl)-3-triethylgermylpropionic acid and
0.44 g (4.0 mmol) of triethylamine. Yield, 2.90 g (75%); viscous liquid. Anal.:
calc. for C40H72O6Si2Ge2Sn (967.87): C, 49.6; H, 7.40%. Found: C, 49.6; H,
7.44%.
Synthesis of Bis(trimethylsilylmethyl)bis(3-phenyl-
3-germatranyl)tin(IV) Propionate (V)
3-Phenyl-3-germatranylpropionic acid (0.81 g, 3.2 mmol) was added slowly
to bis(trimethylsilylmethyl)tin dichloride(0.40 g, 1.1mmol)in athree-necked flask
containing ethanol (20 mL) and triethylamine (0.32 g, 3.2 mmol). The reaction
mixture was refluxed for six hours, cooled and ethanol was removed under vacuum.
The solid was extracted with dichloromethane to yield (V). Yield, 2.62 g (80%),
white solid; m.p. 165–7◦C. Anal.: calc. for C38H62N2O10Si2Ge2Sn (1025.87): C,
44.8; H, 5.98%. Found: C, 44.9; H, 6.04%.
Synthesis of Bis(trimethylsilylmethyl)-bis-3-(4-methoxyphenyl-
3-germatranyl)tin(IV) Propionate (VI)
The procedure adopted for the synthesis of (VI) was the same as described
for (V). Quantities of reagent used were as follows: 1.48 g (5.0 mmol) 3-(4-
methoxyphenyl)-3-germatranylpropionic acid, 0.90 g (2.0 mmol) of bis(trimethyl-
silylmethyl)tin dichloride, 0.5 g (5.0 mmol) of triethylamine. Yield, 4.68 g (80%);
white solid; m.p. 175–7◦C. Anal.: calc. for C40H66N2O12Si2Ge2Sn (1151.87): C,
44.2; H, 5.99%. Found: C, 44.2; H, 6.07%.
Synthesis of Bis(ethyldimethylsilylmethyl)-bis-(3-phenyl-
3-germatranyl)tin(IV) Propionate (VII)
The procedure adopted for (VII) was the same as used for (III). The quanti-
tiesofreagentsusedwereasfollows:1.60g(4.4mmol)of3-phenyl-3-germatranyl-
propionic acid, 0.83g (2.2 mmol) bis(ethyldimethylsilylmethyl)tin dichloride,
0.44 g (4.4 mmol) of triethylamine. Yield, 3.16 g (75%), white solid; m.p. 148–
150◦C. Anal.: calc. for C40H66N2O10Si2Ge2Sn (1053.87): C, 45.4; H, 6.18%.
Found: C, 45.5; H, 6.25%.

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283
Synthesis of Bis(ethyldimethylsilylmethyl)-bis-[3-(3-methoxyphenyl)-
3-germatranyl]tin(IV) Propionate (VIII)
The procedure adopted for the synthesis of (VIII) was the same as used for
(III). The quantities of reagents used were: 1.75 g (4.0 mmol) of 3-methoxyphenyl-
3-germatranylpropionic acid, 0.83 g (2.0 mmol) of bis(ethyldimethyl-silylmethyl)-
tin dichloride, 0.44 g (4.0 mmol) of triethylamine. Yield, 3.34 g (75%); white
solid; m.p. 160–2◦ C. Anal.: calc. for C42H70N2O12Si2Ge2Sn (1113.87): C, 45.2;
H, 6.28%. Found: C, 45.2; H, 6.33%.
Synthesis of Tris(neopentyl)-3-(3-methoxyphenyl)-3-germatranyltin(IV)
Propionate (IX)
The procedure adopted for the synthesis of (IX) was the same as used for
(III). The amounts used were as follows: 1.74 g (4.0 mmol) of 3-(3-methoxy-
phenyl)-3-germatranylpropionic acid, 1.79 g (4.0 mmol) tris(neopentyl)tin bro-
mide, 0.44 g (4.0 mmol) of triethylamine. Yield, 2.22 g (75%), white solid; m.p.
