The first P-stereogenic 1D coordination polymers with the metal centers in the backbone

Article abstract of DOI:10.1002/ejic.201100154

The enantiomeric ligands (R,R)- and (S,S)-bis(o-anisylphenylphosphanyl) methane (R,R-22 and S,S-22) and (R,R)- and (S,S)-bis(phenyl-m-xylylphosphanyl) methane (R,R-23 and S,S-23; dppm*), were treated with [Cu(NCCH ₃)₄](BF₄) and AgBF₄ to produce the binuclear complexes [Cu₂(dppm*)₂(NCCH ₃)₄](BF₄)₂ or [Ag ₂(dppm*)₂](BF₄)₂, respectively. Then, these complexes were used as building blocks to prepare the first P-chirogenic 1D coordination polymers {[M₂(dppm*) ₂(dmb)₂](BF₄)₂}_n [dppm* = (R,R)-22, (S,S)-22, (R,R)-23, (S,S)-23, M = Cu, Ag, dmb = 1,8-diisocyano-p-menthane] where M is part of the backbone of the polymer chain. The isostructural nature of these new polymers with the achiral parent polymers, {[M₂(dppm)₂(dmb)₂](BF ₄)₂}_n (M = Cu, Ag), was unambiguously demonstrated with a combination of methods including ¹H NMR, chemical analysis, UV/Vis spectrometry, emission spectroscopy and emission lifetime measurements. The structure of the bimetallic complex [Ag₂(R,R-23) ₂](BF₄)₂ was solved by X-ray crystallography, and all enantiomeric complexes and polymers were characterized by circular dichroism spectroscopy. The (R,R)- and (S,S)-bis(o-anisylphenylphosphanyl) methane and bis(m-xylylphosphanyl)methane ligands (dppm*) react with Cu(BF₄)₂/Cu and Ag(BF₄) to form the chiral binuclear complexes, which in turn react with 1,8-diisocyano-p-menthane (dmb) to give the first P-stereogenic 1D coordination polymers {[M₂(dppm *)₂(dmb)₂](BF₄)₂} _n. The isostrutural nature of these new polymers with the parent symmetric dppm-containing polymers was unambiguously demonstrated by using a combination of several structure elucidation methods. All compounds and polymers were also characterized by circular dichroism spectroscopy.

Full text of DOI:10.1002/ejic.201100154

FULL PAPER
DOI: 10.1002/ejic.201100154
The First P-Stereogenic 1D Coordination Polymers with the Metal Centers in
the Backbone
Christine Salomon,[a,b] Daniel Fortin,[a] Naïma Khiri,[b] Sylvain Jugé,*[b] and
Pierre D. Harvey*[a]
Keywords: Silver / Copper / Phosphane ligands / Chirality / Coordination polymers
The enantiomeric ligands (R,R)- and (S,S)-bis(o-anisylphen-
ylphosphanyl)methane (R,R-22 and S,S-22) and (R,R)- and
(S,S)-bis(phenyl-m-xylylphosphanyl)methane (R,R-23 and
S,S-23; dppm*), were treated with [Cu(NCCH3)4](BF4) and
AgBF4 to produce the binuclear complexes [Cu2(dppm*)2-
(NCCH3)4](BF4)2 or [Ag2(dppm*)2](BF4)2, respectively. Then,
these complexes were used as building blocks to prepare the
first P-chirogenic 1D coordination polymers {[M2(dppm*)2-
(dmb)2](BF4)2}n [dppm* = (R,R)-22, (S,S)-22, (R,R)-23, (S,S)-
23, M = Cu, Ag, dmb = 1,8-diisocyano-p-menthane] where
M is part of the backbone of the polymer chain. The iso-
structural nature of these new polymers with the achiral par-
ent polymers, {[M2(dppm)2(dmb)2](BF4)2}n (M = Cu, Ag), was
unambiguously demonstrated with a combination of methods
including 1H NMR, chemical analysis, UV/Vis spectrometry,
emission spectroscopy and emission lifetime measurements.
The structure of the bimetallic complex [Ag2(R,R-23)2](BF4)2
was solved by X-ray crystallography, and all enantiomeric
complexes and polymers were characterized by circular di-
chroism spectroscopy.
Introduction
Design of coordination polymers and crystal engineering Since these early reports, the field has been totally domi-
using diphosphane assembling ligands is a topic of current nated by coordination polymers based on copper(I) and
interest.[1,2] The most common diphosphane bridging li- silver(I).[5–9] The resulting 1D polymers are invariably built
gands are those of the type Ph2P(CH2)mPPh2 with m = 1– upon mixed bridging ligands (i.e. dppm or dmpm and an
6. The smallest of the series is bis(diphenylphosphanyl)- assembling ligand) and there is often only a single bridging
methane (dppm), but one can also associate the structurally ligand keeping the polymer chain together (see 4,[5] 5,[6] 6,[6]
related bis(diphenylarsanyl)methane (dpam) and bis(di- 7,[7] 8–10,[8] 11, 12,[9] 13–16,[10] and 17;[11] Scheme 2).
methylphosphanyl)methane (dmpm). In the early days, co-
ordination polymers were obtained by bridging binuclear
complexes of the 4th and 5th row transition elements by
dppm or dmpm such as polymers 1–3 (Scheme 1).[3,4]
On some occasions, however, 1D polymers could also be
built upon multi-bridging strategies such as those illustrated
in Scheme 3 (see polymers 18,[12] 19,[13] 20, and 21[14]). They
exhibit two general structures, ladder (18) and rigid rods
(19–21), and consequently they are symmetric objects.
To the best of our knowledge, no chiral-dppm or P-chir-
ogenic coordination polymer with the metal atoms in the
backbone has been reported. There is one example of a P-
chirogenic polymer, polymer 25 (Scheme 4), that falls into
this category but the metal fragment, PtCl2, is not part of
the backbone.[15] The diphosphane binap [2,2Ј-bis(diphenyl-
phosphanyl)-1,1Ј-binaphthyl] has also been used to produce
chiral coordination polymeric materials but in such cases
the P atom is not chirogenic as it is in this case.[16]
Scheme 1.
Recently, the enantiomeric ligands (R,R)- and (S,S)-
bis(o-anisylphenylphosphanyl)methane [dppm*; (R,R)-22,
(S,S)-22; Scheme 5] were used to prepare the C3-symmetry
[Pd3(dppm*)3-(CO)(O2CCF3)](CF3CO2) clusters which
were characterized by X-ray crystallography and circular di-
chroism spectroscopy.[17]
[a] Département de Chimie, Université de Sherbrooke,
Sherbrooke, PQ, Canada, J1K 2R1
Fax: +1-819-821-8017,
E-mail: Pierre.Harvey@USherbrooke.ca
[b] Institut de Chimie Moléculaire de l’Université de Bourgogne
(ICMUB), UMR CNRS 5260, Université de Bourgogne,
9 avenue Alain Savary, B. P. 47870, 21078 Dijon Cedex, France
Fax: +33-3-80396113
We now wish to report the first P-chirogenic 1D (and
rigid rod) coordination polymers {[M2(dppm*)2(dmb)2]-
E-mail: sylvain.juge@u-bourgogne.fr
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Scheme 2.
Scheme 3.
