Synthesis and structure of sulfonamido cyclopentadiene titanium complexes: X-ray structure of Ti(η5:σ-C5H4CH2CH 2NSO2C6H4CH3)Cl 2

Article abstract of DOI:10.1016/S0022-328X(97)00577-9

The reaction of Ti(NMe₂)₄ with the bidentate ligand C₅H₄CH₂CH₂NHSO₂C ₆H₄CH₃ yields the titanium sulfonamido cyclopentadiene complex Ti(η⁵

Full text of DOI:10.1016/S0022-328X(97)00577-9

Ž
.
Journal of Organometallic Chemistry 553 1998 387–392
Synthesis and structure of sulfonamido cyclopentadiene titanium
complexes: X-ray structure of
Ti h :s-C5H4CH2CH2 NSO2C6 H4CH3 Cl2
5
ž
/
)
Cornelis Lensink
The New Zealand Institute for Industrial Research and DeÕelopment, PO Box 31-310, Lower Hutt, New Zealand
Received 19 July 1997
Abstract
The reaction of Ti NMe2 with the bidentate ligand C5H4CH2CH2NHSO2C6H4CH3 yields the titanium sulfonamido cyclopentadi-
Ž
.
4
5
Ž
.Ž
.
.
ene complex Ti h :s-C5H4CH2CH2NSO2C6H4CH3 NMe2 2. This compound reacts with two equivalents Me3SiCl to give the novel
dichloride complex Ti h :s-C5H4CH2CH2NSO2C6H4CH3 Cl2 whose molecular structure was determined by single crystal X-ray
crystallography. q 1998 Elsevier Science S.A.
5
Ž
Keywords: Titanium; Sulfonamido; Cyclopentadiene; Crystal structure
1. Introduction
typically around 40, it is anticipated that the metal
sulfonamido bond will be less susceptible to aminolysis
or alcoholysis then, for example, amine functionalized
cyclopentadiene complexes.
The synthesis of cyclopentadiene complexes using
the aminolysis reaction of tetradialkylamide metal pre-
cursors is now a well established route. It was first
described for the synthesis of Group 4 metal complexes
The synthesis of metal complexes, in particular of
Group 4 metals, with chelating cyclopentadiene ligands
has received considerable attention. In particular Lewis
base functionalized cyclopentadienes in which the cy-
clopentadiene is bonded via a bridge to a group contain-
w
x
w x
w x
w x
ing an amine 1,2 , ether 3 , amide 4 or alkoxide 5
group.
w x
8 . This route has also been used to prepare cyclopenta-
dienyl-amide complexes of titanium, zirconium and
Recently we described a facile synthesis of ethylsul-
fonamido substituted cyclopentadiene and indene lig-
w
x
hafnium with bidentate ligands 4,9 . It was further
developed for the preparation of ansa-bisindenyl com-
w
x
ands 6,7 . These compounds were obtained using a
simple two step procedure starting from amino alcohols.
Because of the ease of preparation of these compounds
it is possible to synthesize a variety of these ligands and
this was demonstrated by the synthesis of chiral, enan-
tiomerically pure sulfonamide indene ligands.
w
x
plexes of zirconium 10 . This study reports on the
aminolysis reaction of the novel sulfonamido cyclopen-
Ž .
tadiene ligands C5H4CH2CH2 NHSO2C6 H4CH3
and C9 H4CH2CH2 NHSO2C6 H4CH3 2 with Ti NR2
1
Ž .
Ž
.
4
Ž
.
RsMe, Et .
It is our expectation that a bidentate sulfonamido
cyclopentadiene ligand binds strongly with Group 4
metals and forms stable complexes. Given that the pKa
of sulfonamides are typically about 12–15, in the same
range as cyclopentadienes , and the pKa of HNR2 is
Ž
2. Results and discussion
.
Ž
.
The reaction of ligand 1 with Ti NMe2 in benzene
4
or toluene proceeds fast at room temperature and is
completed in only a few minutes to yield compound 3
which could be isolated in 85% yield. The reaction of
)
Corresponding author. Tel.: q64-4-569-0000; fax: q64-4-569-
Ž
.
the same ligand 1 with Ti NEt2 in benzene on the
0142; e-mail: c.lensink@irl.cri.nz.
4
0022-328Xr98r$19.00 q 1998 Elsevier Science S.A. All rights reserved.

