O,N-Chelated germanium, tin and lead compounds containing 2-[N,N-(dimethylamino)methyl]phenolate as ligand

Article abstract of DOI:10.1016/j.jorganchem.2013.02.033

Thirteen organotin(IV) and low valent complexes of group 14 (Ge, Sn, Pb) containing L^NO ligand(s) (where L^NO is 2-(N,N-dimethylaminomethyl)phenolate) were synthesized and its structure described by NMR techniques in solution and X-ray techniques in the solid state (for L₂^NOSnPh₂, L₂ ^NOSnCl₂, L₂^NOGe and L ^NOSnCl which forms a dimer). Structures and properties of prepared species have been compared with previously published germanium and tin compounds containing -OCH₂CH₂NMe₂ as O,N- or L ^CN (where L^CN is 2-(N,N-dimethylaminomethyl)phenyl) as C,N-chelating ligands. The solid state structures containing L^NO ligand(s) reveal much stronger intramolecular N → Sn coordination than complexes containing latter two ligands.

Full text of DOI:10.1016/j.jorganchem.2013.02.033

Journal of Organometallic Chemistry 733 (2013) 71e78
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Journal of Organometallic Chemistry
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O,N-Chelated germanium, tin and lead compounds containing
2-[N,N-(dimethylamino)methyl]phenolate as ligand
*
ꢀ
ꢀ
ꢀ
ꢀ ꢁꢀ ꢀ
Martin Novotný, Zdenka Padelková, Jaroslav Holecek, Ales Ruzicka
Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, CZ-532 10 Pardubice, Czech Republic
a r t i c l e i n f o
a b s t r a c t
Thirteen organotin(IV) and low valent complexes of group 14 (Ge, Sn, Pb) containing LNO ligand(s) (where
LNO is 2-(N,N-dimethylaminomethyl)phenolate) were synthesized and its structure described by NMR
techniques in solution and X-ray techniques in the solid state (for LN2OSnPh2, L2NOSnCl2, L2NOGe and LNOSnCl
which forms a dimer). Structures and properties of prepared species have been compared with previ-
ously published germanium and tin compounds containing eOCH2CH2NMe2 as O,N- or LCN (where LCN is
2-(N,N-dimethylaminomethyl)phenyl) as C,N-chelating ligands. The solid state structures containing LNO
ligand(s) reveal much stronger intramolecular N / Sn coordination than complexes containing latter
two ligands.
Article history:
Received 27 January 2013
Received in revised form
27 February 2013
Accepted 28 February 2013
Keywords:
Germanium
Tin
Ó 2013 Elsevier B.V. All rights reserved.
Lead
Phenolate
NMR
XRD
1. Introduction
reported by groups of Zemlyansky, Khrustalev and Nechaev [6]. The
authors described tetrylenes, their reactivity towards oxidizing
A couple of decades after its discovery in w1970, low valent
group 14 metal and metalloid complexes received growing interest
because of similar properties as the transition metal complexes
mainly with respect to small molecule activation, as for example
dihydrogen, ammonia, carbon dioxide and others [1]. The appli-
cation of germanium and lead complexes in oxidative addition
reactions is also studied in this class of compounds [2]. For the
stabilization of metalloid or metal centre in oxidation state þII, a
plethora of different ligand systems has been developed. These
ligands can be divided to subclasses where bulky [3] or various
C,N-, N,C,N-, O,C-, O,C,O-, P,C,P-chelating ligands are the most pop-
ular. For purposes of stabilization of organotin compounds, a C,N-
chelating ligand (Fig. 1A), has been studied in our group [4].
Similarly, the hybrid N,N-chelating aminoeamido ligand (Fig. 1B)
was used by us for the preparation of low valent germanium, tin
and lead compounds very recently [5]. The difference between
mentioned two ligands is that the N,N-chelating one is able to make
a six-membered diazametalla cycle, which is for desired stabiliza-
tion surprisingly more efficient, instead of the five-membered one.
Related papers on structure and reactivity of group 14 complexes
using the 2-(N,N-dimethylamino)ethanol (Fig. 1C) as a ligand are
agents, low valent transition metal complexes, together with
behaviour of complexes with metal in higher oxidation state and
theoretical explanations and/or predictions. Unfortunately, there
is lack of the 119Sn NMR spectra determination of these com-
pounds where only two particular values for Sn(OCH2CH2NMe2)2
(
d
(
119Sn ¼ ꢀ309.9 ppm [6e])) and [Ph(C6F5)Sn(OCH2CH2NMe2)2]
[H2O$B(C6F5)3] (
d
(
119Sn) ¼ ꢀ395.6 ppm [6d]) are reported.
It seems that the development of group 14 chemistry of O,N-
chelating ligand (Fig. 1D, 2-(N,N-dimethylaminomethyl)pheno-
late, LNO), is a logical step within this field of chemistry. The main
difference between 2-(N,N-dimethylamino)ethanolate based and
suggested ligand systems is the ring size (five- or six-membered),
and the presence of the aromatic fragment within the LNO ligand
which will presumably lead to the differences in structure and
reactivity of the target compounds. The LNO ligand is mentioned
for preparation of organotin(IV) compounds in a patent from
1965, but no physico-chemical data are available [7]. The same
ligand and very similar bis-chelating ligands have been used for
the preparation of alkaliemetal complexes [8] and later applied
for vanadium(IV) or molybdenum(VI) chemistry by van Koten [9]
and Mösch-Zanetti [10]. It also attracted attention of Barrau [11]
who prepared and studied the reactivity of potentially tris-
chelating ligand in the class of group 14 metals.
This paper describes both synthesis and structural character-
ization of germanium(II), tin(II) and lead(II) complexes as well as
* Corresponding author. Fax: þ420 466037068.
ꢁꢀ ꢀ
E-mail address: ales.ruzicka@upce.cz (A. Ruzicka).
0022-328X/$ e see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2013.02.033

72
M. Novotný et al. / Journal of Organometallic Chemistry 733 (2013) 71e78
Scheme 3. Unexpected formation of 8 from 10.
because of the presence of two LNO ligands, the rest of compounds
reveal one set of narrow signals in 1H, 13C and 119Sn NMR spectra.
The labile geometry at the central metal atom in solution can
affect the width of the resonances in the NMR spectra of 8, 10 and
11, too. Unfortunately, also very low solubility at decreased tem-
peratures was observed for these compounds which thwarted the
low-temperature NMR measurements. In the case of 7, which is
almost insoluble in common deuterated solvents, only 1H NMR
spectrum was recorded. For the rest of compounds, all possible
NMR spectra parameters of usual nuclei (1H, 13C and 119Sn) were
determined. In general, the chemical shift values, integral in-
tensities and multiplicity of each resonance in the 1H NMR spectra
of 1e13 correspond well to proposed composition with the
respect to the number and nature of substituents bound to the
central metal/metalloid atom.
Fig. 1. Schematic drawings of common chelating ligands.
Fig. 2. General numbering of ligands and substituents used.
organotin(IV) compounds containing the LNO ligand(s) or both LNO
and C,N-chelating (LCN) ligands (Fig. 2).
In the 1H NMR spectra of compounds containing two LNO ligands
(e.g. 8,10 and 11), broad resonances were observed for all functional
groups from which especially the signals for methylene and methyl
groups are close to decoalescence. There are two exceptions of this
behaviour for LNO2Sn(n-Bu)2 (1) and LNO2Ge (9) where well resolved
spectra were obtained.