164–6◦C. Anal.: calc. for C31H55NO6GeSn (741.28): C, 51.1; H, 7.15%. Found:
C, 51.1; H, 7.60%.
Synthesis of Tris(neopentyl)-3-phenyl-3-germatranyltin(IV)
Propionate (X)
The method used for the synthesis of (X) was the same as described for
(III). The amounts used were as follows: 1.60 g (4.0 mmol) of 3-phenyl-3-
germatranylpropionic acid, 1.78 g (4.0 mmol) tris(neopentyl)tin bromide,
0.44 g (4.0 mmol) of triethylamine. Yield, 2.0 g, (75%), white solid; m.p. 186–
8◦ C. Anal.: calc. for C30H53NO5GeSn (698.28): C, 51.5; H, 7.59%. Found: C,
51.6; H, 7.64%.
X-ray Crystallography of Cl3GeCH(Ph)CH2COOH
A crystal of the approximate dimensions 0.2 × 0.2 × 0.5 mm was used for
data collection.
Crystal Data
C9H9Cl3GeO2, M = 328.10, Triclinic, a = 8.428(3), b = 11.714(6), c =
❛
❛
14.671(6) A, α = 75.46(4), β = 76.23(3), γ = 69.19(3)◦, U = 1293(1) A3, space

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CHOUDHARY ET AL.
group P-1(No. 2), Z = 4, Dc = 1.686 gcm−3, µ(Mo-K ) = 2.967 mm−1, F(000) =
648. Crystallographic measurements were made at 293(2)◦ K on a CAD4 auto-
matic four-circle diffractometer in the range 2.16 < θ < 23.92◦. Data (4362 reflec-
tions) were corrected for Lorentz and polarization and also for decay (60% approx.)
in the X-ray beam. In the final least squares cycles all atoms were allowed to vibrate
anisotropically. Hydrogen atoms on carbon atoms were included at the calculated
positions where relevant. The solution of the structure (SHELX86) (18) and re-
finement (SHELX93) (19) converged to a conventional [i.e. based on 2156 F2 data
ꢀ
with Fo > 4σ(Fo)] R1 = 0.0655 and wR2 = 0.1847. Goodness of fit = 0.991.
❛
The max. and min. residual densities were 0.824 and 0.404 eA−3, respectively.
The asymmetric unit (shown in Fig. 1), along with the labeling scheme used was
produced using ORTEX (20).
[R1 Si(CH3)2CH2]2SnCl2 + 2HO2CCH2(R2)CHGeR3
Solvent (C2H5)3N
CH3
R1 Si
O
C
CH
R2
Ge
R3
Sn
CH2
O
CH2
CH3
2
2
R1
R2
R3
(I)
CH3
CH3
C2H5
CH3
4-CH3OC6H4
C6H5
CH3
CH3
(II)
C6H5
(III)
(IV)
C2H5
C2H5
3-CH3OC6H4
C6H5
(V)
CH3
CH3
N(CH2CH2O)3
N(CH2CH2O)3
4-CH3OC6H4
(VI)
(VII)
C2H5
C2H5
C6H5
N(CH2CH2O)3
N(CH2CH2O)3
(VIII)
3-CH3OC6H4
Figure 1. Nature of R Groups.

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285
[(CH3)3CCH2]3SnBr
+
HO2CCH2(R1)CHGe(R2)3
Solvent (C2H5)3N
CH3
C
O
CH3
CH2 Sn
O
C
CH2 CH Ge R2
R1
CH3
3
R1
R2
(IX)
(X)
3-CH3OC6H4
C6H5
N(CH2CH2O)3
N(CH2CH2O)3
Figure 2. Nature of R Groups.
RESULTS AND DISCUSSION
Synthesis
Eight new diorganotin dicarboxylates have been synthesized by the reaction
of a diorganotin dihalide and substituted germylpropionic acid in the presence of
a base (Fig. 1).
Two new triorganotin compounds have been prepared similarly by the reac-
tion of tris(neopentyl)tin(IV) bromide with substituted germenyl propionic acid in
presence of a base (Fig. 2).
