1H,89Y HMQC and further NMR spectroscopic and X-ray diffraction investigations on yttrium-containing complexes exhibiting various nuclearities

Article abstract of DOI:10.1002/chem.201102636

2D ¹H,⁸⁹Y heteronuclear shift correlation through scalar coupling has been applied to the chemical-shift determination of a set of yttrium complexes with various nuclearities. This method allowed the determination of ⁸⁹Y NMR data in a short period of time. Multinuclear NMR spectroscopy as function of temperature, PGSE NMR-diffusion experiments, heteronuclear NOE measurements, and X-ray crystallography were applied to determine the structures of [Y₅(OH)₅(L-Val) ₄(Ph₂acac)₆] (1) (Ph₂acac= dibenzoylmethanide, L-Val=L-valine), [Y(2)(OTf)₃] (3), and [Y ₂(4)(OTf)₅] (5) (2: [(S)P{N(Me)N=C(H)Py}₃], 4: [B{N(Me)N=C(H)Py}₄]^-) in solution and in the solid state. The structures found in the solid state are retained in solution, where averaged structures were observed. NMR diffusion measurements helped us to understand the nuclearity of compounds 3 and 5 in solution. ¹H,¹⁹F HOESY and ¹⁹F,¹⁹F EXSY data revealed that the anions are specifically located in particular regions of space, which nicely correlated with the geometries found in the X-ray structures.

Full text of DOI:10.1002/chem.201102636

FULL PAPER
DOI: 10.1002/chem.201102636
1
89
H, Y HMQC and Further NMR Spectroscopic and X-ray Diffraction
Investigations on Yttrium-Containing Complexes Exhibiting Various
Nuclearities
[
a]
[b]
[a]
Matthias W. Lçble, Marꢀa Casimiro, Dominique T. Thielemann,
[
a]
[b]
[a]
[a]
Pascual OÇa-Burgos, Ignacio Fernꢁndez,* Peter W. Roesky,* and Frank Breher*
Dedicated to Professor Dieter Fenske on the occasion of his 70th birthday
1
89
Abstract: 2D H, Y heteronuclear
shift correlation through scalar cou-
pling has been applied to the chemical-
shift determination of a set of yttrium
complexes with various nuclearities.
This method allowed the determination
mine the structures of [Y (OH)
Val) ACHTUGNTRENN(NUG Ph acac) ] (1) (Ph acac=diben-
4 2 6 2
ACHTUNGTRENNUNG( l-
5
found in the solid state are retained in
solution, where averaged structures
were observed. NMR diffusion meas-
urements helped us to understand the
nuclearity of compounds 3 and 5 in so-
5
zoylmethanide, l-Val=l-valine), [Y(2)-
(OTf) ] (3), and [Y (4)(OTf) ] (5) (2:
A
H
U
G
R
N
U
G
ACHTUNGTRENNUNG
3
2
5
[(S)P{N(Me)N=C(H)Py} ],
4:
3
ꢀ
1
19
[B{N(Me)N=C(H)Py} ] ) in solution
lution.
H, F HOESY
and
4
89
19 19
of Y NMR data in a short period of
time. Multinuclear NMR spectroscopy
as function of temperature, PGSE
NMR-diffusion experiments, heteronu-
clear NOE measurements, and X-ray
crystallography were applied to deter-
and in the solid state. The structures
F, F EXSY data revealed that the
anions are specifically located in partic-
ular regions of space, which nicely cor-
related with the geometries found in
the X-ray structures.
Keywords: cluster compounds · li-
gand effects · NMR spectroscopy ·
X-ray diffraction · yttrium
Introduction
paramagnetic lanthanides owing to their similar ionic radii
and chemical behavior.
As a monoisotopic species with spin I=1/2, the Y nu-
89
Rare-earth-metal complexes and/or clusters have attracted
considerable interest in recent years owing to their utility as
highly active catalysts for a variety of processes
useful compounds in several biological and medical applica-
cleus is attractive for NMR studies. The chemical-shift range
[1–7]
89
and as
of Y spans about 1300 ppm, and therefore it is quite sensi-
tive to small changes in the coordination sphere of the
[8–10]
[14,15]
C
tions.
Rare-earth-metal cations are paramagnetic for all
metal center.
However, the rather low receptivity (D =
1
13
[14–17]
89
configurations from 4f to 4f , and therefore many research-
ers have chosen to investigate the chemistry of the diamag-
0.7) and the long T relaxation times
of Y make con-
ventional pulse-acquisition Y NMR measurements very
1
8
9
3+
3+
3+
[15,18]
netic cations Sc , Y , and La , as they do not possess any
time-consuming,
thus they are still far away from being
2+
3+
4
f electrons. To a lesser extent, Yb and Lu , which exhibit
used in routine experiments. Valuable coupling information
a completely filled 4f shell, have also been investigated.
From an NMR spectroscopic point of view, all five nuclei
has mainly been extracted from 1D spectra of nuclei to
8
9
1
89 [19–24] 13
which Y is scalarly coupled, that is, Hꢀ Y,
Cꢀ
[11–14]
89
89
[20,24]
[29,30]
15
89 [25]
29
89
[26]
31
89
[26–29]
77
have been directly observed.
ing these diamagnetic ions—such as Y —can be used to
model the structures and reactivities of related complexes of
Metal complexes contain-
Y,
Y.
Nꢀ Y,
Siꢀ Y,
Pꢀ Y,
and
Seꢀ
3+
The alternative procedures proposed for acquiring
8
9
Y NMR data under more-convenient conditions include:
) increasing the amount of substance, 2) using NMR tubes
1
[14,17,30]
with larger diameters (10–25 mm),
3) the addition of
[28,31,32]
[
a] Dr. M. W. Lçble, Dr. D. T. Thielemann, Dr. P. OÇa-Burgos,
Prof. Dr. P. W. Roesky, Prof. Dr. F. Breher
Institute of Inorganic Chemistry
paramagnetic reagents,
4) the application of polariza-
tion-transfer techniques through the nuclear Overhauser
[
17]
[33]
[34]
effect (g<0, negative NOE), INEPT, or DEPT, and
Karlsruhe Institute of Technology (KIT)
Engesserstrasse 15, 76131 Karlsruhe (Germany)
E-mail: roesky@kit.edu
8
9
[35–37]
5) creating hyperpolarized Y complexes.
