Titanium (IV) complexes based on substituted 2-[(2-hydroxyethyl)]aminophenols

Article abstract of DOI:10.1016/j.jorganchem.2007.10.020

Novel substituted 2-[(2-hydroxyethyl)]aminophenols, MeN(CHR¹CR²R³OH)(C₆H₄-o-OH) (2-5), were synthesized by the reaction of 2-methylaminophenol with corresponding oxiranes. Titano-spiro-bis(ocanes) [Me

Full text of DOI:10.1016/j.jorganchem.2007.10.020

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Journal of Organometallic Chemistry 693 (2008) 173–179
www.elsevier.com/locate/jorganchem
Note
Titanium (IV) complexes based on substituted
2-[(2-hydroxyethyl)]aminophenols
a,
a
b
c
Kirill V. Zaitsev *, Yuri F. Oprunenko , Andrei V. Churakov , Judith A.K. Howard ,
a,
a
Sergey S. Karlov *, Galina S. Zaitseva
a
Chemistry Department, Moscow State University, Leninskie Gory, 119899 Moscow, Russia
Institute of General and Inorganic Chemistry, RAS, Leninskii Pr. 31, 119991 Moscow, Russia
b
c
Department of Chemistry, University of Durham, South Road, DH1 3LE Durham, UK
Received 8 August 2007; received in revised form 8 October 2007; accepted 11 October 2007
Available online 18 October 2007
Abstract
Novel substituted 2-[(2-hydroxyethyl)]aminophenols, MeN(CHR1CR2R3OH)(C6H4-o-OH) (2–5), were synthesized by the reaction of
2-methylaminophenol with corresponding oxiranes. Titano-spiro-bis(ocanes) [MeN(CHR1CR2R3O)(C6H4-o-O)]2Ti 6–9 (2, 6, R1 = H,
R2 = R3 = Me; 3, 7, R1 = R2 = Ph (treo-), R3 = H; 4, 8, R1 = Ph, R2 = R3 = H; 5, 9, R1 = R2 = H, R3 = Ph) based on [ONO]-ligands
have been synthesized. The obtained compounds were characterized by 1H and 13C NMR spectroscopy and elemental analysis data. The
complex [Ti(l2-O){O-o-C6H4}{l2-CMe2CH2}NMe]6 (10) was obtained by controlled hydrolysis of 6. Molecular structure of 10 was
determined by X-ray structure analysis.
ꢀ 2007 Published by Elsevier B.V.
Keywords: Alkanolaminophenols; Transannular interaction; Alkoxydes; Titano-spiro-bis(ocanes); Crystal structure; [ONO]-ligands
1. Introduction
a few publications concerned with related hybrid systems
[11].
Currently a considerable efforts are being intended to
develop the new chelating [OXO] (X = S, N, O) ligand sys-
tems for group IV metals, since their complexes have found
widespread application as catalysts in various organic reac-
tions. Indeed, Ti(IV) complexes based on polydentate
ligands such as thiobisphenol [OSO] [1,2], aminobismethyl-
phenols [ONO] [3,4] or dialkanolamines [ONO] [5–9] have
been used as olefin polymerization catalysts or ring open-
ing polymerization catalysts [10]. Both phenolate and
aminoalkanolate ligands are important for construction
of catalytic active Ti(IV) complexes and it is important to
combine these functionalities in one ligand molecule to syn-
thesize hybrid [ONO] alkanolaminophenols. There are only
In continuation of our studies of Ti(IV) complexes with
tri- and dialkanolamines [12–14], we present the synthesis
and characterization of titanium complexes (6–9) – tit-
ano-spiro-bis(ocanes) – based on the new hybrid tridentate
alkanolaminophenol ligands. Their structure in solution is
discussed basing on NMR spectroscopy data. We estab-
lished that crystalline compound 10 formed upon con-
trolled hydrolysis of 6. The structure of compound 10
was determined by single-crystal X-ray analysis.
2. Results and discussion
2.1. Synthesis
*
Corresponding authors. Tel.: +7 4959393887; fax: +7 4959328846 (S.S.
For synthesis of alkanolaminophenols 2–5 we investi-
gated the reaction of 2-methylaminophenol (1) with the
number of alkene oxides (Scheme 1). The reactions were
Karlov).
E-mail addresses: zaitsev@org.chem.msu.ru (K.V. Zaitsev), sergej@
org.chem.msu.ru (S.S. Karlov).
