The transannular interaction germanium-nitrogen in germocanes: The influence of substituents

Article abstract of DOI:10.1016/j.jorganchem.2006.08.011

The reaction of RN(CH₂CH₂OH)CHR¹CR²R ³OH (1-8) with a stoichiometric amount of tetrachloro(bromo)germane leads to the corresponding RN(CH₂CH₂O)(CHR¹CR²R

Full text of DOI:10.1016/j.jorganchem.2006.08.011

Journal of Organometallic Chemistry 691 (2006) 5710–5724
www.elsevier.com/locate/jorganchem
The transannular interaction germanium–nitrogen in germocanes:
The influence of substituents
a
a
a,
*
Elmira Kh. Lermontova , Anastasia A. Selina , Sergey S. Karlov
,
b
c
a
Andrei V. Churakov , Judith A.K. Howard , Yuri F. Oprunenko ,
d
e
a
Mikhail Yu. Antipin , Jo¨rg Sundermeyer , Galina S. Zaitseva
a
Department of Chemistry, Moscow State University, Leninskie Gory 1, str. 3, 119899 Moscow, Russia
b
Institute of General and Inorganic Chemistry, RAS, Leninskii Pr. 31, Moscow 119991, Russia
c
Department of Chemistry, University of Durham, South Road, DH1 3LE Durham, UK
d
A.N. Nesmeyanov Institute of Organoelement Compounds, RAS, Vavilova str. 28, 119991 Moscow, Russia
Fachbereich Chemie, Philipps-Universita¨t Marburg, Hans-Meerwein-Strasse, D-35032 Marburg/Lahn, Germany
e
Received 1 June 2006; received in revised form 25 July 2006; accepted 7 August 2006
Available online 17 August 2006
Abstract
The reaction of RN(CH2CH2OH)CHR1CR2R3OH (1–8) with a stoichiometric amount of tetrachloro(bromo)germane leads to the
corresponding RN(CH2CH2O)(CHR1CR2R3O)GeHal2 (9–21). Difluorenylgermocane 22 was prepared by treatment of diethoxydifluor-
enylgermane with N-methyldiethanolamine. Different dialkanolamines were found to be successive precursors of dimethylgermocanes,
RN(CH2CH2O)(CHR1CR2R3O)GeMe2 (23–26). The chemical properties of simple and easy to access germocanes RN(CH2CH2O)2-
GeX2 [X = OH, Br (28), Cl (29)] were studied and the difluoro (27), haloalkoxy (30–32), and dialkoxy (33, 34) derivatives were prepared.
The structures of the compounds 16, 20–22, and 26 were confirmed by X-ray diffraction and the structural features in solution of 23 and
26 were studied by NMR spectroscopy (NOEs). The relationship between the nature of substituents at different positions of the germo-
cane skeleton and the strength of the intramolecular Ge N bond is discussed.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Germocanes; Germanium; Intramolecular interaction; Alkoxides; Dialkanolamines
1. Introduction
research is the elucidation of the nature of the transannular
M donor bond, which is strongly affected by the design
of the substituents at the metal atom and donor block [3–
5]. On the other hand, hypervalent compounds have found
application in organic synthesis as intermediates in several
coupling reactions [6,7] and in medicinal chemistry and
pharmacology as compounds displaying a wide range of
biological activity [8,9]. The alkanolamine moiety is a part
of the widespread ligands for the formation of hypervalent
compounds of Group 14 elements [10,11]. Among these
species, compounds of silicon and tin are the most heavily
investigated, while the derivatives of germanium have been
less studied [3,4,12].
One of the most important points of interest in the
chemistry of main group elements is the study of the struc-
ture and properties of derivatives of so-called hypervalent
atoms. The coordination number of the central atom in
these compounds exceeds that permitted according to the
‘‘octet’’ rule [1,2]. The hypercoordination results from the
intermolecular contact of main group element with free
Lewis base or from the formation of intramolecular trans-
annular bond with donor group. The main focus of the
*
Corresponding author. Tel.: +7 495 939 3887; fax: +7 495 932 8846.
Germatranes, N(CH2CH2O)3Ge–X, as well as their ana-
logues with substituents at carbon atoms in atrane skeleton,
E-mail addresses: sergej@org.chem.msu.su (S.S. Karlov), jsu@chemie.
uni-marburg.de (J. Sundermeyer).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.08.011

E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
5711
are the most intensively and systematically studied class of
compounds with hypervalent germanium atom [3,12]. The
information concerning germocanes, RN(CH2CH2O)2-
Ge(X)Y – closely related analogues of germatranes – is
rather limited [13–28]. However, one might expect that ger-
mocanes possess greater chemical and structural flexibility
since they have more possibilities to vary substituents R,
X, and Y and, hence, to modulate the effect that these
groups have on the transannular Ge N bond strength.
This conclusion was supported by a series of works by Dra¨-
ger et al., Cea-Olivares et al., Tschach et al. and others in
which the closely related systems such as RN(CH2CH2-
CH2)2Ge(X)Y, O(CH2CH2Z)2Ge(X)Y, S(CH2CH2Z)2Ge-
(X)Y (Z = CH2, O, S) and their Sn, As, Sb, Bi analogues
were studied and some conclusions about the nature of
transannular bonds have been drawn [4,29–38]. Dra¨ger
has proposed that several factors are responsible for the
strength of intramolecular bond in these systems: the nature
of donor (its donor capacity), the nature of the axial substi-
tuent at the metal centre (its electronegativity and ability of
lone pair interaction), the type of equatorial ligands, the
geometrical flexibility of donor group. However, in general,
the mutual influence of these factors depends on the nature
of central atom and should be an object of investigations in
each specific case.
by X-ray diffraction and NMR spectroscopy, respectively.
Our motivation was to prepare germocanes with the
strength of intramolecular Ge–N interaction varying in
the wide range and to estimate the influence of substituents
nature on the degree of this interaction. This report is the
first systematic investigation upon the variation of wide
range substituents at different positions of metallocane,
RN(CH2CH2O)2M(X)Y, skeleton where M is a Group 14
element.
2. Results and discussion
2.1. Synthesis
According to the literature, trimethylsilyl ethers of
dialkanolamines are the most suitable intermediates for
the preparation of dihalogermocanes [15,28]. In this study,
we used two methods for the preparation of ethers 1–8:
silylation of dialkanolamines with hexamethyldisilazane
(A, Scheme 1) or with the system Me3SiNEt2/Me3SiCl
(cat.) (B, Scheme 2) [45]. These derivatives were prepared
in high yields. Compound 3 contains a small amount of 4
due to the presence of parent dialkanolamine in starting
material [46]. This mixture was used in further reactions
without purification.
Several synthetic methods have been used for the forma-
tion of germocane skeleton. Most of them represent the
reaction between dialkanolamines and suitable germanium
derivatives [13,18–20,22–28]. A different approach, viz.,
the reaction of GeHal4 with trimethylsilyl ethers of dietha-
nolamines, RN(CH2CH2OSiMe3)2, leading to the corre-
sponding 2,2-dihalogermocanes, was used by us [28] and
others [15]. No chemical properties of germocanes were
investigated to date except the reaction of 2,2-
dihydroxygermocanes with bidentate ligands and the ger-
mocane–germatrane rearrangement [14,22–25]. Although
the structure of germocanes was explored by X-ray diffrac-
tion studies in the solid state, by 1H, 13C, 73Ge NMR spec-
troscopy in solution, and by mass-spectrometry (electron
impact) in gas phase [13,15–17,19–23,26], the relationships
between key structural parameters of germocanes and the
electronic and steric properties of substituents bound to
the Ge and N atoms are still not clarified due to the narrow
scope of R, X, Y groups [28].
Silyl ethers 1–8 react with an equimolar amount of
GeHal4 at reflux temperature in chloroform or toluene
solution to give the corresponding 2,2-dihalogermocanes
9–21 in 12–87% yields (Scheme 3).
Our efforts to prepare germocane 22 with donor fluore-
nyl substituents at the Ge atom by an analogous metathet-
ical reaction of MeN(CH2CH2OSiMe3)2 with Flu2GeCl2
failed. We believe that this method is successful only for
the synthesis of germocanes containing acceptor substitu-
ents at the Ge atom. The compound 22 was obtained using
(Me3Si)2NH
RNCH2CH2OH
CHR1CR2R3OH
RNCH2CH2OSiMe3
CHR1CR2R3OSiMe3
- NH3
1,2
1, R = Me, R1-R2 = (CH2)4, R3 = H
2, R = Ph, R1 = R2 = R3 = H
(Me3Si)2NH
- NH3
MeNCH2CH2OSiMe3 + MeNCH2CH2OSiMe3
MeNCH2CH2OH
CH2CHPhOH
CH2CHPhOSiMe3
CHPhCH2OSiMe3
In continuation of our investigations in the chemistry of
metallatranes [39–44] and metallocanes [28] we focused our
efforts on the synthesis and characterization of germocanes
bearing various substituents at the Ge and N atoms, as well
as at the carbon atoms of ocane skeleton. It should be noted
that the latter compounds with substituents at C atoms are
almost unexplored to date. Herein we report the synthesis of
novel 2,2-dihalo-, 2,2-dimethyl-, 2,2-difluorenyl-, and 2,2-
dialkoxygermocanes which contain different substituents
at N and C atoms of ocane skeleton. Some of them were
obtained from the substitution reactions at the Ge atom
proceeding with the retention of ocane skeleton. Their
structures in the solid state and in solution were established
3 (90%)
4 (10%)
Scheme 1.
Me3SiNEt2 / Me3SiCl (cat.)
- Et2NH
MeNCH2CH2OH
CHR1CR2R3OH
MeNCH2CH2OSiMe3
CHR1CR2R3OSiMe3
5-8
5, R1 = H, R2 = Me, R3 = H
6, R1 = R2 = Ph (erythro), R3 = H
7, R1 = R2 = Ph (threo), R3 = H
8, R1 = H, R2 = R3 = Ph
Scheme 2.