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)
388
C. LensinkrJournal of Organometallic Chemistry 553 1998 387–392
other hand proceeds in a step wise fashion. In the first
and fast step the sulfonamido NH reacts with the metal
precursor to eliminate one equivalent diethylamine to
can be clearly identified in the 1H and 13C NMR spectra
by the triplets for the coordinated cyclopentadiene pro-
tons at 5.53 and 5.48 ppm and the carbon signals at
113.3 and 110.8 ppm respectively.
Ž
yield intermediate complex Ti C 5 H 5 CH 2 CH 2
.Ž . Ž .
NSO2C6 H4CH3 NMe2 7 in which the cyclopenta-
Similarly, the reaction of the indene ligand 2 with
3
Ž
.
diene ring has not yet coordinated to the titanium center
Ti NMe2
in benzene also proceeds in a stepwise
4
1
Ž
.
Ž
.
Scheme 1a . The H NMR spectrum of the reaction
fashion Scheme 1b . The first step is the rapid reaction
of the sulfonamido group with the metal precursor with
the liberation of an equivalent of dimethylamine. The
1H NMR spectrum of the mixture immediately after
mixing again clearly shows the disappearance of the
sulfonamido NH, the appearance of dimethylamine and
a small shift in the p-toluene proton signals. The in-
mixture, recorded immediately after mixing, clearly
shows the disappearance of the NH signal and the
appearance of signals which can be attributed to dieth-
ylamine. The signals for the cyclopentadiene protons
remain unchanged. At this stage of the reaction there is
no NMR evidence for the coordination of the cyclopen-
tadiene ring to the metal center. Heating the reaction
Ž
.
denyl signal at 5.84 ppm CH remains virtually un-
changed. In order for this reaction to reach completion
it is necessary to reflux the reaction mixture in toluene
for several days. Compound 6 was formed exclusively
Ž
.
mixture to reflux or better, in refluxing toluene over a
period of several days with a slow, continuous purge of
nitrogen over the top of the reflux condenser in order to
drive of the liberated amine, drives the reaction to
completion with the formation of compound 5 which
and shows the characteristic H and 13C signals for a
1
Ž
.
coordinated indene at 6.19 and 5.94 ppm doublets and
Scheme 1.

(
)
C. LensinkrJournal of Organometallic Chemistry 553 1998 387–392
389
5
Ž
.
117.9 and 99.6 ppm respectively. The lower reactivity
compound Ti h :s-C5H4CH2CH2 NSO2C6 H4CH3 Cl2
Ž
.
Ž .
of ligand 2 towards Ti NMe2 reflects the higher pKa
4 precipitated from the reaction mixture overnight as a
4
of indene when compared with cyclopentadiene and it is
not uncommon that the amine elimination reactions with
indenyl compounds require more forcing condition than
cyclopentadiene.
yellow solid and was isolated in 50% yield. The same
compound was also prepared in 87% in one pot synthe-
sis.
Yellow crystals of 4 suitable for a X-ray crystallo-
graphic structure determination were obtained from
CDCl3. Fig. 1 shows the structure of compound 4 with
selected bond lengths and angles.
Compound 4 is a monomeric complex. The geometry
about the central titanium atom is a slightly deformed
tetrahedron with equal angles Cg–Ti–Cl1 and Cg–Ti–
Cl2 of 111.08 and 110.68 respectively and a smaller
The indene ligand 2 exhibits planar chirality and as a
result complex 6 is chiral. This manifests itself in the
1H and 13C NMR spectra. For example, two signals are
1
observe in the H NMR spectrum for the two dimeth-
ylamide groups at 3.45 and 2.48 ppm and two signals at
51.8 and 46.9 ppm in the 13C NMR. Also, the proton
signals for the ethylene bridge show a ABCD pattern as
expected.
The bis amide complexes 3, 5, and 6 were all
obtained as extremely air sensitive dark orange pow-
ders. Purification of these compounds can be accom-
plished by careful washing with a minimum amount of
pentane to yield analytically pure compounds. The com-
pounds are extremely soluble in aromatic solvents but
only sparingly soluble in pentane or hexane.
Ž
angle Cg–Ti–N of 101.08 Cg is the center of gravity of
.
the cyclopentadiene carbon atoms . The bond C9–C10
bends out of the plane of the cyclopentadiene ring,
towards the titanium atom, by about 6.88. The nitrogen
atom has a trigonal planar geometry and although the
angles are not equal, the sum of the angles is 358.58.