0022-328X/$ - see front matter ꢀ 2007 Published by Elsevier B.V.
doi:10.1016/j.jorganchem.2007.10.020

174
K.V. Zaitsev et al. / Journal of Organometallic Chemistry 693 (2008) 173–179
R3
O
Me
Me
2
3
Me
R2
OH
O1
R1
N
OH
NCH2CMe2OH
OH
O
Ti(O-i-Pr)4
-4 i-PrOH
2
Me
2
Ti
O
Ph
3
Ph
3
1 2
2
O
NCHR CR R OH
Me
NH
Me
OH
cis-
1
O 1
R1
R2
N
Me
NCHPhCHPhOH
2, 3, (4 + 5)
R3
3 (treo-)
Me
6, 7, (8 + 9)
Ph
2
3
2, 6: R1 = R2 = Me, R3 = H; 3, 7: R1 = H, R2 = R3 = Ph (treo-);
4, 8: R1 = R2 = H, R3 = Ph; 5, 9: R1 = Ph, R2 = R3 = H
OH
OH
OH
O1
+
Ph
NH
Me
NCHPhCH2OH
Me
4 (80%)
NCH2CHPhOH
Me
1
Me
5 (20%)
N
O
Ph
OH
O
Ph
Ph
2
3
Ti(O-i-Pr)4
OH
OH
Ti
1/2
O1
O
N
-2 i-PrOH
-1/2 Ti(O-i-Pr)4
NCHPhCHPhOH
Me
O
NH
Me
NCH2CPh2OH
Me
Ph
1
3 (treo-)
Me
Ph
7 (treo-, treo-)
Scheme 1.
2
2
6 (6) + 6 H2O
[Ti(μ -O){O-1,2-C6H4}{μ -OCMe2CH2}NMe]6
- 6 (2)
carried out by heating of reactants in the atmosphere of
argon. In the case of isobutylene oxide the reaction pro-
ceeded regiospecifically, only one expected product (2)
formed. Only one diastereomer (3) formed in the reaction
of 1 with cis-stilbene oxide. On the contrary, the reaction
of 1 with styrene oxide resulted in the formation of both
possible not separable products (4 + 5) in ratio 4:5 = 4:1
(according to NMR data). It is known from the literature
that analogous reaction of alkanolamines with styrene
oxide also led to the mixture of two compounds [15,16]
with prevalence of the product formed under substitution
on C3–O bond. That is contrasting to the case of 1 where
the main product (4) formed under substitution on C2–O
bond. To our opinion this fact may be explained by the
more acidity of phenol OH-group in (1) in comparison with
that in alkanolamines.
The reaction of 1 with 2,2-diphenyloxirane failed. In this
case according to NMR data the reaction mixture con-
tained only initial and unidentified compounds even after
prolonged heating. Thus, the structures and yields of prod-
ucts of reaction of 2-methylaminophenol (1) with different
alkene oxides depend on the substituent nature in the oxi-
rane molecule.
10
Scheme 2.
ligands [17] and may be explained by the tendency of the tita-
nium atom to adopt an octahedral geometry at the absence
of the bulk substituent in the ortho-position of aromatic ring.
Furthermore in the ligand 3 the phenolic OH-group is more
acidic than the other, so in the process of synthesis the former
may react with Ti(O-i-Pr)4 more readily with obtaining of the
titano-spiro-bis(ocane).
The obtained complexes 6–9 are very hydrolytically
unstable. We carried out the controlled hydrolysis of 6 with
forming of the polynuclear oxo complex 10 (Scheme 2).
The main idea of such complexes preparation was to pre-
pare more stable species which are also useful as above
mentioned catalysts. Recently, related complex [Ti(l2-O)-
{OCH2CH2}{l2-OCH2CH2}NMe]6 based on N-methyldi-
ethanolamine has been obtained in analogous conditions
[18]. The molecular structure of 10 was investigated by
X-ray analysis. Moreover, the close related tetranuclear
titanatrane obtained from hydrolysis reaction was capable
of polymerizing ethylene [19].
According to the literature, the most suitable approach
to the alkoxy titanium chelate complexes is the transalk-
oxylation reaction of Ti(OAlk)4 with free ligand containing
OH-groups. We have found that Ti(O-i-Pr)4 readily reacted
with two equivalents of corresponding alkanolaminophe-
nols 2–5. Compounds 6–9 were obtained at reflux in tolu-
ene in high yields (Scheme 2).