In case the
yttrium cation shows couplings to any protons located in
close spatial proximity or at the periphery of the molecule,
the alternatives are HMQC or HSQC sequences, which
have previously been applied by Anwander and co-work-
breher@kit.edu
[
b] M. Casimiro, Prof. Dr. I. Fernꢀndez
Laboratory of Organic Chemistry, University of Almerꢁa
Carretera de Sacramento s/n 04120 Almerꢁa (Spain)
E-mail: ifernan@ual.es
[
38–40]
ers.
Very recently, some of us have reported the indirect
3
1
89
P detection of Y in the product of the reaction of yttrium
nitrate with triphenylphosphine oxide in THF, and in the
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201102636.
[41]
Chem. Eur. J. 2012, 18, 5325 – 5334
ꢂ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
5325

characterization of 1:1 and 2:1 complexes that were formed
between yttrium nitrate and a new class of tridentate ligand
that contained two diphenylphosphinic amide side-arms con-
faces, three metal atoms are linked by one m -O atom each.
3
All these linking oxygen atoms represent fragments of the
hydroxy bridges, which stabilize the pyramidal shape from
inside. The amino acids, which were deprotonated under
basic conditions at the carboxy group, coordinate through
the nitrogen atom of the amino group and through one
oxygen atom of the carboxy group in a chelating fashion to
[42]
nected through a phenylphosphine oxide moiety.
1
Herein, we report the application of indirect H detection
89
of Y by using 2D HMQC sequences with gradients for co-
8
9
herence selection, thus allowing rapid access to Y NMR
data on a set of yttrium-containing compounds. Moreover,
[43]
one basal metal atom each.
In addition, this carboxy
1
19
1
19
the use of H, F PGSE NMR diffusion and H, F heteronu-
clear NOE experiments provided additional information on
how cationic complexes interact with their counteranions in
solution. These results were compared with those obtained
from X-ray diffraction analysis. We studied three com-
pounds that had different numbers of yttrium cations to
show the scope of the methods used.
oxygen atom also bridges the chelated basal metal atom
with an adjacent metal atom.
Regarding the mono- and dinuclear yttrium complexes,
[44]
we focused on multifunctional,
chemically robust, and
readily accessible N-donor ligands to provide stoichiometri-
cally well-defined 1:1 and 1:2 coordination compounds with
yttrium.
Ligand [(S)P{N(Me)N=C(H)Py} ] (2) was prepared in
3
a two-step synthesis starting from phosphorylsulfide and N-
Results and Discussion
methylhydrazine according to a modified literature proce-
[45–47]
dure.
In the first step, both compounds were reacted at
Syntheses of the metal complexes: To obtain compounds
with various numbers of yttrium cations, we synthesized
mono- and dinuclear complexes, as well as a pentanuclear
cluster. We recently reported the synthesis of the pentanu-
08C in dry CHCl to afford tris(methylhydrazido)phosphor-
3
ylsulfide, followed by condensation with 2-picolinealdehyde
in MeOH in the presence of magnesium sulfate to form the
product in good yield (80%). The molecular structure of
compound 2 (see the Supporting Information, Figure S1)
clear hydroxy cluster [Y (OH) ACTHUNGTERNNGNU( l-Val) CAHTUNGTENRUNN(G Ph acac) ] (1), which
5 4 2 6
5
features the simultaneous ligation of both an a-amino acid
confirmed the expected atomic framework.
[43]
ꢀ
and a b-diketonate ligand.
from the reaction of yttrium trichloride hexahydrate [YCl3-
(H O) ] with dibenzoylmethane (Ph acacH), l-valine (l-
Compound 1 was obtained
The mononuclear complex [Y(2)
A
H
U
G
R
N
U
G
3
ꢀ
CF SO ) was obtained from the reaction of ligand 2 with
3
3
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
yttrium triflate, Y ACHTUNGERTNNUGN( OTf) , in THF (Scheme 2). The product
2
6
2
3
ValH), and a base (Scheme 1). The structure of compound
was insoluble in THF and precipitated only a few minutes
after adding a solution of the ligand to a suspension of the
metal precursor in THF. Thus, the solid was easily isolated
by filtration. Re-crystallization of the crude product from
MeCN/Et O afforded single crystals of compound 3 that
2
were suitable for X-ray analysis (see below).
Scheme 1. a) Synthesis of compound 1; b) schematic representation of the
solid-state structure of compound 1, which shows the heavy-atom scaffold
and the principal coordination of the ligands.
1
1
was established by X-ray diffraction and by routine H
13
[43]
and C NMR measurements, as well as by PGSE studies.
PGSE studies showed that compound 1 retains its pentanu-
clear structure when dissolved in CDCl . The Y core of
3
5
compound 1 displays a square-based pyramidal arrange-
ment, that is, the metal atoms occupy the vertices of
a square pyramid. In the square base, four yttrium atoms
Scheme 2. Synthesis of [(S)P{N(Me)N=C(H)Py}] (2) and the mononu-
are linked by one m -O atom, whereas in the four triangular
3
clear complex [Y(2) ACHUTNGTNERNU(G OTf) ] (3).
4
5326
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ꢂ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2012, 18, 5325 – 5334

Yttrium-Containing Complexes with Various Nuclearities
FULL PAPER
To obtain a dinuclear complex, we needed to develop
a ligand that is capable of linking several metal centers. The
vealed an ABCX spin system for the l-valine moiety, in
which each of the amino protons showed significantly differ-
1
13
protonated precursor of the boron-containing ligand
ent chemical shifts (Figure 1). Second, 2D H, C gHMQC
spectra showed no scalar interactions for any of the signals
ꢀ
[
B{N(Me)N=C(H)Py}4] (4) was synthesized according to
[48]
a modified literature procedure. H[B{N(Me)N=C(H)Py}4]
H-4) was obtained by heating four equivalents of 2-(2-
at d =1.68 and 5.15 ppm.
H
(
The two NH resonances were unambiguously correlated
2
8
9
methylhydrazono)methylpyridine to reflux in toluene for
several hours with one equivalent of tris(dimethylamido)-
borane. Subsequent washing with n-hexane and MeCN af-
forded a yellow crude solid, which turned out to be a mixture
of the hydrazone and ligand H-4 in a 1:2.4 ratio (Scheme 3).