2. Results and discussion
2.1. Synthesis
The target O,N-chelated group 14 metal complexes were pre-
pared by two different synthetic strategies, (i) conversion of sodium
salt LNONa with tri- and diorganotin(IV) chlorides (1e8; Scheme 1)
and (ii) protonolytic reactions of the Lappert’s type germylene,
2.2.2. NMR studies on triorganotin(IV) compounds 2, 4, 5 and 6
Surprisingly, in 119Sn NMR spectra of triorganotin(IV) com-
stannylenes and plumbylene with phenol
L
NOH (for 9e13;
pounds 4 (
d
(
119Sn) ¼ 135.7 ppm) and 5 (
d
(
119Sn) ¼ 105.2 ppm)
Scheme 2). Both pathways gave low to sufficient yields (20e80%)
of desired compounds which are generally instable in the air. Sur-
prisingly, compound 8 was also isolated from the reaction of
homoleptic stannylene 10 with 1 M equivalent of (1,5-cyclo-
octadiene)palladium(II) dichloride. This reaction has been per-
formed in order to prepare a heterobimetallic complex of Pd and Sn
but the reduction of the palladium occurred essentially quantita-
tively (Scheme 3).
signals at very low field were detected. This is in strong contrast to
119Sn chemical shift values reported for related C,N-chelated five-
coordinated triorganotin(IV) compounds as for example LCN(n-
Bu)2SnCl and LCNMe2SnCl (
d
(
119Sn) z ꢀ50 ppm) [12]. So, based on
these findings, we assume that the six-membered azaoxastanna
ring is not closed because of none or very limited intramolecular
N / Sn interaction in 4 and 5. This fact and the presumption of
four-coordinated tin centre with pseudotetrahedral geometry in 4
and 5 (Table 1) is further supported by the close chemical shift
values reported for starting chlorides Me3SnCl and (n-Bu)3SnCl
2.2. NMR studies in solution
(d(
119Sn) ¼ 164 and 141 ppm, respectively) in which the central tin
2.2.1. General remarks
Except for compounds and 8, 10 and 11 (Table 1), where the
dynamic behaviour of the CH2N(CH3)2 parts of molecules occurs
Table 1
Numbering and selected NMR spectra parameters of LNOR1R2R3M and LNOR1M types
of compounds under investigation.
Cpd
R1
R2
R3
M
d(
119Sn) C6D6 [ppm]
1
2
3
4
5
6
7
8
9
LNO
n-Bu
n-Bu
n-Bu
Me
n-Bu
Ph
n-Bu
n-Bu
Cl
Me
n-Bu
Ph
Sn
Sn
Sn
Sn
Sn
Sn
Sn
Sn
Ge
Sn
ꢀ201.0
ꢀ86.9
ꢀ157.7b
135.7
LCN
n-Bu
Me
Scheme 1. Preparation of compounds 1e8 (for 1 R ¼ n-Bu; for 2 R0 ¼ LCN, R ¼ n-Bu; for
3 R0 ¼ Cl, R ¼ n-Bu; for 4 R0 ¼ R ¼ Me; for 5 R0 ¼ R ¼ n-Bu; for 6 R0 ¼ LCN, R ¼ Ph; for
7 R ¼ Ph; and for 8 R ¼ Cl).
n-Bu
105.2
LCN
ꢀ212.4
LNO
LNO
LNO
LNO
Ph
Cl
Ph
Cl
a
ꢀ575.9b
e
e
e
10
e
e
ꢀ528.0
ꢀ538.1c
e
11
12
13
LNO
Cl
N(SiMe3)2
e
e
e
e
e
e
Pb
Sn
Sn
ꢀ379.5b
ꢀ53.4
a
Insufficiently soluble for 119Sn NMR investigation.
Measured in THF-d8.
Measured in toluene-d8 at ꢀ50 ꢁC.
b
c
Scheme 2. Preparation of compounds 9e13 (for 9 M ¼ Ge; for 10 M ¼ Sn; for
11 M ¼ Pb; for 12 M ¼ Sn, R ¼ Cl; and for 13 M ¼ Sn, R ¼ N(SiMe3)2).

M. Novotný et al. / Journal of Organometallic Chemistry 733 (2013) 71e78
73
atom is obviously four-coordinated in the solution of a non-
coordinating solvent [13].
2.2.5. NMR studies on germanium(II), tin(II) and lead(II)
compounds 9e13 bearing LNO ligand(s)
Last two triorganotin(IV) compound of the series e LNOLCNSn(n-
Bu)2 (2) and LNOLCNSnPh2 (6) e contain two potentially chelating
ligands. Nevertheless, according to the observed 119Sn chemical
shift values of ꢀ86.9 ppm (2) and ꢀ212.4 ppm (6), we suggest that
only one of them acts as a chelating one while the second one
exhibits a monodentate bonding fashion with respect to the tin
atom. In addition, these values are in a parallel to the C,N-chelated
di-n-butyl and diphenyltin(IV) compounds bearing a negative
substituent (for example Cl (ꢀ51.7 and ꢀ177.1 ppm, respectively)
[12,14], F (ꢀ77.1 and ꢀ198.6 ppm, respectively) [15] and O (ꢀ55.4
and ꢀ173.2 ppm) [16]) where the pentacoordinated tin atom was
reported. Due to the reasons described above we assume the
pentacoordination of the tin atom in both 2 and 6.
For homoleptic divalent compounds of the LN2OM type (where
M ¼ Ge (9), Sn (10), Pb(11)) different 1H NMR spectral patterns were
found. Thus, for the complex of the smallest element e germanium
(9) e well resolved spectra with narrow signals were found while
broad resonances have been observed for remaining two complexes
10 and 11. It could be explained by the fact that the germanium atom
is probably not able efficiently accommodate available electron
density. The 119Sn NMR spectrum of 10 reveals very high upfield shift
of ꢀ528.0 ppm when compared to the starting Lappert’s stannylene
(d(
119Sn) ¼ 770 ppm) [18] and even to the only reported
d(
119Sn) for
Sn(OCH2CH2NMe2)2 (
d
(
119Sn) ¼ ꢀ309.9 ppm) [6e].
Two novel heteroleptic stannylenes LNOSnCl (12) and LNOSnN(-
SiMe3)2 (13) were prepared and characterized by 1H and 119Sn NMR
spectroscopy. Both 12 and 13 reveal the dynamic behaviour with
broad signals in 1H NMR spectra. Moreover, two signals were found
2.2.3. NMR studies on diorganotin(IV) compounds 1, 3 and 7
From three synthesized diorganotin(IV) compounds, LNO2SnPh2
(7) is sparingly soluble and moreover crystallizes rapidly in the
magnetic field of the NMR machine, that is why only 1H NMR
spectrum of 7 is reported. The 1H NMR spectrum of 7 displays
resonances attributable to both two phenyl and two LNO sub-
stituents at predictable positions.
for both methylene (
d
(1H) ¼ 3.83 and 2.47 ppm, respectively) and
methyl groups (
d
(1H) ¼ 1.99 and 1.56 ppm, respectively) in 13.
Different coordination polyhedra of both compounds is deduced
from
d
(
119Sn) values being ꢀ379.5 ppm for 12 and ꢀ53.4 ppm for
13, respectively. This can be easily explained by presumably dimeric
structure of 12 and a monomeric structure of 13 in the solution.