We also tried to prepare dialkoxytitanocanes
[MeN(CHR1CR2R3O)(C6H4-o-O)]Ti(O-i-Pr)2, but the reac-
tion of the equimolar amounts of 3 and Ti(O-i-Pr)4 led to the
corresponding titano-spiro-bis(ocane) (7) (Scheme 2). Anal-
ogous results were found for related RN(CH2-o-ArOH)2
2.2. Solution structures (NMR spectroscopy data)
Compounds 6–9 which contain in coordination sphere
of Ti atom two tridentate [ONO] ligands form octahedral
monomeric complexes. The circumstantial evidence of the
existence of two coordination Ti–N bonds in complexes
is a shift of signals of NCH3-, NCH2- or NCH-groups to
the weak field in comparison with the corresponding free
ligands 2–5.
Octahedral titanium complexes based on two identical
[ONO] ligands may exist as three geometric isomers (A, B

K.V. Zaitsev et al. / Journal of Organometallic Chemistry 693 (2008) 173–179
175
and C) which differ in mutual positions of N atoms (cis-;
trans-) and ligands (facial, fac-; meridional, mer-) in the
coordination sphere of Ti atom.
N
N
N
O
O
O
O
O
O
Ti
Ti
Ti
O
N
O
O
O
O
O
N
N
cis-, fac-
trans-, fac-
trans-, mer-
A
B
C
Compounds 6–9 are prepared from the ligands contain-
ing three different substituents at N atom. So in 6–9 N
atoms are asymmetric and each of the above mentioned
geometric isomer (A, B and C) may exist as C2- or C1-sym-
metry complexes, where nitrogen atoms have correspond-
ingly the same ((R,R) or (S,S)) or different absolute
configurations ((R,S) or (S,R)).
1H and 13C NMR spectra of 6 contain one set of signals
corresponding to phenolate- and NCH3-groups that indi-
cated the formation of a single geometric isomer (A, B or
C). The methyl groups in the OCMe2 fragment and protons
in the NCH2 group are diastereotopic that accord with
overall C2-symmetry of the complex. Thus it may be
assumed that 7–9 exist as single geometric isomer in solu-
tion, too. At the same time it is evident that 6 is monomeric
in solution, so we may assume that the introduction of the
phenyl substituents to the carbon atoms in 7–9 does not
lead to dimerisation.
The complexes 7–9 were synthesized using the racemic
mixtures of corresponding dialkanolamines. On the basis
of our previous results [13] two ligands in coordination
sphere of titanium are identical and the corresponding asym-
metric carbon atoms have the same absolute configuration.
According to the NMR spectra complexes 7–9 exist in solu-
tion (CDCl3) as a mixture of two diastereomers. We assume
that these diastereomers differ in nitrogen configuration. In
each case the dominant isomer (7a, 8a and 9a) contains
one set of signals that corresponds to C2-symmetry complex.
On the contrary, the minor isomer (7b, 8b and 9b) contains
two sets of signals that corresponds to C1-symmetry com-
plex. It is interesting to note that the ratio 7a/7b, 8a/8b, 9a/
9b exceeds 7:3 and does not change with time.
Fig. 1. Molecular structure of 10; hydrogen atoms and solvated molecules
are omitted for clarity.
central atoms are in a distored octahedral coordination
geometry such as the nitrogen atom and one of Ti–O–Ti–
oxygen, another Ti–O–Ti–oxygen and phenolic oxygen,
and two bridging l2-NCH2CMe2O-groups occupy corre-
spondingly the trans positions.
The titanium atoms form flat slightly distorted hexagon.
In molecule there are six [Ti–O]2 fragments in which the
torsion angle TiOTiO equal to 167.5(2)ꢁ, 170.39(2)ꢁ,
172.02(2)ꢁ. The angle formed by the two O–Ti–O frag-
ments near one titanium atom is equal to 73.2(2)ꢁ,
74.2(2)ꢁ, 75.1(2)ꢁ.