Without further purification, the mixture was reacted in hot
to the
Y
NMR resonance at dY =141.5 ppm by
1
89
H, Y gHMQC NMR experiments (Figure 2). When the
preparation delay was optimized for coupling constants
below 7 Hz, we observed interactions between the two dif-
ferent Ph acac methine protons (at d =6.22 and 6.44 ppm)
2
H
and the two magnetically different yttrium nuclei, one of
which belongs to the aforementioned yttrium resonance at
toluene with two equivalents (relative to H-4) of Y
ACHTUNGTNRENUNG( OTf) in
3
THF to afford the dinuclear complex [Y (4)(OTf) ] (5). This
AHCTUNGTRENNUNG
2
5
latter compound was purified by re-crystallization from an
MeCN solution that was layered with Et O.
2
NMR investigations and solid-state structures: To confirm
1
89
the general applicability of the H, Y gHMQC NMR se-
quence for all three compounds, we first used compound
1
to perform some experiments in addition to the previously
[43]
reported PGSE studies.
1
In the H NMR spectrum of compound 1, a few diagnostic
signals were observed for the Ph acac ligands in the aromat-
2
ic region, plus two well-defined singlets at d =6.22 and
H
6
.44 ppm in a 1:2 ratio, which were due to the methine
bridges. As underlined by the X-ray structure of compound
, this observation originates from two different coordina-
1
tion environments: the more intense signal was ascribed to
those Ph acac ligands that coordinate to the basal metal
2
atoms, whereas the other environment was assigned to those
Ph acac ligands that coordinate to the apical yttrium atom.
2
Figure 1. 1D gTOCSY NMR (500.13 MHz) expansion of pentanuclear
The NH protons were assigned with the help of two differ-
2
cluster 1 in CHCl
3
at ambient temperature (tSL =120 ms; tSL: duration of
ent experiments: 1D gTOCSY NMR measurements re-
the spin-lock pulse). The asterisks indicate the irradiated signal.
4 2 5
Scheme 3. Syntheses of [H(B{N(Me)N=C(H)Py} )] (H-4) and the dinuclear complex [Y (4) ACHTNUTGRENNUNG( OTf) ] (5).
Chem. Eur. J. 2012, 18, 5325 – 5334
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5327

I. Fernꢀndez, P. W. Roesky, F. Breher et al.
crystallography or quantum-
chemical calculations. The cal-
culated rH values assume spher-
ical shapes; hence, they do not
represent the real shape of the
molecules. Nevertheless, their
use has been well-established
for the purposes of comparison
because they offer a rapid and
facile method to recognize ion-
pairing. To learn more about
how ions interact and to specifi-
cally determine whether there
1
89
3
Figure 2. H, Y gHMQC spectrum (400 MHz) of cluster 1 (60 mm) in CDCl at 292 K. A complete data set
1
was acquired in 2 h 40 min, with a preparation delay optimized for a 7 Hz coupling constant. 1D H NMR and might be a preferred structure
8
9
1
D
Y NMR spectra are shown along their respective edges. The references used were TMS and Y
A
H
U
G
E
N
N
3 3
) for
for the yttrium salts described
1
89
1
19
above, we measured H, F
2
4
1
19
PGSE and H, F HOESY spec-
H
nated to the basal Y atoms of the square pyramid, and between the Ph
both the apical and basal yttrium metal atoms.
2
acac methine protons coordinated to tra of the two cationic yttrium
complexes. Diffusion data of
cluster 1 have been reported
[43]
previously. We used solutions
dY =141.5 pm and the other represented a new resonance lo-
of compounds 3 and 5 in MeCN for these measurements be-
[58,59]
cated at d =59.2 ppm. These two important cross-peaks al-
cause, as we have previously reported,
some dicationic
Y
lowed us to unequivocally assign the two yttrium signals as
basal and apical atoms, respectively (Figure 2).
ruthenium species have shown a surprisingly large degree of
ion-pairing, which had a significant implication on the catal-
ysis outcome.
8
9
To confirm this assignment, a 1D Y NMR spectrum was
acquired (Figure 2, left axis; also see the Supporting Infor-
mation, Figure S2), which confirmed the formation of the
two expected signals in a 4:1 ratio. In addition, an extra
cross-peak was detected in the 2D map (Figure 2), which
arises from the coupling between the m -OH resonance
4
(
dH =1.07 ppm) and the square-based pyramidal yttrium res-
onance (d =141.5 ppm), thus supporting their assignment.
Y
89
1
The H, Y gHMQC 2D maps of compounds 3 and 5
showed scalar interactions with the imine protons
(
Figure 3). In the case of mononuclear complex 3, only one
imine signal correlates with the metal nucleus (d =
Y
ꢀ
4.9 ppm), whereas in complex 5, the chemically inequiva-
lent imine protons identify the yttrium signal at d =
Y
0.4 ppm.
Pulsed gradient spin-echo (PGSE) NMR-diffusion meth-
[49–53]
ods are widely used,
in particular when associated with
ion-pairing. PGSE measurements, in combination with
homo and/or hetero NOE methods, offer a new perspective
on the interactions between transition-metal-salt-derived
[54–57]
cations and anions in solution.
Furthermore, the solvent
dependencies of the diffusion constants (D) offer a hint as
to which extent any solvent promotes ion-pairing. Dissolving
a variety of organic and inorganic salts in CHCl often leads
3
to more than 95% ion-pairing, whereas the use of coordi-
nating solvents, such as MeOH or MeCN, affords much-less
or no ion-pairing at all.
As demonstrated in previous studies, it is assumed that up
to 100% ion pairing occurs, if the cation and the anion
reveal approximately identical D values, thereby affording
hydrodynamic radii rH (from the Stokes–Einstein equation)
that are substantially greater than those estimated by either
1
89
Figure 3. H, Y gHMQC spectrum (500 MHz) for a) complex 3 (60 mm)
and b) compound 5 (30 mm) in CD CN at 294 K. Complete data sets
3
were acquired in 1 h 20 min with a preparation delay optimized for
a 12 Hz coupling constant. The internal projections (left edge) and the
H NMR spectra (top edges) are both shown. The references signals
used were TMS and Y
1
1
D
1
89
3 3
ACHTUNGTNERNUNG( NO ) for H and Y, respectively. The gradient
ratio was calculated according to the g values and was set to 60:20:43.9.
5328
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ꢂ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2012, 18, 5325 – 5334

Yttrium-Containing Complexes with Various Nuclearities
FULL PAPER
Table 1. D and r
H
values for yttrium complexes 3 and 5 at ambient tem-
metal cation in the solid state: two are lodged between the
gaps between the hydrazonyl arms of the ligand, whilst the
third is coordinated from underneath. The coordination of
the triflate groups is responsible for the different angles be-
tween the central yttrium cation and the coordinating pyrid-
yl nitrogen atoms (N7-Y-N8 about 1408, N6-Y-N7 about
1258, and N6-Y-N8 about 748), and most likely, also for the
trigonal twist of the ligand.
perature in CD
3
CN.