IR Spectra
Important IR bands for structure determination of all the complexes are
given in Table I. Characteristic vibrational frequencies have been identified by
comparing the spectra of the complexes with their precursors and literature values
of absorption frequencies of similar compounds (21–23). The complex formation
by deprotonation of substituted germylpropionic acid ligand is evidenced by the
absence of the ν(OH) band at 3400–3500 cm−1, whereas a new band in the range of
416–456 cm−1 indicates the presence of a Sn O C moiety in all of the complexes.
– –

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CHOUDHARY ET AL.
Figure 3. The structure of Cl3GeCH(Ph)CH2COOH showing its dimeric nature.
Further evidence of formation of a tin carboxylate bond comes from ꢀν (difference
between asymmetric and symmetric absorption frequency values) which falls in
the range of 250–350 cm−1 (Table I) indicating tetrahedral geometry around the tin
moiety (21). The 1H NMR data of the compounds (I)-(X) are presented in Table II.
All the protons in the compounds have been identified and the total number of
Table I. Characteristic IR Absorption Frequencies in cm−1
Comp.
No.
ν (CO)
asym, sym
–
–
–
ꢀν
ν(Ge O) ν(Ge →N)
ν(Sn C)
ν(Sn O)
(I)
(II)
(III)
(IV)
(V)
1599 s, 1382 s 217
1600 s, 1397 s 221
1642 s, 1412 s 230
1596 s, 1494 s 202
1602 s, 1381 s 221
–
–
–
–
–
–
–
601 m, 567 m
600 s, 566 s
602 m, 531 s
599 s, 447 w
615 m, 536 w
428 w
428 m
439 s
456 m
430 s
–
900 w,
836 s
900 w,
802 m
913 w,
830 m
903 w,
842 m
898 w,
801 m
915 w,
833 m
697 s
(VI)
(VII)
(VIII)
(IX)
1601 s, 1378 s 223
1534 s, 1398 s 236
1622 s, 1421 s 201
1641 s, 1436 s 205
1600 s, 1386 s 214
697 w
714 m
710 m
714 s
614 s, 535 m
607 s, 525 w
610 w, 535 m
598 m, 533 s
597 w, 541 m
426 s
425 w
433 m
432 w
416 w
(X)
716 m

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287
Table II. 1H NMR Data (ppm)
(I) 0.04 (s, 36H, SiCH3, GeCH3), −0.06 (s, 4H, SnCH2), 2.74–2.76 (m, 4H,
CH2-CHGe), 3.70–3.72 (m, 2H, CH2CHGe), 3.79 (s, 6H, OCH3), 6.53–7.10
(m, 8H, phenyl)
(II) 0.50 (s, 36H, SiCH3, GeCH3), −0.1 (s, 4H, SnCH2), 2.77–2.92 (m, 4H,CH2
CHGe), 3.69–3.82 (m, 2H, CH2CHGe), 7.00–7.23 (m, 10H, phenyl)
(III) 0.08–0.09 (m, 22H,CH3CH2Si(CH3)2), −0.1 (s, 4H, SnCH2), 0.85–0.96 (m,
30H, CH3CH2Ge), 2.91–2.98 (m, 4H, CH2CHGe), 3.10–3.17 (m, 2H, CH2-
CHGe), 7.17–7.23 (m, 8H, phenyl)
(IV) 0.16 (s, 18H, SiCH3), −0.16 (s, 4H, CH2Sn), 0.94–0.98(30H, CH3CH2Ge),
3.08–3.10 (m, 6H, CH2CHGe), 3.79 (s, 6H, OCH3), 7.23–7.30 (m, 8H, phenyl)
