Synthesis and coordination chemistry of N,N-diallylbispidine

Article abstract of DOI:10.1021/om200824c

The synthesis of 3,7-diallyl-3,7-diazabicyclo[3.3.1]nonane (C ₇H₁₂N₂allyl₂, 3) has been revisited, and several hitherto undetected byproducts have been identified. Pure 3 and these byproducts were isolated by both prep-GC and column chromatography. Monoprotonated 3 in the form of the PF₆ salt [(C₇H ₁₃N₂allyl₂]PF₆ (9) and the addition complexes of 3 to Ni(acac)₂ and CuI, (C₇H ₁₂N₂allyl₂)Ni(acac)₂ (10) and {(C₇H₁₂N₂allyl₂)Cu(μ-I)} ₂ (11), have been prepared. From the reactions of {(η³-C₃H₅)M(μ-X)}₂ (M = Ni, Pd, Pt; X = Cl, Br) with 3 and TlPF₆ the complexes [(C ₇H₁₂N₂allyl₂)M(η³- C₃H₅)]PF₆ (M = Ni (12a), Pd (12b), Pt (12c)) were obtained. Compounds 9-11 and 12b were characterized by X-ray crystallography. The reaction of (1,5-hexadiene)PtCl₂ with 3 gave, after HCl elimination, monomeric {C₇H₁₂N ₂(C₃H₅)CH=CHCH₂}PtCl (13a), and the presence of MeOH afforded {C₇H₁₂N₂(C ₃H₅)CH₂CH(OMe)CH₂}PtCl (13b), both compounds featuring novel anionic tridentate ligands. Furthermore, chiral N,N′-bis((R)-1-phenylethyl)-1,7-octadiene-(S,S)-4,5-diamine (15) reacts with CuI to give [{(C₃H₅)₂C₂H ₄N₂(CHMePh)₂}Cu(μ-I)]₂ (16). The unbound N-allyl functions on the ligands in the product complexes allow for immobilization of the transition metal complexes on polyester fibers.

Full text of DOI:10.1021/om200824c

Article
pubs.acs.org/Organometallics
Synthesis and Coordination Chemistry of N,N-Diallylbispidine
Huiling Cui, Richard Goddard, and Klaus-Richard Porschke*
̈
Max-Planck-Institut fu
̈ ̈
r Kohlenforschung, D-45466 Mulheim an der Ruhr, Germany
*
S Supporting Information
ABSTRACT: The synthesis of 3,7-diallyl-3,7-diazabicyclo-
3.3.1]nonane (C H N allyl , 3) has been revisited, and
[
7
12
2
2
several hitherto undetected byproducts have been identified.
Pure 3 and these byproducts were isolated by both prep-GC
and column chromatography. Monoprotonated 3 in the form
of the PF salt [(C H N allyl ]PF (9) and the addition
6
7
13
2
2
6
complexes of 3 to Ni(acac) and CuI, (C H N allyl )Ni-
2
7
12
2
2
(
acac) (10) and {(C H N allyl )Cu(μ-I)} (11), have been
2 7 12 2 2 2
3
prepared. From the reactions of {(η -C H )M(μ-X)} (M =
3
5
2
Ni, Pd, Pt; X = Cl, Br) with 3 and TlPF the complexes
6
3
[
(C H N allyl )M(η -C H )]PF (M = Ni (12a), Pd (12b), Pt (12c)) were obtained. Compounds 9−11 and 12b were
characterized by X-ray crystallography. The reaction of (1,5-hexadiene)PtCl with 3 gave, after HCl elimination, monomeric
7
12
2
2
3
5
6
2
{
C H N (C H )CHCHCH }PtCl (13a), and the presence of MeOH afforded {C H N (C H )CH CH(OMe)CH }PtCl
7
12
2
3
5
2
7
12
2
3
5
2
2
(13b), both compounds featuring novel anionic tridentate ligands. Furthermore, chiral N,N′-bis((R)-1-phenylethyl)-1,7-
octadiene-(S,S)-4,5-diamine (15) reacts with CuI to give [{(C H ) C H N (CHMePh) }Cu(μ-I)] (16). The unbound
3
5 2
2
4
2
2
2
N-allyl functions on the ligands in the product complexes allow for immobilization of the transition metal complexes on polyester
fibers.
INTRODUCTION
base and nickel(0) as a soft Lewis acid as being unfavorable.
The existence of these atypical complexes impressively
demonstrates the outstanding coordination properties multi-
■
1
Ever since their first synthesis by Mannich and Mohs,
2
bispidines have attracted a lot of attention. Bispidines can be
considered as two piperidine rings that are fused over three C
atoms, which gives rise to a relatively rigid bicyclic structure.
10b
dentate ligands can attain by heeding the principles of the
macrocyclic effect, i.e., “preposition of donor atoms” and
16,17
2
“preorganization of ligand conformation”.
Whereas bispidines with sp hybridization at nitrogen appear to
3
3
In continuation of our studies on bispidines, we became
interested in the question as to whether bispidines are suitable
for immobilization of metals on heterogeneous surfaces, such as
textile fibers. An earlier attempt by Waldmann to anchor
bispidines on hydroxymethyl polystyrene was based on the
coupling of the 9-(pentanoic acid)-substituted bispidines with
prefer a chair−chair conformation, sp hybridization stabilizes
the chair−boat conformation. This can be induced by various
4
steric and electronic effects, as exemplified by sparteine, 9-ol
5
derivatives, and 3,7-dimethyl-1,5-dinitro-3,7-diazabicyclo-
2
b,6
[
3.3.1]nonane.
In the chair−chair conformation, the amine
functions in bispidines are almost ideally prepositioned for
trapping one or two protons by intramolecular N−H···N and
N−H···Cl···H−N hydrogen bridges, as well as for chelating
metal centers.
18
the hydroxy functions under Steglich conditions. For our
purpose we found radical reaction of N-allyl-substituted
bispidines with a polyester fiber under UV irradiation as the
19
method of choice.
The ability of bispidine itself to coordinate to Ni(II) and
Cu(II) was noted as early as 1957. Since then, particularly in
We have revisited the synthesis of N,N′-diallylbispidine (3)
and the parent bispidine 4 and report here on the synthesis
and structure of the products obtained from the reaction of
N,N′-diallylbispidine with various transition metal salts.
7
the case of the alkaloid (−)-sparteine, coordination to main
8
group metals (Mg) and transition metals (Ni, Co, Cu, Zn, Mn,
9
a,b
9c 9d
Fe, Pd, Pt ) has been established. More recent reports on
metal coordination of substituted bispidin-9-ones and bispi-
RESULTS AND DISCUSSION
1
0a,11
11,12
11
■
dines refer to Cu,
Pd,
and Pt. To date, a plethora of
2,13
On the Synthesis of N,N′-Diallylbispidine (3). Miyahara
complexes of related types has been reported.
the metal is in its divalent state.
Some time ago we showed that N,N′-dimethylbispidine may
In most cases
2
0a
et al.
have described a “convenient synthesis” of the
parent bispidine (4) via N,N′-diallylbispidin-9-one (2) and
N,N′-diallylbispidine (3) as intermediates (Scheme 1). On the
coordinate even to nickel(0), coligated by olefinic or acetylenic
21
1
4
classical route outlined by Douglass and Ratliff, the readily
ligands. The isolated complexes such as (C H N Me )Ni-
7
12
2
2
(
C H ) and (C H N Me )Ni(C H ) represent limiting cases
2 4 7 12 2 2 2 2
15
of the Pearson hard−soft acid−base (HSAB) concept, which
assesses the combination of a tertiary amine as a hard Lewis
Received: September 2, 2011
Published: October 25, 2011
©
2011 American Chemical Society
6241
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Scheme 1. Synthesis of the Intermediate Bispidin-9-one 2
and Bispidines 3 and 4 and Formation of the Byproducts 5−8
for several months, we found no indication of thermolability of
either compound in pure state (contrary to an assertion made
previously for 2).