Compound
Nucleus
D
r
[ꢃ]
H
[b]
r
X
[ꢃ]
ꢀ
10
2
ꢀ1 [a]
[c]
[10 m s
]
1
3
H
F
9.022
6.6
5.2
1.6
6.8
–
6.4
7.6
1
9
11.455
36.15
8.806
1
1
1
1
H (free CH
H
3
3
CN)
CN)
5
9
[d]
F
n.d.
H (free CH
35.98
1.6
The fact that all of the triflate anions coordinate to the
central yttrium cation is important for deciding where to
place the anion in 3D space. We assigned the only cross-
[
a] Experimental error in the D values was (ꢁ2)%. [b] The viscosity (h)
ꢀ
3
ꢀ1 ꢀ1
used in the Stokes–Einstein equation was 0.363ꢄ10 kgm . Values
s
of h were taken from http://www.knovel.com. [c] Deduced from the X-
ray structure by considering the volume of the crystallographic cell divid-
ed by Z. This value was only an estimate because both molecular struc-
tures contained several solvent molecules in the crystal lattice (See the
Experimental Section). [d] Not detected, owing to the broadness of the
fluorine signal (W1/2 =42 Hz).
1
19
peak detected in the H, F HOESY spectrum (Figure 5) to
a coupling between the pyridyl alpha proton (H2) with the
ꢀ
proximal OTf anions. This interaction clearly suggested
that, in solution, the anion is (on average) located in close
proximity to the metal center, most likely on the bottom of
the complex. The fact that the D values were found to be
different for the cationic and anionic moieties suggested
that not all of the triflate molecules are bound to the metal
cation in solution, thereby providing an averaged diffusion
Table 1 shows the self-diffusion constants (D) for com-
plexes 3 and 5 in MeCN at concentrations of 60 and 30 mm,
respectively. Notably, the D values for the cationic ( H of
the ligand) and anionic ( F of the triflate anions) parts of
compound 3 are not identical. The D value for the anion
was small and the r value correspondingly large (the ex-
pected value for a solvated triflate group in, for example,
MeOH is about 3 ꢃ). As a consequence, the r value of
1
19
coefficient. 1D F NMR measurements as a function of
1
9
temperature supported this statement, as they showed
a second fluorine resonance at ꢀ408C, which was assigned
to a free triflate anion. Following heteronuclear NOE analy-
sis, we found no contacts to other pyridine protons and no
interactions with the NMe group.
H
H
5
.2 ꢃ (60 mm) was indicative of a relatively large amount of
Analogous to the investigations on compound 3, a series
of 2D experiments (COSY45 and NOESY) helped to assign
key protons in complex 5, even though there was not much
signal-overlap in the aromatic region. Table 1 summarizes
ion-pairing, even in MeCN.
1
19
An assessment of the H, F HOESY results for com-
pound 3 required a detailed assignment of the most impor-
tant protons (see below) and an
understanding of the molecular
structure of the cationic com-
plex. The preferred coordina-
3
+
tion numbers of Ln ions, and
3+
specifically of Y ions, are in
[60]
the range 8–12.
The yttrium
cation is expected to coordinate
to at least two of the three ni-
trogen atoms of each arm of
the tripodal ligand (2); there-
fore, one may assume that the
yttrium atom saturates its coor-
dination sphere by binding to
the oxygen atoms of the triflate
[61]
anions.
These assumptions were sup-
ported by X-ray diffraction on
single crystals of complex 3,
which revealed that six N-
donor atoms of the ligand are
3+
coordinated to the central Y
cation, thus forming a distorted Figure 4. Molecular structure of compound 3 (left). Ellipsoids set at 30% probability (arbitrary radii for tri-
flate anions). Top right: Local coordination environment around the Y1 atom. Lower right: View along the P-
S-Y axis. Selected bond lengths [pm] (also see the Supporting Information, Table S1): Y1–N5 253.9(4), Y1–N8
trigonal prismatic coordination
polyhedron (Figure 4). Further-
more, all three triflate counter-
2
2
54.4(4), Y1–N7 254.8(4), Y1–N6 254.9(4), Y1–N4 260.8(4), Y1–N9 267.2(4), Y1–O3 231.1(3), Y1–O8A
32.0(4) (disordered triflate anion), Y1–O1 232.9(4), S1–P1 190.9(2), P1–N3 165.0(4), P1–N1 168.1(4), P1–N2
anions are coordinated to the 169.0(4).
Chem. Eur. J. 2012, 18, 5325 – 5334
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5329

I. Fernꢀndez, P. W. Roesky, F. Breher et al.
minally coordinated. The bond
lengths between the pyridyl ni-
trogen atoms and the cations
vary
between
251.9
and
2
56.0 pm, whilst those to the
imine nitrogen atoms lie be-
tween 253.7 and 258.7 pm. A
summary of other relevant
bond lengths and angles is
given in the Supporting Infor-
mation, Table S2.
1
19
The H, F HOESY cross-
peaks for the 60 mm and 30 mm
solutions (Figure 5) were specif-
ic, but they did not differ much
between complexes 3 and 5.
The
key
features
were:
1
) strong interactions between
the alpha protons (H2) and
both non-equivalent donor
arms, and 2) a selective interac-
tion to one of the two donor
arms through the H5 proton
1
19
Figure 5. The H, F HOESY (300 MHz) spectra of a) complex 3 (60 mm) and b) complex 5 (30 mm) in
CD CN at ambient temperature, showing the selective interactions. For numbering see Scheme 4.
3
(
Figure 6b, Scheme 4). Again,
we did not observe significant
cross-peaks owing to either
other pyridine protons or to
the NMe groups.
Exchange spectroscopy has
become the method of choice
for studying multisite exchange
and slow dynamic process-
[62–67]
es.