˚
˚
The distance Ti–N in 10 [2.367(5) A, 2.362(6) A,
˚
2.376(6) A] is close to that previously found [2.310(2)–
2.471(2) A] for hexacoordinated titanium complexes,
˚
based on dialkanolamines: titano-spiro-bis(ocanes) [13],
dimeric titanocanes [20] and [Ti(l2-O){OCH2CH2}{l2-
OCH2CH2}NMe]6 [18]. The phenolic ring conjugated with
nitrogen atom does not significantly increase the Ti–N
bond in complex 10 in comparison with that for Kemmitt’s
hexanuclear structure [18]. At the same time distances Ti–
˚
N in 10 are longer than those [2.248(2)–2.308(4) A] in
related phenolic compounds [RN(CH2-o-ArO)2]2Ti
[10,17]. This fact may be explained by trans disposition
of nitrogen atoms in the coordination sphere of titanium
in [RN(CH2-o-ArO)2]2Ti. The shortest Ti–O bond dis-
tances [Ti(1)–O(1) 1.781(5) A, Ti(1)–O(3A) 1.904(4) A]
are observed for oxygen atom of Ti–O–Ti. The Ti–O bond
distances involving the oxygen atom of the phenolic ring
2.3. Solid-state structure (X-ray diffraction data)
The structure of 10 was studied by X-ray diffraction
(Fig. 1). Table 1 lists selected geometrical parameters for
this compound. Compound 10 possesses in the solid state
polynuclear structure which is closely related to that
described earlier for [Ti(l2-O){OCH2CH2}{l2-OCH2CH2}-
NMe]6 [18]. The structure is pseudocentrosymmetric, each
titanium atom tied to two neighbouring metal atoms by
oxygen atoms of Ti–O–Ti bonds and l2-bridging
NCH2CMe2O-groups. In coordination sphere of titanium
the alkanolaminophenol (2) behaves as a tridentate
[ONO]-ligand with a fac-disposition of O, N atoms. So
˚
˚
˚
˚
[1.921(5) A, 1.933(5) A] are close to those previously found
˚
[1.871(5)–1.930(3) A] for related titanium complexes with
chelating phenolic ligands [9,17,21]. At the same time this
distance is somewhat longer than Ti–O bond distances in
hexacoordinated titanium complexes of dialkanolamines
[13] reflecting the greater polarity of this bond in titanium
compounds with phenolic ligands.

176
K.V. Zaitsev et al. / Journal of Organometallic Chemistry 693 (2008) 173–179
Table 1
˚
Selected bond lengths (A) and angles (ꢁ) for 10
Ti(1)–O(1)
Ti(2)–O(2)
Ti(2)–O(1)
Ti(3)–O(3)
Ti(3)–O(2)
Ti(1)–O(3A)
1.787(5)
1.793(5)
1.880(5)
1.805(4)
1.901(4)
1.904(4)
Ti(1)–O(31A)
Ti(1)–O(11)
Ti(2)–O(11)
Ti(3)–O(21)
Ti(3)–O(31)
Ti(2)–O(21)
2.000(4)
2.032(4)
1.994(5)
1.993(5)
2.006(5)
2.028(5)
Ti(1)–O(12)
Ti(2)–O(22)
Ti(3)–O(32)
1.921(5)
1.933(5)
1.921(5)
Ti(1)–Ti(2)
Ti(1)–Ti(3A)
Ti(2)–Ti(3)
Ti(3)–Ti(1A)
2.985(2)
2.993(2)
2.993(2)
2.993(2)
Ti(1)–N(1)
Ti(2)–N(2)
Ti(3)–N(3)
2.367(5)
2.362(6)
2.372(6)
Ti(1)–O(1)–Ti(2)
Ti(1)–O(11)–Ti(2)
109.0(2)
95.7(2)
Ti(2)–Ti(1)–Ti(3A)
Ti(1)–Ti(2)–Ti(3)
Ti(2)–Ti(3)–Ti(1A)
118.24(5)
122.12(5)
119.56(5)
I(31A)–Ti(1)–N(1)
I(11)–Ti(1)–N(1)
I(12)–Ti(1)–N(1)
109.1(2)
75.6(2)
75.8(2)
I(12)–Ti(1)–O(3A)
I(1)–Ti(1)–O(31A)
I(1)–Ti(1)–O(11)
150.0(2)
97.8(2)
77.9(2)
Table 3
Selected bond lengths (A) and angles (ꢁ) for hydrogen bonds in the 10
The five-membered chelating rings N–CH2–CMe2–O–Ti
adopt an ‘‘envelope’’-like conformation, the carbon atom
in the a-positions to the N atom occupy ‘‘flap’’ sites. On
the contrary, chelating ring formed by the o-aminophenolic
group are almost flat and lie in one plane with the phenolic
ring.
˚
D–HÁ Á ÁA
d(D–H)
d(HÁ Á ÁA)
d(DÁ Á ÁA)
DDHA
O(10)–H(2)Á Á ÁO(3)
0.76(8)
0.79(11)
2.11(9)
2.30(11)
2.851(8)
2.882(9)
165(9)
147(11)
O(10)–H(1)Á Á ÁO(2A)
In complex 10 there are very short Ti–Ti distances
between two neighbouring titanium atoms, but it is obvious
that the intermetallic interaction does not exist. The space
disposition of the atoms result in appearance of macrocy-
clic hole, the size of which may be determined by the dis-
˚
Table 2
tances between oxygen atoms [I(1)–I(11A) 5.491(6) A,
˚
˚
Crystal data, data collection and refinement parameters for 10
I(2)–I(21A) 5.400(6) A, I(3)–I(31A) 5.574(6) A]. Two mole-
cules of water present in the crystal and form the hydrogen
bonds with the oxygen atoms of the closest Ti–O–Ti frag-
ment (Table 3).