(V) 0.06 (s, 18H, SiCH3), −0.11 (s, 4H, CH2Sn), 2.92–3.05 (m, 4H, CH2CHGe),
3.71–3.86 (m, 2H, CH2CHGe), 2.75 [t, 12H, NCH2, 3 J = 5 Hz], 3.64 [t, 12H,
OCH2, 3J = 6 Hz], 7.00–7.32 (m, 10H, phenyl)
(VI) 0.04 (s, 18H, SiCH3), −0.04 (s, 4H, CH2Sn), 2.92–3.00 (m, 4H, CH2CHGe),
3.75–3.80 (m, 2H, CH2CHGe), 2.70 [t, 12H, N CH2, 3J = 5 Hz], 3.70 [t, 12H,
OCH2, 3J = 6 Hz], 3.72 (s, 6H, OCH3), 7.00–7.23 (m, 8H, phenyl)
(VII) 0.03 (s, 12H, CH3Si), 0.83–0.90 (m, 10H, CH3CH2Si), −0.16 (s, 4H, CH2Sn),
3.0–3.10 (m, CH2CHGe), 2.73 [t, 12H, NCH2, 3J = 6 Hz], 3.67 [t, 12H, OCH2,
3J = 6 Hz), 7.16–7.23 (m, 10H, phenyl)
(VIII) 0.09 (s, 12H, CH3Si), 0.75–0.83 (m, 10H, CH3CH2Si), −0.01 (s, 4H, CH2Sn),
2.82–2.92 (m, 6H, CH2CHGe), 2.82 [t, 12H, NCH2, 3J = 6 Hz], 3.62 [t, 12H,
OCH2, 3J = 6 Hz], 3.72 (s, 6H, OCH3), 6.55–7.03 (m, 4H, phenyl)
(IX) 0.9 (s, 27H, (CH3)3C), −0.01 [s, 6H, SnCH2, 2J(H-119Sn = 55.4 Hz], 2.96–3.00
3
(m, 4H, CH2CHGe), 3.02–3.22 (m, 2H, CH2CHGe), 2.71 [t, 6H, NCH2, J =
3
5 Hz), 3.66 (t, 6H OCH2, J = 5 Hz], 3.72 (s, 3H, OCH3), 6.53–7.03 (m, 4H,
phenyl)
(X) 0.91 (s, 27H, (CH3)3C), −0.01 [s, 6H, CH2Sn, 2J(H-119Sn = 55.4 Hz], 2.97–3.00
(m, 4H, CH2CHGe), 3.0–3.11 (m, 2H, CH2CHGe), 2.70 (t, 6H, NCH2, 3J = 5
Hz), 3.66 (t, 6H, OCH2, 3J = 6 Hz), 7.12–7.26 (m, 5H, phenyl)
protons calculated from the integration curve agrees well with that expected from
the molecular formula.
NMR Spectra
From Table II it is clear that the CH2 group attached to silicon and tin
resonated at high-field in the region of −0.02 to 0.06 ppm, which is due to the
electropositive nature of tin and silicon. Here, CHGe is a chiral centre and CH2 is

ORDER
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288
CHOUDHARY ET AL.
Table III. 13C, 29Si, and 119Sn NMR Dataa (ppm)
Comp. No.
RSi
CH2Sn
RGe
CH2
CH OCH3 CO2 119Sn
29Si
(I)
(II)
(III)
−3.7
−3.7
−1.5
0.9
0.8
3.3
0.7
0.8
7.3,
8.3
45.8 35.0 54.9
182.6 −115 −21.7
182.7 −115 −21.9
44.2 35.4
46.9 34.7
–
–
179.5
5
–
(IV)
(V)
1.22
3.47
9.12, 46.50 35
9.18
55.73 191.2 −542
182.0 −89
–
−0.6 −0.5
−0.9 −0.9
51.7,
56.4
52.0,
54.0
51.7,
54.5
51.6,
56.4
52.0,
56.8
45.3 36.8
–
4.1
(VI)
(VIII)
(IX)
(X)
37.3 36.7 56.8
45.3 36.5 56.4
37.3 37.1 54.4
173.0
178.0
177.0
177.5
–
–
–
–
–
–
8.6
31.5
31.6
6.8
38.5
38.8
81
87
37.5 37.4
–
aThe13C resonances of aromatic carbons are not included; other couplings: (IX): 1J(119Sn-
1
2
3
C) = 341 Hz, J(117Sn-C) = 328 Hz, J(119Sn-C) = 19.91 Hz, J(119Sn-C) = 58 Hz (X):
1J(119Sn-C) = 343 Hz, 1J(117Sn-C) = 328 Hz, 2J(119Sn-C) = 20 Hz, 3J(119Sn-C) = 39 Hz.