Proposed dimeric structure of chloride complex 12 could be
compared to the reported structure of oxo-bridged dimer
[Sn(OCH2CH2NMe2)Cl]2 [19]. Similar dimeric structure has been
found for analogous tineamido complex {Sn(OCH2CH2NMe2)
[N(SiMe3)2]}2, too [6c]. On the contrary, purely monomeric struc-
ture of the germanium analogue Ge(OCH2CH2NMe2)[N(SiMe3)2]
has been reported in the same paper. According to this structure
The two remaining members of this group, LN2OSn(n-Bu)2 (1) and
L
NO(n-Bu)2SnCl (3), reveal distinctlydifferent
d
(
119Sn)values ofꢀ201.1
(for 1) and ꢀ157.7 ppm (for 3). This indicates different coordination
vicinity of the tin central atom in 1 and 3, respectively. The coordi-
nation polyhedra of tin centre in 1 can be best described as di-capped
distorted tetrahedron (e.g. [4 þ 2] coordination) and a distorted
trigonal bipyramidfor3. Thisdescriptionisalongwithsimilartrendin
d
(
119Sn) values reported earlier for compounds with comparable
and the d(
119Sn) comparison of 13 with chemical shifts values found
for monomeric three-coordinated tin guanidinates [20], we pro-
pose the monomeric character of 13, too.
composition geometry LC2N(n-Bu)SnCl (
d(
119Sn) ¼ ꢀ118.1 ppm, [4 þ 2]
coordination) and LCN(n-Bu)SnCl2
(d(
119Sn) ¼ ꢀ104.3 ppm, penta-
coordination of the tin atom) [12]. The only reported 119Sn NMR
chemical shift value for diorganotin(IV) compound containing a N,O-
chelating ligand ([Ph(C6F5)Sn(OCH2CH2NMe2)2][H2O$B(C6F5)3] [6d])
is e 395.6 ppm, which is unfortunately incomparable to shifts found
for 1 or 2 because of totally different structure of both compounds.
2.3. Solid state studies
Four molecular structures of compounds 7, 8, 9 and 12 were
determined by X-ray diffraction techniques. The common feature of
first three structures as well as of structures reported in the liter-
ature containing two O,N-chelating ligands is the trans arrange-
ment of the nitrogen donor atoms which are relatively strongly
interacting with the metal centre.
2.2.4. NMR studies on purely inorganic tin(IV) compound 8
Prepared LN2OSnCl2 (8) reveals different behaviour than
LC2NSnCl2 [17] in solution as detected by 1H NMR spectroscopy.
A broad signal with a saddle point was observed for the CH2N
groups while two distinct resonances for methyl groups
The geometry of the tin centre in LN2OSnPh2 (7, Fig. 3) can be best
described as a distorted octahedron with all trans arrangement
which have not been reported so far. Both nitrogen atoms are
(
d
(1H) ¼ 2.94 and 2.78 ppm, respectively) were observed in the 1H
ꢁ
NMR spectrum of 8. Surprisingly, the methyl group resonances
exhibit two different 3J(119Sn, 1H) values being 30 and 41 Hz,
respectively, which is a unique observation among all compounds
studied. In strong contrast to the 1H NMR spectrum of 8, an AX-
spin pattern for CH2 groups along with one broad resonance for
methyls is observed in the 1H NMR spectrum of L2CNSnCl2. Never-
theless, we assume the pseudooctahedral vicinity of the tin atom
in 8 with both oxygen and chlorine atoms being in mutual cis and
both nitrogen atoms in trans arrangement. On the other hand, C,C-
transoidal arrangement is reported for LC2NSnCl2. These 1H NMR
behaviour dissimilarities are further reflected in the different
tightly connected to the tin centre (Sn1eN1 2.380(2) A) clutching
almost perfect straight angle (N1eSn1eN1a ¼ 179.98ꢁ). Similarly
strong intramolecular connection NeSn was found in the structure
of monoorganotin(IV) compound PhSn(OCH2CH2NMe2)2Cl, where
oxygen atoms of the ligand reveal mutual cis arrangement [21]. The
angle between the pivotal carbon atom of the phenyl ring, oxygen
and the tin atom is found to be 126.50(15)ꢁ which is more or less
20ꢁ more opened than is found in compounds bearing the e
OCH2CH2NMe2 ligand forming smaller rings [6,19,21,22].
Complex LN2OSnCl2 (8, Fig. 4) has similar structural arrangement
as PhSn(OCH2CH2NMe2)2Cl [21] with only the phenyl ring
substituted by chlorine atom. The intramolecular contact between
Sn and N atoms is the strongest interaction (Sn1eN12.275(4); Sn1e
119Sn NMR spectra of 8 and L2CNSnCl2 with the 119Sn) values
d(
at ꢀ575.9 ppm found for 8 and ꢀ254.2 ppm reported for LC2NSnCl2,
respectively. This discrepancy can be attributed to a cooperative
effect of carbon atoms for more negative oxygen atoms exchange
within the ligand’s skeleton. The more efficient donation of the
nitrogen atoms lone electron pairs to the tin centre and the use of
THF-d8 as a solvent can be considered as another explanation for
ꢁ
N2 2.269(4) A) ever found in the class of tin(IV) compounds chelated
by an amino group. The direct comparison of 8 and LC2NSnCl2 shows
different arrangement of the tin coordination polyhedra in LC2NSnCl2
with cis-arranged nitrogen atoms and much longer interatomic
ꢁ
distances(SneN 2.618(3) and SneCl 2.4390(3) A). Onthe otherhand,
such different (Dd
(
119Sn) z 320 ppm) 119Sn NMR chemical shift
the SneCl distance in PhSn(OCH2CH2NMe2)2Cl is even longer
values of 8 and LC2NSnCl2.
(2.524 A) and all OeSneO angles are close to the right angle.
ꢁ

74
M. Novotný et al. / Journal of Organometallic Chemistry 733 (2013) 71e78
Fig. 5. Molecular structure of 9 (ORTEP view, 50% probability level). Hydrogen atoms
ꢁ
ꢁ
are omitted for clarity. Selected interatomic distances [A] and angles [ ]: Ge1eO1
1.857(3), Ge1eO2 1.857(3), Ge1eN1 2.306(3), Ge1eN2 2.328(3); O1eGe1eO2
93.94(13); N1eGe1eN2 165.28(11); C10eO2eGe1 130.7(3); C1eO1eGe1 131.5(3).
Fig. 3. Molecular structure of 7 (ORTEP view, 50% probability level). Hydrꢁogen atoms
ꢁ
are omitted for clarity. Selected interatomic distances [A] and angles [ ]: Sn1eN1
2.380(2), Sn1eO1 2.111(2), Sn1eC10 2.171(3), O1eC1 1.338(4), C1eC2 1.408(4), C2eC7
1.506(4), N1eC8 1.479(3); N1eSn1eN1a 179.98(8), O1eSn1eO1a 179.98(9), C10e
Sn1eC10a 180.00(7), O1eSn1eN1 87.82(7), O1eSn1eC10 90.55(9), Sn1eO1eC1
126.51(15), O1eC1eC2 122.8(2), C1eC2eC7 121.5(3), C2eC7eN1113.9(2), C7eN1eSn1
105.64(15), C1 O1 Sn1 126.50(15).
evident when taking different covalent radii of Ge and Sn atoms
into the account.