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E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
R1
Me
Me
F
N
N
R
R2
R3
N
GeHal4
.
BF3 Et2O
RNCH2CH2OSiMe3
CHR1CR2R3OSiMe3
Ge
Ge
O
O
HO
- 2 Me3SiHal
O
O
O
Hal Ge
F
27
OH
O
Hal
9-21
Scheme 6.
R
Me
R1 R2 R3 Hal
R
R1 R2 R3 Hal
9
H
Me
H
H
Br
Br
15 Me Ph Ph
16 Me Ph Ph
17 Me Ph Ph
18 Me
19 Me
20 Ph
21 Ph
H
H
H
Cl (erythro)
Br (erythro)
Br (threo)
10 Me (CH2)4
2,2-Dihalogermocanes, like 1-halogermatranes, are
good starting materials for the preparation of alkoxy deriv-
atives (Scheme 7). It should be noted that previously this
type of compounds possessing one or two alkoxy groups
was inaccessible except for the cyclic diolates (see, for
example, Scheme 8). We have found that the treatment of
the compound 28 with an equimolar amount of Et3SnOMe
led to the selective substitution of one bromine atom with a
methoxy group; in the case of two equivalents of organotin
compound dimethoxygermocane 33 is formed as the only
ocane product. Analogously, the formation of 31 and 34
was established in the reaction of dichloride 29 with one
or two equivalents of organotin L-(ꢀ)-menthol derivative,
respectively. The treatment of the compound 28 with an
equimolar amount of Et3SnOCH2CH2NMe2 led to the
exchange of one chlorine atom for alkoxy group. The for-
mation of the stable complex of 32 with one molecule of
Et3SnCl was confirmed by NMR spectroscopy and elemen-
tal analysis data.
11 Me
12 Me Ph
13 Me
14 Me Ph
H
Ph
H
Ph
H
H
H
H
H
Cl
Cl
Br
Br
H
H
H
H
Ph Ph Cl
Ph Ph Br
H
H
H
H
H
Cl
Br
Scheme 3.
transalkoxylation reaction as an alternative approach
(Scheme 4).
Recently, we reported the preparation of MeN(CH2-
CH2O)2GeMe2 by the reaction of Me2Ge(NMe2)2 with
N-methyldiethanolamine [28]. Following this approach,
diverse 2,2-dimethylgermocanes 23–26 were synthesized in
almost quantitative yields (Scheme 5).
As it was found previously in metallatrane, especially
germatrane, chemistry the compounds containing a simple
but reactive group X at the metal atom serve as convenient
intermediates for the preparation of more complicated
structures. We have found that the treatment of MeN(CH2-
CH2O)2Ge(OH)2 with boron trifluoride etherate led to
difluoride 27 in moderate yield (Scheme 6). This difluoro
derivative seems difficult to access via other methods.
We also investigated the reaction of dibromide 28 with
two equivalents of FluLi, which led to difluorenyl derivative
Me
N
Et3SnOR
- Et3SnHal
Me
N
O
Hal(RO)Ge
Me
O
N
30-32
MeN(CH2CH2OSiMe3)2
Flu2GeCl2
- 2 Me3SiCl
Me
RO
Ge
O
O
Hal Ge
N
O
O
2 Et3SnOR
MeN(CH2CH2OH)2
- 2 EtOH
Hal
28,29
- 2 Et3SnHal
Flu2Ge(OEt)2
O
Ge
O
Hal
28 Br
29 Cl
OR
33, 34
22
Hal
R
Scheme 4.
30 Br
31 Cl
32 Cl
Me
Menth
CH2CH2NMe2
33
34
Me
Menth
R1
O
R
R2
R3
Scheme 7.
N
Me2Ge(NMe2)2
- 2 Me2NH
RNCH2CH2OH
CHR1CR2R3OH
Ge
Me
R
X
Y
Ref.
O
Me
R
X
28 Me
35
36 Me
37 Me
38 Me
39 n-Bu
Br
OH
Br
OH
[28]
[20]
[26]
[18]
[23]
[17]
[16]
N
23-26
H
2-thienyl 2-thienyl
OCH2CH2O
OCPh2C(O)O
R
R1 R2 R3
H
24 Me Ph
Ge
Y
O
O
23 Me
Ph
H
H
H
CH2CH2C(O)O
25 Me Ph Ph H (erythro)
26 Ph
40 HOCH2CH2 CH2CH2C(O)O
H
H
H
Scheme 5.
Scheme 8.

E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
5713
22 only in trace amount. Very recently we have found that
the expected bis(phenylacetylenyl)germocane did not form
in the reaction of 28 with two equivalents of PhC„CLi
[47]. Thus, this method is not appropriate for the prepara-
tion of novel germocanes in contrast to the previous findings
in germatrane chemistry where bromo derivatives were suc-
cessfully converted into germatranes with fluorenyl, phenyl-
acetylenyl and other groups [48–50].
2.2. Solid-state structures (X-ray diffraction data)
The main purpose of the present study was to estimate
how the nature of substituents at different positions of a ger-
mocane skeleton influences the strength of the intramolecu-
lar Ge N bond. In a series of closely related compounds,
such as germocanes, the strength of the bond correlates with
its length. Accordingly, the basic method for the study of
hypervalent compounds is X-ray diffraction. Among previ-
ously reported germocanes, seven compounds have been
structurally characterized (see Scheme 8).
In the course of our studies, the solid-state structures of
16, 20–22, and 26 were determined by single-crystal X-ray
analysis. The molecular structures of these compounds are
shown in Figs. 1–5. Important bond lengths and angles for
16, 20–22, and 26 are summarized in Table 1. The studied
compounds may be divided into groups according to the
character of the substituents at the Ge and N atoms. Ger-
mocanes 16, 20, and 21 possess acceptor substituents (hal-
ogens) at the Ge atom, however, 16 possesses the donor
group (Me) at the N atom, while in 20 and 21 the N atom
is bound to the acceptor group (Ph). In the compound 22
having the donor methyl group at the N atom the Ge atom
Fig. 2. Molecular structure of 20.
Fig. 3. Molecular structure of 21.
is adjacent to two donor and bulky fluorenyl groups.
Finally, germocane 26 contains the donor methyl groups
at the Ge atom and the acceptor phenyl group at the N
atom. It should be noted that 16 is the first X-ray structur-
ally studied germocane with substituents at the carbon
Fig. 1. Molecular structure of 16.

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E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
Fig. 4. Molecular structure of 22; hydrogen atoms are omitted for clarity.
Fig. 5. Molecular structure of 26.
atoms of ocane moiety. We believed that the analysis of the
geometry parameters for 16, 20–22, and 26 and the com-
parison with those previously found for 28, 35–40 would
provide a better insight into the influence of substituents
on the strength of the Ge–N intramolecular bond. Here,
it should be noted that the usual values of the Ge–N cova-
Another important value is the sum of the non-bonding
radii of Ge and N (2.72 A), according to the Glidewell
approach [52].
The coordination polyhedron of the germanium atom in
16, 20, and 21 is the common one for germocane deriva-
tives 28, 35–40 and represents a slightly distorted trigonal
bipyramid (TBP) with the N and one halogen atoms in
the apical positions. The oxygen atoms O(1), O(2) and
˚
˚
lent bond vary in the range 1.80–1.90 A [41], while the sum
˚
of the van der Waals radii of Ge and N is 3.72 A [51].

E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
5715
Table 1
as the radius of silicon atom is smaller than that of germa-
nium atom. On the other hand, the GeHal2 groups are
unambiguously more attractive for the formation of addi-
tional interaction than SiPh2 group.
˚
Selected bond lengths (A) and angles (ꢁ) for germocanes,
N(CH2CH2O)(CHR1CR2R3O)GeX2 (16, 20–22, and 26)
16
20
21
22
26
Ge–N
Ge–O
2.217(2)
1.771(2)
1.788(2)
2.202(2)
1.773(2)
1.775(2)
2.202(4)
1.775(4)
1.777(3)
2.739(1)
1.776(1)
1.785(1)
3.182(1)
1.781(1)
1.781(1)
The same trend of invariability of Ge N bond distance
was observed in germocanes with substituents at the carbon
atoms of ocane skeleton. The formal replacement of two
˚
Ge–Xax
Ge–Xeq
DGea
2.3790(4) 2.2180(6) 2.3848(6) 1.994(2)
2.3282(4) 2.1658(6) 2.3200(7) 1.982(1)
0.103
0.468
1.926(2)
1.925(2)
0.553
hydrogen atoms in 28 [d(Ge N) = 2.166(5) A] [28] with
˚
two phenyl groups in 16 [d(Ge N) = 2.217(2) A] leads
0.095
0.442
0.086
0.442
0.346
0.451
168.32(5) 165.37(6)
88.47(5)
74.51(4)
74.70(5)
to only slight elongation of Ge N bond, probably due
to the steric reasons. A more appreciable effect results from
the replacement of the equatorial oxygen atoms with the
DNb
0.148
N–Ge–Xax
N–Ge–Xeq
N–Ge–O
169.10(6) 171.75(5) 170.9(1)
94.40(6)
83.15(8)
84.11(8)
92.61(5)
84.26(7)
84.72(7)
93.4(1)
84.4(2)
84.8(1)
79.22(6)
68.68(4)
69.12(4)
˚
donor CH2 groups. The Ge N bond in 20 (2.202(2) A)
is notably shorter than that in i-C4H9N(CH2CH2CH2)2-
˚
O–Ge–O
O–Ge–Xeq
126.55(9) 122.83(8) 122.0(2)
116.24(6) 114.08(6) 114.5(1)
116.35(7) 122.33(5) 122.9(1)
115.61(5) 108.23(5)
115.19(6) 112.65(7)
118.90(6) 112.90(7)
GeCl2 (2.389(4) A) [31]. This is also in accordance with
the general trend observed in atrane structures: more elec-
tronegative equatorial groups yield shorter M N trans-
annular distances.
O–Ge–Xax
90.48(6)
92.57(6)
91.00(5)
92.23(5)
90.6(1)
91.4(1)
98.36(6)
100.88(6) 104.06(7)
102.75(7)
The replacement of two bromine atoms in 28 with two
donor and bulky fluorenyl groups causes a sizeable elonga-
Xax–Ge–Xeq 96.49(1)
C–N–C
95.63(2)
109.4(2)
112.7(2)
112.9(2)
95.78(2)
109.6(4)
112.6(4)
112.6(4)
103.17(6) 115.37(8)
˚
108.0(2)
110.3(2)
113.9(2)
109.3(1)
110.0(1)
113.6(1)
118.16(13)
119.26(13)
119.46(13)
tion of the Ge N distance in 22 (2.739(1) A). Although
this distance is shorter than the sum of the van der Waals
radii of Ge and N, according to the Glidewell approach
[52], this compound possesses very weak Ge N bond.
The coordination polyhedron of Ge represents a strongly
distorted TBP with the nitrogen and one carbon in the api-
cal positions and the oxygen atoms and the other carbon
atom occupying equatorial sites. The DGe value in 22
C–N–Ge
101.2(2)
105.6(1)
117.1(2)
99.3(1)
101.4(1)
120.4(1)
99.3(3)
101.1(3)
120.8(3)
94.02(9)
96.36(9)
132.5(1)
86.75(9)
85.99(9)
114.50(9)
a
Displacement of the Ge atom from the plane defined by the two
oxygen atoms and the Xeq atom towards the Xax atom.
b
Displacement of the N atom from the plane defined by the three car-
˚
(0.346 A) is expectedly greater than those in dihalogermo-
bon atoms towards the Ge atom.
˚
canes 16, 20, and 21 (DGe = 0.086–0.103 A).
the other halogen atom occupy equatorial sites. The N–
Ge–Xax fragment is close to linear (169.10(6)–171.75(5)o).
The germanium atom is displaced from the equatorial
plane defined by the two oxygen atoms and the Xeq atom
towards Xax by 0.086–0.103 A. These DGe values corre-
spond to a very slight distortion of TBP geometry and con-
In germocane 26, where the acceptor phenyl group is
bound to the N atom and two donor Me groups are bound
to the Ge atom the Ge N interaction is absent. The value
˚
of the Geꢁ ꢁ ꢁN distance is 3.182(1) A. The coordination poly-
˚
hedron of Ge represents a slightly distorted tetrahedron.
Thus, the variation of substituents in different positions
of germocane molecules allows the preparation of germo-
canes with a strong transannular germanium–nitrogen
interaction (16, 20, and 21), with a weak one (22), and with-
out this interaction (26). Our data and the analysis of the
previously reported results on X-ray diffraction studies car-
ried out by Cea-Olivares et al. [4] testify to the very great
sensitivity of the Ge N bonding in germocanes and clo-
sely related structures [Z0(CH2CH2Z)2Ge(X)Y, where
Z = CH2, O, S and Z0 = RN, O, S] primarily to the nature
of substituents at the Ge atom and secondly to the nature
of substituents at the N atom when Z0 = RN.
sequently to strong Ge N interaction. The Ge N
˚
distances in 16, 20, and 21 (2.217(5)–2.202(4) A) slightly
exceed those previously found in germocanes 28, 35, 37–
˚
40 (2.080(3)–2.16(1) A) [17,23] with electronegative substit-
uents adjusted to the germanium atom and are sufficiently
˚
shorter than that in 36 (2.446(8) A) [26], where the thienyl
substituents are weak electron acceptor groups but their
steric bulkiness is considerably greater than that for other
studied compounds. The formal replacement of the donor
methyl group at nitrogen in 28 with the phenyl group in
20 and 21 decreases the basicity of the N atom due to the
possibility for the nitrogen lone pair to interact with the
aromatic ring. However, in the case of acceptor substitu-
ents at the germanium atom such replacement does not
drastically change the length of the Ge N bond. This
result is unexpected because previously in silocane chemis-
try a considerable elongation of the Si N bond distance
In the dihalogermocanes 16, 20, and 21 possessing the
noticeable Ge N interaction the Ge–Xax bond distances
are considerably longer than the Ge–Xeq ones. The weak-
ening of the Ge N bond in 22 and 26 leads to the level-
ling of these values. The previously reported data for 28, 35
and 36 confirm this tendency [20,26,28]. This difference in
37 is small due to the considerable steric requirements for
substituents where Xax + Xeq are OCH2CH2O group [18].
Of interest, the comparison of the Ge–Clax bond dis-
˚
was found in PhN(CH2CH2O)2SiPh2 (3.08(1) A) in com-
˚
parison with that in MeN(CH2CH2O)2SiPh2 (2.68(1) A)
[53]. This difference between germanium and silicon deriv-
atives may be explained, on the one hand, by steric reason
˚
tance in 20 (2.2180(6) A) with that in closely related