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P-Stereogenic 1D Coordination Polymers
(S)-chlorophosphane–borane 26 afforded the protected
(R,R)-diphosphane–diborane 28 in good yields. The enan-
tiomeric purity was checked by chiral HPLC using racemic
samples of 28. The desired free dppm* ligand 22 was ob-
tained cleanly after decomplexation of the diborane com-
plex 28 with DABCO (Scheme 6).
Scheme 4.
The chiral coordination polymers were synthesized in
two steps. First, the binuclear complexes [Cu2(dppm*)2-
(NCCH3)4](BF4)2 {from dppm* + Cu(BF4)2 + Cu in
CH3CN}[19a] or [Ag2(dppm*)2](BF4)2 (from dppm* +
AgBF4 in CH3CN)[19b] {dppm* = (R,R)-22, (S,S)-22,
(R,R)-23, (S,S)-23} were prepared in the same manner as
the parent achiral dppm complexes using the P-chirogenic
dppm* ligands, with isolated yields ranging from 50–98%
(Scheme 7). Thus, four new P-chirogenic (binuclear) com-
plexes in both enantiomeric forms were prepared and char-
acterized.
(BF4)2}n [dppm* = (R,R)-22, (S,S)-22, (R,R)-23, (S,S)-23
(Scheme 5), M = Cu, Ag, dmb = 1,8-diisocyano-p-men-
thane] where M is part of the polymer backbone. In the
absence of X-ray structure determination, 1H NMR, chemi-
cal analysis, UV/Vis spectrometry, emission spectroscopy,
and photophysical measurements were used to unambigu-
ously demonstrate the isostructural nature of these new
polymers with the parent dppm-containing polymers 20
and 21.[14]
In the [Ag2{(R,R)-23}2](BF4)2 case, the X-ray crystal
structure was obtained (Figure 1). As expected, this com-
plex exhibits two (R,R)-23 ligands bridging two AgI metals,
Results and Discussion
Syntheses and characterization. The stereoselective syn- forming an eight-membered ring in a “boat” conformation.
theses of the (R,R)- and the (S,S)-ligands 22 were per- The Ag atoms are separated by 2.932(1) Å, a distance typi-
formed in several steps using the (+)- or (–)-ephedrine cal of complexes containing the Ag2(P P)22+ frame with no
∧
methodology, via formation of the chlorophosphane– formal Ag–Ag bond.[20,21] The global C2-symmetry of the
borane intermediate 26.[18] The key step of the synthesis complex is also evident. Full details of the structure are
is the methano bridge formation from the reaction of the provided in the Supporting Information. The 31P NMR
carbanion derived from the methylphosphane–borane 27 spectra of the bimetallic [Ag2(dppm*)2](BF4)2 complexes
1
with the chlorophosphane–borane 26; see Scheme 6, only exhibit a doublet of apparent triplets, due to the JAgP
the (R,R)-version is shown.[18]
coupling between phosphorus and the combination of the
Thus, the reaction of the (S)-o-anisylchlorophenylphos- silver isotopes 107Ag and 109Ag, in 48 and 52% natural
phane–borane 26 with the MeLi reagent affords the corre- abundance, respectively (Table 1).[22] Conversely, the
sponding (R)-methylphosphane–borane 27 with inversion [Cu2(dppm*)2(NCCH3)4](BF4)2 species are characterized by
1
of configuration at the P-centre. After deprotonation of the a singlet consistent with the absence of direct J coupling
methylphosphane–borane 27 with nBuLi, reaction with the (Table 2).
Scheme 5.
Scheme 6.
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–
Scheme 7. L = CH3CN; BF4 anions not shown.
nide ligand dmb. The general reactions are shown in Equa-
tions (1) and (2), with dppm* = (R,R)-22, (S,S)-22, (R,R)-
23, and (S,S)-23.
[Cu2(dppm*)2(NCCH3)4](BF4)2 + 2 dmb Ǟ
{[Cu2(dppm*)2(dmb)2](BF4)2}n + 4 CH3CN (1)
[Ag2(dppm*)2](BF4)2 + 2 dmb Ǟ {[Ag2(dppm*)2(dmb)2](BF4)2}n
(2)
The coordination of dmb is evidenced by the change in
ν(NϵC) going from the uncoordinated dmb ligand (at
2135Ϯ5 cm–1) to the coordination polymers (at
2180Ϯ5 cm–1). Both 1H NMR and chemical analyses agree
with the stoichiometry of the polymers. The isolated yields
are compared in Table 1 and all appear good to excellent
Figure 1. ORTEP representation [Ag2{(R,R)-23}2](BF4)2. The ellip-
soids are shown with 50% probability. The H-atoms and counter
anions are not shown for clarity.
The corresponding P-chirogenic coordination polymers except for one case [({Ag2{(R,R)-23}2(dmb)2}(BF4)2),
were prepared by reacting the enantiomeric P-chirogenic bi- 24%]. No attempt was made to increase the yield as there
nuclear complexes with 2 equiv. of the assembling diisocya- was enough material to carry out the characterization.
Table 1. 31P NMR spectroscopic data for Ag2 complexes and their coordinating polymers with dmb.
[b]
[b]
3
[b]
Entry
δ[a,c]
1J107Ag–P
1J109Ag–P
|1JAg–P + JAg–P
|
1
2
3
4
5
6
(R,R)-22
–31.2
–33.5[d]
+2.2
+8.5
+0.2
–
–
487
471
–
–
–
561
543
–
–
–
525
508
425
402
(R,R)-23
[Ag2{(R,R)-22}2](BF4)2
[Ag2{(R,R)-23}2](BF4)2
{[Ag2{(R,R)-22}2(dmb)2](BF4)2}n
{[Ag2{(R,R)-23}2(dmb)2](BF4)2}n
+3.6
375
429
[a] δ in ppm relative to H3PO4. [b] In Hz. [c] CD3CN at 295 K. [d] CDCl3 at 295 K.
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P-Stereogenic 1D Coordination Polymers
Table 2. 31P NMR spectroscopic data for Cu2 complexes and their
coordinating polymers with dmb.
Entry
δ[a,b]
1
2
7
8
9
10
(R,R)-22
–31.2
–33.5[c]
–16.9
–10.9
–20.7
–7.6
(R,R)-23
[Cu2{(R,R)-22}2(NCCH3)4](BF4)2
[Cu2{(R,R)-23}2(NCCH3)4](BF4)2
{[Cu2{(R,R)-22}2(dmb)2](BF4)2}n
{[Cu2{(R,R)-23}2(dmb)2](BF4)2}n
[a] δ in ppm relative to H3PO4. [b] CD3CN at 295 K. [c] CDCl3 at
295 K.
Attempts to obtain crystals suitable for X-ray crystal
structure determinations stubbornly failed. In order to
demonstrate the isostructurality of the polymers with the
parent dppm-containing polymers 20 and 21 (Scheme 3),
UV/Vis and luminescence spectroscopy were used and,
more importantly, emission lifetime measurements were
also performed. The argument is that if the chromophore
[M(CNR)2(P)2] is the same for all cases, the position of the
emission bands should be the same. In addition, if the emis-
sion lifetimes are also in the same neighbourhood, then the
overall structure must be the same for both the dppm- and
dppm*-containing polymers. This point will be discussed
further below. Moreover, the use of the absorption data
alone is not ideal since these features appear below 400 nm
and many overlapping bands appear in this same spectral
range (200–400 nm).