20a
The bispidin-9-one 2 (either pure or as a mixture with 5) was
subjected to Wolff−Kishner reduction for several days
(
diethylene glycol, hydrazine hydrate, and potassium acetate;
bath temperature around 170 °C) to afford the expected
product 3, but also the hitherto unmentioned byproducts 7 and
8
. Possibly present 5 in the reaction mixture became reduced
to N,N′,N″-triallyl-1-(aminomethyl)bispidine (6) as a further
component (Scheme 1). All components 3, 6, 7, and 8 of the
product mixture were separated by preparative GC and
characterized in pure form by NMR and MS. N-Allylbispidine
(
7) results from thermally induced propene elimination at one
N-allyl function of 2 or 3 and can be considered as a precursor
for the synthesis of 4. Byproduct 8 was identified as the new
3
,8
5
-allyl-9-methyl-1,5-diazatricyclo[5.3.1.0 ]undecane. Appa-
rently, after formation of the 9-hydrazone and N elimination,
2
the generated bispidin-9-yl anion, instead of recapturing a
proton to form 3, assumes a chair−boat conformation and
attacks the N-allyl group of the boat ring at the substituted
olefinic carbon atom to afford tricyclic 8 (eq 1).
accessible N-allyl-4-piperidone (1) was subject to double-
Mannich condensation with allylamine and formaldehyde to
give the bispidin-9-one 2. Without isolation 2 underwent
Wolff−Kishner reduction to afford the bispidine 3 in 51% yield.
Cleavage of the N-allyl groups provided 4 in 72% yield,
corresponding to an overall yield of 37% from 1. No impurities
in 2, 3, or 4 were found. Making use of the N-allyl functionality
by Miyahara et al. provides a notable improvement in the
synthesis of 4, as is illustrated by the fact that N,N′-
dibenzylbispidine resists cleavage of the benzyl groups under
2
0a
similar conditions.
Looking again at the literature syntheses of 3 and 4 in more
detail, we noted some variation in the yield of 1 when we
repeated the reaction, even under what we believe to be
identical conditions. Nevertheless, a mean yield of 80% was
within reach. We also found that the double-Mannich
condensation of 1 with stoichiometric amounts of allyl amine
and paraformaldehyde (55 °C, 2−3 h) to obtain 2 proceeded
with formation of the byproduct 5 in a content of up to 10%
NMR characterization of intermediate 2 and product 3
(
(
Table 1) and the byproducts 5, 6, and 7 is straightforward
Table 2). For the bispidin-9-ones 2 and 5, besides the obvious
(
Scheme 1). 5 was also formed when the reaction was carried
out at only 30 °C over several days. In order to isolate 5, we
neutralized the clear amber reaction solution (after all (CH O)x
1
13
carbonyl low-field resonances, the H and C resonances of the
2
bridgehead CH (2, δ(H) 2.43, δ(C) 47.4; 5, δ(H) 2.48, δ(C)
had dissolved) with KOH and concentrated it under vacuum to
obtain a viscous oil. This was treated and extracted with THF
to precipitate most potassium acetate. (An alternative treatment
with diethyl ether or pentane appeared impractical due to a
reluctance of the liquids to mix.) After renewed concentration,
the remaining amber oil was distilled under high vacuum (bath
temperature 135 °C) to yield a mixture of colorless 2 and the
byproduct 5 in a total yield of 80%. The mixture was separated
by preparative gas chromatography. According to NMR and EI
mass spectrometry, 5 is N,N′,N″-triallyl-1-aminomethylbispidin-
4
7.6) are at relatively low field as compared to the cor-
responding bispidines 3 (δ(H) 1.88, δ(C) 30.5) and 6 (δ(H)
.95, δ(C) 30.6). For both 5 and 6 the signals of the substituted
bridgehead C6 and the adjacent C2 (5, δ(C6) 51.1, δ(C2) 63.0;
, δ(C6) 35.9, δ(C2) 62.1) are at still lower field than those of
the unsubstituted C5 and adjacent C1 (5, δ(C5) 47.6, δ(C1)
9.0; 6, δ(C5) 30.6, δ(C1) 58.1); the latter shifts agree with the
corresponding shifts of 2 (δ(C) 47.4 and 58.9) and 3 (δ(C)
0.5 and 58.4). In contrast, C11 of the 6-CH NH(C H )
1
6
5
3
2
3
5
substituent in 5 (δ 53.5) is at higher field than in 6 (δ 60.1),
whereas it is the other way around for the corresponding
methylene protons.
9
-one, formed by a third Mannich condensation. The formation
of such a byproduct in the course of Douglass−Ratliff bispidin-
22a
9
-one syntheses has been noted before by Smissman et al.
14
and ourselves. Although the isolated 2 reacts further under
the given Mannich conditions to give a mixture of products
including 5, it seems likely that starting from 1 some of
the intermediately generated N,N′-diallyl-3-aminomethyl-4-
piperidone (1′) in a side-reaction forms N,N′,N″-triallyl-3,5-
di(aminomethyl)-4-piperidone (1″), which undergoes
The mono-N-C
made up to one half from the bis-N-C
3
H
5
-substituted 7 can be viewed as being
substituted 3 and to
H
5
3
the other from the parent 4. Thus, C1 of the substituted
piperidine in 7 (δ 60.4) is similar to that in 3 (δ 58.4), whereas
1
3
all other C resonances of the skeleton of 7 (δ(C3) 53.5,
δ(C5) 31.5, δ(C7) 34.4) are like the corresponding values of 4
(δ 53.7, 31.1, 35.1). This is also true for the shifts of the
inequivalent geminal methylene protons at C7 (δ(H) 1.80,
ring-closure with CH O to give byproduct 5. Keeping the
isolated 2 and 5 at ambient temperature in an inert atmosphere
2
6
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6
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Article
1
1
.64), which are closer to the corresponding shift of 4 (δ(H7)
.70) than that of 3 (δ(H3) 1.49). Similarly, the bridgehead
CH signal of 7 (δ(H5) 1.50) is close to the signal of 4 (δ(H)
.43), whereas that of 3 (δ(H2) 1.88) is at lower field. We also
note that within 7 the H 1 (3.05) and H 1 (2.27) differ-
1
e
a
entiation of the NCH protons in the N-C H -substituted
2
3
5
piperidine ring is much larger than that of H 3 (2.94) and H 3
e
a
(
2.83) in the unsubstituted piperidine. While the former data
are similar to those of the certainly chair-shaped piperidine ring
in 8 (see below), the latter data are close to those of the parent
bispidine 4 (δ(H ) 3.02, δ(H ) 2.91). It seems likely that in 7
e
a
the proton of the secondary amine undergoes intramolecular H
23
bond bridging to the second N atom, similar to the parent 4.
Thus, the data suggest that in the N-C H -substituted
3
5
piperidine ring of 7, having the additional H bridge bond, the
chair conformation is more pronounced, whereas in the
unsubstituted ring it is more flattened.
For 8 (Table 2) an unambiguous assignment of all proton
and carbon resonances has been achieved by employing various
2D and double-resonance NMR techniques. The chiral 8
comprises intertwining bispidine and quinuclidine structures.
Thus, a bispidine with chair−boat conformation shares its
boat-shaped piperidine ring with a quinuclidine, resulting in
high structural rigidity of the molecule. For the chair-shaped
piperidine ring, the axial NCH2 protons H 1 and H 2
a
a
resonate at much higher field than the equatorial H 1 and
e
H 2, whose shifts are normal. The quinuclidine moiety displays
e
three faces of boat-shaped piperidine rings. Here, besides the
2
3
J(H,H) geminal couplings of about 13 Hz, the J(H,H)
couplings between eclipsed protons are largest (10 Hz), 120°-
gauche couplings are of medium magnitude (4−6 Hz), and
6
0°-gauche couplings are smallest (2.8 Hz), close to the values
predicted by the Karplus equation. In addition, four W long-
range couplings ( J(H,H) = 2.2−2.4 Hz) are apparent.
Of the two geminal CH N protons at C15 of the quinuclidine,
4
2
H 15 (δ 2.05) resonates at markedly higher field than H 15
Z
E
(
δ 2.86) (Z and E with respect to CH ). A model NMR
3
investigation of 2-azabicyclo[2.2.2.]octane derivatives is given
in ref 24.
Since the bispidines and bispidine-9-ones in this study are
fundamental, relatively small, easily vaporized, and available in
pure form, a detailed EI and ESIpos mass spectral character-
ization appeared also worthwhile, complementing a previous
25
study by Ruenitz et al. Strikingly, we note that, despite the
structural diversity of the bicyclic and tricyclic bispidines and
bicyclic bispidine-9-ones, all undergo similar fragmentation into
an iminium cation and a piperidinium- or 4-piperidonium-
derived part, which includes also a proton shift between the six-
membered ring and the acyclic moiety. The observed
fragmentation is reminiscent of a partial reversal of the Mannich
synthesis. Moreover, the EI mass spectra of the bicyclic
bispidine 3 and its tricyclic isomer 8 can hardly be distinguished.
This suggests an essentially common fragmentation mechanism
for all compounds. Loss of the R substituents at nitrogen is of
only minor importance.
As far as the fragmentation is concerned, it seems instructive
to start with the most unsymmetrical compound, the tricyclic 8.