Compound
10
Empirical formula
C
66H90N6O18Ti6 Æ 2H2O Æ 0.66
CH2Cl2
Formula weight
Colour, habit
Crystal size (mm)
Crystal system
Space group
1634.92
In conclusion, we have synthesized a new type of polyd-
entate [ONO]-ligands which we used for obtaining the tita-
nium complexes. These complexes are hydrolytically
unstable and may easily be converted to polynuclear Ti
compounds.
Yellow, block
0.10 · 0.05 · 0.04
Monoclinic
P 21/n
Unit cell dimensions
˚
a (A)
11.8058(18)
˚
b (A)
16.931(3)
19.713(3)
3. Experimental
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
90
96.439(4)
90
3915.4(10)
2
1.387
0.697
All manipulations were carried out under argon atmo-
sphere using standard Schlenk techniques. Solvents were
dried by standard methods and distilled before use.
Ti(OiPr)4 (Aldrich) was distilled before use. Styrene oxide
(Acros), isobutylene oxide (Acros) were used as supplied.
2-Methylaminophenol 1 [22], cis-stilbene oxide [23], 2,2-
diphenyloxirane [24] were synthesized according to the liter-
ature procedures. CDCl3 was obtained from Deutero
GmbH and dried over CaH2. 1H (400 MHz) and 13C
NMR (100 MHz) spectra were recorded on a Bruker Avance
400 spectrometer (in CDCl3 at 295 K). Chemical shifts in the
1H and 13C NMR spectra are given in ppm relative to inter-
nal Me4Si. Mass spectra (EI-MS) were recorded on a VAR-
IAN CH-7a device using electron impact ionization at
70 eV; all assignments were made with reference to the most
abundant isotopes. Mass spectra (ESI) were recorded in ace-
tonitrile for positive ions. Elemental analyses were carried
out by the Microanalytical Laboratory of the Chemistry
Department of the Moscow State University.
3
˚
Volume (A )
Z
Dcalc (g cmÀ3
Absorption coefficient (mmÀ1
F(000)
Diffractometer
Temperature (K)
Radiation (k, A)
h Range (ꢁ)
Index ranges
)
)
1703
Bruker SMART 1K
120
0.71073
˚
1.59–26.00
À14 6 h 6 5,
À20 6 k 6 20,
À22 6 l 6 23
18377
7381 [Rint = 0.1566]
11837/0/858
0.895
R1 = 0.0837; wR2 = 0.1441
R1 = 0.1929; wR2 = 0.1739
0.537/À0.459
Reflections collected
Independent reflections
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I > 2r(I)]
R indices (all data)
Largest difference peak/hole
À3
˚
(e A
)

K.V. Zaitsev et al. / Journal of Organometallic Chemistry 693 (2008) 173–179
177
3
3.1. Synthesis of substituted ortho-aminophenols
3JHH = 2 Hz, JHH = 10 Hz, 1H, OCH), 3.18–3.10 (m,
1H, NCH(H)), 3.00–2.94 (m, 1H) (NCH(H)), 2.80 (s, 3H,
NCH3). Other proton resonances could not be located
due to the overlap with those for major isomer. 13C
NMR (100.61 MHz, CDCl3, ppm): d = 151.17, 141.69,
139.60, 128.73, 126.73, 125.84, 125.18, 120.75, 119.78,
115.14 (aromatic carbons), 71.73 (OCH), 65.43 (NCH2),
41.45 (NCH3). MS (EI, m/z, %): 213(16) [M+ÀCH2O],
212 (100) [M+ÀCH2OÀH], 136 (37) [M+ÀCH2OÀPh],
122 (12) [M+ÀCH2OÀPhCH2], 93 (2) [PhO+], 91 (27)
[PhCH2+], 77 (18) [Ph+], 65 (18) [C5H5+]. Anal. Calc. for
C15H17NO2 (243.30): C, 74.05; H, 7.04; N, 5.76. Found:
C, 73.78; H, 6.76; N, 5.34%.