For complex 5, we mea-
sured a series of 2D phase-sen-
1
9
sitive F EXSY spectra at low
temperatures (ꢀ108C) with dif-
A
H
U
G
R
N
U
G
ferent mixing times (t ) to in-
m
Figure 6. Molecular structure of compound 5. Ellipsoids set at 30% probability (arbitrary radii for OTf anions
and coordinated MeCN molecules). Right: Local coordination environment around the Y1 atom. Selected yt-
vestigate the exchange process-
trium–nitrogen bond lengths [pm] (also see the Supporting Information, Table S2): Y1–N3 255.7(5), Y1–N4 es between the bridging (B)
2
2
58.8(5), Y1–N6 254.5(5), Y1–N8 252.4(5), Y1–N11 260.9(5), Y2–N5 259.8(5), Y2–N7 253.5(5), Y2–N12
59.9(5), Y2–N13 255.4(5), Y2–N14 252.8(5), Y2–N15 252.7(6), Y2–N16 247.6(5).
and terminal triflate groups
T1 and T2). It was found that
(
the bridging mode of one tri-
the self-diffusion constants in MeCN for bimetallic triflate
salt 5. Unfortunately, the fluorine signal was too broad to be
observed under pulse gradient spin echo conditions; hence,
no ion-pairing conclusions could be drawn. However, the
D value and the calculated hydrodynamic radius suggested
a bimetallic structure in solution, which showed a good cor-
relation with the radius deduced by X-ray analysis.
The molecular structure of homobimetallic complex 5 is
¯
shown in Figure 6 (space group: P1). Both yttrium cations
are ninefold coordinated by the N-donor atoms of the
ligand, one acetonitrile molecule each, and all of the triflate
counter anions. Two of the NMe entities of the ligand are lo-
cated at a bridging position. Furthermore, one triflate anion
bridges both yttrium cations, whereas the other four are ter-
Scheme 4. The structures of compounds 3 and 5 in solution were identi-
fied by heteronuclear NOE measurements in acetonitrile solution.
5330
www.chemeurj.org
ꢂ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2012, 18, 5325 – 5334

Yttrium-Containing Complexes with Various Nuclearities
FULL PAPER
flate moiety in solution is quite rigid. At the shortest mixing
time (0.1 ms, the instrumental limit), any exchange was too
slow to be detected and the spectrum showed only diagonal
plexes (3 and 5). The PGSE data revealed a relatively large
amount of ion-pairing for compounds 3 and 5, even in
MeCN solution. Close contacts between the anions and the
yttrium cations were also detected by X-ray diffraction. By
applying HOESY and EXSY techniques, the triflate anions
were found to be located in par-
peaks. For t =25 ms, cross-peaks between both triflates T1
m
and T2 with B were clearly observed (Figure 7). Increasing
ticular regions of space and in
close proximity to the yttrium
cations, which might have a fur-
ther impact on the overall reac-
tivity of the complexes in solu-
tion.
Experimental Section
General considerations: All reactions
and manipulations were carried out
under an atmosphere of dry argon by
using standard Schlenk techniques.
Air-sensitive compounds were stored
and weighed in a glove box (Braun
MB150 G-I and Unilab system). THF
was dried over potassium/benzophe-
1
9
19
Figure 7. F, F EXSY at various mixing times (t
m
) for compound 5 at ꢀ108C shows that the terminal triflate
anions (T1 and T2) were in fast exchange with each other. In MeCN, the bridging mode of the third triflate
moiety (B) was still predominant. The numbers shown on the 2D maps correspond to the relative cross-peak
integrals.
2
none, Et O was dried over sodium-po-
tassium alloy/benzophenone, MeCN
the mixing time to 100 ms favored the random exchange
was dried over CaH , and acetone was
2
dried over CaSO
ferred from CaH
4
and molecular sieves (3 ꢃ). CD
3
CN was vacuum trans-
among all of the species in solution, although triflates B and
T1/T2 were found to be exchanging at a significant slower
rate, as deduced from the low intensities of their cross-
peaks. These results indicated that terminal triflate counter-
ions T1 and T2 preferably exchange between themselves,
that is, they break up and subsequently recombine, whereas
the exchange with the bridging triflates is inhibited signifi-
2
into thoroughly dried glassware equipped with Young
teflon valves. Elemental analysis and mass spectrometry were performed
in the institutional technical laboratories. Elemental analysis of com-
pounds 3 and 5 could not be obtained owing to the high fluorine content.
Melting points were determined in sealed capillary tubes under an argon
atmosphere and are uncorrected.
Solution NMR spectroscopy: Solution NMR spectra were recorded with
1
Bruker Avance instruments operating at H Larmor frequencies of 300,
cantly. The forward (k ) and reverse rate constants (k ) as-
1
ꢀ1
13
4
00, and 500 MHz. Chemical shifts are given relative to TMS for C and
sociated with the exchange process were calculated from the
1
19
31
H nuclei, relative to CFCl
3
for F nuclei, relative to H
3
PO
4
for
P
8
9
buildup of the cross-peak intensities on the 2D map, which
nuclei, relative to Y(NO ) for Y nuclei, and relative to NH3 (liquid)
AHCTUNGTRENNUNG
3
3
[68]
15
for N nuclei. Coupling constants (J) are given in Hertz as positive
values regardless of their real individual signs. PGSE NMR diffusion
measurements were carried out by using the stimulated echo pulse se-
quence. A rectangular shape was used for the gradient pulses and their
strengths changed automatically during the course of the experiments.
are directly related to the exchange matrix. At a mixing
time of 100 ms, the k and k values between T1 and T2
1
ꢀ1
ꢀ
1
were found to be 20.21 and 11.56 s , respectively. The cor-
[70]
responding exchange rates between B versus T1 and B
ꢀ
1
ꢀ1
versus T2 are 4.71(k )/4.08
A
H
U
T
E
N
N
(k ) s and 5.04(k )/7.62
A
H
U
G
R
N
N
(k ) s ,
The D values were determined from the slope of the regression line ln
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(I/
1
ꢀ1
1
ꢀ1
2
I ) versus G , according to Equation 1. I/I =observed spin echo intensity/
0 0
intensity without gradients, G=gradient strength, D=delay between the
midpoints of the gradients, D=diffusion coefficient, d=gradient length.
respectively.
Based on these data, it was reasonable to assume that the
structures shown in Scheme 4 are predominant in solution.
I
d
2
2
lnð Þ ¼ ꢀðgdÞ G ðD ꢀ 3ÞD
ð1Þ
I
0
Conclusion
The measurements were performed without spinning. The calibration of
the gradients was carried out by means of a diffusion measurement of
HDO in D O (DHDO =1.902 10 m s ). The experimental error in D
2
values was estimated to be smaller than ꢁ2% (three standard devia-
tions). All of the data that led to the reported D values afforded lines
with correlation coefficients above 0.999. The gradient strength was in-
cremented in 4% steps from 2% to 98%, so that, depending on the
signal/noise ratio, 20–25 points could be used for regression analysis.