For 8 (evaporation temperature −10 °C), the molecular ion
+
[
C H N (C H )] (m/e = 206, 100%) is found as the base
1
0
17
2
3
5
+
ion, which fragments into [CH N(CH )(C H )] (84, 45)
2
3
3
5
+
and [C H N] (122, 45). Ionization of amines occurs at
8
12
nitrogen. Here it is the nitrogen atom outside the quinuclidine
moiety that loses one of the lone-pair electrons. This triggers
6
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Organometallics
one α-C−C bond cleavage and radical formation at the
Article
2
6
+
+
+
[C H N] (70, 44), from M to afford [3 − H] (205, 58) also
occurs.
A somewhat different situation arises for the parent bispidine
(20 °C) and the singly N-substituted N-allylbispidine 7
−10 °C). In both cases loss of the lone-pair electron occurs
at an unsubstituted nitrogen, and the resulting molecular ions
4, 126; 7, 166; base peaks) undergo the usual α-cleavage and
4
8
3
-position in the quinuclidine. Next, for stabilization of the radical,
the iminium pendant may remove an H atom from the quinucli-
dine 2-position, which lies within reach due to the ring’s boat
conformation, whereas proton removal from the 4-position would
cause violation of Bredt’s rule. As a consequence, 2,3-dehydro-
27
4
(
quinuclidine and N−CH moieties are formed, with recovery of
3
(
the nitrogen radical. This triggers the second α-C−C bond
cleavage, affording the free iminium cation and the 2,3-
dehydroquinuclidin-5-yl radical, which, after an H atom shift and
H atom transfer to again give a 2,3-dehydropiperidine, bearing
a methyleneamine radical tether (eq 4). Second α-cleavage
+
by loss of the radical electron, forms the cation [C H N] (eq 2).
8
12
affords the 2,3,5-dehydropiperidine radical, which then
stabilizes by H atom abstraction. Ionization yields the 2,3-
Clearly, following a very similar mechanism, in the EI mass
+
27
+
dehydropiperidine radical cation [C H NR] (4, 83; 7, 123;
5
8
spectrum of 3 (20 °C) the molecular ion [C H N (C H ) ]
7
12
2
3
5 2
+
each ∼75%), which eliminates R to form the commonly
(
206, 24) fragments into [CH N(CH )(C H )] (84, base
2
3
3
5
28
+
+
observed cyclic nitrenium cation [C H N] (82, ∼80%). The
+
5
8
ion) and [C H N(C H )] (122, 23), although partial C H
5 7 3 5 3 5
+
+
imine radical cation [CH NCH ] (43), concomitantly
2
3
elimination from M to generate [C H N (C H )] (165, 20)
7
12
2
3
5
generated for both compounds, appears to disproportionate
also takes place. Again, after the first α-C−C bond cleavage a
-piperidinyl radical is formed. If the remaining ring is present in
+
into the 2-azaallene cation [CH NCH ] (42) and the
2
2
3
+
acyclic nitrenium ion [N(CH ) ] (44).
3
2
boat conformation, the 5-tethered iminium can abstract one H
atom from the 2-position, giving rise to 2,3-dehydropiperidine
having a methyleneamine radical pendant. The high-energy
amine radical then stabilizes by a second α-C−C bond fission.
Finally, we note the EI mass spectra of N,N′-diallylbispidin-9-
one, 2 (−10 °C), and its 1-(allylaminomethyl) derivative, 5
(
30 °C). Both compounds display the molecular ions (2, 220,
3
5; 5, 289, 2), whose fragmentation again proceeds by tandem
α-C−C bond cleavage and H atom abstraction from the
-position of the remaining ring in boat conformation, quite
similar to eq 3. Besides the iminium cation [CH N(CH )-
4
,5-H-atom migration yields the 2−4-dehydropiperidinum
+
cation [C H N(C H )] (eq 3). By the same mechanism, the
5
7
3
5
2
2
3
+
(
C H )] (84, base peaks), the 2,3,5-dehydro-4-piperidon-5-yl
3 5
radical presumably undergoes a 6,5-H atom shift and after
electron loss yields a 2,3,6-dehydro-4-piperidonium cation
+
[
(R′)C H ONC H ] (2, R′ = H, m/e = 136, 62%; 5, R′ =
5
5
3
5
CH NH(C H ), 205, 16%) (eq 5). For both molecular ions
2
3
5
1
4,25
molecular ion of N,N′-dimethylbispidine,
[C H N -
7 12 2
+
+
(
7
CH ) ] (154, 23), fragments into [CH N(CH ) ] (58,
3
2
2
3 2
+
7) and [C H NCH ] (96, 77). The 1-(allylaminomethyl)-
5 7 3
+
substituted bispidine 6 (−21 °C) M (275, 100) can fragment
+
into [CH N(CH )(C H )] (84, 100) and [(C H N)-
2
3
3
5
4
8
+
C H N(C H )] (191, 11), while cleavage of the 1-substituent,
5
6
3
5
6
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Organometallics
Article
cleavage of the N−C H bonds and for 5 cleavage of the
in 88% yield (eq 7). The compound fuses at 225 °C to give a
brown oil. Complex 11 dissolves very well in CH Cl and
3
5
1
-(allylaminomethyl) substituent are insignificant.
2
2
The ESIpos spectra (MeOH as solvent) of 2−8 are
+
dominated by the protonated molecular ions [M + H] . In
2
−7 chair−chair conformation of the bispidine permits
23
hydrogen bridging to the second nitrogen atom. In addition,
for the MeOH solutions of the bispidin-9-ones 2 and 5 a second
+
ion [M + CH OH + H] is found (20−50%), which results
3
from partial hemiketal formation of the carbonyl with MeOH.
We have also prepared protonated 3 in the form of its PF6
salt [C H N allyl ]PF (9). Compound 9 was first obtained
7
13
2
2
6
moderately well in THF, but otherwise is scarcely soluble in
most solvents. Solutions of 5 are very sensitive to air and
immediately turn blue due to formation of Cu(II). In the
ESIpos mass spectrum (MeCN solution) prominent ions are
while attempting to synthesize complex 13c when inadvertent
water was present in the starting Pt complex. Straightforward
synthesis of 9 involves reaction of equimolar amounts of 3,
HCl, and TlPF to give colorless crystals. NMR data of 9 are
6
+
the dinuclear [(C H N ) Cu I] (m/e = 665) and
1
3
22
2
2
2
listed in Table 1. In the ESIpos spectrum of 9 (MeCN
+
+
[(C H N ) Cu CN] (564) and mononuclear [(C H N )-
solution), [3 + H] (m/e = 207) is the base ion. Interestingly,
13 22 2 2 2 13 22 2
+
+
+
6
Cu] (269), besides the protonated ligand [C H N ] (207)
13 23 2
[
C H N allyl ] PF (559, 30%) is found as an additional
7
13
2
2 2
1
13
as the base ion. The H and C NMR chemical shifts of 11
(Table 1) are best compared with those of the free ligand (3)
prominent ion, which indicates that NH···F bonding between
+
−
the [C H N allyl ] cations and the PF anion is significant
7
13
2
2
6
and the protonated ligand, [C H N (allyl) ]PF (9). For 11,
(
cf. the single-crystal structure of 9 below).
N,N′-Diallylbispidine (3) As a Ligand for Transition
7
13
2
2
6
the meso proton of the N-allyl group (H5) lies at remarkably
low field. The crystal structure of 11 is described below.
Complex 11 is related to the hitherto prepared and
Metals. Compound 3 struck us as an interesting ligand for
transition metal complexes, since it is a highly preorganized
bidentate ligand and the allyl substituents provide a useful
functional group for further reactions. Recalling our previous
crystallographically characterized complexes {(died)Cu(μ-I)}
2
3
1a
(B) (died = N,N′-diisopropylethylenediamine)
and
31b,c
preparation of (tmeda)Ni(acac) (A) (tmeda = N,N′-tetra-
{(tmeda)Cu(μ-I)}
2
(C).
Both complexes 10 and 11 are
2
29
30
methylethylenediamine), we reacted the trimeric Ni(acac)2
acac = acetylacetonate) with 3 in pentane. Within about an
hour the solid dissolved to give a blue solution, from which
also related to (N,N′-diallyl-1,5-diphenylbispidin-9-one)CuCl
2
32
(
(D), which has also been structurally characterized.