The dimeric structure of LNOSnCl (12, Fig. 6) formed by OeSn
contacts to dissymmetric non-planar four membered dioxadis-
tanna ring was determined by crystallographic techniques. Simi-
lar type of structures of O,N-chelated compounds are reported
for {Sn(OCH2CH2NMe2)Cl}2, {Sn(OCH2CH2NMe2)F}2 [6e] and
{Sn(OCH2CH2NMe2)N3}2 [22] but all these compounds are charac-
teristic by planar central ring and the coordinated nitrogen atoms
from ligands are located not far from this plane, too. On the other
hand, the central ring in 12 reveals high degree of distortion with
In divalent compounds 9 and 12, the angle between the pivotal
carbon atom of the phenyl ring, oxygen and the metalloid or metal
atom is even bigger than in the tin(IV) compounds. On the other
hand, the
J-trigonal bipyramidal structure, with nitrogen atoms in
axial positions and oxygen atoms and the lone electron pair in the
equatorial plane, of LN2OGe (9, Fig. 5) is comparable to the structure
of Ge(OCH2CH2NMe2)2 [6e] with only slightly different angles
within the germanium primary coordination sphere. Also similar-
ities between structure of 9 with Sn(OCH2CH2NMe2)2 [6e] are
ꢁ
Sn2 and Sn4 atoms about 1 A out for the plane defined by Sn1, O27
and O29, and Sn3, O19 and O20, respectively. Also the interatomic
Fig. 6. Molecular structure of 12 (ORTEP view, 50% probability level). Hydrogen atoms
are omitted for clarity. Boꢁth independent molecules are shown. Selected interatomic
ꢁ
distances [A] and angles [ ]: Sn1eO27 2.109(3), Sn1eO29 2.366(3), Sn1eN1 2.407(4),
Sn1eCl1 2.4856(12), Sn2eO29 2.123(3), Sn2eN2 2.438(4), Sn2eCl2 2.4784(12), Sn2e
O27 2.480(3), Sn3eO19 2.090(3), Sn3eO20 2.363(3), Sn3eN3 2.426(4), Sn3eCl4
2.4965(11), Sn4eO20 2.133(3), Sn4eN4 2.456(4), Sn4eCl3 2.4681(12); O27eSn1eO29
70.01(11), O27eSn1eN1 81.99(12), O29eSn1eN1 147.93(12), O27eSn1eCl1 91.83(9),
O29eSn1eCl1 81.02(7), N1eSn1eCl1 84.67(10), C1eO27eSn1 133.9(3), C1eO27eSn2
116.7(3), Sn1eO27eSn2 104.49(12), C10eO29eSn2 132.6(3), C10eO29eSn1 114.1(2),
Sn2eO29eSn1 108.05(12), O19eSn3eO20 70.84(11), O19eSn3eN3 82.31(12), O20e
Sn3eN3 149.82(11), O19eSn3eCl4 90.78(9), O20eSn3eCl4 81.13(8), N3eSn3eCl4
85.83(9), O29eSn2eN2 81.92(12), O29eSn2eCl2 91.92(8), N2eSn2eCl2 94.25(9),
O29eSn2eO27 67.55(10), N2eSn2eO27 145.69(11), Cl2eSn2eO27 101.77(8), O20e
Sn4eN4 82.63(12), O20eSn4eCl3 89.37(9), N4eSn4eCl3 92.41(10).
Fig. 4. Molecular structure of 8 (ORTEP view, 50% probability level). Hydrogen atoms
and THF molecules are omitted for clarity. Selected interatomic distances [A] and
ꢁ
angles [ꢁ]: Sn1eO1 2.024(3), Sn1eO2 2.023(3), Sn1eCl1 2.4101(13), Sn1eCl2
2.4058(13), Sn1eN1 2.275(4), Sn1eN2 2.269(4), O1eC1 1.346(5); N1eSn1eN2
178.95(13), N1eSn1eCl2 98.23(10), O1eSn1eCl2 177.62(9), O2eSn1eCl1 178.17(9),
O2eSn1eO1 90.63(9), C1eO1eSn1 119.7(3), C10eO2eSn1 120.9(3).

M. Novotný et al. / Journal of Organometallic Chemistry 733 (2013) 71e78
75
distances within the tin polyhedra are elongated in 12 when related
to other reported compounds, with the biggest difference in Sn4e
respectively. Values of 13C chemical shifts were calibrated to signals of
THF (d(
13C) ¼ 67.6 ppm) or benzene (
d(
13C) ¼ 128.4 ppm). The 119Sn
ꢁ
ꢁ
O19 (2.600(3) A) in comparison to 2.282 A found for the longest
SneO distance in {Sn(OCH2CH2NMe2)F}2 [6e]. In all previously re-
ported compounds similarly as in 12, the tin coordination geometry
is square pyramidal with chlorine atom in the top and the rest of
coordinated atoms as well as the lone electron pair in the basement
of the pyramid.
chemical shift values are referred to external neat tetramethyl-
stannane (
d
(
119Sn) ¼ 0.0 ppm). Positive chemical shift values denote
shifts to the higher frequencies relative to the standards. 119Sn NMR
spectra were measured using the inverse gated-decoupling mode. All
13C NMR spectra were measured using standard proton-decoupled
experiment and CH and CH3 vs. C and CH2 were differentiated by
the help of APT method [23] and the rest of the signals was assigned
according to the standard 2D measurements. Only mean values of
3J(1H, 1H) of the observed dd resonances are given.
3. Conclusion
In conclusion, thirteen new compounds of group 14 metalloid/
metals containing O,N-chelating ligand(s) were prepared and
structurally characterized. It seems, the intramolecular coordina-
tion between nitrogen and tin atoms, and thus the formation of the
six-membered ring, is rather strong, and even stronger in the direct
comparison to analogous compounds with five-membered rings
with OCH2CH2NMe2 as O,N- or LCN as C,N-chelating ligands. Com-
pounds bearing two LNO ligands prefer mutual trans arrangement of
the donor groups, the rest of the groups are arranged trans in
diorganotin(IV) compounds or cis in the purely inorganic com-
pound LN2OSnCl2. In the cases of low valent complexes, monomeric
bischelated germylene was observed while dimeric heteroleptic
stannylene with bridging LNO ligands and highly distorted was
determined.
4.2. Crystallography
The X-ray data (Table 2) obtained from colourless crystals for all
compounds were acquired at 150 K using an Oxford Cryostream
low-temperature device on a Nonius KappaCCD diffractometer
ꢁ
with MoKa radiation (
l
¼ 0.71073 A), a graphite monochromator,
and in the and
f
c
scan mode. Data reductions were performed
with DENZO-SMN [24]. The absorption was corrected by integra-
tion methods [25]. Structures were solved by direct methods
(Sir92) [26] and refined by full matrix least-square based on F2
(SHELXL97) [27]. Hydrogen atoms were mostly localized on a dif-
ference Fourier map, but in order to ensure uniformity of the
treatment of the crystal, all hydrogen atoms were recalculated into
idealized positions (riding model) and assigned temperature fac-
tors Hiso(H) ¼ 1.2 Ueq (pivot atom) or of 1.5 Ueq for the methyl
4. Experimental part
ꢁ
moiety with CeH ¼ 0.96, 0.97 and 0.93 A for methyl, methylene and
hydrogen atoms in aromatic rings, respectively.