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E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
i-C4H9N(CH2CH2CH2)2GeCl2 (2.319(4) A) [31] shows a
large difference between these two values, the longer bond
being observed in the compound with weaker transannular
Ge N interaction. In our opinion, two factors should be
considered when these values are discussed. The first one is
the transannular interaction (‘‘trans’’-effect) which makes
the Ge–Xax bond longer, the second is the influence of
equatorial groups. According to Bent’s rule, more electro-
negative groups (oxygen atoms in the pair O and CH2)
stimulate the shortening of the Ge–Xax bond [54]. Thus,
in the case of 20 these factors do not act in concert, while
in i-C4H9N(CH2CH2CH2)2GeCl2 both factors lead to the
elongation of the Ge–Xax bond. The values of Ge–O bonds
(AA0XY system). However, we cannot judge the strength of
˚
the Ge N interaction in these compounds in solution on
1
the basis of the appearance of their H NMR spectra. An
additional argument for the rigidity of the compound 27
in solution is provided by the 19F NMR spectrum, which
exhibits two resonances for two non-equivalent axial and
equatorial fluorine atoms. Consequently, Berry pseudorota-
tion is hindered in this compound.
1
The H NMR spectra of the germocanes with substitu-
ents at carbon atoms of ocane skeleton are more compli-
cated due to the non-equivalence of all protons of ocane
skeleton (as previously found for germatranes [50]). More-
over, these compounds were prepared as mixtures of diaste-
reomers. According to Dra¨ger and Engler [55], such
compounds, when they possess the ‘‘boat–chair’’ conforma-
tion of eight-membered ring exist as racemic mixture of two
enantiomers. Thus, all protons of these compounds are dia-
stereotopic, and the appearance of the asymmetric centre in
ocane skeleton due to the presence of substituent(s) results
in the formation of diastereomeric mixtures of 9–19.
˚
(1.771(2)–1.788(2) A) are close in all the compounds 16,
20–22, and 26. The latter may be explained by the com-
bined influence of two above named factors: the strong
Ge N interaction elongates the Ge–O distances, while
the presence in the axial position at the Ge atom of an
acceptor group which causes this strong intramolecular
interaction shortens the Ge–O distances.
The nitrogen atom in 16 and 20–22 possesses an approx-
imately tetrahedral environment. The considerable shifts of
the nitrogen atom towards the Ge atom from the plane
defined by the three carbon atoms (DN = 0.442–0.468 A)
were found in these compounds. On the contrary, in the
In our opinion, two approaches may be used for the esti-
mation of the strength of the Ge N interaction in germo-
canes in solution. The first one is the analysis of the 1H NMR
chemical shifts for the protons bound with carbon atoms at
the N atom. Of interest, the NCH2 and NMe proton signals
˚
1
compound 26 the nitrogen atom is nearly planar and the
in H NMR spectra of dichloro and dibromo derivatives
˚
shift towards the Ge atom is smaller (DN = 0.148 A). All
11–16 are shifted to lower field compared to those of the cor-
responding dimethylgermocanes 23–25. According to Tan-
dura et al. [56], this implies strengthening of the Ge N
bond in 11–16 in comparison with 23–25 in CDCl3 solution.
However, this approach has some limitations such as in the
case of 22. The presence of the aromatic fragments (fluorenyl
groups) at the Ge atom accounts for the considerable upfield
shift of the NCH2 and NMe proton signals.
Very recently we have found that dimethylgermocane
MeN(CH2CH2O)2GeMe2 possesses a short Ge N con-
tact in CDCl3 solution [28]. This fact has been established
by the presence of the strong NOE from H0 protons of
Me–N group to the H1 protons of Me–Ge groups, which
is possible on assuming the conformation A in solution
(Scheme 9). On the contrary, our investigation of the com-
pounds 23 and 26 has shown no NOE from protons of Me–
N group to the protons of Me–Ge groups in 26 (CDCl3
solution) and only weak NOE from H0 protons of Me–N
group to H1 protons of one Me–Ge group in 23. NOE
was also detected between H2 and H3 protons in 23. Thus,
the five-membered metallacycles –Ge–O–C–C–N– are not
planar with the C atoms in a-positions to the N atoms
maximally deviated from the least-squares planes. The
exceptions are the phenyl substituted cycle in compound
16 and both –Ge–O–C–C–N– cycles in 26 where b-carbon
atoms deviate from the plane. Conformation of the eight-
membered cycles –Ge–O–C–C–N–C–C–O– in 16 and 20–
22 may be considered as ‘‘boat–chair’’, while in 26 it is a
‘‘crown’’.
2.3. Solution structures (NMR spectroscopy data)
1
The H and 13C NMR spectra of the prepared com-
pounds are in accord with the suggested structures. The ger-
mocanes without substituents at the carbon atoms of the
ocane skeleton may be divided into two groups, according
to the appearance of the signals of the germocane skeleton
protons. The methylene protons of the first group com-
pounds (20–22, 26 and MeN(CH2CH2O)2GeMe2) appear
as two triplets of the AA0XX0 spin system. These spectra
indicate the non-rigidity of ocane skeleton in these com-
pounds in solution. On the contrary, ABXY system as a
set of three multiplets (two multiplets for NCH2 groups
and one for OCH2) of NCH2CH2O moiety appears in the
1H NMR spectra of 27, 30–32 and, for example, previously
studied 28 and 29. These compounds are in one ‘‘frozen’’
conformation in CDCl3 solution at room temperature.
The compounds 32 and 33 with two alkoxy groups at the
Ge atoms mediate with the spectra showing one triplet for
OCH2 groups and one or two multiplets for NCH2 groups
2
H
H2C
1
0
H
CH3
CH3 Ge
3
H
H
CH2 Ge
Ph
CH2
1
H2C
H
O
O
Ge
N
CH3
O
O
O
O
0
N
N
H
C6H5
26
23
CH2
A
B
Scheme 9.

E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
5717
the conformations B may be considered as prevailing for
these compounds in solution (Scheme 9). The compound
26 retains the solid-state structure (see above) in solution.
Of interest, as previously pointed out, the replacement of
hydrogen atoms in MeN(CH2CH2O)2GeBr2 (28) [28] with
phenyl groups does not noticeably affect the strength of
the Ge N interaction in erythro-MeN(CH2CH2O)-
(CHPhCHPhO)GeBr2 (16). On the contrary, the analogous
replacement in MeN(CH2CH2O)2GeMe2 leads to a sub-
stantial elongation of the Geꢁ ꢁ ꢁN contact in MeN(CH2-
CH2O)(CH2CHPhO)GeMe2 (23).
Varian VXR 400 spectrometers at 300 K. 1H and 13C
chemical shifts are reported in ppm relative to Me4Si as
external standard. Mass spectra (EI-MS) were recorded
on a VARIAN CH-7a device using electron impact ioniza-
tion at 70 eV; all assignments were made with reference to
the most abundant isotopes. Elemental analyses were car-
ried out at the Microanalytical Laboratory of the Chemis-
try Department of Moscow State University.
3.1. General procedures for the synthesis of
bis(trimethylsilyl)ethers of dialkanolamines
In conclusion, the combined X-ray diffraction and
NMR studies of the germocane structures allowed to state
the relationships between the strength of the Ge N inter-
action and the nature of substituents in different positions
of ocane skeleton. The determining factor is the nature of
substituents at the Ge atom: a strong acceptor group leads
to strong interaction; no important influence of substitu-
ents at the N and C atoms was detected in this case. The
presence of donor substituents at the Ge atom generally
results in the weakening of the Ge N interaction along
with a considerable increase of the influence of substituents
at the N and C atoms on its strength. In this case, an accep-
tor substituent at the N atom and bulky substituents at car-
bon atoms stimulate the weakening of the Ge N
interaction.
A:
A mixture of dialkanolamine (0.05 mol) and
HN(SiMe3)2 (0.13 mol) was heated under reflux (Table
2). All volatile materials were evaporated, and the residue
was distilled in vacuum or was used without additional
purification for the synthesis of germocanes.
B: A mixture of dialkanolamine (0.01 mol), Me3SiNEt2
(0.04 mol), Me3SiCl (0.004 mol), and ethylacetate (25 mL)
was heated under reflux (Table 2). The solvent and all vola-
tile materials were evaporated, and the residue was distilled
in vacuum or was used without additional purification for
the synthesis of germocanes.
3.1.1. MeN(CH2CH2OSiMe3)CH(C4H8)CHOSiMe3 (1)
1H NMR (CDCl3, 400 MHz): d = 0.08 (s, 9H, SiMe3),
0.09 (s, 9H, SiMe3), 1.07–1.29 (m, 4H), 1.56–1.72 (m,
3H), 1.82–1.89 (m, 1H) (4CH2 groups), 2.33 (s, 3H,
MeN), 2.27–2.36 (m, 1H), 2.67–2.71 (m, 2H), 3.53–3.61
(m, 3H) (NCH2, OCH2, NCH, and OCH groups). 13C
NMR (CDCl3, 100 MHz): d = ꢀ0.44 (SiMe3), 0.87
(SiMe3), 24.58, 25.34, 28.04, 36.05 (CH2 groups), 38.87
(MeN), 57.05 (NCH2), 61.86 (OCH2), 68.72 (NCH),
72.46 (OCH). MS (EI, m/z, %): 317 (<1) [M+], 302 (2)
[M+ꢀMe], 214 (57) [M+ꢀSiMe3ꢀCH2O], 171 (8)
[M+ꢀ2SiMe3], 73 (100) ½SiMeþ3 ꢂ. Anal. Calc. for
C15H35NO2Si2 (317.62): C, 56.72; H, 11.11; Si, 17.69.
Found: C, 56.88; H, 11.32; Si, 17.89%.
3. Experimental
All manipulations were performed under dry, oxygen-
free argon atmosphere using standard Schlenk techniques.
PhN(CH2CH2OH)2 (Aldrich) was used as supplied.
(Me3Si)2NH, Me3SiCl, and BF3 Æ Et2O (Aldrich) were dis-
tilled before use. MeN(CH2CH2OH)CH2CH(Me)OH [57],
MeN(CH2CH2OH)CH2CH(Ph)OH + MeN(CH2CH2OH)-
–CH(Ph)CH2OH as a 9:1 mixture [44], erythro-MeN(CH2-
CH2OH)CH(Ph)CH(Ph)OH,
threo-MeN(CH2CH2OH)-
CH(Ph)CH(Ph)OH, MeN(CH2CH2OH)CH2C(Ph)2OH
and MeN(CH2CH2OH)CH(C4H8)CHOH [46], Me3SiNEt2
[45], Flu2GeCl2 [58], MeN(CH2CH2OSiMe3)2 [59], MeN-
(CH2CH2O)2GeCl2 and MeN(CH2CH2O)2GeBr2 [28],
Me2Ge(NMe2)2 [60], Et3SnOMenth [61], and MeN(CH2-
CH2O)2Ge(OH)2 [24] were prepared according to the liter-
ature. Solvents were dried by standard methods and
distilled prior to use. 1H and 13C NMR spectra were
recorded on a Bruker AC200, DRX 300, DPX 500, and
3.1.2. PhN(CH2CH2OSiMe3)2 (2)
1H NMR (CDCl3, 400 MHz): d = 0.10 (s, 18H, 2SiMe3),
3
3
3.49 (t, J = 7 Hz, 4H, 2NCH2), 3.71 (t, J = 7 Hz, 4H,
2OCH2), 6.63–6.69, 7.17–7.21 (2m, 5H, Ph). 13C NMR
(CDCl3, 100 MHz): d = ꢀ0.56 (SiMe3), 53.44 (NCH2),
59.29 (OCH2), 111.35, 115.73, 129.31, 147.60 (Ph). MS
(EI, m/z, %): 325 (4) [M+], 222 (100) [M+ꢀSiMe3ꢀCH2O],
Table 2
Synthesis of bis(trimethylsilyl)ethers of dialkanolamines
Compound
Method
Refluxing time (h)
Isolated yield (%)
B.p. (ꢁC)
MeN(CH2CH2OSiMe3)CH(C4H8)CHOSiMe3 (1)
PhN(CH2CH2OSiMe3)2 (2)
A
A
A
70
9
21
86
87
76
90–92 (1 mmHg)
144–145 (1 mmHg)
78–82 (0.2 mmHg)
MeN(CH2CH2OSiMe3)CH2CH(Ph)OSiMe3 (3) +
MeN(CH2CH2OSiMe3)CH(Ph)CH2OSiMe3 (4)
MeN(CH2CH2OSiMe3)CH2CH(Me)OSiMe3 (5)
erythro-MeN(CH2CH2OSiMe3)CH(Ph)CH(Ph)OSiMe3 (6)
threo-MeN(CH2CH2OSiMe3)CH(Ph)CH(Ph)OSiMe3 (7)
MeN(CH2CH2OSiMe3)CH2C(Ph)2OSiMe3 (8)
B
B
B
B
40
33
39
65
79
98
97
98
56–61 (1 mmHg)
–
–
–