[(N,N′-Diallylbispidine)M(C H )]PF (M = Ni (12a), Pd
3
5
6
(
C H N allyl )Ni(acac) (10) separated in quantitative yield
(12b), and Pt (12c)). In addition to the straightforward
coordination complexes 10 and 11, we were interested in pre-
paring N,N′-diallylbispidine−metal complexes containing M−C
bonded coligands, since they should provide potentially reactive
sites for catalytic reactions. As prototypical examples we chose
the series of ionic complexes (C H N allyl )M(C H )]PF
6
7
12
2
2
2
(eq 6). Compound 10 melts at 138 °C without decomposition.
7
12
2
2
3
5
1
2a
(
M = Ni−Pt), for which there was already a precedent.
A solution of {(η -C H )Ni(μ-Br)} in acetonitrile reacted
3
3
5
2
with stoichiometric amounts of 3 and TlPF by precipitating
6
TlBr. Exchanging the solvent for THF afforded (−30 °C) dark
red crystals of 12a in 69% yield (eq 8). Solid 12a decomposes
at 160 °C without melting. The compound is very soluble in
CH Cl and MeCN, but only sparingly soluble in THF at 20 °C
Monomeric 10 is highly soluble in the usual organic solvents.
NMR characterization is however impractical due to its
paramagnetism. In the EI mass spectrum (75 °C) the molecular
ion is found (m/e = 462, 4%), which mainly fragments by cleavage
2
2
and insoluble in diethyl ether. Solutions of 12a appear stable to
moisture, but are very sensitive to air. Upon exposure, their
color immediately changes from red to green.
+
of acac to give the base ion [(C H N )Ni(acac)] , but to a
13
22
2
+
minor extent, by cleavage of the diamine, [Ni(acac) ] (26%). The
2
3
Similarly, when a THF solution of {(η -C H )Pd(μ-Cl)}
3
5
2
ESIpos mass spectrum (CH Cl solution) reveals [(C H N )-
2
2
13 22
2
+
and 3 was treated with TlPF off-white crystals of 12b were
6
Ni(acac)] (40%) as the only prominent complex ion, while [3 +
H] is the base ion. Thus, cleavage of ligand 3 from 10 under mass
+
obtained in 82% yield (eq 8). 12b is more soluble in THF than
spectrometry conditions appears as a viable process. By contrast,
the ESIpos mass spectrum (CH Cl solution) of A furnishes
2
2
+
+
[
(tmeda)Ni(acac)] as the base ion, but no [tmeda + H] . Further
insight into the relative stability of 10 and A was gained when 10
was recrystallized from a pentane solution containing a 5-fold
excess of tmeda. ESIpos mass spectroscopy furnished the ions
+
+
[
(C H N )Ni(acac)] and [(tmeda)Ni(acac)] in 1:3 ratio,
13 22 2
suggesting that the coordination strength of 3 and tmeda versus
Ni(acac) is about the same. Possibly, the larger bulk of 3
2
attenuates its coordination strength in the hexacoordinate product.
Similarly, we reacted CuI with 3 in refluxing acetonitrile
12a, but still insoluble in diethyl ether. Solid 12b decomposes
at 140 °C, forming a black oil. The molecular structure of 12b
3
(
82 °C) to afford a colorless solution, from which large
is described below. The related reaction of {(η -C H )Pt(μ-
3
5
colorless crystals of {(C H N allyl )Cu(μ-I)} (11) separated
Cl)} with 3 and TlPF as a suspension in THF is rather slow.
7
12
2
2
2
4
6
6
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However, stirring the mixture at 50 °C for 1 day affords
complex 12c in 83% yield (eq 8). 12c is very soluble in THF.
No EI mass spectra could be obtained for the ionic 12a−c. In
for the given type of complex for M = Ni (12a) but not for M =
Pd, Pt (12b,c).
Reactions of (1,5-Hexadiene)PtCl with 3. Previously,
2
33
the ESIpos mass spectrum of the Ni complex 12a (MeCN as
(1,5-hexadiene)PtCl2 was reported to react with various
+
solvent) the cation [M − PF ] (m/e = 305, 85%) eliminates
1,5-diphenylbispidin-9-ones in refluxing CHCl to afford the
6
3
+
11
the π-allyl group to form [(C H N )Ni] (264) as base ion.
corresponding (bispidin-9-one)PtCl complexes. More re-
1
3
22
2
2
+
The ion of the protonated ligand, [3 + H] (207, 35%), is also
cently, (MeCN) PtCl was reacted with (−)-sparteine in
2
2
9d
found. In the ESIpos mass spectra (MeCN, CH Cl ) of the Pd
CH Cl to give ((−)-sparteine)PtCl in low yield. In general,
2
2
2
2
2
+
and Pt complexes 12b,c the cation [M − PF ] furnishes the
platinum complexes are less reactive than palladium analogues
and therefore require longer reaction times and higher reaction
temperatures, giving rise to more byproducts.
6
base peak. This cation undergoes propene elimination (as
distinct from allyl elimination) for both complexes. Presumably,
the π-allyl group deprotonates one of the N-allyl substituents
In an attempt to synthesize (C H N allyl )PtCl we reacted
7
12
2
2
2
at NCH to become liberated as propene. The deprotonated
(C H )PtCl with 3 in DMF at 70 °C for 1 h. Evaporation of
2
6 10 2
N-allyl substituent, after a CC bond shift, ends up as an
the solvent led to a yellow residue consisting of several
azapalladacyclopentene moiety (eq 9, step a). A similar
components including {C H N (C H )(CHCHCH )}PtCl
7
12
2
3
5
2
(
13a), as shown by NMR. When K CO was added to the
2 3
reaction mixture, 13a could be isolated by column chromatog-
raphy as pale yellow microcrystals in 18% yield (eq 10a).
rearrangement was found in the synthesis of the Pt complexes
1
1
3a,b (see below). While no further significant ion arises for
2c (M = Pt), in the case of 12b (M = Pd) a second propene
elimination occurs. Apparently, the remaining N-allyl sub-
stituent cleaves, together with NCH proton abstraction from
2
the bispidine skeleton, to afford a Schiff base functional group
(
step b). During the fragmentation of both 12b,c the transition
metals become durably coordinated to the now tridentate
+
Presumably, in the presence of a base (still unreacted 3 or
ligand, rendering formation of [3 + H] insignificant.
1
13
K CO ) the intermediate square-planar (C H N allyl )PtCl
2 3 7 12 2 2 2
For a description of the H and C NMR spectra of 12a−c it
is most convenient to start with the sharply resolved spectra of
the Pd complex 12b. The coordination geometry of 12b is
is deprotonated at the NCH group of one of the N-allyl
2
substituents. Thereby, concomitant with a shift of the CC
bond, the terminal CH group can transform into a carbanion.
2
square-planar, C symmetrical, and fully rigid in solution at
s
The carbanionic CH possibly then nucleophilically attacks the
2
2
5 °C, with the mirror plane perpendicular to the coordination
Pt(II) center to displace chloride and afford 13a. It seems that
for this type of reaction the square-planar coordination geometry
of the metal is essential to allow for an in-plane attack of the
plane and passing through C2, C2′, and C3 of the bispidine
skeleton and C7 of the allyl group (Table 1). There are seven
1
13
H and five C resonances for the bispidine skeleton due to the
terminal allyl-CH group at the metal center.
2
inequivalence of C1 and C1′ as well as C2 and C2′, positioned
on different sides of the coordination plane. The axial protons
H 1 lie about 1 ppm at higher field than the geminal H 1. The
In complex 13a a Pt(II)−σ-allyl group is bound to the
coordinated bispidine to form an azaplatinacyclopentene
structural unit. The ligand can be viewed as a new tridentate
anionic ligand for mer coordination. The reaction has some
precedent in the reaction of N,N-dimethylallylamine with
Li PdCl in MeOH, which, by MeO addition and Cl elimina-
a
e
distinction between H 1 and H 1′ (0.5 ppm) is larger than that
e
e
between H 1 and H 1′ (0.2 ppm), reflecting the proximity of
a
a
the former to the allyl group. The protons H4 of the N-allyl
substituents are diastereotopic. The π-C H group (H7, H 8,
2
4
34
3
5
E
tion, affords an azapalladacyclopentane complex. Such a
transformation appears to occur in the ESIpos mass spectrum
of the Pd complex 12b (eq 9). When the synthesis of 13a is
carried out in the presence of MeOH or when 13a is
recrystallized from MeOH, the methoxy-substituted azaplatina-
cyclopentane derivative 13b is isolated (eq 10b), which
represents the addition product of 13a with MeOH.
1
and H 8) gives rise to an AM N H NMR spin system.