4.1. NMR spectroscopy
NMR spectra were recorded from solutions in benzene-d6,
toluene-d8 or THF-d8 ona BrukerAvance500 spectrometer(equipped
4.3. Synthesis
with Z-gradient 5 mm probe) at frequencies for 1H (500.13 MHz), 13
C
All syntheses were performed using standard Schlenk tech-
niques under an inert argon atmosphere. Solvents and reactants
were purchased from commercial sources and purified by standard
procedures when necessary. Solvents were distilled over K/Na alloy,
degassed and then stored over a K-mirror under an argon atmo-
sphere. Single crystals suitable for XRD analyzes are obtained under
argon from corresponding saturated solutions of products in
toluene or hexane at ꢀ30 ꢁC. Melting points were measured under
{1H} (125.76 MHz), and 119Sn{1H} (186.50 MHz) at 295 K. All deuter-
ated solvents were degassed and stored over a potassium mirror
under an argon atmosphere. Samples were obtained by dissolving
approximately 40 mg (when possible) of each compound approxi-
mately in 0.5 mL of deuterated solvent. Values of 1H chemical
shifts were calibrated to internal standard e tetramethylsilane
(d
(1H) ¼ 0.00 ppm) or to residual signals of benzene (
d
(1H) ¼ 7.16
ppm), toluene (
d
(1H) ¼ 2.09 ppm) or THF (
d
(1H) ¼ 1.73 ppm),
a film of inert perfluoroalkylether and were uncorrected. 1H and 13
C
Table 2
Selected crystallographic parameters of 7, 8$THF, 9, and 12.
Compound reference
7
8$THF
9
12
Chemical formula
Formula mass
Crystal system
Space group
C30H34N2O2Sn
573.28
Monoclinic
P21/c
10.0780(3)
9.1359(4)
16.1161(7)
90
119.910(4)
90
1286.20(10)
2
C18H24Cl2N2O2Sn, C4H8O
C18H24GeN2O2
372.98
Monoclinic
Cc
13.2800(3)
16.0423(5)
8.6390(6)
90
98.102(3)
90
1822.10(15)
4
C18H24Cl2N2O2Sn2
608.67
Monoclinic
P21/c
14.7980(8)
9.4580(11)
31.752(3)
90
100.763(5)
90
562.09
Orthorhombic
P212121
9.5610(9)
13.0670(7)
19.4551(16)
90
90
90
2430.6(3)
4
1.296
ꢁ
a [A]
ꢁ
b [A]
ꢁ
c [A]
a
b
g
[ꢁ]
[ꢁ]
[ꢁ]
3
ꢁ
Unit cell volume [A ]
4365.8(7)
8
2.547
Z
m
[mmꢀ1
]
1.023
1.692
No. of reflections measured
No. of independent reflectionsa
Rint
12,518
2165
0.0344
0.0417
0.0522
1.081
17,143
4646
0.0436
0.0480
0.0699
1.112
11,125
3127
0.0596
0.0669
0.0710
1.143
27,143
7476
0.0442
0.0362
0.0590
1.172
Final R1 values (I > 2
s
(I))b
Final wR(F2) values (I > 2
s
(I))b
Goodness of fit on F2 c
P
P
a
b
c
Rint
¼
P
jF2o ꢀ F2o,meanj/ F2o.
P
P
P
P
½
Weighting scheme : w ¼ [
s
2(F2o) þ (w1P)2 þ w2P]ꢀ1, where P ¼ [max(Fo2) þ 2Fc2], R(F) ¼ jjFoj ꢀ jFcjj/ jFoj, wR(F2) ¼ [ (w(Fo2 ꢀ Fc2)2)/( w(F2o)2)]
.
S ¼ [ (w(F2o ꢀ F2c)2)/(Ndiffr. ꢀ Nparam.)]
.
½

76
M. Novotný et al. / Journal of Organometallic Chemistry 733 (2013) 71e78
NMR spectra of starting 2-[(dimethylamino)methyl]phenol were
determined in deuterated chloroform. Preparation of starting com-
pounds containing LCN ligand [12], LNONa [8], and [(Me3Si)2N]2M [2]
is published elsewhere, the rest of the compounds of sufficient purity
was obtained from commercial sources (SigmaeAldrich).
64.9 (CH2N); 46.9 (N(CH3)2); 33.0 (br, C(
a
), 1J(119Sn, 13C) ¼ could not
be read); 27.7 (C(
b
), 2J(119Sn, 13C) ¼ 28 Hz); 25.8 (C(
g
), 3J(119Sn,
13C) ¼ 101 Hz); 12.5 (C(
d
)). 119Sn NMR (THF-d8, 295 K, ppm)
d: ꢀ157.7. Elemental analysis (%): found: C, 49.0; H, 7.4; N, 3.3. Calcd
(%) for C17H30ClNOSn (418.58): C 48.78; H 7.22; N 3.35.
4.3.1. General method for preparation of tin(IV) and phenolates
To a solution (suspension) of appropriate starting organotin(IV)
chloride in toluene (4, 5, 7), benzene (2) or THF (1, 3, 6 and 8) at
room temperature, corresponding equivalent(s) of starting sodium
2-(N,N-dimethylaminomethyl)phenolate was added. Reaction mix-
tures were stirred overnight and filtered. Afterwards all volatiles
from obtained filtrates were evaporated in vacuo giving desired
products of sufficient purity. Products were washed with hexanes
when necessary.
4.3.1.4. Preparation of LNOSnMe3 (4). 0.869 g of LNONa (5.02 mmol)
and 1.000 g (5.02 mmol) of Me3SnCl was mixed in 30 ml of toluene.
After the workup of the reaction mixture, the crude product was
washed with hexane to give 0.667 g (42%) of white crystalline 4. 1H
NMR (C6D6, 295 K, ppm): 7.48 (d, 1H, H(3), 3J (1H(4),
1H(3)) ¼ 8.7 Hz); 7.22 (m, 1H, H(5)); 6.94 (dd, 1H, H(4), 3J ¼ 9.1 Hz);
6.78 (d, 1H, H(6), 3J (1H(5), 1H(6)) ¼ 9.7 Hz); 3.61 (s, 2H, CH2N); 2.22
(s, 6H, N(CH3)2); 0.26 (s, 9H, Sn(CH3)3, 2J(119Sn, 1H) ¼ 57 Hz). 13C
NMR (C6D6, 295 K, ppm): 161.7 (C(1), 2J(119Sn, 13C) was not
observed); 131.8 (C(3)); 129.0 (C(5)); 123.9 (C(2)); 120.1 (C(4));
119.2 (C(6)); 60.0 (CH2N); 46.2 (N(CH3)2); ꢀ2.9 (Sn(CH3)3, 1J(119Sn,
4.3.1.1. Preparation of L2NOSn(n-Bu)2 (1). 0.725 g of (n-Bu)2SnCl2
(2.39 mmol) and 0.826 g of LNONa (4.78 mmol) was mixed in 40 ml
of tetrahydrofuran. 0.974 g (76%) of yellow oily 1 was obtained. 1H
NMR (C6D6, 295 K, ppm): 7.11 (m, 6H, H(3, 5, 6)); 6.73 (dd, 2H, H(4),
3J ¼ 7.2 Hz); 3.38 (s, 4H, CH2N); 2.07 (s, 6H, N(CH3)2); 1.72 (br, 4H,
13C) ¼ 392 Hz). 119Sn NMR (C6D6, 295 K, ppm)
d: 135.7. Elemental
analysis (%): found: C, 45.9; H, 6.7; N, 4.5. Calcd (%) for C12H21NOSn
(314.00): C 45.90; H 6.74; N 4.46.