5718
E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
73 (26) ½SiMeþꢂ. Anal. Calc. for C16H31NO2Si2 (325.59): C,
66.45; H, 8.97; Si, 13.51. Found: C, 66.65; H, 8.83; Si,
13.50%.
3
59.02; H, 9.60; Si, 17.25. Found: C, 59.10; H, 9.92; Si,
17.06%.
3.1.6. threo-MeN(CH2CH2OSiMe3)CH(Ph)CH(Ph)-
OSiMe3 (7)
3.1.3. MeN(CH2CH2OSiMe3)CH2CH(Ph)OSiMe3 (3)
and MeN(CH2CH2OSiMe3)CH(Ph)CH2OSiMe3 (4)
The approximate ratio of isomers is 3:4 = 9:1 (according
to 1H NMR). NMR data for MeN(CH2CH2OSiMe3)CH2-
CH(Ph)OSiMe3 (3): 1H NMR (CDCl3, 200 MHz): d = 0.01
(s, 9H, SiMe3), 0.08 (s, 9H, SiMe3), 2.34 (s, 3H, MeN),
2.51–2.76 (m, 4H, 2NCH2 groups), 3.60 (t, 3J = 7 Hz,
1H NMR (CDCl3, 400 MHz): d = ꢀ0.01 (s, 9H, SiMe3),
0.10 (s, 9H, SiMe3), 2.37 (s, 3H, MeN), 2.59–2.66 (m, 1H),
2.88–3.00 (m, 1H) (NCH2), 3.65 (t, 3J = 7 Hz, 2H, OCH2),
3.83 (d, 3J = 8 Hz, 1H, NCH), 5.11 (d, 3J = 8 Hz, 1H,
OCH), 7.02–7.14 (m, 10H, 2Ph). 13C NMR (CDCl3,
100 MHz): d = ꢀ0.50 (SiMe3), 0.30 (SiMe3), 40.33 (MeN),
56.38 (NCH2), 61.42 (OCH2), 75.39 (NCH), 76.10 (OCH),
126.67, 126.87, 127.48, 127.52, 129.40, 138.25, 142.88
(2Ph). Anal. Calc. for C23H37NO2Si2 (415.72): C, 66.45; H,
8.97; Si, 13.51. Found: C, 66.33; H, 8.84; Si, 13.25%.
3
2H, OCH2), 4.78 (dd, 3J = 8 Hz, J = 5 Hz, 1H, OCH),
7.18–7.32 (m, 5H, Ph). 13C NMR (CDCl3, 75 MHz):
d = ꢀ0.52 (SiMe3), 0.23 (SiMe3), 43.65 (MeN), 59.77,
60.69 (2NCH2 groups), 66.92 (OCH2), 73.54 (OCH),
126.19, 127.11, 128.01, 144.01 (Ph). NMR data for
1
MeN(CH2CH2OSiMe3)CH(Ph)CH2OSiMe3 (4): H NMR
3.1.7. MeN(CH2CH2OSiMe3)CH2C(Ph)2OSiMe3 (8)
1H NMR (CDCl3, 400 MHz): d = ꢀ0.09 (s, 9H, SiMe3),
(CDCl3, 200 MHz): d = ꢀ0.02 (s, 9H, SiMe3), 0.05 (s,
9H, SiMe3), 2.29 (s, 3H, MeN), 3.75–3.99 (m, 2H,
OCH2). Other proton resonances could not be located
due to the overlap with those for major isomer. 13C
NMR (CDCl3, 75 MHz): d = ꢀ0.61 (2SiMe3), 40.39
(MeN), 56.80, 60.85, 64.46 (2OCH2 and NCH2 groups),
70.54 (NCH), 127.04, 127.96, 128.61 (Ph). The fourth aro-
matic signal was not observed, probably due to the low
concentration of minor isomer. MS (EI, m/z, %): 324 (5)
[M+ꢀMe], 236 (35) [MeN(CH2CH2OSiMe3)CH(Ph)+],
3
0.07 (s, 9H, SiMe3), 2.16 (s, 3H, MeN), 2.51 (t, J = 7 Hz,
3
2H, NCH2), 3.33 (s, 2H, NCH2), 3.40 (t, J = 7 Hz, 2H,
OCH2), 7.19–7.30, 7.35–7.38 (2m, 10H, 2Ph). 13C NMR
(CDCl3, 100 MHz): d = ꢀ0.51 (SiMe3), 2.05 (SiMe3),
44.55 (MeN), 60.66, 61.40, 68.69 (2NCH2 and OCH2
groups), 81.69 (C(Ph)2), 126.67, 127.40, 127.72, 146.70
(Ph). Anal. Calc. for C23H37NO2Si2 (415.72): C, 66.45; H,
8.97; Si, 13.51. Found: C, 66.29; H, 8.91; Si, 13.72%.
160 (100) ½MeNðCH2CH2OSiMe3ÞCHþꢂ, 147 (10)
3.2. The synthesis of the 2,2-dihalogermocanes 9–21
2
½MeNCH2CH2OSiMeþꢂ, 117 (11) ½CH2CH2OSiMeþꢂ, 73
3
3
(28) ½SiMeþꢂ. Anal. Calc. for C17H33NO2Si2 (339.62): C,
3.2.1. MeN(CH2CH2O)(CH2CH(Me)O)GeBr2 (9)
0.50 ml (4.0 mmol) of germanium tetrabromide were
added to a stirred solution of 1.11 g (4.0 mmol) of
MeN(CH2CH2OSiMe3)CH2CH(Me)OSiMe3 (5) in CHCl3
(10 ml). The reaction mixture was refluxed for 20 h, and
the solvent was then removed under reduced pressure. To
the residue as a brown oil diethyl ether (10 ml) was added.
Upon vigorous stirring the product transferred into a solid,
which was filtered, washed with diethyl ether (2 · 5 ml),
and dried in vacuum to give 0.61 g (42%) of 9 as a light
3
60.12; H, 9.79; N, 4.12. Found: C, 60.10; H, 9.68; N, 4.40%.
3.1.4. MeN(CH2CH2OSiMe3)CH2CH(Me)OSiMe3 (5)
1H NMR (CDCl3, 400 MHz): d = 0.07 (s, 9H, SiMe3),
3
0.08 (s, 9H, SiMe3), 1.11 (d, J = 6 Hz, 3H, Me), 2.25 (s,
3H, MeN), 2.26–2.38 (m, 2H), 2.44–2.57 (m, 2H)
(2NCH2 groups), 3.61 (t, 3J = 7 Hz, 2H, OCH2), 3.79–
3.86 (m, 1H, OCH). 13C NMR (CDCl3, 100 MHz):
d = ꢀ0.50 (SiMe3), 0.26 (SiMe3), 22.26 (Me), 44.02
(MeN), 60.36, 60.81 (2NCH2 groups), 66.30, 66.99
(OCH2 and OCH groups). MS (EI, m/z, %): 277 (<1)
[M+], 262 (2) [M+ꢀMe], 174 (15) [M+ꢀSiMe3ꢀCH2O],
1
brown powder, m.p. 129–134 ꢁC (dec.). H NMR (CDCl3,
400 MHz): d = 1.30 (d, 3J = 6 Hz, 3H, Me), 1.33 (d,
3J = 6 Hz, 3H, Me), 2.63 (s, 3H, MeN), 2.64 (s, 3H,
MeN), 2.47–2.55 (m, 2H), 2.74–2.78 (m, 2H), 2.88–3.13
(m, 4H) (4NCH2 groups), 3.85–3.91, 3.99–4.11, 4.18–4.26
(3m, 6H, 2OCH2 and 2OCH groups). 13C NMR (CDCl3,
100 MHz): d = 20.13 (Me), 21.03 (Me), 45.14 (MeN),
45.85 (MeN), 54.73, 56.56, 59.23, 59.42 (4NCH2 groups),
60.86, 61.90, 65.27, 65.89 (2OCH2 and 2OCH groups).
Two diastereomers. MS (EI, m/z, %): 283 (3) [M+ꢀBr],
102 (7) [M+ꢀCH2OꢀGeBr2+1], 88 (97) [M+ꢀMeCHOꢀ
160 (73) [M+ꢀSiMe3ꢀMeCHO], 73 (100) ½SiMeþꢂ. Anal.
3
Calc. for C12H31NO2Si2 (277.55): C, 51.93; H, 11.26; Si,
20.24. Found: C, 52.20; H, 11.40; Si, 19.73%.
3.1.5. erythro-MeN(CH2CH2OSiMe3)CH(Ph)CH(Ph)-
OSiMe3 (6)
1H NMR (CDCl3, 400 MHz): d = ꢀ0.15 (s, 9H, SiMe3),
0.03 (s, 9H, SiMe3), 2.17 (s, 3H, MeN), 2.33–2.40 (m, 1H),
2.61–2.68 (m, 1H) (NCH2), 3.31–3.41 (m, 2H, OCH2), 3.64
GeBr2+1], 57 (24) ½MeNCH2CHþꢂ, 28 (100). Anal. Calc.
2
3
3
(d, J = 7 Hz, 1H, NCH), 5.14 (d, J = 7 Hz, 1H, OCH),
7.16–7.29 (m, 10H, 2Ph). 13C NMR (CDCl3, 100 MHz):
d = ꢀ0.56 (SiMe3), 0.12 (SiMe3), 40.06 (MeN), 56.35
(NCH2), 60.93 (OCH2), 75.26 (NCH), 75.42 (OCH),
126.67, 126.95, 127.10, 127.24, 127.51, 129.98, 137.17,
143.94 (2Ph). Anal. Calc. for C23H37NO2Si2 (415.72): C,
for C6H13Br2GeNO2 (363.59): C, 19.82; H, 3.60; Ge,
19.97. Found: C, 20.27; H, 3.91; Ge, 19.44%.
3.2.2. MeN(CH2CH2O)(CH(C4H8)CHO)GeBr2 (10)
Analogously to the synthesis of 9, germocane 10 was pre-
pared from 0.63 ml (5.0 mmol) of GeBr4 and 1.59 g