Z
2
2
As for 12b, the NMR spectra of the Pt derivative 12c are
sharply resolved and support a square-planar, C symmetrical
s
and rigid structure at 25 °C (Table 1). Most bispidine signals of
12c are very similar to those 12b (largest deviations are found
for H4 and C4 of the N-allyl substituents). The π-C H group
3
5
displays additional 1 Pt couplings, and its signals are shifted
95
As a solid, complex 13a is thermally very stable. It dissolves
very well in CH Cl and DMF and reasonably well in THF and
markedly to higher field.
2
2
In contrast, for the Ni derivative 12a the signals of H 1, H 1,
H2, H4, C1, and C2 are broad and unresolved at 25 °C,
MeCN, whereas it is insoluble in diethyl ether. In the EI
mass spectrum (190 °C) of 13a the molecular ion is found
(m/e = 435, 37%), which eliminates HCl (399, base ion) to
then undergo 2-fold propene elimination. The ESIpos mass
e
a
whereas all other signals are sharp (Table 1). Cooling to −75
°
C affords pairwise splitting of the broad signals, which is
1
3
+
+
best seen for the C NMR spectrum. The retained π-C H
spectrum (MeCN) shows [M] (base ion) and [M − Cl]
3
5
1
1
AM N H NMR spin system of 12a at 25 °C (as for 12b) rules
(80%) as the almost exclusive ions. According to the H and
2
2
1
3
out dynamic π−σ-allyl isomerization. The spectral behavior is
therefore consistent with π-allyl rotation, which appears feasible
C NMR spectra of 13a (Table 1), the coordination geometry
at Pt(II) is square planar, with the coordination plane as a
6
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Organometallics
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mirror plane, which therefore rules out the presence of a π-allyl
1
13
group. There are a total of 14 H and 10 C resonances. Within
the bispidine, the NCH H resonances at N(vinyl) (H 1′, H 1′,
e
a
e
a
and C1′) are all at lower field than those of the corresponding
nuclei at N(allyl). For the azaplatinacyclopentene moiety, the
signals of PtCH are found at δ(H7) 3.54 and δ(C7) 78.9, with
2
all other signals as expected.
We have also prepared the colorless crystalline (C H -
7
12
N allyl )MgMe (14) by addition of 3 to an ethereal solution of
2
2
2
MgMe . Compound 14 is likewise obtained from (tmeda)-
2
3
5
MgMe2 by displacing tmeda with an equimolar amount of 3,
thereby proving that 3 is more strongly bound than tmeda. In
this Mg complex ligand 3 is coligated by two strongly basic
methyl groups in tetrahedral coordination geometry. As shown
by DSC, compound 14 melts at 71 °C, while it recrystallizes
from the melt only at 10−20 °C with substantial supercooling.
Fused 14 is stable at 80 °C over prolonged periods (NMR) and
is volatile under vacuum. No azametallacyclopentene moiety is
formed by deprotonation (cf. 13a). As a model shows, attack of
Figure 1. Molecular structure of [(C H N allyl ]PF (9). Selected bond
7
13
2
2
6
distances (Å) and a nonbonding distance (Å): N1−C1 = 1.5096(10),
N1−C6 = 1.5121(10), N1−C8 = 1.5081(10), N2−C3 = 1.4749(10),
N2−C4 = 1.4726(10), N2−C11 = 1.4747(10), N1···N2 = 2.734.
the terminal allyl-CH group at the metal center is prevented in
2
the tetrahedral coordination geometry.
distance at 2.73 Å, although slightly longer than the values
observed for the majority of proton-bearing compounds of this
type (2.65−2.68 Å), is markedly shorter than in neutral
{
N,N′-Bis((R)-1-phenylethyl)-(S,S)-4,5-diamine-1,7-
octadiene}CuI (16). For a comparison with 11, we reacted
N,N′-bis((R)-1-phenylethyl)-(S,S)-4,5-diamine-1,7-octadiene
23
3
6
bispidines lacking the NH function (2.85−3.07 Å). The ring
(
15) with CuI in acetonitrile to afford colorless crystals of
torsion angles about the N2−C bonds of the piperidine ring are
close to ideal for chair conformation (58−59°), and the length
of the N2−C bonds is as typical for an azan N atom (1.47 Å,
mean). The ring torsion angles about the N1−C bonds of the
piperidinium ring are less (51°) and the chair conformation is
flattened here, concomitant with elongation of the azanium
N1−C bonds (1.51 Å, mean). Both N-allyl substituents are in
exo positions, with the N1−C8 and N2−C11 bonds lying in
one plane. Here again, the bond N1−C8 at the azanium N
atom (1.508(1) Å) is longer than N2−C11 at the azan N atom
(1.475(1) Å). The N2···N1−C8−C9 and N1···N2−C11−C12
torsion angles are 63° and −58°, corresponding to a syn-
dinuclear [{(C H ) (CH) (NH) (CHMePh) }Cu(μ-I)] (16)
3
5 2
2
2
2
2
in 81% yield. Here, the two allyl substituents are positioned on
the carbon backbone of the diamine ligand, rather than on the
nitrogen atoms, and the ligand is free of the bispidine skeleton.
Complex 16 melts at 139 °C without apparent decomposition.
However, when heated in a vacuum, the complex loses the
diamine ligands at 95 °C. Accordingly, its EI mass spectrum
corresponds to that of the free ligand 15. Ready cleavage of the
central C−C bond is characteristic for 15. Complex 16
dissolves very well in CH Cl , THF, CH CN, and DMF, but
2
2
3
1
13
seems insoluble in diethyl ether. The H and C NMR spectra
Table S1) are in agreement with D point group symmetry of
(
37
2
gauche−gauche conformation. It seems as if the vinyl groups
1
6. In the ESIpos mass spectrum (MeCN as solvent) the
+
are jointly directed away from the PF anion closest to the N1−
6
largest significant ion is [(C H N ) Cu I] (m/e = 949, 18%),
2
4
32 2 2
2
H1···N2 bridge. The shortest distance between cations and
anions is 2.365 Å between H1···F1.
which predominantly exchanges iodide for CN to generate the
+
base ion [(C H N ) Cu CN] (848). Elimination of one
24
32 2 2
2
The structure of complex 10 in the solid is shown in Figure 2.
diamine ligand from the dinuclear core of these ions affords
8
+
+
The d nickel atom is coordinated by the four O atoms of the
[
(C H N )Cu I] and [(C H N )Cu CN] . Eventually
24 32 2 2 24 32 2 2
+
mononuclear [(C H N )Cu] is formed. All in all diamine
2
4
32
2
coordination appears substantially weaker for complex 16 than
for the bispidine complex 11.
Molecular Structures of 9, 10, 11, and 12b. The crystal
structures of 9−11 and 12b have been determined (Table S2).
The structure of 9 is shown in Figure 1. The protonated
bispidine cation in 9 consists of piperidinium (involving N1)
and piperidine (N2) ring structures, both of chair conforma-
tion. The NH proton of the piperidinium ring is in an endo
position with respect to the concave face of the ion, which
enables N1−H1···N2 hydrogen bridging to the second nitrogen
atom (N1−H1 = 0.88 Å, N2···H1 = 2.13 Å). The N1···N2
Figure 2. Molecular structure of (C H N allyl )Ni(acac) (10).
7
12
2
2
2
Selected bond distances (Å), a nonbonding distance (Å), and bond
angles (deg): Ni1−N1 = 2.1980(7), Ni1−O1 = 2.0250(6), Ni1−O2 =
2.0419(6), N1···N1* = 2.891, N1−Ni1−N1* = 82.25(4), N1−Ni1−
O2 = 178.08(2), O1−Ni1−O1* = 176.8.
two chelating acac anions and the two N atoms of the bispidine
ligand in an almost ideally octahedral geometry (Figure 2).
6
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The complex sits on a crystallographic 2-fold axis of symmetry
passing through the Ni center and C6 of the bispidine ligand,
rendering both the two N-allyl groups and the two acac ligands
equivalent. The coordination sphere of Ni1 is best compared to
the contiguous N-allyl functions. One of the N-allyl groups
assumes a gauche conformation (Cu−N2−C11−C12 torsion
angle of 64.1°), whereas the other is forced to adopt a trans
conformation (Cu−N1−C8−C9 torsion angle of 179.8°).