The atoms Ti, N, S, O2 and C10 are all within one
plane with the largest deviation of the mean plane of
˚
In a preliminary investigation in the chemical proper-
ties of the novel compounds 3 was reacted, in toluene,
0.049 A for S. This plane is oriented almost perpendicu-
lar to the plane of the cyclopentadiene ring at an angle
of 85.78.
Ž
.
with two equivalents of Me3SiCl Scheme 1c . The
5
Ž
.
Fig. 1. View of the molecular structure of Ti h :s-C5H4CH2CH2 NSO2C6 H4CH3 Cl2 , 4, with the non-hydrogen atom labeling scheme. The
˚
w
x
Ž .
Ž . Ž .
Ž .
Ž .
Ž .
thermal ellipsoids are scaled to 30% probability 11 . Selected bond lengths
A
Ž .
and angles 8 : Ti–N 1.963 2 , Ti–Cl 1 2.266 1 , Ti–Cl 2
Ž . Ž . Ž . Ž . Ž . Ž .
Ž . Ž . Ž . Ž . Ž .
2.289 1 , Ti–Cg 2.024 3 , Ti–O 2 2.556 2 , Ti–S 2.914 1 , S–O 1 1.432 2 , S–O 2 1.454 2 , S–N 1.619 2 , N–Ti–Cl 1 112.35 7 ,
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž
.
Ž .
N–Ti–Cl 2 112.27 7 , Cg–Ti–N 101.04, Cl 1 –Ti–Cl 2 109.37 3 , O 1 –S–O 2 118.4 13 , O 1 –S–N 111.63 13 , O 2 –S–N 100.73 12 ,
Ž . Ž .
Ž
.
Ž
.
Ž .
C 8 –N–S 118.65 18 , C 8 –N–Ti 131.46 18 , S–N–Ti 108.40 12 .

(
)
390
C. LensinkrJournal of Organometallic Chemistry 553 1998 387–392
˚
.
Ž
.
The distance Cp–Ti of 2.024 A is only slightly
mmol in toluene 3 ml at room temperature. The
reaction mixture was stirred at room temperature for 2
h. The solvent was subsequently removed under re-
duced pressure. The crude product was washed once
i
Ž
.
shorter than the distance found in e.g., CpTi N Pr2 2Cl2
˚
˚
. w
Ž
.
.
w
x
Ž
x
2.035 A 12 , CpTiCl3 2.04 A 13 and Cp2TiCl2
˚
˚
Ž
w x
2.059 A 14 . The Ti–N distance of 1.963 A is
˚
A
Ž
.
approximately 0.1
C p T i N P r 2 2 C l 2
longer than in e.g.,
with pentane 5 ml and dried in vacuo. An orange solid
was isolated in a yield of 0.84 g, 1.68 mmol, 85% .
Anal. Calc. for C18 H27 N3O2 STi: C, 54.4; H, 6.8; N,
10.6. Found: C, 54.1; H, 6.8; N, 9.4. H NMR be-
i
˚
A
Ž
.
Ž
.
w
x
Ž
.
1 .8 6 5
1 2
o r
C5H4CH2CH2 Ni PrTiCl2 1.864 A . This is a possi-
1
˚
Ž
.
1
Ž
.
Ž
.
Ž
ble indication that a N pp ™M dp bonding contribu-
tion is not as prominent as is the case for other titanium
amide complexes. The close proximity of O2 to Ti,
which could be interpreted as a bonding interaction of
an oxygen lone pair towards Ti, may influence and
3
.
Ž
.
nzene-d6 d 7.73 d, 2H, JH – H s8.2 Hz, C6 H4 , 6.67
3
3
Ž
.
Ž
d, 2H, JH – H s8.2 Hz, C6 H4 , 5.53 t, 2H, JH – H s2.6
3
.
Ž
.
Hz, C53H4 , 5.48 t, 2H, JH – H s2.6 Hz, C5H4 , 3.45
Ž
.
Ž
.
t, 2H, JH – H s6.4 Hz, N–CH2 , 3.06 s, 12H, NCH3 ,
3
Ž
.
Ž
.
˚
Ž
.
Ž
diminish the N pp ™M dp bonding interaction. The
1.98 t, 2H, JH – H s6.4 Hz, CH2–C–N , 1.85 s, 3H,
13
.
Ž
.
Ž
.
long Ti–N distance of 1.965 A is more an indication of
CH3 . C NMR benzene-d6 d 141.9 C6 H4 para ,
Ž
.
Ž
.