Circular dichroism. In order to demonstrate that the tar-
get four P-chirogenic binuclear complexes (Scheme 5) and
the four P-chirogenic polymers in both enantiomeric forms
were obtained, circular dichroism spectroscopy (CD) was
used. The typical UV/Vis spectra of a ligand [(R,R)-22 for
example] and its corresponding binuclear complex and co-
ordination polymer are shown in Figure 2. The ligand ab-
sorbs in the 200–310 nm range (typical for π,π*-type transi-
tions for substituted benzenes), whereas the binuclear com-
plex and coordination polymer absorb in the 200–380 nm
window. These absorptions indicate a region where CD ac-
tivity is expected. Indeed, the CD spectra for the ligands
exhibit positive and negative signals for both enantiomeric
forms precisely in this same spectral window (see Figure 3
as an example).
Figure 3. Comparison of the CD of the ligands (R,R)-22, (S,S)-22,
the corresponding binuclear complexes, [Cu2(dppm*)2](BF4)2 and
coordination polymers {[Cu2(dppm*)2(dmb)2](BF4)2}n [dppm* =
(R,R)-22, (S,S)-22] as typical examples; solvent: acetonitrile.
The appearance of a new red shifted bands in both the
UV/Vis and CD spectra in the 320–360 nm region going
from the uncoordinated ligand to the binuclear complexes
and coordination polymers is common and fully consistent
with new spin-allowed electronic transitions involving the
metallic center appearing on the low energy side of the
spectra. Indeed, these were previously theoretically ad-
dressed for polymers of the type [M(dmb)2+]n (M = Cu, Ag)
and Cu2(dppm)2(O2CCH3)+.[23,24] These bands are expect-
edly assigned to metal-to-ligand-charge-transfer (MLCT)
for the d10 electronic configurations for CuI and AgI.
The CD data for the binuclear complexes and polymers
are listed in Table 3. Again, the CD spectra of both enantio-
meric forms of the binuclear complexes and coordination
polymers exhibit the expected mirror-image relationship. A
slight red shift of the low-energy (positive and negative) sig-
nals for the binuclear complexes and coordination polymers
in comparison with that of the corresponding ligands is also
observed following the same trend that is observed in the
UV/Vis spectra.
Figure 2. Examples of solid state UV/Vis spectra of the ligand
(R,R)-22, the binuclear complex [Cu2{(R,R)-22}2](BF4)2 and coor-
dination polymer {[Cu2{(R,R)-22}2(dmb)2](BF4)2}n at 298 K.
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Table 3. CD data for the [Cu2(dppm*)2(CH3CN)4](BF4)2 and [Ag2(dppm*)2](BF4)2, binuclear complexes, and the {[M2(dppm*)2(dmb)2]-
(BF4)2}n, polymers in acetonitrile at 298 K.
Binuclear complex (R,R)
λmax [nm]
(S,S)
λmax [nm]
θ [mdeg](a)
θ [degcm2 dmol–1](b)
θ [mdeg](a)
θ [degcm2 dmol–1](b)
dppm* = 22
210
226
238
265
294
212
228
248
254
284
201
224
259
276
297
207
249
272
281
288
25.2
–14.2
5.1
–5.3
3.3
–18.3
3.2
1.3
190000
–107000
38200
–39900
24500
–137000
23500
9500
11200
–6900
319000
–122000
–12900
93900
–45200
–319000
8300
10000
14600
12500
212
225
238
263
296
213
226
249
258
285
206
224
253
278
301
209
248
273
280
289
–16.8
14.7
–4.2
4.6
–4.5
18.7
–6.5
–1.7
–1.3
1.1
–47.1
13.5
2.6
–15.4
6.4
–127000
110000
–31200
34800
–34000
126000
–43700
–11400
–8700
7100
–335000
95500
18400
–110000
45500
M = Cu
dppm* = 23
M = Cu
1.5
–0.9
49.9
–19.0
–2.0
14.7
–7.1
–45.1
1.2
dppm* = 22
M = Ag
dppm* = 23
M = Ag
45.3
–0.7
–1.3
–1.7
–1.5
262000
–5100
–9400
–12300
–10800
1.4
2.1
1.8
Polymer
(R,R)
λmax [nm]
(S,S)
λmax [nm]
θ [mdeg](a)
θ [degcm2 dmol–1](b)
θ [mdeg](a)
θ [degcm2 dmol–1](b)
dppm* = 22
208
222
240
294
335
210
226
246
278
207
225
234
256
278
213
241
258
271
298
12.5
–10.0
–10.3
7.6
–2.2
–18.3
3.1
82000
–65300
–67300
49900
–14200
–119000
20200
6400
7600
181000
–8400
42900
–35100
97800
–174000
13900
–8200
16400
209
225
241
292
332
208
228
245
278
208
224
235
254
276
212
239
259
273
297
–15.3
12.1
11.9
–9.7
2.2
18.3
–4.0
–1.4
–1.0
–32.0
3.5
–5.4
5.0
–13.3
21.1
–1.7
1.0
–120000
94800
93400
–76000
17600
119000
–25900
–8900
–6400
–220000
23900
–37100
34900
–92100
145000
–11700
7100
M = Cu
dppm* = 23
M = Cu
1.0
1.2
dppm* = 22
M = Ag
26.2
–1.2
6.2
–5.1
14.2
–25.2
2.0
–1.2
2.4
–1.5
dppm* = 23
M = Ag
–2.3
1.1
–15600
7800
–10500
Uncertainties: (a) Ϯ0.5 mdeg. (b) θ: (θexp. ϫM/cϫlϫ10)Ϯ100 degcm2 dmol–1 with M: molar mass (gmol–1), c: concentration (gmL–1),
l: optical path length, 0.2 cm.
One of the concerns in coordination polymers is that in
the solid state these polymers could be real polymers but in
solution these could break down in very small oligomers
including even a monomer. Our group spent a large amount
of time investigating mono-ligand and mixed-ligand coordi-
nation polymers, namely for isocyanides and phosphanes,
and demonstrating clearly the presence of oligomer (solu-
tion) and polymer (solid state) equilibrium. The most strik-
ing example is the {[Ag(dmb)2]+}n polymer which is 7–9
units long in acetonitrile solution (Scheme 8).[25]
Scheme 8.
{[Ag(U-dmb)2]+}n ↔ {[Ag(U-dmb)(Z-dmb)]+}n ↔
{[Ag(U-dmb)2]+}n (3)
But also show an obvious equilibrium between the U-
This finding shows that the isocyanine systems are in-
shaped and Z-shaped coordinated dmb ligand (Scheme 9) deed dynamic and exists as oligomers in solution. However,
as crystallographically demonstrated in Equation (3).[26]
they return to polymers when these oligomers return to the
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P-Stereogenic 1D Coordination Polymers
solid state. Moreover, in the mixed-ligand diphosphane-
dmb polymers (Scheme 10) exhibit oligomers lengths vary-
ing from 7 to 16, somewhat similar to the polymers pre-
sented in Schemes 7 and 8).[27]
The fact that the lowest energy CD signals of the ligands
and the oligomers (dimers and oligomers) are different
meaning that the oligomers are not very small (simple di-
Scheme 9.
Scheme 10.
Scheme 11.