E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
5719
(5.0 mmol) of MeN(CH2CH2OSiMe3)CH(C4H8)CHO-
SiMe3 (1) by reflux for 30 h in 10 ml of CHCl3. The product
(1.19 g, 59%) was isolated in form of a beige powder, m.p.
201–202 ꢁC (dec.). 1H NMR (CDCl3, 400 MHz):
d = 1.12–1.47 (m, 8H), 1.75–1.80 (m, 4H), 1.85–1.91 (m,
4H) (8CH2 groups), 2.46 (s, 3H, MeN), 2.55 (s, 3H,
MeN), 2.00–2.05, 2.25–2.32, 2.37–2.61, 2.83–3.02, 3.57–
3.64, 3.69–3.75, 3.82–3.89, 4.01–4.05 (8m, 12H, NCH2,
OCH2, NCH, and OCH groups). 13C NMR (CDCl3,
100 MHz): d = 22.73, 23.24, 23.38, 23.47, 24.82, 24.91,
33.23, 33.32 (CH2 groups), 39.04, 42.29 (MeN), 49.87,
53.48 (NCH2), 59.25, 59.32 (OCH2), 66.39, 67.88 (NCH),
71.93, 72.78 (OCH). Two diastereomers. MS (EI, m/z, %):
373 (14) [M+ꢀCH2O], 324 (41) [M+ꢀBr], 294 (18)
[M+ꢀBrꢀCH2O], 170 (15) [M+ꢀGeBr2ꢀH], 141 (22)
[M+ꢀCH2OꢀGeBr2], 112 (19) [NCH(C4H8)CHO+]. Anal.
Calc. for C9H17Br2GeNO2 (403.66): C, 26.78; H, 4.24; N,
3.47. Found: C, 26.89; H, 4.23; N, 3.33%.
3.08–3.16 (m, 1H), 3.22–3.32 (m, 1H) (4NCH2 groups),
3.89–3.99 (m, 1H), 4.01–4.11 (m, 3H) (2OCH2 groups),
4.99 (dd, 3J = 11 Hz, 3J = 4 Hz, 1H, OCH), 5.10 (dd,
3J = 11 Hz, 3J = 5 Hz, 1H, OCH), 7.27–7.40 (m, 10H,
2Ph). 13C NMR (CDCl3, 75 MHz): d = 44.82 (MeN),
45.51 (MeN), 54.44, 55.95, 59.26, 59.39 (4NCH2 groups),
60.78, 61.90 (2OCH2 groups), 71.24, 71.43 (2OCH groups),
125.62, 125.85, 128.44, 128.76 (three unresolved signals),
139.20, 139.79 (2Ph). Two diastereomers. MS (EI, m/z,
%): 346 (37) [M+ꢀBr], 319 (63) [M+ꢀPhCHO], 240 (100)
[M+ꢀPhCHOꢀBr], 226 (8) [M+ꢀCH2CH(Ph)OꢀBr], 196
(5) [CH2 = CHOGeBr+], 153 (7) [GeBr+], þ86 (32)
[M+ꢀPhCHOꢀGeBr2ꢀH], 57 (92) ½MeNðCH2Þ ꢂ. Anal.
2
Calc. for C11H15Br2GeNO2 (425.66): C, 31.04; H, 3.55; N,
3.29. Found: C, 30.99; H, 3.65; N, 3.20%. The reaction mix-
ture also contained small amount (10–15%) of MeN(CH2-
CH2O)(CH(Ph)CH2O)GeBr2 (14). 1H NMR (CDCl3,
300 MHz): d = 2.28 (s, 3H, MeN), 2.45 (s, 3H, MeN).
Two diastereomers. Other proton resonances could not be
located due to the overlap with those for major isomer.
3.2.3. MeN(CH2CH2O)(CH2CH(Ph)O)GeCl2 (11)
1.26 ml (11.0 mmol) of germanium tetrachloride were
added to a stirred solution of 3.40 g (10.0 mmol) of the
mixture of bis(trimetylsilyl)ethers (3 + 4) in 15 ml of tolu-
ene. The reaction mixture was refluxed for 3 h. The precip-
itated solid was filtered, washed with pentane (2 · 10 ml),
and dried in vacuum to give 2.23 g (66%) of 11 as a white
powder. 1H NMR (CDCl3, 300 MHz): d = 2.66 (s, 3H,
MeN), 2.80 (s, 3H, MeN), 2.68–2.85 (m, 2H), 2.89–3.09
(m, 4H), 3.14–3.29 (m, 2H) (4NCH2 groups), 3.89–4.14
3.2.5. erythro-MeN(CH2CH2O)(CH(Ph)CH(Ph)O)-
GeCl2 (15)
1.04 ml (9.0 mmol) of germanium tetrachloride were
added to a stirred solution of 3.74 g (9.0 mmol) of ery-
thro-MeN(CH2CH2OSiMe3)CH(Ph)CH(Ph)OSiMe3 (6) in
20 ml of toluene. The reaction mixture was refluxed for
18 h. The precipitated solid was filtered, washed with
diethyl ether (2 · 5 ml), and dried in vacuum to give
3.14 g (85%) of 15 as an off-white powder. 1H NMR
(CDCl3, 400 MHz): d = 2.31 (s, 3H, MeN), 2.70 (s, 3H,
MeN), 2.29–2.33, 2.43–2.47, 2.81–2.82, 3.02–3.12, 3.19–
3.27, 3.48–3.55 (6m, 4H, 2NCH2), 3.80–3.87, 3.92–4.02,
4.15–4.19 (3m, 4H, 2OCH2), 4.08 (d, 3J = 5 Hz, 1H,
NCH), 4.29 (d, 3J = 6 Hz, 1H, NCH), 5.54 (d, 3J =
6 Hz, 1H, OCH), 5.64 (d, 3J = 5 Hz, 1H, OCH), 7.06–
7.37 (m, 20H, 4Ph). 13C NMR ((CD3)2SO, 100 MHz,
80 ꢁC): d = 42.21 (MeN), 57.56 (NCH2), 58.82 (OCH2),
70.61 (NCH), 71.53 (OCH) (one diastereomer), 45.80
(MeN), 53.68 (NCH2), 58.97 (OCH2), 71.73 (NCH),
73.69 (OCH) (the other diastereomer), 125.23, 125.86,
126.46, 127.56, 127.61, 127.67, 128.26, 128.40, 128.84,
130.99, 132.83, 139.35 (4Ph for both diastereomers).
Two diastereomers. Other signals of aromatic carbons
were not found due to the poor solubility of 15 in
(CD3)2SO and probably due to coalescence of some sig-
nals. MS (EI, m/z, %): 378 (6) [M+ꢀCl], 307 (77)
[M+ꢀPhCHO], 272 (22) [M+ꢀPhCHOꢀCl], 162 (34)
[M+ꢀPhCHOꢀGeCl2ꢀH], 132 (100) [M+ꢀPhCHOꢀ
GeCl2ꢀCH2OꢀH], 118 (17) [CH2NCHPh+]. Anal. Calc.
for C17H19Cl2GeNO2 (412.85): C, 49.46; H, 4.64; N,
3.39. Found: C, 49.81; H, 4.53; N, 3.40%.
3
3
(m, 4H, 2OCH2 groups), 4.98 (dd, J = 11 Hz, J = 4 Hz,
3
3
1H, OCH), 5.04 (dd, J = 11 Hz, J = 4 Hz, 1H, OCH),
7.28–7.40 (m, 10H, 2Ph). 13C NMR (CDCl3, 75 MHz):
d = 44.42 (MeN), 45.01 (MeN), 54.55, 56.20, 58.67, 58.73
(4NCH2 groups), 61.32, 61.81 (2OCH2 groups), 70.47,
70.78 (2OCH groups), 125.60, 125.83, 128.48, 128.78,
129.26, 129.54 (2Ph). Two diastereomers. The quaternary
carbons of phenyl groups were not detected due to the poor
solubility of 11 in CDCl3. MS (EI, m/z, %): 307 (5)
[M+ꢀCH2O], 300 (19) [M+ꢀCl], 231 (67) [M+ꢀPhCHO],
106 (6) [PhCHO+], 57 (100) ½MeNðCH2Þþꢂ. Anal. Calc.
2
for C11H15Cl2GeNO2 (336.76): C, 39.23; H, 4.49; N, 4.16.
Found: C, 39.31; H, 4.47; N, 3.99%. The reaction mixture
also contained small amount (10–15%) of MeN(CH2-
CH2O)(CH(Ph)CH2O)GeCl2 (12). 1H NMR (CDCl3,
300 MHz): d = 2.24–2.29 (m, 1H, NCH2), 2.30 (s, 3H,
MeN), 2.49 (s, 3H, MeN). Two diastereomers. Other pro-
ton resonances could not be located due to the overlap with
those for major isomer.
3.2.4. MeN(CH2CH2O)(CH2CH(Ph)O)GeBr2 (13)
Analogously to 11, germocane 13 was prepared from
1.15 ml (9.1 mmol) of GeBr4 and 3.10 g (9.1 mmol) of the
mixture of bis(trimetylsilyl)ethers (3 + 4) by reflux for
30 h in 15 ml of CHCl3. The product (1.03 g, 27%) was iso-
lated as a slightly yellow powder. 1H NMR (CDCl3,
300 MHz): d = 2.63 (s, 3H, MeN), 2.76 (s, 3H, MeN),
2.69–2.78 (m, 2H), 2.83–2.97 (m, 3H), 2.99–3.07 (m, 1H),
3.2.6. erythro-MeN(CH2CH2O)(CH(Ph)CH(Ph)O)-
GeBr2 (16)
Analogously to 15, germocane 16 was prepared from
0.88 ml (7.0 mmol) of GeBr4 and 2.91 g (7.0 mmol) of