Ž
Ž
a Ti–N single bond which has been estimated to be
1.96–1.97 A 15–17 . The two Ti–Cl bond distances
differ by about 0.02 1 A and are typical Ti–Cl dis-
tances for titanium amide complexes but are signifi-
140.7 C6 H4 ipso , 136.9 C5H4 ipso , 129.1 CH of
˚
w
x
.
Ž
.
.
C6 H4 , 127.6 CH of C6 H4 , 113.3 CH of C5H4 ,
˚
Ž .
Ž
.
Ž
.
Ž
.
110.8 CH of C5H4 , 59.7 NCH2 , 48.7 NCH3 , 29.1
Ž
.
Ž
.
CH2–C–N , 21.1 CH3 .
˚
. w x
Ž
cantly shorter than in e.g., Cp2TiCl2 2.36 A 14 and
˚
. w x
Ž
. Ž
.
Ž
CH2 C5H4 2TiCl2 2.35 A 18 . The Ti–O2 dis-
5
2
(
3.2. Synthesis of Ti h :s -C 5 H 4 C H 2 C H 2
( )
˚
tance of 2.556 A is smaller than the sum of the van der
Waals radii and this distance and the overall geometry
of the complex suggests a bonding interaction between
Ti and O2. The S–O1 distance is slightly smaller than
)
NSO2C6 H4CH3 Cl2
4
Ž
.
To a solution of compound 3 0.23 g, 0.58 mmol in
benzene 4 ml was added a solution of Me3SiCl 0.13
g, 1.20 mmol in benzene 2 ml . The reaction mixture
was stirred overnight at room temperature. The volume
was reduced to 50% under reduced pressure. Pentane
10 ml was added to the reaction mixture and a yellow
solid was isolated via filtration. The crude product was
washed with a small amount of pentane and dried under
vacuo to yield 0.11 g 0.29 mmol, 50% of compound 2
as a yellow solid. Anal. Calc. for C14 H15Cl2 NO2 STi:
C, 44.2; H, 4.0; N, 3.7. Found: C, 44.5; H, 4.3; N, 3.5.
Ž
.
Ž
˚
the S–O2 distance by 0.02 A. The molecular geometry
.
Ž
.
of 4 in the solid state is chiral and this renders the two
H atoms on C8 inequivalent as well as the two H atoms
on C9. In solution, however, the 1H NMR spectrum of 4
at room temperature shows a A2 X2 pattern of two
triplets for these protons indicating a dynamic system
where O2 and O1 are exchanging coordination to the
titanium.
Ž
.
Ž
.
1
3
Ž
.
Ž
H NMR CDCl3 d 7.87 d, 2H, JH – H s8.2 Hz,
3. Experimental
3
.
Ž
.
Ž
C6 H4 , 7.24 d, 2H, JH – H s8.2 Hz, C6 H4 , 6.94 t,
3
3
.
Ž
2H, JH – H s2.6 Hz, C5H4 , 6.39 t, 2H, JH – H s2.6
All manipulations were carried out under an inert
atmosphere of nitrogen or argon or were carried out
3
.
Ž
.
Hz, C5H4 , 4.21 t, 2H, JH – H s7.0 Hz, N–CH2 , 3.01
t, 2H, JH – H s7.0 CH2–C–N , 2.36 s, 3H, CH3 . 13C
3
Ž
.
Ž
.
Ž
.
inside a glovebox Innovative Technology . Solvents
were dried using conventional methods. NMR spectra
were recorded on a AC300 Bruker spectrometer. Ele-
mental analysis were performed by Campbell Analytical
Laboratory, University of Otago, Dunedin, New
Ž
.
Ž
.
Ž
NMR benzene-d6 d 148.7 C6 H4 para , 144.9 C6 H4
.
Ž
.
Ž
Ž
.
ipso , 134.4 C5H4 ipso , 129.8 CH of C6 H4 , 128.2
Ž
.
.
Ž
CH of C6 H4 , 121.9 CH of C5H4 , 119.4 CH of
.
Ž
.
Ž
.
Ž
.
C5H4 , 64.3 NCH2 , 28.3 CH2–C–N , 21.6 CH3 .
Ž
.
Ž
.
Zealand. Ti NMe2 and Ti NEt2 were prepared ac-
4
4
5
(
3.3. One pot synthesis of Ti h :s-C5 H4 CH2CH2
NSO2C6 H4CH3 Cl2
w
x
cording to a literature method 19 .
)
( )
4
5
(
3.1. Synthesis of Ti h :s -C 5 H 4 C H 2 C H 2
)(
NSO2C6 H4CH3 NMe2
) ( )
3
2
Ž
.