H(
a
)); 1.35 (br, 4H, H(
b
)); 1.28 (m, 4H, H(
g
)); 0.83 (t, 6H, H(
d
),
4.3.1.5. Preparation of
L
NOSn(n-Bu)3 (5). 1.146
g
of LNONa
3J ¼ 7.3 Hz). 13C NMR (C6D6, 295 K, ppm): 162.5 (C(1), 2J(119Sn, 13C)
was not observed); 131.1 (C(3)); 129.6 (C(5)); 126.0 (br, C(2)); 121.0
(C(4)); 118.0 (C(6), 3J(119Sn, 13C) ¼ 56 Hz); 62.4 (CH2N); 46.4
(6.61 mmol) and 2.153 g (6.61 mmol) of (n-Bu)3SnCl was mixed in
40 ml of toluene overnight. Resulting suspension was filtered and
the filtrate was evaporated to dryness in vacuo. 1.44 g (49%) of pale
yellow oily 5 was obtained. 1H NMR (C6D6, 295 K, ppm): 7.37 (d, 1H,
H(3), 3J (1H(4), 1H(3)) ¼ 7.4 Hz); 7.07 (dd, 1H, H(5), 3J ¼ 7.7 Hz); 6.78
(N(CH3)2); 28.2 (C(
b
), 2J(119Sn, 13C) ¼ 30 Hz); 27.6 (C(
g
), 3J(119Sn,
13C) ¼ 64 Hz); 21.8 (br, C(
a
), 1J(119Sn, 13C) could not be read); 14.2
(C(
d
)). 119Sn NMR (C6D6, 295 K, ppm): ꢀ201.0. Elemental analysis
(dd, 1H, H(4), 3J
¼
7.5 Hz); 6.64 (d, 1H, H(6), 3J(1H(5),
(%): found: C, 57.7; H, 7.9; N, 5.0 Calcd (%) for C26H42N2O2Sn
(533.33): C 58.56; H 7.94; N 5.25.
1H(6) ¼ 7.9 Hz)); 3.52 (s, 2H, CH2N); 2.20 (s, 6H, N(CH3)2); 1.56 (m,
6H, H(
b
)); 1.25 (m, 6H, H(
g
)); 1.12 (t, 6H, H(
a
), 3J ¼ 6.1 Hz, 2J(119Sn,
1H) ¼ 51 Hz); 0.85 (t, 9H, H(
d
), 3J ¼ 6.2 Hz). 13C NMR (C6D6, 295 K,
4.3.1.2. Preparation of
L
NOLCNSn(n-Bu)2 (2). 0.272
g
of LNONa
ppm)d
: 161.9 (C(1), 2J(119Sn, 13C) was not observed); 131.5 (C(3));
(1.57 mmol) and 0.632 g of LCNBu2SnCl (1.57 mmol) was mixed in
130.3 (C(2)); 128.4 (C(5)); 119.5 (C(4)); 118.8 (C(6)); 59.7 (CH2N);
30 ml of benzene. 0.520 g (64%) of pale yellow oily 2 was obtained.
46.5 (N(CH3)2); 28.6 (C(
b
), 2J(119Sn, 13C) ¼ 21 Hz); 27.8 (C(
g),
3
1H NMR (C6D6, 295 K, ppm): 8.38 (d, 1H, H(60), J(1H(50),
3J(119Sn, 13C) ¼ 61 Hz); 16.6 (C(
a
), 1J(119Sn, 13C) ¼ 350 Hz); 14.3
1H(60)) ¼ 6.9 Hz, 3J(119Sn, 1H) ¼ 56 Hz); 7.64 (d, 1H, H(6), 3J(1H(5),
1H(6)) ¼ 7.2 Hz); 7.16e7.11 (m, 3H, H(40, 50, 6)); 6.91 (d, 1H, H(30),
3J(1H(30), 1H(40)) ¼ 6.5 Hz); 6.85 (dd, 2H, H(4, 5), 3J ¼ 7.0 Hz); 3.84 (s,
2H, CH2N (LNO)); 3.04 (s, 2H, CH2N (LCN)); 2.38 (s, 6H, N(CH3)2
(C(d
)). 119Sn NMR (C6D6, 295 K, ppm): 105.2. Elemental analysis (%):
found: C, 57.5; H, 9.1; N, 3.2. Calcd (%) for C21H39NOSn (440.25): C
57.29; H 8.93; N 3.18.
(LNO)); 1.74 (s, 6H, N(CH3)2 (LCN)); 1.72 (m, 4H, H(
b
)); 1.35 (m, 4H,
4.3.1.6. Preparation of
L
NOLCNSnPh2 (6). 0.431
g
of LNONa
H(
g
)); 1.23 (t, 4H, H(
a
), 3J ¼ 7.6 Hz, 2J(119Sn, 1H) ¼ 59 Hz); 0.87 (t, 6H,
(2.49 mmol) and 1.102 g (2.49 mmol) of LCNPh2SnCl was mixed in
50 ml of THF. The mixture was heated to reflux for 2 h. Obtained
suspension was filtered and the resulting filtrate was evaporated to
dryness in vacuo. The residue was washed with hexane, and the
product was extracted with benzene. Evaporation of benzene
extract in vacuo gave 0.507 g (36%) of white crystalline 6. 1H NMR
H(
d
), 3J ¼ 7.4 Hz). 13C NMR (C6D6, 295 K, ppm): 163.3 (C(1), 2J(119Sn,
13C) was not observed); 143.5 (C(20), 2J(119Sn, 13C) was not
observed); 142.6 (C(10), 1J(119Sn, 13C) was not observed); 138.9 (br,
C(60)); 131.0 (C(3)); 129.7 (C(2), 3J(119Sn, 13C) was not observed);
129.3 (C(5)); 128.7 (C(40)); 127.9 (C(50), 3J(119Sn, 13C) was not
observed); 127.3 (C(30)); 119.0 (C(4)); 116.8 (C(6), 3J(119Sn, 13C) was
not observed); 65.7 (CH2N (LCN), nJ(119Sn, 13C) ¼ 25 Hz); 59.5 (CH2N
3
1
(C6D6, 295 K, ppm): 8.92 (d, 1H, H(60), J(1H(50), H(60)) ¼ 7.0 Hz,
3J(119Sn, 1H) ¼ 61 Hz); 7.75 (d, 4H, H(200), 3J(1H(300), 1H(200)) ¼ 7.8 Hz,
(LNO)); 46.2 (N(CH3)2 (LCN)); 45.2 (N(CH3)2 (LNO)); 28.6 (C(
b
),
),
3J(119Sn, H) ¼ 57 Hz); 7.43e7.38 (m, 2H, H(3, 50)); 7.27 (m, 1H,
1
2J(119Sn, 13C) ¼ 29 Hz); 27.5 (C(
g
), 3J(119Sn, 13C) ¼ 79 Hz); 16.0 (C(
a
H(40)); 7.17 (m, 6H, H(300, 400)); 7.00 (d, 1H, H(30), 3J ¼ 9.0 Hz); 6.88
1J(119Sn, 13C) ¼ 479 Hz); 14.0 (C(
d
)). 119Sn NMR (C6D6, 295 K,
(dd, 1H, H(5), 3J
¼
9.1 Hz); 6.72 (d, 1H, H(6), 3J(1H(5),
ppm): ꢀ86.9. Elemental analysis (%): found: C, 60.2; H, 8.1; N, 5.2.
1H(6)) ¼ 9.0 Hz); 6.66 (dd, 1H, H(4), 3J ¼ 7.6 Hz); 3.73 (s, 2H, CH2N
(LNO)); 3.08 (s, 2H, CH2N (LCN)); 2.30 (s, 6H, N(CH3)2 (LNO)); 1.43 (s,
6H, N(CH3)2 (LCN)). 119Sn NMR (C6D6, 295 K, ppm): ꢀ212.4.