Thus, within the dimeric molecule there are two pairs of
gauche−trans orientated vinyl groups, with the vinyl groups of
the different halves of the dimer being at a distance of about 5
29
that of the closely related (tmeda)Ni(acac) (A). While the
2
nonbonding N1···N1* distance at 2.89 Å is the same, for the
bispidine ligand in 10 the Ni1−N1 bond at 2.1980(7) Å is
longer than the corresponding bond in A (Ni−N = 2.16 Å,
mean). This causes a slight reduction in the N1−Ni1−N1*
angle to 82.3° (A, N1−Ni−N2 = 83.9°). The N atoms are close
to ideally tetrahedral, all angles at N ranging 106.7−111.9°. The
conformation of the N-allyl groups is such that the vinyl
moieties are gauche (69.7°) to the Ni atom with respect to the
N−C bonds, so the vinyl moieties are in an anti-gauche−gauche
conformation and appear to fill the octahedral holes
next to the two acac ligands. The length of the Ni−O bonds
at 2.03 Å (mean) is very similar in both complexes, with Ni−O
trans to N being slightly longer than Ni−O′ trans to O.
9
Å to one another. By way of comparison, the structure of the d
(bispidinone)CuCl complex D (two independent molecules)
2
is distorted tetrahedral. Due to its shorter Cu−N distances of
2.01 Å (mean), the angle N−Cu−N is even wider (88.2°,
mean) and the nonbonding N···N distance is substantially
shorter (2.80 Å, mean) than in 11. The angle Cl−Cu−Cl is also
32
relatively small (104.1°).
The crystal structure of the Pd complex 12b is shown in
Figure 4. The Pd cations and PF
anions appear well separated,
6
Complex 11 is dinuclear and comprises two coplanar (N,N′-
diallylbispidine)Cu(I) entities tetrahedrally bridged by two
iodide ions (Figure 3). The two halves of the dimer are related
3
Figure 4. Molecular structure of the cation in [(C H N allyl )Pd(η -
7
12
2
2
C H )]PF (12b). C15 of the allyl group is disordered over two
3
5
6
positions, A and B, of which only A is shown. Selected bond distances
(
2
2
Å), a nonbonding distance (Å), and bond angles (deg): Pd1−N1 =
.142(2), Pd1−N2 = 2.161(2), Pd1−C14 = 2.138(3), Pd1−C16 =
.125(3), N1···N2 = 2.938, N1−Pd1−N2 = 86.12(8).
as the closest distances between the ions are 2.582 Å for
H4A···F3 and 2.633 Å for H4A···F5. The bonding of the
bispidine to the metal is quite similar to that of the Cu complex
1
1 as far as the mean Pd−N distance of 2.15 Å, the N1−Pd1−
N2 angle of 86.1°, and the nonbonding N1···N2 distance of
.94 Å are concerned. Likewise, the conformation of the vinyl
2
Figure 3. Molecular structure of {(C H N allyl )Cu(μ-I)} (11).
Selected bond distances (Å), nonbonding distances (Å), and bond
7
12
2
2
2
groups is also gauche−trans, as the vinyl moiety bound to
N1−C8 is gauche (Pd1−N1−C8−C9 torsion angle of 64.7°)
and the one bound to N2−C11 is trans (Pd1−N2−C11−C12
torsion angle of 172.5°). The angles at nitrogen range from
angles (deg): Cu−I = 2.6098(3), Cu−I* = 2.5997(2), Cu−N1 =
2.1520(12), Cu−N2 = 2.1512(12), Cu···Cu* = 2.5859(4), N1···N2 =
2.956, N1−Cu−N2 = 86.76(4), I−Cu−I* = 120.480(7), Cu−I−Cu* =
59.520(7).
107.0° to 112.9° (N1) and 105.2° to 111.4° (N2).
While the chair−chair conformation of the bispidine skeleton
by an inversion center. The (bispidine) Cu (μ-I) skeleton
2
2
2
is uniform in all four structures, the (nonbonding) N···N
distance is shortest for the protonated 9 (2.73 Å), intermediate
for the Ni complex 10 (2.89 Å), and longer and of similar
magnitude for the Cu and Pd complexes 11 (2.96 Å) and 12b
itself, including the four methylene C atoms of the N-allyl
functions, exhibits almost ideal D symmetry. The geometry at
2
h
the nitrogen atoms is again tetrahedral, all angles ranging
07.2−112.0°. Although the Cu−N bond lengths at 2.15 Å
1
(
2.94 Å). Depending on the geometrical constraint of the
(
mean) are slightly shorter than the Ni−N bonds in 10, the
compounds, the conformation of the N-allyl substituents varies
between syn-gauche−gauche (9), anti-gauche−gauche (10),
and gauche−trans (11, 12b).
N1−Cu−N2 angle at 86.8° is relatively wide, affording inside
the bispidine a N1···N2 distance of 2.96 Å. For the Cu (μ-I)
2
2
rhombus the angle I−Cu−I* is wide (120.5°) and Cu−I−Cu*
is sharp (59.5°), allowing for a close Cu···Cu* contact of
CONCLUSIONS
2
.586 Å. These data are in close agreement with those of
■
31b
{
(tmeda)Cu(μ-I)} (C).
Thus, by virtue of the Cu (μ-I)
Revisiting the literature synthesis of N,N′-diallylbispidine (3),
we isolated pure 3 and the new byproducts 5−8. Protonation of
3 by HCl/TlPF afforded crystalline [(C H N allyl ]PF (9).
2
2
2
rhombus, both (bispidine)Cu entities are held in close
proximity, and due to the constraint of the rigid bispidine
skeleton, the same is true for the coplanar methylene groups of
6
7
13
2
2
6
Comparison of the EI mass spectra of compounds 2−9 allowed
6
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+
]+, 30).
for identification of a common fragmentation principle for the
various bispidines. For 9 both the ESIpos mass spectrum and
(MeCN): m/e (%) = 207 ([M − PF
6
] , 100), 559 ([2 M − PF
6
Anal. Calcd for C H F N P (352.3): C, 44.32; H, 6.58; F, 32.36; N,
13 23
6
2
7
.95; P, 8.79. Found: C, 44.17; H, 6.56; F, 32.40; N, 7.84; P, 8.77. For
NMR data, see Table 1.
C H N allyl )Ni(acac) (10). A suspension of 1.285 g (5.00
mmol) of Ni(acac) in 40 mL of pentane was stirred with 1.07 mL
5.05 mmol) of 3. In the course of one hour the solid dissolved and
X-ray structural data suggest (weak) N−H···F bonding between
−
the cation and the PF anion. Compound 3 has been used to
6
(
7
12
2
2
2
prepare a series of metal complexes, of which the derivatives
with M = Cu(I) (11) and Ni(II) (10 and 12a) are easily
accessible but not robust, the derivative with M = Pd(II) (12b)
is both easily accessible and robust, and the derivative for M =
Pt(II) (12c) is also robust, but it has a more laborious
2
(
the solution was filtered to remove insoluble impurities. Between 0
and −78 °C large dark blue cubes crystallized: yield 2.29 g (99%). Mp:
+
+
138 °C. EI MS (75 °C): m/e (%) = 462 ([M] , 4), 363 ([M − acac] ,
3
+
synthesis. Consequently, [(C H N allyl )Pd(η -C H )]PF
100), 256 ([Ni(acac)
−
2
] , 26). ESIpos (CH
2
Cl
acac] , 35), 207 ([3 + H] , 100). Anal. Calcd for C H N NiO
4
2
): m/e (%) = 363 ([M
7
12
2
2
3
5
6
+
+
(
12b) in particular appears suited for further applications. In
23 36
2
3
(463.2): C, 59.63; H, 7.83; N, 6.05; Ni, 12.67. Found: C, 59.75; H,
.82; N, 6.05; Ni, 12.59.
(C H N allyl )Cu(μ-I)} (11). To a suspension of CuI (952 mg,
solution the structure of the cations in [(C H N allyl )M(η -
7
12
2
2
7
C H )]PF is rigid for M = Pd (12b) and Pt (12c), but
3
5
6
{
7
12
2
2
2
dynamic for Ni (12a), the latter undergoing π-allyl rotation.
While the isolated complexes 10, 11, and 12a−c contain the
5
.00 mmol) in 40 mL of MeCN was added 3 (1.07 mL, 5.05 mmol).
When the mixture was heated to reflux (82 °C), the solid dissolved.
Recooling to ambient temperature afforded large colorless crystals:
yield 1.745 g (88%). Anal. Calcd for C H Cu I N (793.6): C, 39.35;
unaltered N,N′-diallylbispidine ligand, in the case of Pt, NCH
2
deprotonation of an N-allyl substituent appears as a viable
process, as exemplified by the formation of 13a,b. The novel
anionic tridentate ligands in 13a,b, containing the bispidine-
conjoined metallaazacyclopentene and -pentane moieties,
represent particularly stable structural motifs containing a free
vinyl group and, as such, deserve further attention.