a prochiral centre and the three hydrogens in the CH2CHGe unit comprise three
non-equivalent protons. In (I), (III), (V) and (VI) these appear as an ABX system
and give rise to two multiplets in the regions of 2.76–3.00 ppm and 3.80–3.96 ppm,
respectively, whereas the compounds (IV), (VII) -(X) show a pattern arising from
three nuclei whose chemical shifts are very similar and thus give rise to a single
multiplet in the region 2.9–3.1 ppm.
13C NMR spectral data are presented in Table III. The shifts of methylene
carbons attached to silicon and tin atoms indicate involvement with tin and silicon
atoms. When silicon is replaced by carbon [(IX), (X)] a low-field shift of about
1
2
40 ppm is observed. The coupling constants J(119Sn-13C) and J(119Sn-13C) in-
dicate tetrahedral coordination around the tin atoms (24a). Ge-C absorptions are
sensitive to the nature of the alkyl group, that is why a shift of 8 ppm towards low-
field is observed when CH3 is replaced by C2H5 in (III). Further, in the germatranes
carbon atoms bonded to tin atoms through oxygen and nitrogen resonate at 56 and
51 ppm, respectively. The 119Sn NMR spectrum of (IV) (−542 ppm) shows an
octahedral environment around the tin in solution. Such structural changes are pos-
sible through intramolecular coordination to yield a trans-R2SnO4 coordination
sphere (24b).

ORDER
REPRINTS
DIORGANOTIN COMPOUNDS
289
Table IV. Crystal Data and Structure Refinement for the Compound in Fig. 3
Identification code
97kcm7
Empirical formula
Formula weight
Temperature
C9H9Cl3 GeO2
328.10
293(2)◦K
❛
Wave length
Crystal system
Space group
0.70930 A
Triclinic
P-1(No. 2)
❛
Unit cell dimensions
a = 8.428(3) A α = 75.46(4)◦
❛
b = 11.714(6)A β = 76.23(3)◦
❛
c = 14.671(6)A γ = 69.19(3)◦
❛
Volume
1292.7(10)A3
Z
4
Density (calculated)
Absorption coefficient
F(000)
1.686 g/cm3
2.967 mm−1
648
Crystal size
Theta range for data collection
Index ranges
0.2 × 0.2 × 0.5 mm
2.16 to 23.92◦.
0<=h<=9; −12<=k<=13; −16<=l<=16
4362
4047 [R(int) = 0.0503]
Full-matrix least-squares on F2
4047 / 0 / 272
Reflections collected
Independent reflections
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I>2σ(I)]
R indices (all data)
Largest diff. peak and hole
Weighting scheme
0.991
R1 = 0.0655 wR2 = 0.1847
R1 = 0.0969 wR2 = 0.1942
❛
0.824 and −0.404 eA−3
2
Calc. w = 1/ [σ (Fo2) + (0.1114P)2 + 0.2564P]
where P = (Fo2 + 2Fc2)/ 3
Extinction coefficient
Extinction expression
10918.3203(4627383)
Fc* = kFc[1 + 0.001 × Fc2λ3/ sin(2θ)]−1/4
Crystal Structure
As part of this work we had cause to confirm crystallographically the nature
of Cl3GeCH(Ph)CH2CO2H, one of the precursors used in this study. Subsequent
to our analysis we discovered that this structure had already been reported (25),
and our crystal data (space group, cell dimensions etc) are consistent with this
work. We here include a discussion, however, as the earlier report has missed
or ignored its most salient features. The species is not monomeric but dimeric
through hydrogen bonds linking Cl . . . HO units (Figure 1). Unlike the pattern of
conventional carboxylic acid hydrogen bonds, dimerisation takes place through

ORDER
REPRINTS
290
CHOUDHARY ET AL.