1
89
2
D
H, Y heteronuclear shift correlation through scalar
coupling has successfully been applied for the determination
9
2 ꢀ1 [71]
8
9
of Y NMR chemical shifts of a series of yttrium complexes
in short periods of time. Thus, this technique is a valuable
tool for the structural determination of yttrium compounds
in solution, in particular when combined with other NMR
methods as well as with solid-state structures obtained by X-
ray diffraction. By applying all of these data to three yttrium
complexes of various nuclearities, we confirmed previous re-
sults (1) and determined the structures of two new com-
[69]
1
9
EXSY (exchange spectroscopy) F NMR spectra were acquired at
76.5 MHz, by using the phase-sensitive NOESY pulse-program without
3
1
19
H-decoupling. EXSY F NMR spectra were collected with 1 K points in
by using a spectral width of 3765 Hz (10 ppm) and a mixing time of
0.1–100 ms. Typically, 256 t experiments were recorded and zero-filled to
t
2
1
Chem. Eur. J. 2012, 18, 5325 – 5334
ꢂ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
5331

I. Fernꢀndez, P. W. Roesky, F. Breher et al.
1
K. For each t
1
value, 16 scans were signal-averaged by using
Table 2. Crystallographic data for compounds 2, 3, and 5.
a recycle delay of 2 s.
Compound
formula
2
3
5
IR spectroscopy: IR spectra were measured by using either the
ATR (attenuated total reflection) technique or on NaCl plates
C
21
H
24
N
9
PS
C
24
H
24
F
(C
9
N
9
O
9
PS
4
Y·
C
37 14 15 5 2
H38BF15N O S Y ·
2
ꢄ0.5
1042.70
monoclinic
P2 /c
A
H
U
G
R
N
U
G
2
H
3
N)
2 3
2.75 ACHTUNRTGNNEG(U C H N)
1665.64
triclinic
(
Nujol mull) with a Bruker Vertex 70 spectrometer in the
ꢀ
1
M
r
465.52
monoclinic
P2 /n
892.8(2)
2126.3(4)
1219.0(2)
range 4000–400 cm by using a KBr beam splitter. The intensi-
ty of the absorption bands is indicated as vw (very weak), w
crystal system
[
76]
¯
space group
a [pm]
b [pm]
c [pm]
a [8]
1
1
P1
(
(
weak),
broad).
m (medium), s (strong), vs (very strong), or br
972.4(2)
1982.0(4)
2235.0(5)
1425.4(3)
1565.6(3)
1838.3(4)
75.70(3)
82.61(3)
64.39(3)
3583.5(12)
1.863
1.544
X-ray diffraction: Crystal-structure determination: Single crys-
tals of compound 3 suitable for X-ray diffraction were ob-
tained by re-crystallization from a concentrated solution of
b [8]
93.91(3)
96.22(3)
MeCN/iPr
2
O under ambient conditions; single-crystals of com-
O and pure
g [8]
V ꢄ10 [pm ]
m [mm
pounds 5 and 2 were obtained from MeCN/Et
2
6
3
2308.7(8)
0.238
1.339
4281.9(15)
1.691
1.617
MeCN, respectively. To avoid decomposition during the meas-
urements, the single crystals were covered with perfluoropo-
lyalkyl ether oil and then mounted on top of a glass fiber. Sub-
sequently, they were placed in the cold nitrogen stream of
a low-temperature device to achieve solidification of the oil.
Data collection was performed with a STOE STADI 4 diffrac-
tometer equipped with a CCD area detector, a graphite-mono-
chromated MoKa (0.71073 nm) radiation source, and a low-
temperature device. All calculations were performed with
ꢀ1
]
ꢀ3
1
calcd [gcm
]
crystal dimensions
mm]
0.15ꢄ0.15ꢄ0.10 0.20ꢄ0.20ꢄ0.10
0.10ꢄ0.10ꢄ0.05
[
Z
4
4
2
T [K]
2qmax [8]
total reflns
unique reflns
200(2)
50
200(2)
50
29050
7507
646/110
0.0617
0.1638
1.014/ꢀ0.715
150(2)
50
15772
4055
292/0
0.0829
0.2319
24867
12431
1031/221
0.0739
0.2170
2.400/ꢀ0.706
[
72,73]
SHELXTL (v6.12) and SHELXL-97.
solved by direct methods and successive interpretation of the
difference Fourier maps, followed by full-matrix least-squares
The structures were
parameters/restraints
R
1
[Iꢂ2s(I)]
wR (all data)
2
2
refinement (against F ). All non-hydrogen atoms were refined
max./min. res. electron 0.788/ꢀ0.391
anisotropically. The contribution of the hydrogen atoms, in
their calculated positions, was included in the refinement by
using a riding model. Upon convergence, the final Fourier dif-
ference map of the X-ray structures showed no significant
peaks.
ꢀ6
ꢀ3
density ꢄ10 [pm
]
oily residue was washed with n-hexane (20 mL) and MeCN (10 mL) to
remove most of the hydrazone. The off-white residue was subsequently
One triflate counteranion of compound 3 and two counteranions of com-
pound 5 were disordered over two sites. In these cases, the two positions
were refined against each other by using one free variable (FVAR) with
occupation factors of 35% (3) and 45% (5) for the disordered position
with appropriate restraints (SADI and DFIX instructions within
SHELXL). Complex 3 crystallized with two MeCN molecules in the crys-
tal lattice, both of which were refined with 50% occupancy. Compound 5
crystallized with four MeCN molecules in the crystal lattice, two of which
were refined with 100% occupancy and the other two with 50 and 25%
occupancies, respectively. Repeated measurements of several single crys-
tals (also from other solvents) of compounds 3 and 5 did not lead to im-
proved datasets, in particular regarding the triflate disorder or the
number of solvent molecules in the crystal lattice.
filtrated and dried under a high vacuum. Yield (mixture of hydrazone
1
and H-4): 340 mg; H NMR (CD
3
CN, 400.1 MHz): d=2.94 (m, 12H;
NCH
Ar), 7.74–7.77 (m, 4H; HAr), 8.46–8.48 ppm (m, 4H; HAr); C NMR
CD CN, 100.6 MHz): d=32.9, 118.7, 121.6, 132.7, 136.0, 149.0,
3
), 7.13–7.17 (m, 4H; HAr), 7.48 (s, 4H; HC=N), 7.64–7.73 (m, 4H;
1
3
H
(
1
3
1
1
55.9 ppm; B NMR (CD
576 (w), 1462 (m), 1386 (s), 1321 (m), 1279 (m), 772 (m), 625 cm (m).