5720
E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
erythro-MeN(CH2CH2OSiMe3)CH(Ph)CH(Ph)OSiMe3 (6)
by reflux for 35 h in 15 ml of toluene. The product
(0.95 g, 27%) was isolated as dark brown crystals. 1H
NMR (CDCl3, 400 MHz): d = 2.28 (s, 3H, MeN), 2.70 (s,
3H, MeN), 2.24–2.33, 2.41–2.45, 2.84–2.85, 3.00–3.09,
3.19–3.26, 3.45–3.54 (6m, 4H, 2NCH2), 3.81–4.05, 4.13–
4.16 (2m, 4H, 2OCH2), 4.08 (d, 3J = 5 Hz, 1H, NCH),
4.26 (d, 3J = 6 Hz, 1H, NCH), 5.54 (d, 3J = 6 Hz, 1H,
400 MHz): d = 2.45 (s, 3H, MeN), 2.68–2.74 (m, 1H),
2.87–2.93 (m, 1H) (NCH2), 3.65 (AB system, J = 13 Hz,
2
2H, NCH2C(Ph)2), 3.83–3.94 (m, 2H, OCH2), 7.18–7.24
(m, 2H), 7.28–7.34 (m, 4H), 7.51–7.58 (m, 4H) (2Ph). 13C
NMR (CDCl3, 100 MHz): d = 46.75 (MeN), 57.02, 58.72
(2NCH2 groups), 63.69 (OCH2), 77.56 (OC(Ph)2), 125.16,
125.29, 127.57, 128.60, 128.72, 144.90, 145.41 (2Ph). A sig-
nal of aromatic carbon was not found probably due to coa-
lescence of two signals. MS (EI, m/z, %): 378 (5) [M+ꢀCl],
231 (57) [M+ꢀPh2CO], 161 (6) [M+ꢀPh2COꢀ2Cl], 105 (5)
3
OCH), 5.67 (d, J = 5 Hz, 1H, OCH), 6.99–7.39 (m, 20H,
4Ph). 13C NMR ((CD3)2SO, 100 MHz, 80 ꢁC): d = 41.08
(MeN), 41.61 (MeN), 54.81 (NCH2), 57.42 (NCH2), 57.98
(OCH2), 58.11 (OCH2), 70.38, 71.08, 71.31, 71.47 (2NCH
and 2OCH groups), 125.23, 125.90, 126.58, 127.53,
127.62, 127.70, 127.84, 128.14, 128.55, 128.84, 130.34,
132.40, 139.28 (4Ph). Two diastereomers. Other signals of
aromatic carbons were not found due to the poor solubility
of 16 in (CD3)2SO and probably due to coalescence of
some signals. MS (EI, m/z, %): 422 (11) [M+ꢀBr], 395
(30) [M+ꢀPhCHO], 316 (100) [M+ꢀPhCHOꢀBr], 162
(26) [M+ꢀPhCHOꢀGeBr2ꢀH], 132 (42) [M+ꢀPhCHOꢀ
GeBr2ꢀCH2OꢀH], 118 (9) [CH2NCHPh+], 58 (26)
[NCH2CH2O+]. Anal. Calc. for C17H19Br2GeNO2
(501.76): C, 40.69; H, 3.82; N, 2.79. Found: C, 41.02; H,
3.78; N, 2.96%.
[PhCO+], 57 (100) ½CH3NðCH2Þþꢂ. Anal. Calc. for
2
C17H19Cl2GeNO2 (412.85): C, 49.46; H, 4.64; N, 3.39.
Found: C, 49.81; H, 4.53; N, 3.40%.
3.2.9. MeN(CH2CH2O)(CH2C(Ph)2O)GeBr2 (19)
Analogously to 15, germocane 19 was prepared from
0.72 ml (5.8 mmol) of GeBr4 and 2.40 g (5.8 mmol) of
MeN(CH2CH2OSiMe3)CH2C(Ph)2OSiMe3 (8) by reflux
for 28 h in 20 ml of toluene. The product (1.55 g, 53%)
was isolated as a beige powder. 1H NMR (CDCl3,
400 MHz): d = 2.44 (s, 3H, MeN), 2.68–2.75 (m, 1H),
2.87–2.93 (m, 1H) (NCH2), 3.64 (s, 2H, NCH2C(Ph)2),
3.86–3.96 (m, 2H, OCH2), 7.19–7.24 (m, 2H), 7.29–7.35
(m, 4H), 7.53–7.59 (m, 4H) (2Ph). 13C NMR (CDCl3,
100 MHz): d = 47.22 (MeN), 56.82, 59.31 (2NCH2 groups),
63.50 (OCH2), 125.19, 125.37, 127.57, 128.62, 128.74,
144.88, 145.49 (2Ph). The signal of OC(Ph)2 group was
not found due to the low solubility of the product in
CDCl3. One signal of aromatic carbon was not found prob-
ably due to coalescence of two signals. Anal. Calc. for
C17H19Br2GeNO2 (501.76): C, 40.69; H, 3.82; N, 2.79.
Found: C, 40.85; H, 3.73; N, 3.13%.
3.2.7. threo-MeN(CH2CH2O)(CH(Ph)CH(Ph)O)GeBr2
(17)
0.47 ml (3.73 mmol) of germanium tetrabromide were
added to a stirred solution of 1.55 g (3.73 mmol) of threo-
MeN(CH2CH2OSiMe3)CH(Ph)CH(Ph)OSiMe3 (7) in 10 ml
of chloroform. The reaction mixture was refluxed for
24 h. The precipitated solid was filtered, washed with chlo-
roform (2 · 8 ml), and dried in vacuum to give 0.91 g (49%)
1
of 17 as a white powder. H NMR ((CD3)2SO, 400 MHz):
3.2.10. PhN(CH2CH2O)2GeCl2 (20)
d = 2.63 (s, 3H, MeN), 3.43–3.49, 3.80–3.86, 4.05–4.10 (3m,
Analogously to 9, germocane 20 was prepared from
1.50 ml (13.0 mmol) of GeCl4 and 4.24 g (13.0 mmol) of
PhN(CH2CH2OSiMe3)2 (2) by reflux for 3 h in 15 ml of
chloroform. The product (1.10 g, 26%) was isolated as a
light brown powder. 1H NMR (CDCl3, 400 MHz): d =
3.48 (t, J = 5 Hz, 4H, 2NCH2), 4.23 (t, J = 5 Hz, 4H,
2OCH2), 7.03–7.10 (m, 3H), 7.31–7.35 (m, 2H) (Ph). 13C
NMR was not measured due to the poor solubility of ger-
mocane 20 in CDCl3. MS (EI, m/z, %): 323 (14) [M+], 293
(15) [M+ꢀCH2O], 149 (100) [M+ꢀCH2OꢀGeCl2], 119 (96)
[M+ꢀ2CH2OꢀGeCl2], 105 (13) ½PhNCHþ2 ꢂ, 91 (33)
[PhN+]. Anal. Calc. for C10H13Cl2GeNO2 (322.73): C,
37.22; H, 4.06; N, 4.34. Found: C, 37.32; H, 4.33; N, 4.24%.
3
4H, NCH2 and OCH2 groups), 4.26 (d, J = 11 Hz, 1H,
3
NCH), 5.53 (d, J = 11 Hz, 1H, OCH), 7.16–7.33, 7.39–
7.45, 7.65–7.75, 7.84–7.88 (4m, 10H, 2Ph). The signals of
MeN, NCH, and OCH groups of two other diastereomers
are observed at the total rate of about 30%. 13C NMR
((CD3)2SO, 100 MHz): d = 43.63 (MeN), 52.18 (NCH2),
57.63 (OCH2), 72.79 (NCH), 73.79 (OCH), 127.36,
127.51, 127.94, 128.39, 129.59, 131.75, 139.09, 141.32
(2Ph). MS (EI, m/z, %): 422 (30) [M+ꢀBr], 395 (51)
[M+ꢀPhCHO], 316 (100) [M+ꢀBrꢀPhCHO], 162 (11)
[M+ꢀPhCHOꢀGeBr2ꢀH], 153 (22) [GeBr+], 132 (72)
[M+ꢀPhCHOꢀGeBr2ꢀCH2OꢀH], 118 (22) [CH2N-
CHPh+], 105 (15) [PhCO+], 77 (28) [Ph+], 58 (16) [NCH2-
CH2O+]. Anal. Calc. for C17H19Br2GeNO2 (501.76): C,
40.69; H, 3.82; N, 2.79. Found: C, 40.99; H, 3.79; N, 2.76%.
3
3
3.2.11. PhN(CH2CH2O)2GeBr2 (21)
Analogously to 9, germocane 21 was prepared from
1.25 ml (10.0 mmol) of GeBr4 and 3.26 g (10.0 mmol) of
PhN(CH2CH2OSiMe3)2 (2) by reflux for 30 h in 15 ml of
toluene. The product (0.49 g, 12%) was isolated as a white
powder. 1H NMR (CDCl3, 300 MHz): d = 3.52 (t,
3.2.8. MeN(CH2CH2O)(CH2C(Ph)2O)GeCl2 (18)
Analogously to 15, germocane 18 was prepared from
0.48 ml (4.2 mmol) of GeCl4 and 1.75 g (4.2 mmol) of
MeN(CH2CH2OSiMe3)CH2C(Ph)2OSiMe3 (8) by reflux
for 28 h in 10 ml of toluene. The product (1.51 g, 87%)
was isolated as a brown powder. 1H NMR (CDCl3,
3
3J = 5 Hz, 4H, 2NCH2), 4.20 (t, J = 5 Hz, 4H, 2OCH2),
6.87–6.90 (m, 2H), 6.96–7.00 (m, 1H), 7.26–7.33 (m, 2H)
(Ph). 13C NMR (CDCl3, 75 MHz): d = 57.68 (NCH2),