3.1.1. Synthesis of MeN(CH2CMe2OH)(C6H4-o-OH) (2)
A mixture of 1 (1.50 g, 12.2 mmol) and isobutylene
oxide (1.06 g, 14.6 mmol) was heated at 80 ꢁC for 26 h in
the Schlenk tube equipped with a J. Young valve. The res-
idue was dried in vacuum to give 2.36 g (100%) of 2 as a
yellowish oil. 1H NMR (400.1 MHz, CDCl3, ppm):
d = 7.09–7.04 (m, 1H), 6.96–6.89 (m, 1H), 6.87–6.83 (m,
1H), 6.79–6.72 (m, 1H) (aromatic hydrogens), 5.27 (br s,
2 H, 2 OH), 2.84 (s, 2H, NCH2), 2.78 (s, 3H, NCH3),
1.17 (s), 1.18 (s) (6H, 2 CH3). 13C NMR (100.61 MHz,
CDCl3, ppm): d = 151.09, 141.68, 125.21, 121.44, 119.79,
115.28 (aromatic carbons), 71.81 (Me2CO), 68.49
(NCH2), 43.51 (NCH3), 27.90 (C(CH3)2). MS (EI, m/z, %):
195 (2) [M+], 162 (6) [M+ÀCH3ÀH2O], 136 (100)
[M+ÀHÀMe2CO], 120 (7) [M+ÀCH3ÀH2OÀC3H5ÀH],
93 (1) [PhO+], 65 (5) [C5H5+]. Anal. Calc. for C11H17NO2
(233.40): C, 67.66; H, 8.78; N, 7.17. Found: C, 67.08; H,
8.16; N, 6.84%.
3.1.4. The reaction of MeN(H)(C6H4-o-OH) (1) with
2,2-diphenyloxirane
A mixture of 1 (1.49 g, 12.1 mmol) and 2,2-diphenyloxi-
rane (2.38 g, 12.1 mmol) was heated at 100 ꢁC for 28 h.
According to NMR spectroscopic data, the mixture of ini-
tial and unidentified compounds was formed.
3.1.2. Synthesis of treo-MeN(CHPhCHPhOH)
(C6H4-o-OH) (3)
3.2. Synthesis of complexes
A mixture of 1 (0.79 g, 6.4 mmol) and cis-stilbene oxide
(1.26 g, 6.4 mmol) was heated at 100 ꢁC for 56 h. The resi-
due was recrystallized from ether/hexane (1:2) mixture to
give 1.12 g (55%) of 3 as a beige solid. 1H NMR
(400.1 MHz, CDCl3, ppm): d = 7.29–7.25 (m, 2H), 7.18–
7.11 (m, 6H), 7.03–6.96 (m, 2H), 6.86–6.83 (m, 2H),
6.70–6.65 (m, 1H), 6.48–6.47 (m, 1H) (aromatic hydro-
3.2.1. Synthesis of [MeN(CH2CMe2O)(C6H4-o-O)]2Ti
(6)
Ti(O-i-Pr)4 (0.95 mL, 3.2 mmol) was added dropwise to
a stirred solution of 1.24 g (6.4 mmol) of 2 in toluene
(20 mL). After 7 h refluxing, the solvent was evaporated
under reduced pressure. The residue was recrystallized
from dichloromethane/heptane (1:1) mixture to give
3
gens), 5.31 (d, JHH = 12 Hz, 1H, OCH), 4.25 (d,
1.15 g (83%) of 6 as a
yellow solid. 1H NMR
3JHH = 12 Hz, 1H, NCH), 3.60 (br s, 2H, 2OH), 2.60 (s,
3H, NCH3). 13C NMR (100.61 MHz, CDCl3, ppm):
d = 151.49, 140.63, 138.47, 133.40, 129.66, 128.35, 128.04,
127.61, 127.53, 127.48, 125.28, 123.53, 119.25, 115.33 (aro-
matic carbons), 73.28 (OCH), 72.70 (NCH), 34.85 (NCH3).
Anal. Calc. for C21H21NO2 (319.40): C, 78.97; H, 6.63; N,
4.39. Found: C, 78.00; H, 6.39; N, 4.12%.
(400.1 MHz, CDCl3, ppm): d = 7.20–7.08 (m, 4H), 6.77–
6.70 (m, 4H) (aromatic hydrogens), 3.85 (d, 2H), 3.32 (d,
2H) (2JHH = 12 Hz, 2NCH2), 2.64 (s, 6H, 2NCH3), 1.27
(s, 6H), 0.83 (s, 6H) (4CH3). 13C NMR (100.61 MHz,
CDCl3, ppm): d = 162.59, 141.27, 138.48, 121.82, 118.44,
116.19 (aromatic carbons), 82.67 (OCMe2), 73.50
(NCH2), 49.51 (NCH3), 30.10, 28.73 (2 CH3). MS (ESI,
m/z): 435.3 [M++1]. Anal. Calc. for C22H30N2O4Ti
(434.35): C, 60.83; H, 6.96; N, 6.45. Found: C, 60.60; H,
6.55; N, 6.24%.