Table V. Atomic Coordinates (×104) and Equivalent Isotropic Displacement Para-
❛
meters(A2 × 103) for the Compound in (Fig. 3). U(eq) Is Defined as One Third of the
Trace of the Orthogonalized Uij Tensor
Atom
x
y
z
U(eq)
Ge(1)
Ge(2)
Cl(1)
Cl(2)
Cl(3)
Cl(4)
Cl(5)
Cl(6)
O(1)
O(2)
O(3)
O(4)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
2029(2)
210(3)
1061(8)
7016(2)
8275(2)
8763(5)
6674(7)
5668(6)
8255(7)
9984(7)
6841(7)
1595(1)
6560(2)
727(4)
2613(4)
722(5)
81(1)
96(1)
119(2)
133(2)
134(2)
139(2)
168(4)
135(2)
110(5)
109(4)
111(4)
95(4)
78(4)
104(7)
99(6)
106(6)
117(7)
111(7)
104(6)
93(5)
−57(8)
2812(9)
2433(9)
5528(5)
7048(7)
7727(4)
3652(9)
4062(9)
4662(9)
5223(9)
2183(12)
1430(13)
1197(14)
498(15)
18(16)
231(15)
932(15)
2961(12)
3595(9)
6031(11)
6723(13)
6579(14)
7154(18)
7910(18)
8142(16)
7546(16)
5735(11)
5198(12)
−638(9)
995(9)
5249(20)
6358(19)
−2907(20)
−2175(17)
3926(20)
5316(29)
5459(29)
6743(32)
7948(36)
7824(20)
6526(27)
4454(26)
5396(26)
−1505(26)
−3225(38)
−4389(29)
−5991(34)
−6230(24)
−5013(25)
−3491(27)
−884(24)
−2061(29)
7194(12)
5117(12)
7602(12)
5621(12)
6987(16)
7330(17)
8485(18)
8748(21)
7850(24)
6717(26)
6424(19)
5886(16)
6108(19)
8053(14)
8346(14)
9384(22)
9734(23)
8932(28)
7724(27)
7457(20)
6826(17)
6606(18)
86(5)
84(5)
122(9)
106(6)
120(8)
131(10)
130(9)
109(6)
85(5)
96(6)

ORDER
REPRINTS
DIORGANOTIN COMPOUNDS
291
❛
Table VI. Bond Lengths [A] and Angles [◦] for the Compound in Fig. 3
Ge(1)-C(1)
1.976(12)
2.115(5)
2.106(6)
2.108(6)
1.91(2)
2.107(6)
2.119(6)
2.121(7)
1.26(2)
1.29(2)
1.31(2)
1.18(2)
1.50(2)
1.50(3)
1.35(3)
1.40(3)
1.37(3)
1.38(3)
1.32(3)
1.39(3)
1.48(2)
1.48(2)
1.54(3)
1.27(3)
1.41(3)
1.39(3)
1.29(3)
1.44(3)
1.35(3)
1.52(3)
C(10)-Ge(2)-Cl(4)
C(10)-Ge(2)-Cl(5)
Cl(4)-Ge(2)-Cl(5)
C(10)-Ge(2)-Cl(6)
Cl(4)-Ge(2)-Cl(6)
Cl(5)-Ge(2)-Cl(6)
C(8)-C(1)-C(2)
C(8)-C(1)-Ge(1)
C(2)-C(1)-Ge(1)
C(3)-C(2)-C(7)
C(3)-C(2)-C(1)
C(7)-C(2)-C(1)
C(2)-C(3)-C(4)
C(5)-C(4)-C(3)
C(4)-C(5)-C(6)
C(5)-C(6)-C(7)
C(2)-C(7)-C(6)
C(1)-C(8)-C(9)
110.4(5)
Ge(1)-Cl(1)
Ge(1)-Cl(2)
Ge(1)-Cl(3)
Ge(2)-C(10)
Ge(2)-Cl(4)
Ge(2)-Cl(5)
Ge(2)-Cl(6)
O(1)-C(9)
112.6(5)
107.2(3)
112.4(5)
106.7(3)
107.3(3)
117.9(14)
114.7(12)
110.5(12)
118(2)
123(2)
119(2)
121(2)
122(2)
119(2)
121(2)
120(2)
112.4(14)
124(2)
121(2)
115(2)
116(2)