2
6
44
2 2
4
H, 5.59; Cu, 16.02; I, 31.98; N, 7.06. Found: C, 39.57; H, 4.92; Cu,
16.64; I, 31.32; N, 6.94. ESIpos MS (MeCN): m/e (%) = 665 ([M −
+
+
+
I] , 70), 564 ([(C13H N ) Cu CN] , 80), 269 ([(C13H N )Cu] ,
22 2 2 2 22 2
+
4
0), 207 ([C H N ] , 100). For NMR data, see Table 1.
13 23 2
3
[
(C H N allyl )Ni(C H )]PF (12a). A solution of {(η -C H )Ni-
7 12 2 2 3 5 6 3 5
(
μ-Br)} (180 mg, 0.50 mmol) and 3 (0.22 mL, 1.04 mmol) in 20 mL
2
of MeCN was stirred with solid TlPF (360 mg, 1.00 mmol) at 20 °C.
6
EXPERIMENTAL SECTION
The reactions were performed under argon with Schlenk-type glassware.
Synthesis of 1, 3, and 4 was done according to the literature. For a
detailed description of the properties of 4, see ref 23. N,N′-Bis((R)-1-
phenylethyl)-1,7-octadiene-(S,S)-4,5-diamine (C H N , 348.5) (15)
was obtained as a gift from MCAT, Konstanz (Germany).
Separations of 2 and 5 and of 3 and 6−8 by Preparative
GC. Isolation of the individual compounds from the product mixtures
of the Mannich reaction (2 and 5) and subsequent Wolff−Kishner
reduction (3 and 6−8) was performed by preparative GC of the
volatile raw products on an AMPG-60 instrument (Gerstel Company,
Immediately, light yellow TlBr precipitated. After 30 min the solid was
removed by filtration. The resulting deep red solution was con-
centrated under vacuum to a volume of about 2 mL. After addition of a
■
20a
1
0-fold volume of THF the solution was cooled to −30 °C to afford
dark red crystals: yield 310 mg (69%). Dec: 160 °C. Anal. Calcd for
C H F N NiP (451.1): C, 42.61; H, 6.03; F, 25.27; N, 6.21; Ni,
3
6
2
4
32
2
16 27
6
2
1
3.01; P, 6.87. Found: C, 42.56; H, 6.05; N, 6.18; Ni, 13.02; P, 6.86.
+
ESIpos MS (MeCN): m/e (%) = 305 ([M − PF ] , 85), 264
6
+
+
([(C H N )Ni] , 100), 207 ([C H N ] , 35). For NMR data, see
13 22
2
13 23
2
Table 1.
[(C
H
N
allyl
)Pd(C
(183 mg, 0.50 mmol) and 3 (0.22 mL, 1.04
mmol) in 20 mL of THF was combined with a THF solution of TlPF
H )]PF (12b). A bright yellow solution of
7
12
2
2
3 5 6
3
Mu
̈
lheim, Germany); Volaspher A4 column (Methylsilicone, Merck),
{(η -C H )Pd(μ-Cl)}
3 5 2
length 10 m, internal diameter 20 mm; injector temperature 280 °C,
6
−1
column temperature 180 °C; N gas flow rate 600 mL min . Although
(360 mg, 1.00 mmol) at 20 °C. Immediately, a white precipitate of
TlCl formed. After 30 min the solid was removed by filtration and the
solution was concentrated to about 10 mL. Cooling to −30 °C
afforded off-white cuboids, whose crystallization was completed at −78
2
the separations were accompanied by considerable decomposition,
samples of 0.5−5 g of the pure compounds were collected, serving in
particular for characterization of the byproducts 5−8.
Isolation of 2 and 3 by Column Chromatography. Larger
amounts of pure 2 and 3 were obtained by subjecting the raw products
to column chromatography. For example, Wolff−Kishner reduction of 2
°C: yield 407 mg (82%). ESIpos MS (CH
2
Cl
)(C
)Pd] , 40). Anal. Calcd for C16H F N
27 6 2
2
): m/e (%) = 353 ([M −
+
+
PF
([C
] , 100), 311 ([C
H
N
(C
H
H
3 4
)Pd] , 30), 269
PdP
6
7
12
2
3
5
+
H
N
(C
H
7
11
2
3
4
2
0a
and 5 afforded, after azeotropic distillation, an oil containing bispidine
(498.8): C, 38.53; H, 5.46; F, 22.85; N, 5.62; P, 6.21; Pd, 21.34.
Found: C, 38.58; H, 5.56; N, 5.59; P, 6.23; Pd, 21.28. For NMR data,
see Table 1.
3
and byproducts 6−8. The oil was diluted in hexane, washed with
water, and dried over Na SO . Hexane was removed in a vacuum, and
2
4
the raw product (10−20 g) was purified by column chromatography
over silica gel (length of column 40 cm, diameter 7 cm), eluting with
acetic acid ethyl ester/hexane/triethylamine (30/70/5). Elution was
controlled by TLC, colorized by ninhydrin (3, R = 0.42). After
evaporation of the eluent using a rotary evaporator, analytically pure 3
remained: yield 5−10 g.
Data of Components. 3,7-Diallyl-3,7-diazabicyclo[3.3.1]nonan-
[(C
anhydrous {(C
THF was stirred with 3 (206 mg, 1.00 mmol) and TlPF
7
H
12
N
2
allyl
2
)Pt(C
3
H
5
)]PF
(272 mg, 0.25 mmol) in 40 mL of
(360 mg,
6
(12c). A yellow suspension of
H
)Pt(μ-Cl)}
3
5
4
6
1.00 mmol) at 50 °C for 1 day. After removal of TlCl by filtration the
f
solution was concentrated to a volume of 2 mL. At −78 °C beige-
colored crystals separated: yield 490 mg (83%); mp 158 °C dec.
+
ESIpos MS (MeCN): m/e (%) = 442 ([M − PF
] , 100), 400
6
+
9
-one (2), C H N O (220.3). 3,7-Diallyl-3,7-diazabicyclo[3.3.1]-
([{C H N (C H )(C H )}Pt] , 45). Anal. Calcd for C16H F N PtP
7 12 2 3 5 3 4 27 6 2
13
20
2
−
1
−1
nonane (3), C H N (206.3), ρ = 0.974 g mL = 4.72 mmol mL .
(587.5): C, 32.71; H, 4.63; F, 19.40; N, 4.77; P, 5.27; Pt, 33.21.
Found: C, 32.66; H, 4.65; N, 4.76; P, 5.26; Pt, 33.18. For NMR data,
see Table 1.
13
22
2
1
(
-(N-allylaminomethyl)-3,7-diallyl-3,7-diazabicyclo[3.3.1]nonan-9-one
5), C H N O (289.4). 1-(N-allylaminomethyl)-3,7-diallyl-3,7-
1
7
27
3
diazabicyclo[3.3.1]nonane (6), C H N (275.4). 3-Allyl-3,7-
{C
7
H
12
N
2
(C
3
H
5
)CHCHCH
2
6
H10)-
(276
1
7
29
3
diazabicyclo[3.3.1]nonane (7), C H N (166.3). 5-Allyl-9-methyl-
PtCl
2
(348 mg, 1.00 mmol), 3 (206 mg, 1.00 mmol), and K
1
0
18
2
3
,8
1
,5-diazatricyclo[5.3.1.0 ]undecane (8), C H N (206.3). For
mg, 2.00 mmol) was heated in DMF to 70 °C for 1 h. All insolubles
were removed by filtration, and the solvent was evaporated under
vacuum. The yellow residue, for which H NMR indicated the
1
3
22
2
NMR data, see Tables 1 and 2. For MS data, see text.
C H N allyl )]PF (9). A solution of 3 (0.21 mL, 1.00 mmol) in
[
7
13
2
2
6
THF (10 mL) was treated with a 7.8 M ethereal solution of HCl (0.13
mL, 1.01 mmol). When combined with a THF solution (10 mL) of
presence of several components, was purified by column chromatog-
raphy on silica gel, eluting was MeCN/CH Cl /aq NH (40/60/1).
2
2
3
TlPF (360 mg, 1.00 mmol), TlCl immediately precipitated and was
Solvent evaporation left a pure beige-colored microcrystalline
6
removed by filtration. After reducing the volume to 5 mL, cooling to
solid: yield 160 mg (18%). Mp 216 °C dec. EI MS (190 °C): m/e (%) =
+
+
+
−78 °C afforded colorless crystals: yield 280 mg (80%). ESIpos
435 ([M] , 37), 399 ([M − HCl] , 100), 357 ([M − HCl − C H ] , 43),
3
6
6
250
dx.doi.org/10.1021/om200824c|Organometallics 2011, 30, 6241−6252

Organometallics
Article
+
3
(
(
3
15 ([M − HCl − 2C H ] , 17). ESIpos MS (MeCN): m/e (%) = 435
(8) Fraenkel, G.; Cottrell, C.; Ray, J.; Russell, J. Chem. Commun.