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C. Salomon, D. Fortin, N. Khiri, S. Jugé, P. D. Harvey
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mers, trimers or tetramers) but are somewhat longer and to 2.75 averaging 2.37 μs.[28] This comparison indicates a
retain the dmb in the coordination sphere. All in all, four clear relationship between the structure (cis vs. trans) and
P-chirogenic binuclear complexes and the four P-chirogenic the photophysical data. The replacement of an axial bridg-
polymers in both enantiomeric forms have been prepared ing diphosphane ligand by two monodentate PPh3 axial li-
and characterized by CD spectroscopy.
gands does not drastically change the position and lifetime
Luminescence Spectroscopy. As stated above, in the ab- of the emission band. The AgI species can also be separated
sence of X-ray diffraction data for the coordination poly- into two categories as well, chelate and bridging diphos-
mers, luminescence spectroscopy and measurement of emis- phanes. The mononuclear complex [Ag(dppe)(CNtBu)]+
sion lifetimes (τe) were used to confirm the isostructural 1- and polymer {Ag(dppe)(dmb)+}n in the solid state at 298 K
D nature of these new materials. Prior to doing so, literature exhibit MLCT excited state with similar emission maxima
precedents are necessary to explain the method. Scheme 11 at 515 and 548 nm and similar emission lifetimes of 21 and
compares the emission maxima and lifetime of several ex- 27 μs, respectively.[28] This means that the replacement of
amples of mixed-ligand d9-d9 Pd2-bonded species and d10 dmb by two CNtBu ligands does change drastically the
AgI species, both monomers and oligomers where the li- electronic and steric effect on the excited state properties
gands are dmb, tert-butyl isocyanide and diphos- and the local structure. This observation corroborates that
phanes.[14,27,28]
seen for the replacement of an axial diphosphane ligand by
The d9-d9 Pd2-bonded species, both monomeric and two axial monodentate PPh3 groups as stated above. The
oligomeric species are characterized by lowest energy singlet 1D {Ag(dpppen)(CNtBu)2+}n and {Ag2(dppm)2(dmb)2
}
2+
n
and triplet dσǞdσ* energy excited states. This series can (21)[14] coordination polymers in the solid state at 298 K
be separated into two categories, chelating diphosphanes exhibit emission maxima at 491 and 499 nm, with lifetimes
[such as bis(diphenylphosphanyl)ethane (dppe) and -pro- of 55 and 27 μs, respectively. Although there is no change
pane (dppp)][28] and bridging diphosphanes [such as bis- in emission maxima, due to the good similarity in chemical
(diphenylphosphanyl)butane (dppb), -pentane (dpppent), environment, the emission lifetime changes by a factor
-hexane (dpph), and -ethynylene]. The former series in of 2. This change reflects the change in polymer
PrCN at 77 K exhibits emission maxima between 500 and structure ···Ag(diphos)Ag(diphos)··· vs. ···Ag(diphos)2Ag-
+
510 nm and an emission lifetime between 1.50 and 1.98 μs (dmb)···. Similarly, the {Cu(dpppen)(CNtBu)2
}
and
n
(average 1.80 μs).[27] The latter series exhibits emission max- {Cu2(dppm)2(dmb)22+}n (20) exhibit emission lifetime of 42
ima ranging from 627 to 638 nm, and lifetimes from 1.87 and 24 μs, respectively.[14]
Figure 4. Absorption (in butyronitrile solution at 298 K; dark grey), excitation (light grey) and emission spectra (black) of the chiral and
achiral {[Cu2(dppm*)2(dmb)2](BF4)2}n polymers (dppm* = dppm, 22, 23) in the solid state at 77 K.
2604
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Eur. J. Inorg. Chem. 2011, 2597–2609

P-Stereogenic 1D Coordination Polymers
Both binuclear complexes and polymers are strongly lu- (P)2] chromophore locked inside the 1D polymer structure
minescent at 77 K (Figure 4). In this work, the [M(CNR)2- in comparison with those of the binuclear complexes
(P)2] chromophore environment can also be confirmed from [Cu2(dppm)2(NCCH3)4](BF4)2 and [Ag2(dppm)2](BF4)2
–
the comparison of the emission maxima between the struc- where looser Cu–NCCH3 and Ag+···F–BF3 interactions
turally known {[M2(dppm)2(dmb)2](BF4)2}n polymers (M = takes place.
Cu, Ag) and the corresponding chiral {[Cu2(dppm*)2-
In order to corroborate the similarity in 1D structure of
(dmb)2](BF4)2}n ones (dppm* = 22, 23; see Figure 4 and the {[Ag2(dppm*)2(dmb)2](BF4)2}n polymers and 20, we
Table 4).
also have examined the steric environment about the ortho-
and meta-positions of the dppm ligand in the parent achiral
polymer (Figure 5). While the meta-positions are clear from
obstruction, some of the ortho-positions are less so. Indeed,
there are a total of eight possible ortho-positions per repeti-
tive unit where OMe groups can be placed. Of these eight,
two are simply cluttered (labelled with #), and two others
sterically difficult (labelled with §) but available. The four
other ortho-positions are fully accessible. Hence, the forma-
tion of the polymers {[Cu2(dppm*)2(dmb)2](BF4)2}n and
{[Ag2(dppm*)2(dmb)2](BF4)2}n [dppm* = (R,R)-22, (S,S)-
22, (R,R)-23, and (S,S)-23] are corroborated from a simple
modeling stand point.
Table 4. UV/Vis and luminescence data (solid state) of the binuclear
complexes and polymers.
λem [nm] 77K[a] τe 77K[b]
{[Cu2(22)2(dmb)2](BF4)2}n
{[Cu2(23)2(dmb)2](BF4)2}n
{[Cu2(dppm)2(dmb)2](BF4)2}n 543
{[Ag2(22)2(dmb)2](BF4)2}n
{[Ag2(23)2(dmb)2](BF4)2}n
{[Ag2(dppm)2(dmb)2](BF4)2}n 481
550
536
435Ϯ15 μs
450Ϯ25 μs
380Ϯ10 μs
210Ϯ10 μs
265Ϯ15 μs
260Ϯ10 μs
479
480
[Cu2(22)2(NCCH3)4](BF4)2
[Cu2(23)2(NCCH3)4](BF4)2
[Cu2(dppm)2(NCCH3)4](BF4)2 488
[Ag2(22)2](BF4)2
[Ag2(23)2](BF4)2
[Ag2(dppm)2](BF4)2
482
492
117Ϯ20 ns
73.5Ϯ1.6 ns
152Ϯ10 ns
34.3Ϯ0.5 ns
36.1Ϯ1.6 ns
40.3Ϯ5 ns
440
449
447
[a] In butyronitrile. [b] λex = 391 nm; λexp.t = 550 nm for all the
polymers, λexp. = 490 nm for all three [Cu2(dppm*)2(NCCH3)4]-
(BF4)2 complexes, and = 450 nm for all three [Ag2(dppm*)2]-
(BF4)2 species.
The 1D nature can be confirmed from the similarity in
τe values based on the fact that the amplitude of the radia-
tive (ke) and non-radiative (knr) rate constants [τe = 1/(ke +
knr)] are properties dependent upon the molecular struc-
tures (molecular symmetry and relative frequencies of the
Franck–Condon active vibrations). In this way, we can dis-
tinguish between known 1D {[M2(dppm)2(dmb)2](BF4)2}n
polymers (M = Cu, Ag) and any other network (i.e. 2D and
3D).