E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
5721
65.24 (OCH2), 116.47, 121.27, 129.17, 148.40 (Ph). MS (EI,
3.4. The synthesis of the 2,2-dimethylgermocanes 23–26
3.4.1. MeN(CH2CH2O)(CH2CH(Ph)O)GeMe2 (23)
m/z, %): 411 (4) [M+], 381 (6) [M+ꢀCH2O], 302 (29)
[M+ꢀCH2OꢀBr], 149 (100) [M+ꢀCH2OꢀGeBr2], 119
(17) [M+ꢀ2CH2OꢀGeBr2], 105 (11) ½PhNCHþꢂ, 91 (9)
A mixture of 0.57 g (2.93 mmol) of isomeric dialkanolam-
2
[PhN+]. Anal. Calc. for C10H13Br2GeNO2 (411.63): C,
29.18; H, 3.18; N, 3.40. Found: C, 29.42; H, 3.15; N, 3.24%.
ines
MeN(CH2CH2OH)–CH2CH(Ph)OH + MeN(CH2-
CH2OH)CH(Ph)CH2OH, 0.67 g (3.51 mmol) of Me2Ge-
(NMe2)2 and 15 ml of toluene was heated at 70 ꢁC for 15 h.
All volatile materials were removed under reduced pressure,
and the residue was dried in vacuum for 4 h to give 0.87 g
(100%) of a mixture of germocane 23 (95%) and isomeric
MeN(CH2CH2O)(CH(Ph)CH2O)GeMe2 (24) (5%) in form
3.3. The synthesis of the 2,2-difluorenyl-6-methylgermocane
(22)
3.3.1. Flu2Ge(OEt)2
1
A solution of 0.38 ml (2.7 mmol) of triethylamine in
15 ml of ethanol was added dropwise, at 0 ꢁC, to a suspen-
sion of 0.85 g (1.8 mmol) of Flu2GeCl2 in 20 ml of THF.
The reaction mixture was refluxed for 15 h, and then all
volatiles were removed under reduced pressure. Diethyl
ether (5 ml) was added to the residue, and the resulting sus-
pension was stirred for 1 h. The precipitate (Et3N Æ HCl)
was filtered off and washed with ether (2 · 2 ml). After
the volume of the filtrate was reduced to ca. 2 ml, heptane
(10 ml) was added. The precipitated solid was filtered and
dried in vacuum to give 0.30 g of crude Flu2Ge(OEt)2 as
a white powder. This compound was used in the next step
without further purification. 1H NMR (CDCl3, 400 MHz):
of a light yellow oil. H NMR for 23 (CDCl3, 400 MHz):
d = 0.48 (s, 3H, GeMe), 0.58 (s, 3H, GeMe), 2.44 (s, 3H,
MeN), 2.46–2.50 (m, 1H), 2.53–2.59 (m, 1H), 2.62–2.66 (m,
1H), 2.72–2.79 (m, 1H) (2NCH2 groups), 3.73–3.85 (m,
3
3
2H, OCH2), 4.70 (dd, J = 11 Hz, J = 2 Hz, 1H, OCH),
7.19–7.24 (m, 1H), 7.27–7.32 (m, 2H), 7.34–7.38 (m, 2H)
(Ph). 13C NMR for 23 (CDCl3, 100 MHz): d = 2.69 (GeMe),
4.48 (GeMe), 44.00 (MeN), 61.77 (two signals) (2NCH2
groups), 66.49 (OCH2), 73.12 (OCH), 125.88, 127.08,
1
128.16, 143.17 (Ph). H NMR for 24 (CDCl3, 400 MHz):
d = 2.38 (s, 3H, MeN), 3.63–3.66, 3.90–3.94, 4.12–4.18
(3m, NCH2CH2O andNCH(Ph)CH2O moieties). Otherpro-
ton resonances could not be located due to the overlap with
those for major component. 13C NMR for 24 (CDCl3,
100 MHz): d = 2.57 (GeMe), 4.34 (GeMe), 42.36 (MeN),
59.52 (NCH2), 64.09 (NCH(Ph)), 69.47, 70.31 (2OCH2
groups), 125.84, 127.49, 128.30 (Ph). The quaternary carbon
of phenyl group was not detected due to the low concentra-
tion of minor isomer. MS (EI, m/z, %): 297 (18) [M+], 282
(15) [M+ꢀMe], 252 (24) [M+ꢀMeꢀCH2O], 191 (100)
[M+ꢀPhCHO], 176 (71) [M+ꢀPhCHOꢀMe], 161 (35)
[M+ꢀPhCHOꢀ2Me], 147 (42) [MeNCH2CH2OGe+], 105
(56) [PhCO+], 77 (58) [Ph+], 58 (49) [NCH2CH2O+]. Anal.
Calc. for C13H21GeNO2 (295.92): C, 52.76; H, 7.15; Ge,
24.54. Found: C, 52.30; H, 7.48; Ge, 24.96%.
3
3
d = 1.17 (t, J = 7 Hz, 6H, 2CH3), 3.69 (q, J = 7 Hz, 4H,
2OCH2), 4.06 (s, 2H, 2 GeCH), 7.03–7.07 (m, 4H), 7.18–
7.22 (m, 4H), 7.27–7.29 (m, 4H), 7.57–7.59 (m, 4H) (aro-
matic protons of two fluorenyl groups).
3.3.2. MeN(CH2CH2O)2GeFlu2 (22)
A: A mixture of 0.30 g (0.6 mmol) of Flu2Ge(OEt)2,
0.07 g (0.6 mmol) of N-methyldiethanolamine and 20 ml
of toluene was refluxed for 4 h. After 80% of volatile mate-
rials were removed under reduced pressure, hexane (5 ml)
was added. The precipitate was filtered, washed with hex-
ane (2 · 3 ml), and dried in vacuum to give 0.17 g (55%)
1
of germocane 22 as a white powder. H NMR (CDCl3,
400 MHz): d = 1.40 (s, 3H, MeN), 2.23 (t, 4H, 2NCH2),
3.75 (t, 6H, 2OCH2 + br s, 2H, GeCH), 7.12–7.20 (m,
8H), 7.38 (m, 4H), 7.56–7.58 (m, 4H) (aromatic protons
of two fluorenyl groups). 13C NMR (CDCl3, 100 MHz):
d = 44.62 (MeN), 49.90 (GeCH), 57.34 (NCH2), 61.68
(OCH2), 119.50, 125.61, 125.95, 127.55, 140.83, 143.07
(aromatic carbons of two fluorenyl groups). MS (EI, m/z,
3.4.2. erythro-MeN(CH2CH2O)(CH(Ph)CH(Ph)O)-
GeMe2 (25)
Analogously to 23, germocane 25 was prepared from
0.76 g (2.8 mmol) of erythro-MeN(CH2CH2OH)CH(Ph)-
CH(Ph)OH and 0.65 g (3.4 mmol) of Me2Ge(NMe2)2 by
heating for 20 h in 15 ml of toluene. The product (1.02 g,
1
98%) was isolated as a light yellow oil. H NMR (CDCl3,
%): 356 (62) [M+ꢀC13H9], 165 (100) ½C13Hþꢂ. Anal. Calc.
400 MHz): d = 0.48 (s, 3H, GeMe), 0.81 (s, 3H, GeMe),
2.31 (s, 3H, MeN), 2.50–2.55 (m, 1H), 2.63–2.69 (m, 1H)
(NCH2), 3.48 (d, 3J = 3 Hz, 1H, NCH), 3.76–3.82 (m, 1H),
9
for C31H29GeNO2 (520.18): C, 71.59; H, 5.62; N, 2.69.
Found: C, 72.05; H, 5.82; N, 2.51%.
3
B: A mixture of 0.36 g (0.8 mmol) of Flu2GeCl2, 0.20 g
(0.8 mmol) of MeN(CH2CH2OSiMe3)2 and 10 ml of chlo-
roform was refluxed for 3 h. After all volatiles were
removed in vacuum, toluene (5 ml) was added to the resi-
due. The solid was filtered off, the most part of toluene
was evaporated, and then hexane (5 ml) was added. The
precipitate was filtered and dried in vacuum to give
0.15 g of a pink powder, which was found to be a complex
mixture of products difficult to separate and to identify
3.88–3.92 (m, 1H) (OCH2), 5.47 (d, J = 3 Hz, 1H, OCH),
6.96–7.23 (m, 10H, 2Ph). 13C NMR (CDCl3, 100 MHz):
d = 1.38 (GeMe), 4.33 (GeMe), 43.45 (MeN), 58.78
(NCH2), 63.51 (OCH2), 75.00 (NCH), 76.42 (OCH),
125.88, 126.80, 127.10, 127.19, 128.15, 130.66, 137.20,
142.88 (2Ph). MS (EI, m/z, %): 373 (8) [M+], 358 (7)
[M+ꢀMe], 267 (100) [M+ꢀPhCHO], 252 (87) [M+ꢀ
PhCHOꢀMe], 162 (51) [M+ꢀPhCHOꢀGeMe2ꢀH], 132
(46) [M+ꢀPhCHOꢀCH2OꢀGeMe2ꢀH], 118 (21) [CH2 =
NCHPh+], 105 (42) [PhCO+], 77 (32) [Ph+]. Anal. Calc.
1
(according to H and 13C NMR spectra).

5722
E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
for C19H25GeNO2 (372.02): C, 61.34; H, 6.77; Ge, 19.52.
Found: C, 61.10; H, 6.97; Ge, 19.26%.
GeBr2 (28) in 10 ml of chloroform. The precipitate of 28
immediately dissolved, and the reaction mixture was stirred
for 24 h at room temperature. The analysis of the 1H NMR
spectroscopy data revealed the selective formation of
MeN(CH2CH2O)2Ge(Br)OMe (30). 1H NMR (CDCl3,
400 MHz): d = 2.63 (s, 3H, MeN), 2.75–2.81 (m, 2H),
2.90–2.96 (m, 2H) (2NCH2 groups), 3.63 (s, 3H, OMe),
3.91–3.97 (m, 4H, 2OCH2 groups). Upon the treatment of
the reaction mixture with the second equivalent (0.26 g,
1.09 mmol) of Et3SnOMe exclusive formation of MeN(CH2-
3.4.3. PhN(CH2CH2O)2GeMe2 (26)
Analogously to 23, germocane 26 was prepared from
0.41 g (2.28 mmol) of PhN(CH2CH2OH)2 and 0.53 g
(2.78 mmol) of Me2Ge(NMe2)2 by heating for 15 h in
20 ml of toluene. The product (0.65 g, 83%) was isolated
as colourless crystals upon the slow evaporation of the reac-
tion mixture in vacuum. 1H NMR (CDCl3, 400 MHz):
3
1
d = 0.35 (s, 6H, GeMe2), 3.54 (t, J = 4 Hz, 4H, 2NCH2),
CH2O)2Ge(OMe)2 (33) was observed. H NMR (CDCl3,
3
3.98 (t, J = 4 Hz, 4H, 2OCH2), 6.65–6.67 (m, 2H), 6.72–
400 MHz): d = 2.52 (s, 3H, MeN), 2.63–2.68 (m, 2H),
2.75–2.81 (m, 2H) (2NCH2 groups), 3.57 (s, 3H, OMe),
3.63 (br s, 3H, OMe), 3.83 (t, 3J = 6 Hz, 4H, 2OCH2 groups).
Removal of the solvent gave a light yellow oil.
6.75 (m, 1H), 7.20–7.24 (m, 2H) (Ph). 13C NMR (CDCl3,
100 MHz): d = ꢀ1.61 (GeMe2), 57.83 (NCH2), 63.22
(OCH2), 112.13, 117.07, 129.34, 148.18 (Ph). MS (EI, m/z,
%): 283 (34) [M+], 238 (15) [M+ꢀMeꢀCH2O], 119 (100)
½PhNðCH2Þþꢂ, 105 (35) ½PhNCHþ2 ꢂ. Anal. Calc. for
3.6.3. MeN(CH2CH2O)2Ge(Cl)OMenth (31)
2
C12H19GeNO2 (281.90): C, 51.13; H, 6.79; N, 4.97. Found:
C, 51.06; H, 6.84; N, 5.01%.
1.68 g (4.64 mmol) of Et3SnOMenth were added to a
suspension of 1.21 g (4.64 mmol) of MeN(CH2CH2O)2-
GeCl2 (29) in 15 ml of chloroform. The reaction mixture
was stirred for 24 h at room temperature, in 0.5 h the pre-
cipitate of 29 dissolved. After removal of the solvent in vac-
uum, 20 ml of hexane were added to the solid residue. The
suspension was stirred for 2 h, and then the precipitate was
filtered, washed with 5 ml of hexane, and dried in vacuum.
According to 1H NMR data, the resultant white solid
(0.72 g) contained mainly MeN(CH2CH2O)2Ge(Cl)O-
Menth (31) with small admixtures of Et3SnCl and menthol.
1H NMR (CDCl3, 400 MHz): d = 0.79 d, 0.83–0.86 m,
0.71–1.01 m, 1.11–1.19 m, 1.36–1.45 m, 1.52–1.62 m, 1.99–
2.04 m, 2.07–2.14 m, 3.97–4.03 m (19H, menthoxy group),
2.60 (s, 3H, MeN), 2.70–2.77 (m, 2H), 2.87–2.93 (m, 2H)
(2NCH2 groups), 3.89–3.95 (m, 4H, 2OCH2 groups). Fur-
ther attempts to remove admixtures and to obtain an ana-
lytically pure sample of 31 failed.
3.5. MeN(CH2CH2O)2GeF2 (27)
A solution of 0.21 ml (1.6 mmol) of BF3 Æ Et2O in 3 ml
of CH3CN was added dropwise, within 15 min, to a solu-
tion of 0.56 g (2.5 mmol) of MeN(CH2CH2O)2Ge(OH)2
in 5 ml of CH3CN warmed up to 50 ꢁC. The reaction mix-
ture was stirred at 50 ꢁC for 12 h, and then all volatile
materials were removed under reduced pressure. Chloro-
form (15 ml) was added to the residue, and the resulting
suspension was stirred for 2 h. The solid was filtered,
washed with 4 ml of chloroform, dried in vacuum, and then
recrystallized from methanol/H2O to give 0.28 g (48%) of
difluorogermocane 27 as a white powder. 1H NMR
(CDCl3, 300 MHz): d = 2.71 (s, 3H, MeN), 2.83–2.93,
2.96–3.04 (2m, 4H, 2NCH2), 3.87–4.05 (m, 4H, 2OCH2).
13C NMR (CDCl3, 75 MHz): d = 54.82 (NCH2), 57.01
(OCH2). The signal of MeN group was not found due to
the poor solubility of the compound 27 in CDCl3. 19F
3.6.4. MeN(CH2CH2O)2Ge(OMenth)2 (34)
Analogously to described above, the reaction of 1.11 g
(4.26 mmol) of MeN(CH2CH2O)2GeCl2 (29) with 3.08 g
(8.52 mmol) of Et3SnOMenth was performed in 12 ml of
chloroform. Analysis of the reaction mixture with NMR
spectroscopy after 24 h of stirring at room temperature
showed the formation of MeN(CH2CH2O)2Ge(OMenth)2
(34) and Et3SnCl as a by-product. 1H NMR (CDCl3,
400 MHz): d = 0.85 d, 0.71–0.96 m, 1.04–1.12 m, 1.30–
1.38 m, 1.50–1.58 m, 2.05–2.08 m, 2.16–2.22 m, 2.58–
2.65 m, 3.55–3.63 m, 3.82–3.90 m (38H, two menthoxy
groups), 2.46 (s, 3H, MeN), 2.61–2.70 (m, 4H, 2NCH2
groups), 3.78 (t, 3J = 6 Hz, 4H, 2OCH2 groups). 13C
NMR (CDCl3, 100 MHz): d = 16.08, 21.44, 22.50, 23.18,
25.28, 31.83, 34.99, 45.96, 50.31, 73.12 (two menthoxy
groups), 44.59 (MeN), 55.91 (2NCH2), 57.85 (2OCH2).
2
NMR (CDCl3, 188 MHz): d = ꢀ147.0 (d, JF,F = 56 Hz,
2
1F, GeF), ꢀ156.05 (d, JF,F = 56 Hz, 1F, GeF). Anal.
Calc. for C5H11F2GeNO2 Æ H2O (245.77): C, 24.43; H,
5.33; N, 5.70. Found: C, 23.93; H, 5.28; N, 5.48%.
3.6. The synthesis of the 2-halo-2-alkoxygermocanes 30–32
and 2,2-dialkoxygermocanes 33 and 34
3.6.1. Me2NCH2CH2OSnEt3
1H NMR (CDCl3, 400 MHz): d = 0.88–1.23 (m, 15H,
SnEt3), 2.18 (s, 6H, Me2N), 2.35 (t, 3J = 5 Hz, 2H,
NCH2), 3.76 (t, 3J = 5 Hz, 2H, OCH2). 13C NMR (CDCl3,
100 MHz): d = 6.01 (SnCH2), 9.93 (SnCH2CH3), 46.12
(Me2N), 63.81, 63.96 (NCH2 and OCH2 groups).
3.6.2. MeN(CH2CH2O)2Ge(Br)OMe (30) and
MeN(CH2CH2O)2Ge(OMe)2 (33)
3.6.5. Complex MeN(CH2CH2O)2Ge(Cl)OCH2CH2NMe2
(32) Æ Et3SnCl
0.26 g (1.09 mmol) of Et3SnOMe were added dropwise to
a suspension of 0.38 g (1.09 mmol) of MeN(CH2CH2O)2-
1.55 g (5.26 mmol) of Et3SnOCH2CH2NMe2 were
added to a suspension of 1.37 g (5.26 mmol) of MeN-