Ž
.
0.925 g, 4.1 mmol was dissolved in
Ti NMe2
4
Ž
Ž
.
Ž
.
toluene 5 ml . A solution of 1 1.087 g, 4.1 mmol in
Ž .
A solution of C5H4CH2CH2 N H SO2C6 H4CH3
0.52 g, 2.0 mmol dissolved in toluene 3 ml was
added dropwise to a solution of Ti NMe2 0.44 g, 2.0
.
toluene 5 ml was added and the reaction mixture was
stirred at room temperature overnight. The solvent was
removed in vacuo. The resulting dark orange oil was
redissolved in toluene 5 ml . To this solution was
added a solution of Me3SiCl 0.897 g, 8.3 mmol in
Ž
.
Ž
.
Ž
. Ž
4
Ž
.
Ž
.
Ž
.
toluene 5 ml . The reaction mixture was stirred
overnight. The yellow precipitate was isolated via filtra-
1 J.H. Teuben, P.-J. Sinnema, personal communication.

(
)
C. LensinkrJournal of Organometallic Chemistry 553 1998 387–392
391
Ž
.
tion and dried in vacuo. Yield 1.365 g 3.6 mmol, 87%
of 4.
4. X-ray structure determination of 4
Suitable crystals of compound 4 were obtained by
5
Ž
(
crystallization form CDCl3. A yellow crystal 0.35=
3.4. Synthesis of Ti h :s -C 5 H 4 C H 2 C H 2
0.30=0.20 mm3 was selected. Data were collected at
.
)(
NSO2C6 H4CH3 NEt2
) ( )
5
2
room temperature. The unit cell dimensions and inten-
sity data were obtained using a Siemens CCD detector
mounted on a P4 diffractometer and controlled by
SMART software. The data collection nominally cov-
ered over a hemisphere of reciprocal space, by a combi-
nation of two sets of exposures. In the first, each
exposure covered 0.38 for a total of 528 in omega. The
Ž
. Ž
.
0.42 g, 1.25 mmol in
To a solution of Ti NEt2
4
Ž
Ž
.
.
benzene 5 ml was added 1 0.32 g, 1.25 mmol . The
mixture was heated to reflux for 3 days. The solvent
was removed under reduced pressure to yield 5 as a
1
13
dark orange oil. The H and
NMR indicate a near
1
Ž
.
quantitative conversion. H NMR benzene-d6 3 d 7.78
3
Ž
Ž
.
Ž
second run covered 360 degrees in phi the mounting
d, 2H, JH – H s8.1 Hz, C6 H4 , 6.84 d, 2H, JH – H
s
3
.
.
Ž
.
axis also using 0.38 increments between frames. The
7.9 Hz, C6 H43 , 5.77 t, 2H, JH – H s2.6 Hz, C5H4 ,
Ž
.
Ž
Ž
crystal to detector distance was 4.0 cm. All frames were
processed using program SAINT to give raw data sets
which were corrected empirically for absorption using
5.59 t, 2H, JH – H s2.6 Hz, C5H4 , 3.91 m, 1H,
.
Ž
.
N–CHa , 3.40 m, 1H N–CHb , 3.33 m, 1H, CHa–C–
3
.
Ž
.
Ž
N , 1.98 m, 1H, CHb–C–N , 2.38 q, 4H, JH – H s3.4
3
w
x
Ž
..
Ž
SADABS cf. Blessing, Acta Cryst., A51, 1995, 33 .
Hz, N–CH2 ethyl , 2.36 q, 4H, JH – H s3.4 Hz, N–
3
˚
Ž
.
Ž
..
..
Ž
Graphite monochromator, l MoK a s0.71073 A. Tri-
CH2 ethyl , 0.95 t, 6H, JH – H s3.4 Hz, N–C–
3
˚
Ž .
clinic system, space group P-1, as7.434 1 A, bs
Ž
Ž
CH3 ethyl , 0.94 t, 6H, JH – H s3.4 Hz, N–C–
13
˚
˚
Ž .
Ž .
Ž .
Ž .
Ž .
Ž
.. .
Ž
.
Ž
.
7.476 1 A, cs15.174 1 A, as100.25 1 8, bs
CH3 ethyl , 1.95 s, CH3 . C NMR benzene-d6 d
3
˚
.
Ž
Ž
.