] (2): A solution of (S)PCl (5.65 g, 33.4 mmol)
(75 mL) was added dropwise over a period of 1 h to a solution
3
CN, 160.5 MHz): d=0.95 ppm; IR (ATR): n˜ =
ꢀ
1
1
[(S)P{N(Me)N=C(H)Py}
in CHCl
3
3
3
of N-methylhydrazine (9.31 g, 202.0 mmol) in CHCl (75 mL) at 08C. The
3
reaction mixture was allowed to warm to room temperature over
a period of 1 h and was stirred for a further 10 h at this temperature. The
precipitated N-methylhydrazine hydrochloride was filtered and the sol-
vent removed in vacuo to afford a white solid which was dissolved in hot
toluene (75 mL) and cooled. n-Hexane (125 mL) was added and the mix-
Crystallographic data, data-collection, and refinement details are sum-
marized in Table 2. CCDC-841665 (2), CCDC-841666 (3), and CCDC-
8
41667 (5) contain the supplementary crystallographic 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.
2 3
ture was kept at 58C to afford (S)P[N(Me)NH ] as a colorless crystalline
solid.
Materials and reagents: Y
A
H
U
G
R
N
N
(OTf)
3
and [H(B{N(Me)N=C(H)Py}
4
)] (H-4)
A solution of 2-pyridinealdehyde (3.242 g, 0.03 mol) in MeOH (20 mL)
was added dropwise to a stirring solution of (S)P[N(Me)NH2]3 (2 g,
0.01 mol) in MeOH (20 mL) and 1 g of magnesium sulfate at room tem-
perature. After the addition had been completed, the reaction mixture
was heated to reflux for 10 h. The mixture was allowed to cool, filtered,
were prepared according to literature procedures (or modified proce-
[
47,74,75]
dures).
ly.
The synthesis of compound 1 has been published previous-
The Ln oxides, (S)PCl , N-methylhydrazine, 2-pyridinealdehyde,
and B(NMe were purchased from Sigma–Aldrich and used without fur-
[
43]
3
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
2 3
)
ther purification.
and the precipitate was carefully washed with CHCl (3ꢄ50 mL). The fil-
3
Syntheses of H[B{N(Me)N=C(H)Py}
4
] (H-4): 2-Pyridinealdehyde (21.4 g,
trate and the washings were combined and the solvent was removed in
0
.20 mol) was cooled to ꢀ788C and N-methylhydrazine (9.2 g, 0.20 mol)
vacuo. The resulting white solid was re-crystallized from hot MeCN and
was carefully added. The cooling bath was removed and the mixture was
slowly heated to 808C and stirred at that temperature for 3 h. 2-(2-meth-
ylhydrazono)methylpyridine was received as a yellowish oily liquid by
fractional distillation under vacuum (23.0 g, 0.17 mol, 85%).
subsequently cooled to 58C. Yield: 3.77 g (8.1 mmol, 81%); M.p. (sealed
1
tube under an Ar atmosphere): 1698C; H NMR (CDCl , 400.1 MHz):
3
3
d=3.37 (d, 9H, J
A
H
U
G
R
N
U
G
3
H
Ar), 7.60 (m, 3H; HAr), 7.75 (s, 3H; N=CH), 8.55 ppm (m, 3H; HAr);
1
3
2
-(2-Methylhydrazono)methylpyridine (3 g, 22 mmol, 4 equiv) was dis-
solved in toluene (20 mL) and desiccated over molecular sieve (3 ꢃ)
overnight. B(NMe (0.98 mL, 0.79 mg, 5.6 mmol, 1 equiv) was carefully
C NMR (CDCl
N), 149, 155 ppm; P NMR (CDCl
9 Hz); MS (EI): m/z (%): 465.16 (75) [M] , 331 (94) [(S)P(N(Me)N=
3
, 100.6 MHz): d=33 (NCH
3
), 119, 123, 136, 138 (HC=
3
1
3
, 121.4 MHz): d=73.1 ppm (m, J=
+
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
2 3
)
+
] ,
+
] ,
added whilst stirring the mixture. The solution turned pale yellow. After
heating to reflux for 6 h, the solution was allowed to cool to room tem-
perature, then the solvent was removed in vacuo and the orange–brown
C(H)Py)
2
302.1
(64)
[(S)P
A
H
U
G
E
N
N
(NN=C(H)Py)
2
198.0
+
(100)
+
[(S)P(N(Me)N=C(H)Py)] , 134.1 (36) [N(Me)N=C(H)Py] , isotopic dis-
tribution: 465.16 (100), 466.16 (27), 467.16 (6), 467.17 (3), 468.16 (1); IR
5332
www.chemeurj.org
ꢂ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2012, 18, 5325 – 5334

Yttrium-Containing Complexes with Various Nuclearities
FULL PAPER
ꢀ
1
(
(
ATR): n˜ =3061 (vw), 1575 (m), 1434 (w), 1152 (m), 768 (m), 682 cm
m); elemental analysis calcd (%) for C21 PS: C 54.18, H 5.20,
[7] T. E. M u¨ ller, K. C. Hultzsch, M. Yus, F. Foubelo, M. Tada, Chem.
Rev. 2008, 108, 3795–3892.
24 9
H N
N 27.08, P 6.65, S 6.89; found: C 54.30, H 5.265, N 27.52, S 6.832.
[8] C. Kremer, J. Torres, S. Domꢁnguez, A. Mederos, Coord. Chem. Rev.
2
005, 249, 567–590.
9] H. Tsukube, S. Shinoda, Chem. Rev. 2002, 102, 2389–2404.
10] K. Wang, R. Li, Y. Cheng, B. Zhu, Coord. Chem. Rev. 1999, 190–
92, 297–308.
[
(
(
Y(2)
10 mL) was added dropwise to
0.58 mmol, 310.9 mg) in THF (10 mL) over several minutes at room
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(OTf)
3
] (3): A solution of ligand 2 (0.58 mmol, 270.35 mg) in THF
[
a
turbid suspension of (OTf)
Y
A
H
U
G
R
N
U
G
3
[
[
1
temperature. After the addition, the turbid solution slowly cleared and
the product precipitated. After filtering the solid, it was dissolved in
MeCN (5 mL) and layered with 15 to 18 mL of iPr
11] R. K. Harris, B. E. Mann in NMR and the Periodic Table, Vol. Aca-
demic Press, London, 1978.