110.8(13)
109.0(13)
120(2)
121(2)
119(2)
126(2)
115(2)
124(2)
117(2)
119(2)
115(2)
121(2)
124(2)
O(2)-C(9)
O(3)-C(18)
O(4)-C(18)
C(1)-C(8)
C(1)-C(2)
C(2)-C(3)
C(2)-C(7)
C(3)-C(4)
C(4)-C(5)
C(5)-C(6)
O(1)-C(9)-O(2)
O(1)-C(9)-C(8)
O(2)-C(9)-C(8)
C(6)-C(7)
C(8)-C(9)
C(10)-C(17)
C(10)-C(11)
C(11)-C(12)
C(11)-C(16)
C(12)-C(13)
C(13)-C(14)
C(14)-C(15)
C(15)-C(16)
C(17)-C(18)
C(1)-Ge(1)-Cl(1)
C(1)-Ge(1)-Cl(2)
Cl(1)-Ge(1)-Cl(2)
C(1)-Ge(1)-Cl(3)
Cl(1)-Ge(1)-Cl(3)
Cl(2)-Ge(1)-Cl(3)
C(17)-C(10)-C(11)
C(17)-C(10)-Ge(2)
C(11)-C(10)-Ge(2)
C(12)-C(11)-C(16)
C(12)-C(11)-C(10)
C(16)-C(11)-C(10)
C(11)-C(12)-C(13)
C(14)-C(13)-C(12)
C(13)-C(14)-C(15)
C(16)-C(15)-C(14)
C(15)-C(16)-C(11)
C(18)-C(17)-C(10)
O(4)-C(18)-O(3)
O(4)-C(18)-C(17)
O(3)-C(18)-C(17)
111.0(5)
112.7(6)
107.1(3)
112.4(5)
107.1(3)
106.2(3)
114(2)

ORDER
REPRINTS
292
CHOUDHARY ET AL.
❛
Table VII. Anisotropic Displacement Parameters (A2 × 103) for the Compound in for
Fig. 3 the Anisotropic Displacement Factor Exponent Takes the Form: -2pi2[h2 a* 2U11
+ · · · + 2 h k a* b* U12]
Atom
U11
U22
U33
U23
U13
U12
Ge(1)
Ge(2)
Cl(1)
Cl(2)
Cl(3)
Cl(4)
Cl(5)
Cl(6)
O(1)
O(2)
O(3)
O(4)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
89(1)
103(2)
141(4)
119(4)
136(5)
117(4)
131(5)
132(5)
168(14)
131(11)
155(12)
114(9)
72(9)
127(16)
137(17)
140(18)
156(22)
47(9)
106(14)
116(14)
127(14)
132(14)
220(25)
119(16)
129(19)
57(10)
67(12)
93(13)
108(13)
150(18)
75(1)
85(1)
86(3)
155(6)
121(4)
140(5)
139(6)
155(6)
76(8)
71(1)
100(2)
128(4)
110(4)
160(6)
147(5)
269(10)
103(4)
95(9)
−6(1)
−36(1)
22(3)
−11(1)
−11(1)
−63(4)
9(3)
−24(1)
−21(1)
−35(3)
−59(4)
−32(4)
−49(4)
−6(4)
1(4)
−80(4)
−36(4)
−128(6)
−20(4)
−21(7)
−9(7)
−12(4)
28(4)
−57(6)
−30(4)
−52(9)
−46(8)
−35(9)
−42(7)
−46(8)
−3(11)
−6(12)
−33(13)
−33(14)
26(9)
−22(4)
−24(8)
−8(8)
90(9)
86(9)
84(9)
93(9)
96(9)
92(8)
−18(7)
1(7)
−34(8)
−32(7)
−24(8)
13(11)
−54(12)
−58(14)
−69(18)
−48(12)
−24(11)
−34(10)
−59(12)
−24(9)
6(12)
−52(14)
−47(15)
21(14)
−59(15)
−23(11)
−40(10)
−38(12)
95(11)
65(11)
85(13)
94(14)
121(18)
180(23)
90(13)
76(11)
113(15)
58(9)
88(11)
72(11)
94(13)
87(13)
96(15)
113(15)
110(15)
70(10)
28(7)
−29(9)
−4(8)
−36(10)
24(11)
−9(14)
−56(15)
13(11)
14(8)
−53(12)
−7(10)
−16(8)
−6(9)
3(8)
51(8)
−7(7)
33(8)
74(11)
69(11)
101(16)
129(19)