Ž
Ž
99.12 1 8, gs103.72 1 8. Vs788.15 11 A , dcalc
s
142.4, 140.6 C6 H4 , 136.5 C5H4 ipso , 129.1 CH of
C6 H4 , 127.7 CH of C6 H4 , 113.1 CH of C5H4 ,
1.602 Mg my3, Zs2, absorption coefficients1.016
.
Ž
.
Ž
.
mmy1, F 000 s388. Of the 2942 reflections collected
Ž
.
Ž
Ž
.
Ž
.
.
109.5 CH of C5H4 , 59.4 NCH2 , 47.6, 44.3
Ž
.
Ž
..
Ž
Ž
.
2105 were unique Rint s0.0160 . The structure was
NCH2 ethyl , 29.3 CH2–C–N , 21.2 CH3 , 15.8,
..
Ž
Ž
Ž
solved by direct methods using SHELXS-96 Sheldrick,
15.2 N–C–CH3 ethyl .
.
1990 . All non-hydrogen atoms were refined with
5
(
anisotropic displacement parameters. Hydrogen atoms
were located from difference Fourier maps and included
in the final refinement with fixed isotropic thermal
3.5. Synthesis of Ti h :s -C 9 H 6 C H 2 C H 2
)( ) ( )
NSO2C6 H4CH3 NMe2
6
2
Ž .
Ž
. Ž
.
0.68 g, 3.0 mmol in
paramenters related to their parent atoms U H s1.2
To a solution of Ti NMe2
4
Ž .
Ž .
Ž
.
Ž
.
U C and U H s1.5 U C–Me for H7abc. Final
b e n z e n e
5
m l
w a s
Ž
a d d e d
eq
eq
Ž .
.
refinement was done by full-matrix least-squares refine-
C9 H7CH2CH2 N H SO2C6 H4CH3 0.94 g, 3.0 mmol
Ž
.
ment using SHELXL-96 Sheldrick, 1996 . Final R
as a solid in small portions over a period of 30 min. The
reaction mixture was refluxed for two days with a slow
stream of argon blowing over the top of the reflux
condenser to remove liberated dimethylamine. The sol-
vent was removed under reduced pressure. The crude
product was subsequently washed with a small amount
of pentane to yield compound 3 1.13 g, 2.52 mmol,
84% as a dark orange solid. An analytically pure
sample could be obtained by precipitation of a toluene
solution with pentane. Anal. Calc. for C22 H29 N3O2 STi:
C, 59.1; H, 6.5; N, 9.4. Found: C, 59.2; H, 6.7; N, 9.0.
w
Ž .
x
indices I)2s I R1 s0.0329, wR2 s0.0895. R in-
Ž
.
dices all data R1 s0.0367, wR2 s0.0920. Tables of
atomic coordinates, thermal parameters, and bond
lengths and angles have been deposited at the Cam-
bridge Crystallographic Data Centre.
Ž
.
Acknowledgements
The work presented in this paper was funded by the
New Zealand Foundation for Research Science and
Technology under contract no. CO8403. The help of Dr.
Ward Robinson, The University of Canterbury,
Christchurch, New Zealand and Dr Graeme Gainsford,
Industrial Reseach Limited with obtaining the crystal
structure of compound 4 is appreciated.
1
3
Ž
.
Ž
H NMR benzene-d6 d 7.85 d, 2H, JH – H s8.0 Hz,
3
.
Ž
.
.
Ž
C6 H4 , 7.27 d, 1H, JH – H s7.3 Hz , 7.20 d, 1H,
3
3
Ž
.
JH – H s7 Hz , 6.93 d, 2H, JH – H s8.0 Hz, C6 H4 ,
3
Ž
.
Ž
.
6.81 m, 2H , 6.19 d, 1H, JH – H s3.1 Hz, indenyl-C5 ,
3
Ž
.
Ž
5.94 d, 2H, JH – H s3.1 Hz, indenyl-C5 , 4.37 m, 1H,
.
Ž
.
Ž
.
NCH , 3.90 m, 1H, NCH , 3.45 s, 6H, NCH3 , 2.71
Ž
.
Ž
.
Ž
m, 1H, CH–C–N , 2.48 s, 6H, NCH3 , 2.33 m, 1H,
CH–C–N , 2.02 s, 3H, CH3 . C NMR benzene-d6
not all aromatic signals observed, d 129.1, 125.2, 124.8,
124.7, 122.1, 117.9 indenyl-C5 CH , 99.6 indenyl-C5
CH , 60.9 N–CH2 , 51.8 NCH3 , 46.9 NCH3 , 27.6
13
.
Ž
.
Ž
.
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