Elemental analysis (%): found: C, 64.9; H, 6.3; N, 4.9. Calcd (%) for
C30H34N2OSn (557.31): C 64.66; H 6.15; N 5.03.
Calcd (%) for C26H42N2OSn (517.33): C 60.36; H 8.18; N 5.41.
4.3.1.3. Preparation of
L g
NO(n-Bu)2SnCl (3). 1.146 of LNONa
(6.61 mmol) and 2.010 g of (n-Bu)2SnCl2 (6.61 mmol) was mixed in
30 ml of tetrahydrofuran. 2.404 g (68%) of pale yellow oily 3 was
obtained. 1H NMR (THF-d8, 295 K, ppm): 7.13 (dd, 1H, H(5),
3J ¼ 7.5 Hz); 6.99 (dd, 1H, H(3), 3J ¼ 7.5 Hz); 6.71 (d, 1H, H(6),
3J(1H(5), 1H(6)) ¼ 8.0 Hz); 6.60 (dd, 1H, H(4), 3J ¼ 7.4 Hz); 3.80 (s,
4.3.1.7. Preparation of L2NOSnPh2 (7). 1.212 g of LNONa (7.00 mmol)
and 1.203 (3.50 mmol) of Ph2SnCl2 was mixed together in 50 ml of
toluene. Obtained suspension was filtered and the filtrate was
evaporated to dryness in vacuo. White crystalline 7 was obtained.
Single crystals of 7 were obtained from its toluene solution after the
addition of hexane within few days at ambient temperature. M.p.
2H, CH2N); 2.65 (s, 6H, N(CH3)2); 1.78 (m, 4H, H(
b
)); 1.57 (t, 4H,
H(
6H, H(
a
), 3J ¼ 7.5 Hz, 2J(119Sn, 1H) ¼ 80 Hz); 1.36 (m, 4H, H(
g
)); 0.91 (t,
d
), 3J ¼ 7.5 Hz). 13C NMR (THF-d8, 295 K, ppm): 163.9 (C(1),
2J(119Sn, 13C) was not observed); 131.2 (C(3)); 131.1 (C(5)); 123.6
255e256 ꢁC. H NMR (THF-d8, 295 K, ppm): 7.48 (d, 4H, H(200),
1
(C(2), 3J(119Sn, 13C) was not observed); 120.9 (C(4)); 117.8 (C(6));
3J(1H(300), 1H(200)) ¼ 7.8 Hz, 3J(119Sn, 1H) ¼ 54 Hz); 7.32 (br, 2H, H(3));

M. Novotný et al. / Journal of Organometallic Chemistry 733 (2013) 71e78
77
3
7.30 (dd, 2H, H(5), J ¼ 2.0 Hz); 7.27 (m, 4H, H(300)); 6.93 (d, 2H,
4.27 (d, 2H, CH2N, 2J(1H(A), 1H(X)) ¼ 10.4 Hz); 2.56 (d, 2H, CH2N,
2J(1H(A), 1H(X)) ¼ 10.4 Hz); 2.23 (s, 6H, anisochronous N(CH3)2);
2.50 (s, 6H, anisochronous N(CH3)2). 119Sn NMR (toluene-d8, 220 K,
ppm): ꢀ538.1. Elemental analysis (%): found: C, 51.8; H, 5.8; N, 6.4
Calcd (%) for C18H24N2O2Sn (419.09): C 51.59; H 5.77; N 6.68.
H(6), 3J(1H(5), 1H(6)) ¼ 7.6 Hz); 6.67 (br, 2H, H(4)); 3.57 (s, 4H,
CH2N); 2.26 (s, 12H, N(CH3)2). Elemental analysis (%): found: C,
63.1; H, 6.2; N, 4.7 Calcd (%) for C30H34N2O2Sn (573.31): C 62.85; H
5.98; N 4.89.
4.3.1.8. Preparation of LN2OSnCl2 (8). 0.376
g
of (COD)PdCl2
4.3.2.3. Preparation of LN2OPb (11). 0.627
g of [(Me3Si)2N]2Pb
(1.32 mmol) and 0.553 g of SnLN2O (1.32 mmol, (10), see below) was
mixed in 30 ml of THF. Obtained suspension was filtered and the
filtrate was evaporated under vacuo to dryness and washed with
hexane. White powder was obtained. Single crystals of 8 were
isolated from its saturated THF solution which was stored in a
freezing box for several days. M.p. 152 ꢁC (dec.). 1H NMR (THF-d8,
295 K, ppm): 7.04 (m, 4H, H(3, 5)); 6.68 (dd, 2H, (H(4)),
3J ¼ 7.8 Hz); 6.38 (br d, 2H, H(6), 3J(1H(5), 1H(6)) ¼ 7.8 Hz); 4.11 and
4.06 (broad with a saddle point, 4H, CH2N); 2.94 (s, 6H, aniso-
chronous N(CH3)2, 3J(119Sn, 1H) ¼ 30 Hz); 2.78 (s, 6H, anisochro-
nous N(CH3)2, 3J(119Sn, 1H) ¼ 41 Hz). 13C NMR (THF-d8, 295 K,
ppm): 162.5 (C(1), 2J(119Sn, 13C) was not observed); 130.8 (C(3));
130.6 (C(5)); 123.7 (C(2)); 121.4 (C(4)); 118.9 (C(6)); 64.2 (CH2N);
48.0 (anisochronous N(CH3)2); 47.9 (anisochronous N(CH3)2). 119Sn
NMR (THF-d8, 295 K, ppm): ꢀ575.9. Elemental analysis (%): found:
C, 44.1; H, 4.8; N, 5.8. Calcd (%) for C18H24Cl2N2O2Sn (490.01): C
44.12; H 4.94; N 5.72.
(1.19 mmol) and 0.360 g (2.38 mmol) of LNOH were mixed in 30 ml
of toluene. After the workup and re-crystallization from toluene
0.144 g (24%) of white powder was obtained. 1H NMR (THF-d8,
295 K, ppm): 7.08 (dd, 2H, H(5), 3J ¼ 9.3 Hz); 6.92 (d, 2H, H(3),
3J(1H(4), 1H(3)) ¼ 8.8 Hz); 6.72 (broad, 2H, H(4)); 6.49 (br, 2H, H(6));
3.55 (broad, 4H, CH2N); 2.20 (broad, 12H, N(CH3)2). 13C NMR (THF-
d8, 295 K, ppm): 164.3 (br, C(1)); 130.4 (br, C(3, 5)); 125.1 (br, C(2));
120.6 (br, C(4)); 115.3 br, (C(6)); 61.5 (CH2N); 44.0 (N(CH3)2).
Elemental analysis (%): found: C, 42.6; H, 4.8; N, 5.5. Calcd (%) for
C18H24N2O2Pb (507.59): C 42.59; H 4.77; N 5.52.
4.3.3. Preparation of heteroleptic tin(II) phenolates
To a solution of [bis(trimethylsilyl)amino]tin(II) chloride (or bis
[bis(trimethylsilyl)amino]tin(II)) in toluene at room temperature,
one equivalent of starting 2-[N,N-dimethyl(aminomethyl)]phenol
was added. Reaction mixture was stirred until the reaction mixture
became colourless. The solution was then filtered, toluene and
hexamethyldisilazane were evaporated in vacuo. The residue was
washed with petroleum ether to give pure product in sufficient
yields.