At 77 K, the λem values (Table 3) vary with {[Cu2-
(dppm*)2(dmb)2](BF4)2}n (536–550 nm) Ͼ {[Ag2(dppm*)2-
(dmb)2](BF4)2}n (479–481 nm) Ն [Cu2(dppm)2(NCCH3)4]-
(BF4)2 (482–492 nm) Ͼ [Ag2(dppm)2](BF4)2 (440–449 nm)
where dppm* is dppm, 22 or 23. On one hand, these values
confirm the similarity in λem maxima within the same series
of dppm* ligand, confirming the similarity in the [M(CNR)2-
(P)2] chromophore, but also allow for differentiation be-
tween Cu and Ag species and between polymers and dimers.
Figure 5. Bottom: space filling representation of a segment of the
achiral {[Ag2(dppm)2(dmb)2](BF4)2}n polymer stressing the two or-
tho-positions, # [note the Ci symmetry of the Ag2(dppm)2 unit],
that are too sterically demanding to insert a substitutant such as
OCH3. The outside atoms are dummy atoms for drawing purposes.
Similarly, the τe values (Table 3) vary as {[Cu2(dppm*)2- Top; ball and stick model, bottom, space filling model.
(dmb)2](BF4)2}n (380–450 μs) Ͼ {[Ag2(dppm*)2(dmb)2]-
(BF4)2}n (210–265 μs)
Ͼ
[Cu2(dppm)2(NCCH3)4](BF4)2
Thermal stability. During the course of this study, the
(0.07–0.15 μs) Ͼ [Ag2(dppm)2](BF4)2 (0.03–0.04 μs) where thermal stability of the new polymers was tested by thermal
dppm* is dppm, 22 or 23. The similarity in τe within the gravimetric analysis (TGA; Figure 6). The materials are
series confirms the structure about the [M(CNR)2(P)2] stable up to about 190 °C, consistent with what is known
chromophores as being 1D. Moreover, the fact that the τe about the decomposition of the M-dmb unit based on re-
values for the Cu-containing species are shorter than those centstudies on{[M(diphos)(dmb)]BF4}n and{[Pd2(diphos)2-
for the Ag ones, reflects upon the heavy atom effect which (dmb)](ClO4)2}n coordination polymers [M = Cu, Ag; di-
is a consequence of the strong spin-orbit coupling of the phos = Ph2P(CH2)mPPh2, m = 2, 3],[28] {[M2(dppm)2(dmb)2]-
heavier silver atom. The fact that the τe values for the poly- (BF4)2}n (M = Cu, Ag),[14] and {[M2(dppm)2(dmb)]-
mers are larger than those for the binuclear complexes re- (BF4)2}n (M = Pd, Pt).[29] The second major thermal event
flects upon the larger rigidity of the tetrahedral [M(CNR)2- occurs between 260 and 450 °C and is most likely due to
Eur. J. Inorg. Chem. 2011, 2597–2609
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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2605

C. Salomon, D. Fortin, N. Khiri, S. Jugé, P. D. Harvey
FULL PAPER
Figure 6. TGA traces for the {[M2(dppm*)2(dmb)2](BF4)2}n polymers.
decomposition of the dppm* ligand mixed with the loss of
the BF4 anions. All in all, these new materials exhibit a
very strong resemblance with thermal behavior observed for
the aforementioned polymers.
(R,R)- or (S,S)-bis(o-anisylphenylphosphanyl)methane and (R,R)-
or (S,S)-bis(m-xylylphenylphosphanyl)methane were substituted
for dppm. The (R,R)-ligands were prepared via their corresponding
diborane complexes by reaction of the α-carbanion derived from
the (Rp)-(–)-N-methyl-[(1R,2S)(2-hydroxy-1-phenyl)ethyl]amino-o-
anisylphenylphosphane–borane or (Rp)-(–)-N-methyl-[(1R,2S)(2-
hydroxy-1-phenyl)ethyl]aminoxylylphenylphosphane–borane with
the (S)-o-anisylchlorophenylphosphane–borane or (S)-o-xylylchlo-
rophenylphosphane, respectively, employing a modified methodol-
ogy starting from the (+)-ephedrine.[18] The (S,S)-ligands were pre-
pared in a similar way starting from (–)-ephedrine. The chiral phos-
phane–boranes 26 were also prepared by methods described in the
literature.[18] The detailed synthesis of the anisyl derivatives are de-
scribed below. To avoid repetition, only the (R,R)-series are de-
scribed. The synthesis of the corresponding xylyl-containing mate-
rials is reported elsewhere.[31]
–
Conclusions
The first P-chirogenic 1D coordination polymers in both
enantiomeric forms were prepared and characterized by cir-
cular dichroism spectroscopy among other techniques.
These are of the type {[M2(dppm*)2(dmb)2](BF4)2}n where
dppm* is one of the chiral ligands (R,R)-22, (S,S)-22,
(R,R)-23, and (S,S)-23, and M is either Cu or Ag. The iso-
strutural nature of these new polymers with the parent sym-
metric dppm-containing polymers, {[M2(dppm)2(dmb)2]-
(BF4)2}n, was unambiguously demonstrated with a combi-
(RP)-(–)-o-Anisylmethylphenylphosphane–Borane (27): In a 50 mL
two-necked flask equipped with a magnetic stirrer, 2 mmol of the
(RP)-(–)-N-methyl-[(1R,2S)-(2-hydroxy-1-phenyl)ethyl]amino-o-an-
isylphenylphosphane–borane was introduced via an argon inlet and
rubber septum. A solution of HCl in toluene (0.38 m, 11.0 mL,
4.2 mmol, 2.1 equiv.) was next added whilst stirring at room tem-
perature, without previous dissolution of (RP)-(–)-N-methyl-
[(1R,2S)-(2-hydroxy-1-phenyl)ethyl]amino-o-anisylphenylphos-
phane–borane. After 1 h, the precipitate of ephedrine hydrochlo-
ride was filtered off using a Millipore 4 μm filter, and the excess
HCl was removed using several vacuum/argon cycles. The toluene
solution of chlorophosphane–borane 26 obtained was used without
further purification. The solution containing 26 was cooled to
–78 °C and MeLi (0.87 m, 5.7 mL, 5 mmol, 2.5 equiv.) was added.
The reaction mixture was warmed to room temp. over a period of
1 h, and then hydrolysed with water. The organic phase was re-
moved and the aqueous layer was extracted with CH2Cl2. The com-
bined extracts were dried with MgSO4, then concentrated. The resi-
due was purified by chromatography on a short column of silica
gel using a 7:3 by volume mixture of toluene/petroleum ether to
1
nation of methods including H NMR, chemical analysis,
UV/Vis spectrometry, and measurements of the emission
lifetimes in the solid state in comparison with the corre-
sponding achiral analogues for which a crystal structure is
known in which M = Ag.[14] The concept of slight structure
modification of the dppm ligand presented in this work op-
ens the door to new material design in coordination and
organometallic chemistry. For example, the commercial di-
phosphane Ph2P(CH2)mPPh2 ligands (m = 2–9) are well
known for making coordination polymers.[1,2] Correspond-
ing chiral versions of ligands similar to those presented in
this work should lead to new crystal motifs and optical
properties.