1971, 273.
3
6
+
+
[M] , 100), 400 ([M − Cl] , 80). Anal. Calcd for C H ClN Pt
13
21
2
435.9): C, 35.82; H, 4.86; Cl, 8.13; N, 6.43; Pt, 44.76. Found: C,
5.44; H, 4.73; Cl, 8.19; N, 5.90; Pt, 45.27. For NMR data, see Table 1.
C H N (C H )CH CH(OMe)CH }PtCl (13b). When the syn-
(9) (a) Mason, S. F.; Peacock, R. D. J. Chem. Soc., Dalton Trans. 1973,
226. (b) Boschmann, E.; Weinstock, L. M.; Carmack, M. Inorg. Chem.
1974, 13, 1297. (c) Togni, A.; Rihs, G.; Pregosin, P. S.; Ammann, C.
Helv. Chim. Acta 1990, 73, 723. (d) Intini, F. P.; Pacifico, C.; Pellicani, R.
Z.; Roca, V.; Natile, G. Inorg. Chim. Acta 2008, 361, 1606.
(10) (a) Hosken, G. D.; Hancock, R. D. J. Chem. Soc., Chem.
Commun. 1994, 1363. (b) For a discussion of structurally reinforced
macrocyclic ligands, covering also the bispidine group, see: Hancock,
R. D.; Pattrick, G.; Wade, P. W.; Hosken, G. D. Pure Appl. Chem.
{
7
12
2
3
5
2
2
thesis of 13a is carried out in the presence of MeOH or when the
isolated 13a is recrystallized from MeOH, the addition product
with MeOH, 13b, is obtained. ESIpos MS (MeCN): m/e (%) = 432
+
(
[M − Cl] , 100). C H ClN OPt (467.9). Identification by NMR,
1
4
25
2
no elemental analysis.
C H N allyl )Mg(CH ) (14). To a solution of MgMe (54 mg,
35
(
7
12
2
2
3 2
2
1
.00 mmol) in 20 mL of diethyl ether was added 3 (0.21 mL, 1.00
1
993, 65, 473.
11) Black, D. S. C.; Deacon, G. B.; Rose, M. Tetrahedron 1995, 51,
055.
(12) (a) Gogoll, A.; Grennberg, H.; Axen
16, 1167. (b) Gogoll, A.; Grennberg, H.; Axen
998, 17, 5248. (c) Gogoll, A.; Johansson, C.; Axen
Chem.Eur. J. 2001, 7, 396.
13) Comba, P.; Kerscher, M.; Merz, M.; Mu
Remenyi, R.; Schiek, W.; Xiong, Y. Chem.Eur. J. 2002, 8, 5750.
14) Haack, K.-J.; Goddard, R.; Porschke, K.-R. J. Am. Chem. Soc.
997, 119, 7992.
15) (a) Pearson, R. G. J. Am. Chem. Soc. 1963, 185, 3533.
b) Pearson, R. G. J. Chem. Educ. 1968, 45, 3533. (c) Parr, R. G.;
mmol). Cooling to −78 °C afforded large colorless needles: yield 220
(
mg (84%). Mp: 70 °C (DSC). EI-MS (65 °C): m/e (%) = 245 ([M −
2
+
+
CH ] , 80), 229 ([C H N (C H )(C H )Mg] , 40); lower masses as
3
7
12
2
3
5
3
4
́
, A. Organometallics 1997,
, A. Organometallics
, A.; Grennberg, H.
for 3 (see text). Anal. Calcd for C H MgN (260.7): C, 69.11; H,
0.83; Mg, 9.32; N, 10.75. Found: C, 68.92; H, 10.78; Mg, 9.17; N,
0.67. For NMR data, see Table 1.
15
28
2
́
1
1
1
́
[
{(C H ) (CH) (NH) (CHMePh) }Cu(μ-I)] (16). To a suspension
3 5 2 2 2 2 2
(
̈
ller, V.; Pritzkow, H.;
of 190.5 mg (1.00 mmol) of CuI in 10 mL of MeCN was added
48.5 mg (1.00 mmol) of 15, and the mixture was heated to reflux for
0 min. The recooled solution was filtered to remove some insoluble
3
1
(
̈
1
impurities. Cooling to −30 °C afforded colorless cubes: yield 436 mg
(
(
(
(
8
81%). Mp: 139 °C. EI MS (95 °C): m/e (%) = 348 ([(C H N) -
9
11
2
(
+
+
C H ) ] , 1), 307 ([(C H N) (C H )] , 10), 174 ([(C H N)-
3
5
2
9
11
2
3
5
9
11
Pearson, R. G. J. Am. Chem. Soc. 1983, 105, 7512.
(16) (a) Cabbiness, D. K.; Margerum, D. W. J. Am. Chem. Soc. 1969,
91, 6540. (b) Hinz, F. P.; Margerum, D. W. J. Am. Chem. Soc. 1974, 96,
+
+
C H )] , 100). ESIpos MS (MeCN): m/e (%) = 949 ([M − I] , 18),
48 ([(C H N ) Cu CN] , 100), 601 ([(C H N )Cu I] , 20), 500
3
5
+
+
24
32
2
2
2
24 32
2
2
+
+
(
[(C H N )Cu CN] , 10), 411 ([(C H N )Cu] , 15). Anal. Calcd
24 32 2 2 24 32 2
4
993; Inorg. Chem. 1974, 13, 2941.
17) (a) Izatt, R. M.; Bradshaw, J. S.; Nielsen, S. A.; Lamb, J. D.;
for C H N Cu I (1078.0): C, 53.48; H, 5.98; Cu, 11.79; I, 23.55; N,
.20. Found: C, 53.43; H, 5.92; Cu, 11.62; N, 5.21. For NMR data, see
Table S1 of the Supporting Information.
48
64
4
2 2
(
5
Christensen, J. J. Chem. Rev. 1985, 85, 271. (b) Hancock, R. D.;
Martell, A. E. Comments Inorg. Chem. 1988, 6, 237 , and literature cited
therein.
ASSOCIATED CONTENT
Supporting Information
Tables S1 and S2 and crystallographic data in CIF format for 9,
0, 11, and 12b. This material is available free of charge via the
■
(18) Huttenloch, O.; Laxman, E.; Waldmann, H. Chem.Eur. J.
*
S
2002, 8, 4767.
(19) Opwis, K.; Mayer-Gall, T.; Po
20) (a) Miyahara, Y.; Goto, K.; Inazu, T. Synthesis 2001, 364.
b) Miyahara, Y.; Goto, K.; Inazu, T. Tetrahedron Lett. 2001, 42, 3097
and 9097 (corrigendum). (c) Galasso, V.; Goto, K.; Miyahara, Y.;
Kovac, B.; Klasinc, L. Chem. Phys. 2002, 277, 229.
21) Douglass, J. E.; Ratliff, T. B. J. Org. Chem. 1968, 33, 355.
22) (a) Smissman, E. E.; Ruenitz, P. C.; Weis, J. A. J. Org. Chem.
̈
rschke, K.-R. In preparation.
(
1
(
Internet at http://pubs.acs.org.
̌
AUTHOR INFORMATION
Corresponding Author
E-mail: poerschke@kofo.mpg.de.
■
*
(
(
1975, 40, 251. (b) Smissman, E. E.; Ruenitz, P. C. J. Org. Chem. 1976,
1, 1593. (c) Ruenitz, P. C.; Smissman, E. E. J. Heterocycl. Chem. 1976,
13, 1111.
4
ACKNOWLEDGMENTS
■
(
̈
23) Cui, H.; Porschke, K.-R.; Goddard, R. Submitted for
This study is part of the research project IGF Nr. 15691N,
administered by DECHEMA and AiF. Financial support from
the German Ministry of Economy and Technology (BMWi) is
gratefully acknowledged.
publication.
(
24) Fernan
Server, J.; Martin
25) Ruenitz, P. C.; Smissman, E. E.; Wright, D. S. J. Heterocycl.
Chem. 1977, 14, 423.
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́
dez, M. J.; Huertas, R.; Toledano, M. S.; Gal
́
vez, E.;
́
ez-Ripoll, M. Magn. Reson. Chem. 1997, 35, 821.
(
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(
6
252
dx.doi.org/10.1021/om200824c|Organometallics 2011, 30, 6241−6252