3.1.3. Synthesis of MeN(CHPhCH2OH)(C6H4-o-OH) (4)
and MeN(CH2CHPhOH)(C6H4-o-OH) (5)
A mixture of 1 (4.04 g, 30.0 mmol) and styrene oxide
(3.60 g, 30.0 mmol) was heated at 90 ꢁC for 34 h. The
residue was dried in vacuum to give 7.28 g (100%) of a
mixture of 4 and 5 as a yellowish oil. The approximate
ratio of isomers is 4:5 = 4:1 (according to 1H NMR).
3.2.2. Synthesis of treo-[MeN(CHPhCHPhO)
(C6H4-o-O)]2Ti (7)
A: Ti(O-i-Pr)4 (0.36 mL, 1.2 mmol) was added dropwise
to a stirred solution of 0.72 g (2.4 mmol) of 3 in toluene
(20 mL). After 8 h refluxing, the solvent was evaporated
under reduced pressure. The residue was recrystallized
from dichloromethane/heptane (2:1) mixture to give
1
NMR data for MeN(CHPhCH2OH)(C6H4-o-OH) (4): H
NMR (400.1 MHz, CDCl3, ppm): d = 7.36–7.28 (m, 3H),
7.15–6.98 (m, 4H), 6.86–6.76 (m, 2H) (aromatic hydro-
gens), 5.75 (br s, 2H, 2OH), 4.19–4.14 (m, 1H, OCH(H)),
1
0.64 g (83%) of 7 as a yellow solid. H NMR spectroscopy
3
4.09–4.04 (m, 1H, OCH(H)), 3.80 (dd, JHH = 4 Hz,
of 7 in CDCl3 indicated it is a mixture of two diastereomers
with C2- (7a) and C1-symmetry (7b), approximate ratio is
3JHH = 11 Hz, 1H, NCH), 2.48 (s, 3H, NCH3). 13C NMR
(100.61 MHz, CDCl3, ppm): d = 151.96, 137.99, 136.72,
128.48, 128.32, 127.93, 125.85, 123.37, 119.54, 114.88 (aro-
matic carbons), 69.21 (NCH), 62.59 (OCH2), 37.57
(NCH3). NMR data for MeN(CH2CHPhO)(C6H4-o-O)
(5): 1H NMR (400.1 MHz, CDCl3, ppm): d = 4.86 (dd,
1
7a/7b = 70:30. NMR data for 7a: H NMR (400.1 MHz,
CDCl3, ppm): d = 7.31–6.95 (m, 22H), 6.60–6.53 (m, 2H),
6.45–6.40 (m, 2H), 6.28–6.22 (m, 2H) (aromatic hydro-
3
gens), 6.05 (d, JHH = 11 Hz, 2H, 2OCH), 4.46 (d,
3JHH = 11 Hz, 2H, 2NCH), 3.23 (s, 6H, 2NCH3). 13C

178
K.V. Zaitsev et al. / Journal of Organometallic Chemistry 693 (2008) 173–179
NMR (100.61 MHz, CDCl3, ppm): d = 162.59, 141.59,
139.94, 131.04, 129.03, 128.86, 128.16, 127.84, 126.28,
123.05, 117.78, 115.89 (aromatic carbons), 89.69 (OCH),
80.88 (NCH), 37.33 (NCH3). Two signals of aromatic car-
bons were not found probably due to coalescence of several
4.18–4.12 (m, 2H), 3.89–3.81 (m, 2H) (2NCH2), 2.84 (s,
3H), 2.50 (s, 3H) (2NCH3). Other signals could not be
located due to the overlap with those for major isomer or
due to the low concentration in the sample.