4.3.2. General method for the preparation of homoleptic
germanium(II), tin(II) and lead(II) phenolates
To a solution of bis[bis(trimethylsilyl)amino]metal(II) or met-
alloid(II) in toluene at room temperature, two equivalents of
starting 2-[N,N-dimethyl(aminomethyl)]phenol were added. Re-
action mixtures were stirred, until change of colour from yellow to
colourless was observed. The solutions were then filtered, toluene
and formed hexamethyldisilazane were evaporated in vacuo. Resi-
dues were washed with petroleum ether giving desired products of
sufficient purity in relatively low to moderate yields.
4.3.3.1. Preparation of [LNOSnCl]2 (12). 1.450 g (4.61 mmol) of
[bis(trimethylsilyl)amino]tin(II) chloride and 0.697 g (4.61 mmol)
of LNOH was stirred in 50 ml of toluene. 0.490 g (35%) of white
crystalline 12 was obtained. Single crystals of 12 were isolated from
its saturated toluene solution which was kept in a freezing box for
several days. M.p. 165e170 ꢁC. 1H NMR (THF-d8, 295 K, ppm): 7.14
(dd, 1H, H(5), 3J
¼
7.2 Hz); 7.02 (d, 1H, H(3), 3J(1H(4),
1H(3)) ¼ 6.8 Hz); 6.77 (d, 1H, H(6), 3J(1H(5), 1H(6)) ¼ 8.0 Hz); 6.69
(br, 1H, H(4)); 3.88 (s, 2H, CH2N); 2.52 (s, 6H, N(CH3)2). 13C NMR
(THF-d8, 295 K, ppm): 159.6 (C(1), 2J(119Sn, 13C) could not be read);
128.7 (C(3)); 127.9 (C(5)); 124.0 (C(2)); 121.7 (C(4)); 117.7 (C(6));
61.4 (CH2N); 43.1 (N(CH3)2). 119Sn NMR (THF-d8, 295 K,
ppm): ꢀ379.5. Elemental analysis (%): found: C, 35.6; H, 4.1; N, 4.4.
Calcd (%) for monomeric C9H12ClNOSn (304.36): C 35.52; H 3.97; N
4.60.
4.3.2.1. Preparation of LN2OGe (9). 0.459
g of [(Me3Si)2N]2Ge
(1.16 mmol) and 0.351 g of LNOH (2.32 mmol) were mixed in
30 ml of toluene. After the workup, 0.186 g (44%) of white
crystalline 9 was obtained. Single crystals of 9 were isolated from
its saturated toluene solution which was stored in a freezing box
for several days. M.p. 124e125 ꢁC. 1H NMR (toluene-d8, 295 K,
ppm): 7.19 (dd, 2H, H(5) 3J ¼ 7.3 Hz); 6.89 (d, 2H, H(3), 3J(1H(4),
1H(3)) ¼ 7.9 Hz); 6.83 (d, 2H, H(6), 3J(1H(5), 1H(6)) ¼ 6.8 Hz); 6.74
(dd, 2H, H(4), 3J
¼
7.2 Hz); 3.90 (d, 2H, CH2N, 2J(1H(A),
4.3.3.2. Preparation of LNOSnN(SiMe3)2 (13). 0.793 g (1.80 mmol) of
1H(X)) ¼ 12.1 Hz); 2.87 (d, 2H, CH2N, 2J(1H(A), 1H(X)) ¼ 12.1 Hz);
2.00 (s, 12H, N(CH3)2). 13C NMR (toluene-d8, 295 K, ppm): 160.2
(C(1)); 130.8 (C(3)); 130.0 (C(5)); 126.0 (C(2)); 121.4 (C(4)); 118.5
(C(6)); 60.5 (CH2N); 44.0 (N(CH3)2). Elemental analysis (%):
found: C, 57.5; H, 6.8; N, 7.6. Calcd (%) for C18H24N2O2Ge (373.00):
C 57.91; H 6.48; N 7.51.
bis[bis(trimethylsilyl)amino]tin(II) and 0.273 g (1.80 mmol) of
L
NOH was mixed in 30 ml of toluene. After the workup, 0.179 g
(23%) of white powder was obtained. 1H NMR (C6D6, 295 K, ppm):
7.23 (dd, 1H, H(5), 3J ¼ 7.5 Hz); 7.11 (d, 1H, H(3), 3J(1H(4),
1H(3))) ¼ 8.0 Hz); 6.76e6.70 (m, 2H, (H4, 6)); 3.83 (broad, 1H,
anisochronous CH2N); 2.47 (broad, 1H, anisochronous CH2N); 1.99
(broad, 3H, anisochronous NCH3); 1.56 (broad, 3H, anisochronous
NCH3); 0.38 (s, 18H, Si(CH3)3). 13C NMR (C6D6, 295 K, ppm): 162.6
(C(1), 2J(119Sn, 13C) was not observed); 131.4 (C(3)); 128.7 (C(5));
124.9 (C(2)); 122.7 (C(4)); 118.3 (C(6)); 61.6 (CH2N); 45.9 (br, ani-
sochronous NCH3); 44.6 (br, anisochronous NCH3); 6.9 (Si(CH3)3).
119Sn NMR C6D6, 295 K, ppm): ꢀ53.4. Elemental analysis (%):
found: C, 42.2; H, 7.3; N, 6.1. Calcd (%) for C15H30N2OSi2Sn (429.29):
C 41.97; H 7.04; N 6.53.
4.3.2.2. Preparation of LN2OSn (10). 1.441
g of [(Me3Si)2N]2Sn
(3.28 mmol) and 0.991 g of LNOH (6.56 mmol) were mixed in 30 ml
of toluene. After the workup, 0.288 g (21%) of white powder was
obtained. 1H NMR (C6D6, 295 K, ppm): 7.31 (dd, 2H, H(5),
3J ¼ 7.7 Hz); 7.05 (d, 2H, H(3), 3J(1H(4), 1H(3)) ¼ 8.0 Hz); 6.90 (d, 2H,
H(6), 3J(1H(5), 1H(6)) ¼ 6.6 Hz); 6.79 (dd, 2H, H(4), 3J ¼ 7.3 Hz); 4.15
(extremely broad, 2H, anisochronous CH2N); 2.85 (extremely
broad, 2H, anisochronous CH2N); 1.92 (extremely broad, 12H,
N(CH3)2). 13C NMR (C6D6, 295 K, ppm): 162.0 (C(1), 2J(119Sn, 13C) was
not observed); 131.3 (C(3)); 130.2 (C(5)); 125.1 (C(2)); 121.2 (C(4));
117.3 (C(6)); 60.8 (CH2N); 45.3 (N(CH3)2). 119Sn NMR (C6D6, 295 K,
ppm): ꢀ528.0. 1H NMR (toluene-d8, 220 K, ppm): 7.35 (br, 2H,
H(5)); 7.04 (br, 2H, H(3)); 6.87 (br, 2H, H(6)); 6.83 (br, 2H, H(4));
Acknowledgement
The authors would like to thank the Grant Agency of the Czech
Republic (grant no. P207/10/0215) for the financial support of this
work.

78
M. Novotný et al. / Journal of Organometallic Chemistry 733 (2013) 71e78
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ꢀ
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(f) J. Bares, P. Richard, P. Meunier, N. Pirio, Z. Padelková, Z. Cernosek,
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CCDC 921159e921162 contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
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