Experimental Section
Materials: The 1,8-diisocyano-p-menthane (dmb) was prepared ac-
cording to a published procedure[30] in which the bridging ligands
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Eur. J. Inorg. Chem. 2011, 2597–2609

P-Stereogenic 1D Coordination Polymers
give the phosphane–borane 27. It was recrystallized from a mixture
of isopropyl alcohol/n-hexane, affording enantiomerically pure
phosphane–borane as white needle crystals. Enantiomeric excess
was determined by HPLC [Chiralcel OK, n-hexane/iPrOH (80:20),
1 mL/min, λ = 254 nm, tR(R) = 11.1 min, tR(S) = 21.4 min]; yield
90%; white crystals; m.p. 76–77 °C. [α]2D5 = –25.8 (c = 1.3, CH3OH)
(R,R), tR = 52 min; (S,S)-enantiomer tR = 9 min; (R,S), tR =
26 min.
(R,R)-(–)-Bis(o-anisylphenylphosphanyl)methane (22): The diphos-
phane–diborane 28 (0.11 mmol) was placed in a three-necked flask
fitted with a reflux condenser, a magnetic stirrer, and an argon
inlet. A solution of DABCO (0.44 mmol) in toluene (4 mL) was
added, and the flask was purged three times with argon. The mix-
ture was heated to 50 °C for 12 h and the crude product was rapidly
filtered off on a neutral alumina column (15 cm height, 2 cm dia-
meter) using a degassed toluene/AcOEt (9:1) mixture as solvent.
After removal of the solvent, the free ligand 22 was obtained quan-
titatively and used without further purification. Rf = 0.45 (toluene;
for ee Ͼ 99%; R = 0.55 (toluene). IR (KBr): ν = 3060 (C–H),
˜
f
3000–2840 (C–H), 2380 (B–H), 1590, 1580, 1480, 1460, 1430, 1280,
1
1250, 1180, 1135, 1110, 1060, 1020 cm–1. H NMR (CDCl3): δ =
3
2
0.40–1.50 (q, JBH = 88 Hz, 3 H, BH3), 1.94 (d, JPH = 10.6 Hz, 3
H, P–CH3), 3.67 (s, 3 H, OCH3), 6.88 (dd, J = 8.3, J = 3.4 Hz, 1
H, Harom oAn), 7.05 (t, J = 7.4 Hz, 1 H, Harom oAn), 7.33–7.56 (m,
4
H, Harom), 7.56–7.69 (m,
2
H, Harom
)
ppm. 11B
CCM silica gel, flash chromatography on neutral alumina). [α]2D0
=
NMR{1H}(CDCl3): δ = –37.1 (d) JPB = 62.6 Hz. 13C{1H} NMR
1
1
–48 (c = 0.5, CHCl3) for 99% ee. H NMR (CDCl3): δ = 2.82 (s, 2
H, CH2), 3.64 (s, 6 H, OCH3), 6.70 (d, J = 8.19 Hz, 2 H, Ar), 6.79
(t, J = 7.24 Hz, 2 H, Ar), 6.97–7.04 (m, 2 H, Ar), 7.08–7.23 (m, 2
H, Ar), 7.24–7.29 (m, 6 H, Ar), 7.47–7.55 (m, 4 H, Ar) ppm.
13C{1H} NMR (CDCl3): δ = 22.2 (t, JPC = 22 Hz, CH2), 54.3
(OCH3), 109.1 (s, Carom), 119.7 (s, Carom), 126.9 (t, JPC = 4 Hz, Cq),
127.1 (t, JPC = 4 Hz, Carom), 127.4 (s, Carom), 128.9 (s, Carom), 131.5
(t, JPC = 4 Hz, Carom), 132.4 (t, JPC = 11 Hz, Carom), 136.3 (t, JPC
= 4.5 Hz, Cq),159.8 (t, JPC = 6.5 Hz, Cq) ppm. 31P{1H} NMR
1
(CDCl3): δ = 10.7 (d, JPC = 42.3 Hz, P-CH3), 55.4 (OCH3), 129.1
(d, JPC = 11.0 Hz, Carom), 111.6 (d, JPC = 4.9 Hz, Carom), 119.3 (d,
JPC = 62.6 Hz, Carom), 120.8 (d, JPC = 10.9 Hz, Carom), 128.1 (d,
JPC = 10.9 Hz, Carom), 131.1 (d, JPC = 11.6 Hz, Carom), 131.3 (d,
JPC = 2.4 Hz, Carom), 132.0 (d, JPC = 66.1 Hz, Carom), 133.9 (d, JPC
= 11.2 Hz, Carom), 134.1 (d, JPC = 1.7 Hz, Carom) ppm. 31P
1
NMR{1H} (CDCl3): δ = +9.2 (q, JPB = 66.1 Hz) ppm. MS (EI)
m/z (%) 230 (M+ – BH3, 100), 119 (43), 183 (35), 91 (57).
C14H18BOP (244.0769): calcd. C 68.89, H 7.43; found C 68.96, H
7.59.
(CDCl3):
δ = –30.6 ppm. HRESI-MS (CH2Cl2) calcd. for
C27H27O2P2 [M+]: 445.1481; found: 445.1497.
(R,R)-Bis(o-anisylphenylphosphanyl)methane–Borane
(28):
A
[Cu2(dppm*)2(NCCH3)4](BF4)2 (dppm* = 22 and 23) Complexes: To
a flask equipped with a magnetic stirrer and an argon inlet,
0.207 mmol (49.1 mg) of anhydrous Cu(BF4)2 and 5 mL of acetoni-
trile distilled were introduced. Approximately 50 mg of powdered
metallic copper was added. The mixture was stirred for 1.5 h with
exclusion of light. To a second flask equipped with a magnetic stir-
rer and an argon inlet, 0.207 mmol of P-chirogenic diphosphane
22 or 23 and 10 mL of distilled acetonitrile were introduced. The
first solution was transferred to the second flask using a cannula
and the mixture was stirred overnight. After filtration, the volume
of the filtrate was reduced under reduced pressure, and [Cu2(22)2-
(CH3CN)4](BF4)2 or [Cu2(22)2(CH3CN)4](BF4)2, respectively, was
precipitated by adding diethyl ether.
100 mL two-necked flask equipped with a magnetic stirrer, an ar-
gon inlet and a rubber septum was charged with 1.08 g of the phos-
phane–borane 27 (4.40 mmol, 3 equiv.) in 10 mL of THF. The solu-
tion was cooled to 0 °C and 2.8 mL of nBuLi (1.6 m in n-hexane,
4.40 mmol, 3 equiv.) was added dropwise. The reaction was main-
tained at this temperature for 30 min, after which the cooling bath
was removed and the reaction stirred at room temperature for
90 min. After cooling to –78 °C, a freshly prepared toluene solution
of the chlorophosphane–borane 26 (1.47 mmol, 1 equiv.) was
added dropwise with stirring to the anion solution. The mixture
was slowly allowed to increase to room temperature overnight. Af-
ter hydrolysis, the aqueous layer was extracted with 3ϫ30 mL of
CH2Cl2, and the combined extracts were dried with MgSO4, then
concentrated. The residue was purified by chromatography on a
short column of silica gel with toluene as solvent, to give the di-
phosphane–diborane complex. It was recrystallized from CH2Cl2,
by slow diffusion of heptane, affording diastereomerically and en-
antiomerically pure white needle crystals; yield 80%; m.p. 187 °C;
Rf = 0.33 (toluene). [α]2D0 = +45 (c = 0.5, CHCl3) for 99% ee. IR
[Cu2(22)2(NCCH3)4](BF4)2: Yield 92% (0.1291 g), white solid, m.p.