2
O. After one day, col-
orless single crystals suitable for X-ray diffraction had formed. Yield:
[12] J. B. Lambert, F. G. Riddell in The Multinuclear Approach to NMR
Spectroscopy, Reidel, Dordrecht, 1983.
4
1
1
81 mg (0.48 mmol, 82%); M.p. (sealed tube under an Ar atmosphere):
1
3
978C; H NMR (CD
0.5 Hz; NCH ), 7.65 (m, 3H; HAr), 7.80 (m, 3H; HAr), 8.13 (m, 3H;
Ar), 8.35 (s, 3H; HC=N), 8.90 ppm (d, 3H; HAr); C NMR (CD
00.6 MHz): d=36 (NCH ), 117, 126, 127, 140 (HC=N), 149, 150 ppm;
3
CN, 400.1 MHz): d=3.51 (d, 9H,
J
A
H
U
G
R
N
U
(H,P)=
[13] J. Mason in Multinuclear NMR, Plenum Press, New York, 1987.
[14] D. Rehder in Transition Metal Nuclear Magnetic Resonance
(Ed.: P. S. Pregosin), Elsevier, Amsterdam, 1991, pp. 1–58.
[15] R. E. White, T. P. Hanusa, Organometallics 2006, 25, 5621–5630.
[16] J. Kronenbitter, A. Schwenk, J. Magn. Reson. 1977, 25, 147–165.
[17] G. C. Levy, P. L. Rinaldi, J. T. Bailey, J. Magn. Reson. 1980, 40, 167–
173.
[18] J. Eppinger, M. Spiegler, W. Hieringer, W. A. Herrmann, R. Anwan-
der, J. Am. Chem. Soc. 2000, 122, 3080–3096.
[19] W. J. Evans, J. H. Meadows, A. G. Kostka, G. L. Closs, Organometal-
lics 1985, 4, 324–326.
3
1
3
H
3
CN,
1
3
3
1
19
P NMR (CD
3
CN, 121.4 MHz): d=65.4 ppm (m, J=10.5 Hz); F NMR
CN, 282.4 MHz): d=ꢀ79.1 ppm; N NMR (CD
1
5
(
CD
3
3
CN, 50.7 MHz):
d=128.1 (Nhydr), 306.6 (Npyr), 273.6 (Nimine); MS (ESI): m/z (%): 852
+
(
100), 853 (30), 854 (13); calcd for [(S)P[N(Me)N=C(H)Py]
3
Y
A
H
U
G
R
N
U
G
2
] :
m/z (%): 852 (100), 853 (31), 854 (20), 855 (5), 856 (2), 857 (<1), 858 (<
ꢀ1
1
); IR (ATR): n˜ =3031 (vw), 1568 (w), 1441 (w), 1152 (s), 632 cm (m).
(4)(OTf) ] (5): A hot solution of compound H-4 (110 mg, 0.19 mmol
of the ligand, 0.07 mmol of hydrazone) in toluene (10 mL) was added
dropwise to a turbid suspension of Y(OTf) (200 mg, 0.37 mmol) in
[
Y
2
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
5
[
[
[
20] K. H. den Haan, J. H. Teuben, J. Chem. Soc. Chem. Commun. 1986,
82–683.
21] W. J. Evans, M. S. Sollberger, S. I. Khan, R. Bau, J. Am. Chem. Soc.
988, 110, 439–446.
22] D. Stern, M. Sabat, T. J. Marks, J. Am. Chem. Soc. 1990, 112, 9558–
575.
6
A
H
U
T
E
N
N
3
MeCN (10 mL) under vigorous stirring. The clear solution was allowed
to cool to room temperature. After removing the solvent in vacuo, the
pale yellow residue was washed with n-hexane (10 mL) to remove any re-
sidual hydrazone, filtered, and dissolved in MeCN (8 mL) and layered
1
9
[
23] C. J. Schaverien, Organometallics 1994, 13, 69–82.
with Et
2
O (20 mL). After several weeks, yellow single-crystals suitable
[
24] T. I. Gountchev, T. D. Tilley, Organometallics 1999, 18, 2896–2905.
for X-ray diffraction had formed. Yield: 102 mg (0.07 mmol, 19%); M.p.
1
[25] S.-G. Lee, Bull. Korean Chem. Soc. 1996, 17, 589–591.
(
4
H
2
2
9
sealed tube under an Ar atmosphere): 2328C; H NMR (CD
00.1 MHz): d=3.09 (s, 6H; NCH ), 3.22 (s, 6H; NCH ), 7.31 (m, 2H;
Ar), 7.43 (d, 2H, J(H,H)=7.8 Hz; HAr), 7.56 (s, 2H; HC=N), 7.57 (m,
H; HAr), 7.73 (d, 2H, J(H,H)=7.7 Hz; HAr), 7.87 (m, 2H; HAr), 8.05 (m,
H; HAr), 8.47 (s, 2H; HC=N), 9.00 (d, 2H, J(H,H)=5.2 Hz; HAr),
(H,H)=4.9 Hz; HAr); C NMR (CD CN, 100.6 MHz):
3
CN,
[
[
[
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3
3
1
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
1
AHCTUNGTRENNUNG
1
3
.12 ppm (d, 2H, J
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
3
d=38.3, 40.3, 123.4, 126.7, 133.4, 140.0, 140.9, 149.0, 149.6, 150.1, 152.7,
1
1
1
53.9, 153.9 ppm;
B NMR (CD
3
CN, 160.5 MHz): d=5.55 ppm;
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1
9
15
F NMR (CD
3
CN, 282.4 MHz): d=ꢀ79.01 ppm; N NMR (CD
3
CN,
5
0.7 MHz): d=135.4, 267.6, 272.5, 323.5, 322.7 ppm; MS (ESI): m/z (%):
1
320 (21), 1321 (100), 1322 (43), 1323 (26), 1324 (9), 1325 (2), 1326 (1);
+
MS: m/z (%) calcd for [B{N(Me)N=C(H)Py}
4
Y
2
A
H
U
G
R
N
N
(CF
3
SO
3
)
4
] : 1320 (22.4),
1
1
6
321 (100), 1322 (46), 1323 (29), 1324 (10), 1325 (4), 1326 (1), 1327 (<1),
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ꢀ
1
30 cm (s).
[
[
[
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5334
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