E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
5723
(CH2CH2O)2GeCl2 (29) in 15 ml of chloroform. The pre-
3.7. X-ray crystallographic study
cipitate of starting 29 dissolved in 5 min. The reaction
mixture was stirred for 24 h at room temperature, and
then the solvent was removed in vacuum. The residue as
a yellow oil solidified on standing. The crude product
was recrystallized from CH2Cl2/hexane at ꢀ18 ꢁC to give
2.12 g (73%) of a 1:1 adduct of MeN(CH2CH2O)2Ge-
(Cl)OCH2CH2NMe2 (32) with Et3SnCl in form of a light
yellow powder. 1H NMR (CDCl3, 400 MHz): d = 1.17–
1.42 (m, 15H, SnEt3), 2.75 (s, 6H, Me2N), 2.80 (s, 3H,
MeN), 3.06–3.12 (m, 2H), 3.28–3.34 (m, 2H) (2NCH2),
3.14 (t, 2H, NCH2), 3.94–4.00 (m + t, 6H, 3OCH2). 13C
NMR (CDCl3, 100 MHz): d = 10.41, 14.08 (SnEt3),
43.80 (MeN), 46.29 (Me2N), 55.22 (2NCH2), 58.29
(2OCH2), 58.61 (NCH2), 59.06 (OCH2). MS (EI, m/z,
%): 226 (3) [M+ꢀEt3SnClꢀMe2NCH2CH2O], 213 (14)
Crystal data, data collection, structure solution and
refinement parameters for compounds 16, 20–22, and 26
are presented in Table 3. Experimental intensities were
measured on a Bruker SMART CCD diffractometer using
graphite monochromatized Mo Ka radiation (k =
˚
0.71073 A) at 120(2) K. Absorption correction based on
measurements of equivalent reflections were applied. The
structures were solved by direct methods [62] and refined
by full matrix least-squares on F2 [63] with anisotropic
thermal parameters for all non-hydrogen atoms. In the
structures 16, 20, 22, and 26 all H atoms were found from
diff. Fourier synthesis and refined isotropically; in 21 all H
atoms were placed in calculated positions and refined using
a riding model.
[Et2SnCl+], 153 (12) ½GeðClÞOCH2CHþꢂ, 149 (7) [EtSn+],
2
58 (100) ½Me2NCHþꢂ. Anal. Calc. for C15H36Cl2Ge-
Acknowledgement
2
N2O3Sn (554.68): C, 32.48; H, 6.54; N, 5.05. Found: C,
32.17; H, 6.58; N, 5.10%. A solution of 0.64 g (1.15 mmol)
of the adduct 32 Æ Et3SnCl in 5 ml of chloroform was trea-
ted with 0.5 ml (3.59 mmol) of Et3N, followed by crystal-
lization from chloroform/hexane mixture. This treatment
as well as the heating of the product in vacuum
(1 mmHg) at 60–70 ꢁC failed to remove Et3SnCl from
the complex.
A.V.C. is grateful to Russian Science Support
Foundation.
Appendix A. Supplementary data
CCDC-247126 (for 16), CCDC-247128 (for 20),
CCDC-247127 (for 21), CCDC-247125 (for 22), and
Table 3
Crystal data, data collection, structure solution and refinement parameters for 16, 20, 21, 22, and 26
Compound
16
20
21
22
26
Empirical formula
Formula weight
Colour, habit
Crystal size (mm)
Crystal system
C17H19Br2Ge1N1O2 C10H13Cl2Ge1N1O2 C10H13Br2Ge1N1O2 C31H29Br2Ge1N1O2 C12H19Ge1N1O2
501.74
322.70
411.62
520.14
281.87
Colourless block
0.40 · 0.30 · 0.10
Monoclinic
P21/n
Colourless needle
0.40 · 0.20 · 0.10
Monoclinic
P21/c
Colourless block
0.30 · 0.30 · 0.10
Monoclinic
P21/c
Colourless block
0.40 · 0.40 · 0.20
Monoclinic
P21/n
Colourless block
0.30 · 0.20 · 0.20
Monoclinic
P21/c
Space group
Unit cell dimensions
˚
a (A)
8.3771(2)
13.4619(3)
15.5237(4)
93.369(1)
1747.61(7)
4
1.907
6.334
984
8.1768(6)
17.8615(13)
8.4899(1)
106.407(1)
1189.5(2)
4
1.802
3.008
648
8.4202(7)
17.794(1)
8.6179(7)
106.522(1)
1237.9(2)
4
2.209
8.915
792
7.6559(1)
24.4898(4)
12.9850(2)
96.271(1)
2420.01(6)
4
1.428
1.296
1080
7.3212(3)
9.3830(4)
18.6108(8)
97.798(1)
1266.64(9)
4
1.478
2.405
584
˚
b (A)
˚
c (A)
b (ꢁ)
Volume (A )
3
˚
Z
Density (calculated) [g cmꢀ3
Absorption coefficient (mmꢀ1
F(000)
]
)
h Range (ꢁ)
Index ranges
2.00–28.00
ꢀ5 6 h 6 11
ꢀ16 6 k 6 17
ꢀ17 6 l 6 20
10,850
2.28–27.00
ꢀ10 6 h 6 9
ꢀ13 6 k 6 22
ꢀ10 6 l 6 9
7035
2.52–28.00
ꢀ11 6 h 6 11
ꢀ23 6 k 6 10
ꢀ9 6 l 6 11
7066
2.29–27.00
ꢀ9 6 h 6 9
ꢀ31 6 k 6 24
ꢀ16 6 l 6 15
16,313
2.21–28.00
ꢀ8 6 h 6 9
ꢀ12 6 k 6 9
ꢀ24 6 l 6 22
7861
Reflections collected
Independent reflections
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I > 2r(I)]
4196 [Rint = 0.0195] 2600 [Rint = 0.0277] 2938 [Rint = 0.0396] 5268 [Rint = 0.0181] 3069 [Rint = 0.0205]
4196/0/284
1.037
2600/0/197
1.138
2938/0/146
1.056
5268/0/432
1.059
3069/0/221
1.044
R1 = 0.0260,
wR2 = 0.0648
R1 = 0.0346,
wR2 = 0.0675
–
R1 = 0.0349,
wR2 = 0.0947
R1 = 0.0376,
wR2 = 0.0966
–
R1 = 0.0490,
wR2 = 0.1340
R1 = 0.0586,
wR2 = 0.1395
0.0021(9)
R1 = 0.0251,
wR2 = 0.0636
R1 = 0.0294,
wR2 = 0.0652
–
R1 = 0.0219,
wR2 = 0.0541
R1 = 0.0275,
wR2 = 0.0559
–
R indices (all data)
Extinction coefficient
Largest difference in peak/hole (e A
ꢀ3
˚
)
1.724/ꢀ0.403
2.301/ꢀ0.805
1.671/ꢀ1.683
0.391/ꢀ0.259
0.457/ꢀ0.261

5724
E.Kh. Lermontova et al. / Journal of Organometallic Chemistry 691 (2006) 5710–5724
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lographic data for this paper. These data can be obtained
free of charge at www.ccdc.cam.ac.uk/conts/retriev-
ing.html [or from the Cambridge Crystallographic Data
Centre, 12, Union Road, Cambridge CB2 1EZ, UK; fax:
(internat.) +44 1223 336 033; e-mail: deposit@
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