1
signals. NMR data for 7b: H NMR (400.1 MHz, CDCl3,
3.3. Synthesis of [Ti(l2-O){O-o-C6H4}
{l2-OCMe2CH2}NMe]6 (10)
ppm): d = 6.52–6.48 (m, 2H), 6.40–6.33 (m, 2H), 6.20–
3
6.15 (m, 2H) (aromatic hydrogens), 6.13 (d, JHH = 11 Hz,
3
3
1H, OCH), 4.41 (d, JHH = 11 Hz), 4.33 (d, JHH = 14 Hz,
1H) (2NCH), 3.03 (s, 3H), 2.80 (s, 3H) (2NCH3). Other sig-
nals could not be located due to the overlap with those for
major isomer or due to the low concentration in the sam-
ple. Anal. Calc. for C42H38N2O4Ti (682.63): C, 73.90; H,
5.61; N, 4.10. Found: C, 73.06; H, 5.25; N, 3.74%.
A mixture (20 mL) of heptane and moist dichlorometh-
ane (1:2) was added to a saturated solution of 6 (0.2 g) in
dichloromethane. The resulting mixture was storred at
À78 ꢁC over 7 days. The crystalline product precipitated
from solution. X-ray quality crystals were formed on the
side of the flask.
B: Ti(O-i-Pr)4 (0.34 mL, 1.1 mmol) was added dropwise
to a solution of 0.35 g (1.1 mmol) of 3 in toluene (20 mL).
The reaction mixture was stirred for 14 h at room temper-
ature, then the solvent was removed in vacuum. The crude
product was recrystallized from dichloromethane/heptane
(2:1) mixture to give 0.28 g (72%) of 7 as a yellow solid.
3.4. X-ray crystallographic study
Crystal data, data collection, structure solution and
refinement parameters for 10 are listed in Table 2. The
structure was solved by direct methods [25] and refined
by full matrix least-squares on F2 [26] with anisotropic
thermal parameters for all non-hydrogen atoms (except
solvent toluene molecules). Solvent toluene was found to
be disordered over two positions with occupancies ratio
0.69/0.31. All hydrogen atoms of the main metal organic
molecule were found from diff. Fourier synthesis and
refined with isotropic thermal parameters, hydrogen atoms
of solvent toluene molecules were placed in calculated posi-
tions and refined using a riding model.
3.2.3. Synthesis of [MeN(CHPhCH2O)(C6H4-o-O)]2Ti
(8) and [MeN(CH2CHPhO)(C6H4-o-O)]2Ti (9)
Ti(O-i-Pr)4 (1.22 mL, 4.1 mmol) was added dropwise to
a stirred solution of 2.00 g (8.2 mmol) of the mixture of 2-
[(2-hydroxyethyl)]aminophenols
(4 + 5)
in
toluene
(30 mL). After 5 h refluxing, the solvent was evaporated
under reduced pressure. The residue was recrystallized
from toluene/heptane (1:1) mixture to give 1.59 g (73%)
of a mixture of 8 and isomeric 9 as a red solid. The approx-
imate ratio of isomers is 8:9 = 3:1 (according to 1H NMR).
1H NMR spectroscopy in CDCl3 indicated that 8 and 9
exist as a mixture of two diastereomers with C2- (8a, 9a)
and C1-symmetry (8b, 9b); isomers 8a and 9a account for
Acknowledgements
The authors thank Russian Fund of Basic Research
(Grant 06-03-33032-a).
1
more than 80% of the total. NMR data for 8a: H NMR
(400.1 MHz, CDCl3, ppm): d = 7.34–6.84 (m, 18H, aro-
Appendix A. Supplementary material
matic hydrogens), 5.26–5.17 (m, 2H), 4.66 (dd,
3
3
3JHH = 4 Hz, JHH = 11 Hz, 2H), 4.41 (dd, JHH = 7 Hz,
3JHH = 12 Hz, 2H) (2 NCH, 2 OCH2), 2.96 (s, 6H, 2
NCH3). 13C NMR (100.61 MHz, CDCl3, ppm):
d = 161.98, 140.25, 137.74, 130.57, 128.94, 128.13, 125.20,
122.84, 118.03, 116.24 (aromatic carbons), 77.55, 74.41
(NCH, OCH2), 35.22 (NCH3). NMR data for 8b: 1H
NMR (400.1 MHz, CDCl3, ppm): d = 5.58–5.53 (m, 1H),
4.99–4.95 (m, 1H), 4.91–4.86 (m, 1H), 4.53–4.48 (m, 1H)
(2NCH, 2OCH2), 2.71 (s, 3H), 2.38 (s, 3H) (2NCH3). Other
signals could not be located due to the overlap with those
for major isomer or due to the low concentration in the
CCDC 612584 contains the supplementary crystallo-
graphic data for this paper. These data can be obtained
free of charge from The Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif. Supple-
mentary data associated with this article can be found,
in the online version, at doi:10.1016/j.jorganchem.2007.
10.020.
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