226 °C. [α]2D0 = –8.2 (c = 0.09, CHCl ). IR (solid): ν = 2279, 1634,
˜
3
1582, 1481, 1432, 1275, 1245, 1058 cm–1. H NMR (CD3CN): δ =
1
7.73 (br., 4 H, Ar), 7.38 (m, 4 H, Ar), 7.21 (m, 4 H, Ar), 7.10 (br.,
20 H, Ar), 6.45 (br., 4 H, Ar), 3.41 (m, 4 H, CH2), 3.14 (s, 12 H,
OCH3), 1.98 (s, 12 H, CH3CN) ppm. 13C{1H} NMR (CDCl3): δ
= 139.5 (Carom), 139.2 (Carom), 138.7 (Carom), 138.0 (Carom), 136.5
(Carom), 135.0 (Carom), 133.5 (Carom), 126.0 (Carom), 122.7
(CH3CN), 116.8 (Carom), 110.0 (Carom), 60.0 (OCH3), 27.1 (CH2),
2.89–5.06 (CNCH3) ppm. 31P{1H} NMR (CDCl3): δ = –10.3 (s)
ppm. C62H64B2Cu2F8N4O4P4 (1353.80): calcd. C 54.95, H 4.73, O
4.73, N 4.14; found C 55.23, H 4.89, O 4.54, N 3.85. HRESI-MS
(CH2Cl2); found 507.0756 (z = 2) for Cu2(22)2, calcd. 507.0699.
(solid): ν = 3019–2942, 2408, 1589, 1479, 1458, 1435, 1152, 1277,
˜
1152, 1061, 1017 cm–1. 1H NMR (CDCl3): δ = 0.2 (m, JBH
=
1
2
116 Hz, 6 H, BH3), 3.53 (s, 6 H, OCH3), 3.54 (2d, JHH = 13.9,
3
4
2JPH = 11.6 Hz, 2 H, CH2), 6.65 (dd, JHH = 8.3, JPH = 2.9 Hz, 2
3
H, Ar), 6.83 (t, JHH = 7.5 Hz, 2 H, Ar), 7.09–7.21 (m, 6 H, Ar),
7.28–7.37 (m, 6 H, Ar), 7.53–7.64 (dd, 3JHH = 7.6, 3JPH = 14.8 Hz,
2 H, Ar) ppm. 11B NMR {1H}(CDCl3): δ = [ppm] –37.6 (br. s).
13C NMR (CDCl3): δ = [ppm] 18.5 (t, JPC = 28 Hz, CH2), 55.2
[Cu2(23)2(NCCH3)4](BF4)2: Yield 87% (0.1267 g), white solid, m.p.
(OCH3), 111.0 (d, JPC = 4 Hz, Carom), 114.0 (d, JPC = 54 Hz, Cq), 92 °C, [α]2D0 = –6 (c = 0.05, CHCl ). IR (solid): ν = 2316, 2271,
˜
3
121.0 (d, JPC = 14 Hz, Carom), 128.3 (d, JPC = 10 Hz, Carom), 130.2 1632, 1597, 1440, 1054 cm–1. 1H NMR (CD3CN): δ = 7.26 (br., 12
(d, JPC = 2 Hz, Carom), 130.6 (d, JPC = 10 Hz, Carom), 132.5 (d, H, Ar), 7.16 (m, 8 H, Ar), 6.89 (br., 12 H, Ar), 3.42 (m, 4 H, CH2),
1JPC = 60 Hz, Cq), 134.5 (d, JPC = 2 Hz, Carom), 137.3 (d, JPC
=
2.12 (s, 24 H, CH3), 1.97 (s, 12 H, CH3CN) ppm. 13C{1H} NMR
(CDCl3): δ = 143.97 (Carom), 143.74 (Carom), 139.29 (Carom), 137.5
18 Hz, Carom),162.0 (d, JPC = 3 Hz, Carom), 31P{1H} NMR
1
(CDCl3): δ = +13.5 (m, JPB = 34 Hz) ppm. HRESI-MS (CH2Cl2) (Carom), 137.0 (Carom), 135.7 (Carom), 135.1 (Carom), 133.7 (Carom),
calcd. for C27H32B2NaO2P2 [M + Na+]: 495.1961; found: 495.1956.
122.7 (CNCH3), 40.4 (CH2), 25.62 (CH3), 6.12–5.07 (CNCH3)
–5.54 (s) ppm.
Anal. calcd. (%) for C27H32B2O2P2, 0.9CH2Cl2: C 60.70, H 6.17; ppm. 31P{1H} NMR (CDCl3):
δ
=
found: C 60.96, H 6.30. The diastereomeric and enantiomeric ex-
cess was controlled by HPLC analysis on a Chiralpak AD Daicel
column, eluent: n-hexane/iPrOH (9:1), 1 mL/min, λ = 254 nm;
C66H72B2Cu2F8N4P4 (1345.91): calcd. C 58.84, H 5.35, N 4.16;
found C 59.11, H 5.52, N 3.96. HRESI-MS (CH2Cl2); found
1041.1927 (z = 1) for Cu2(23)2Cl, calcd. 1041.1921.
Eur. J. Inorg. Chem. 2011, 2597–2609
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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2607

C. Salomon, D. Fortin, N. Khiri, S. Jugé, P. D. Harvey
FULL PAPER
[Ag2(dppm*)2](BF4)2 complexes (dppm* = 22 and 23) Complexes: A
25 mL two necked flask equipped with a magnetic stirrer, an argon
inlet, and a rubber septum was charged with 22 or 23 (43.6 mg,
0.098 mmol) and Ag(BF4) (19 mg, 0.098 mmol) in distilled acetoni-
trile (5 mL). The mixture was stirred overnight with exclusion of
light. After evaporation of the solvent, the product was precipitated
with a mixture CH2Cl2/n-hexane.
NMR (CDCl3): δ = 143.7 (CN), 139.4 (Carom), 137.5 (br., Carom),
135.9 (Carom), 135.0 (Carom), 134.4 (Carom), 133.6 (Carom), 110.1
(Carom), 48.7 (Cq),41.5 (CH), 33.1 (CH2), 31.5 (CH3), 27.6
(PCH2P), 25.7 (CH3) ppm. 31P{1H} NMR (CDCl3): δ = –2.2 (s)
ppm. (C41H48BCuF4N2P2)n: calcd. C 63.0, H 6.15, N 3.59; found
C 63.13, H 5.87, N 3.81.
{[Ag2(dppm*)2(dmb)2](BF4)2}n (dppm* = 22 and 23) Polymers: These
polymers were prepared in the same manner as the {[Cu2(22)2-
(dmb)2](BF4)2}n and {[Cu2(23)2(dmb)2](BF4)2}n polymers above ex-
cept [Cu2(22)2(CH3CN)4](BF4)2 and [Cu2(22)2(CH3CN)4](BF4)2
were replaced by [Ag2(22)2](BF4)2 (0.100 g; 0.078 mmol) and
[Ag2(23)2](BF4)2 (0.0988 g; 0.078 mmol), respectively.