112(16)
120(17)
57(9)
0(7)
−31(14)
−6(11)
−16(14)
4(11)
130(19)
116(18)
190(25)
198(26)
100(14)
93(12)
70(11)
−11(11)
16(13)
−104(19)
−13(16)
−2(12)
−6(8)
19(11)
−21(12)
−15(9)
−16(10)
57(10)
13(8)
a head-to-tail arrangement generating a 14-membered (HOC3GeCl)2 ring. Al-
though the acid protons could not be located, it is (in part) possible to differen-
==
–
tiate between the C O and C O groups within the carboxylic acid groups on
the basis of bond lengths. Thus, O(4) forms part of the carbonyl group [C(18) =
❛
2(4): 1.18(2) A] while the hydroxyl group is based on O(3) [C(18)-O(3):
❛
1.31(2) A]. The situation in the second CO2H group is unfortunately not clear
❛
[C(9)-O(1): 1.26(2); C(9)-O(2): 1.29(2) A], but there is no reason to assume this

ORDER
REPRINTS
DIORGANOTIN COMPOUNDS
293
Table VIII. Hydrogen Coordinates (×104) and Isotropic Displacement Parameters
❛
(A 3×103) for the Compound in Fig. 3
Atom
x
y
z
U(eq)
H(1)
H(3)
H(4)
H(5)
H(6)
H(7)
H(8A)
H(8B)
H(10)
H(12)
H(13)
H(14)
H(15)
H(16)
H(17A)
H(17B)
3423(20)
4678(29)
6808(32)
8829(36)
8618(20)
6458(27)
5179(26)
3436(26)
-1670(26)
-4153(29)
-6827(34)
-7256(24)
-5260(25)
-2635(27)
232(24)
7693(16)
9106(18)
9552(21)
8039(24)
6107(26)
5622(19)
5171(16)
5695(16)
8683(14)
9961(22)
10492(23)
9149(28)
7153(27)
6702(20)
6736(17)
6184(17)
2518(12)
1515(14)
342(15)
-447(16)
-94(15)
1072(15)
2675(12)
3338(12)
5449(11)
6045(14)
7002(18)
8333(18)
8677(16)
7674(16)
5332(11)
6300(11)
93
118
128
141
134
124
111
111
101
127
144
157
156
131
102
102
-722(24)
group is bonded any differently than that based on C(18). The Cl . . . . O separa-
tions are consistent with weak hydrogen bonds [Cl(2)-O(3): 3.51(2); Cl(4)-O(1):
❛
3.36(2) A].
ACKNOWLEDGMENT
M. Mazhar is thankful to the Pakistan Science Foundation for financing
the project, to Professor T. N. Mitchell, University of Dortmund, Germany, for
gifts of chloromethyltrimethylsilane, tris(neopentyl)tin bromide and germanium
dioxide. M. A. Choudhary is grateful to the University of Azad Jammu & Kashmir,
Muzaffarabad, for granting a study leave.
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Received March 12, 1999
Referee I: G. Eng
Accepted November 22, 2000
Referee II: K. M. Baines

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