[Ag2(22)2](BF4)2: Yield 66% (41.6 mg), white solid, m.p. 186 °C
(dec.), [α]2D0 = –22 (c = 0.51, CHCl ). IR (solid): ν = 1627, 1571,
˜
3
1586, 1473, 1432, 1274, 1249, 1058, 743 cm–1. 1H NMR (CD3CN):
δ = 7.46 (br., 2 H, Ar), 7.41 (br., 8 H, Ar), 7.28 (br., 10 H, Ar),
7.90 (br., 6 H, Ar), 6.80 (br., 8 H, Ar), 6.56 (br., 2 H, Ar), 3.77 (m,
4 H, CH2), 3.48 (s, 12 H, OCH3) ppm. 13C{1H} NMR (CDCl3): δ
= 139.5 (Carom), 138.9 (Carom),137.7 (Carom), 137.5 (Carom), 136.9
(Carom), 135.9 (Carom), 133.8 (Carom), 133.6 (Carom), 126.3 (Carom),
110.0 (Carom), 60.4 (OCH3), 27.3 (CH2) ppm. 31P{1H} NMR
{[Ag2(22)2(dmb)2](BF4)2}n: Yield 51% (66 mg), white product, m.p.
190 °C. [α]2D0 = –9.3 (c = 0.21, CHCl ). IR (solid): ν = 2185, 1591,
˜
3
1480, 1436, 1280, 1250 cm–1. H NMR (CD3CN): δ = 7.72 (br., 2
1
H, Ar), 7.41 (m, 4 H, Ar), 7.15 (m, 26 H, Ar), 6.59 (br., 4 H, Ar),
3.58 (br., 4 H, CH2), 3.44 (s, 12 H, OCH3), 1.62–1.58 (m, 36 H,
dmb) ppm. 13C{1H} NMR (CDCl3): δ = 139.1 (CN), 136.9 (br.,
1
2
(CD3CN): δ = –1.78 and –1.94 (dd, JAg–P = 522, JP,P = 19 Hz)
ppm. C54H52B2Cu2F8O4P4 (1189.59): calcd. C 50.70, H 4.07; found
C 50.80, H 4.27. HRESI-MS (ACN/MeOH); found 551.0482 (z =
2) for Ag2(22)2, calcd. 551.0454.
Carom), 135.7 (br., Carom), 133.7 (Carom), 126.1 (Carom), 117.8–116.9
(Carom), 62.4 (Cq), 60.6 (Cq), 60.5 (OCH3), 40.8 (CH), 31.9 (CH2),
[Ag2(23)2](BF4)2: Yield 95% (70.5 mg), white solid, m.p. 248 °C. IR 31.5 (CH2), 31.1 (CH3), 27.1 (PCH2P), 26.4 (CH3) ppm. 31P{1H}
1
(solid): ν = 1601, 1582, 1488, 1488, 1440, 1058 cm–1. 1H NMR
NMR (CDCl3):
δ
=
5.1 (br. d, JAg–P
=
393 Hz) ppm.
˜
(CD3CN): δ = 7.30 (br., 12 H, Ar), 7.01 (m, 18 H, Ar), 6.85 (br., 2 (C39H44AgBF4N2O2P2)n: calcd. C 56.45, H 5.31, O 3.86; found C
H, Ar), 3.58 (m, 4 H, CH2), 2.06 (s, 24 H, CH3) ppm. 13C{1H}
NMR (CDCl3): δ = 144.3 (Carom), 138.2 (Carom), 137.7 (Carom),
136.5 (Carom), 135.2 (Carom), 135.0 (Carom), 134.2 (Carom),110.1
(Carom), 27.7 (CH2), 25.5 (CH3) ppm. 31P{1H} NMR (CDCl3): δ =
56.34, H 5.20, O 4.14.
{[Ag2(23)2(dmb)2](BF4)2}n: Yield 82% (105 mg), white product, m.p.
154 °C. [α]2D0 = –20 (c = 0.48, CHCl ). IR (solid): ν = 2174, 2134,
˜
3
1599, 1586, 1435, 1372 cm–1. 1H NMR (CD3CN): δ = 7.32 (br., 12
H, Ar), 7.17 (br., 8 H, Ar), 6.96 (br., 12 H, Ar), 3.34 (br., 4 H,
CH2), 2.12 (s, 24 H, CH3), 1.88–1;39 (m, 36 H, dmb) ppm. 13C{1H}
NMR (CDCl3): δ = 143.8 (CN), 138.0–137.4 (Carom), 136.1–135.2
(Carom), 133.9 (Carom), 48.9 (CH3), 41.7 (Cq), 40.36 (Cq), 36.55
(CH), 33.3 (CH2), 31.4 (CH2),30.5 (CH3), 27.4 (PCH2P), 25.6
(CH3) ppm. 31P{1H} NMR (CDCl3): δ = 5.1 (1JAg–P = 383 Hz)
ppm. (C41H48AgBF4N2P2)n: calcd. C 59.64, H 5.82; found C 59.48,
H 5.63.
1
2
7.22 and 7.08 (dd, JAg–P
= 508, JP,P = 18 Hz) ppm.
C58H60Ag2B2F8P4·(CH3CH2)2O (1270.35): calcd. C 55.38, H 5.21;
found C 55.22, H 5.08. HRESI-MS (ACN/MeOH); found 547.0885
(z = 2) for Ag2(23)2, calcd. 547.0868.
{[Cu2(dppm*)2(dmb)2](BF4)2}n (dppm* = 22 and 23) Polymers: These
polymers were synthesized starting from [Cu2(22)2(CH3CN)4]-
(BF4)2 [Cu2(23)2(CH3CN)4](BF4)2 according to a procedure de-
scribed for the achiral polymer {[Cu2(dppm)2(dmb)2](BF4)2}n.[14]
Specifically, [Cu2(22)2(CH3CN)4](BF4)2 (0.1056 g, 0.078 mmol) was
dissolved in 14 mL of distilled acetonitrile. A 29.6 mg (0.156 mmol)
amount of dmb was dissolved separately in a round flask contain-
ing 25 mL of distilled acetonitrile. This latter colorless solution was
slowly added dropwise to the former. The mixture was stirred for
2 h prior to being reduced to 7.5 mL in vacuo. A 75 mL volume of
diethyl ether was added to the reaction mixture precipitating the
white product, which was filtered off and dried in vacuo.
Thermal Gravimetric Analysis: TGA traces were acquired on a
TGA 7 of Perkin–Elmer between 50 and 650 °C at 3 deg/min under
nitrogen atmosphere.
Circular Dichroism Spectra: Circular dichroïsm measurements were
performed on a Jasco J-810 spectropolarimeter equipped with a
Jasco Peltier-type thermostat. The instrument was calibrated with
an aqueous solution of (+)-10-camphorsulfonic acid at 290.5 nm.
Samples were loaded into quartz cells with a path length of 0.1 cm.
Far-UV CD spectra were recorded at the desired temperature from
190–700 nm by averaging three scans at 0.1 nm intervals.
{[Cu2(22)2(dmb)2](BF4)2}n: Yield 73% (89 mg), m.p. 146 °C. [α]2D0
=
–14 (c = 0.24, CHCl ). IR (solid): ν = 2185, 1585, 1470, 1436, 1275,
˜
3
1245, 1058 cm–1. H NMR (CD3CN): δ = 7.86 (br., 3 H, Ar), 7.49
1
X-ray Structure: Crystals were grown by slow evaporation of a
CH2Cl2/n-hexanes mixture at room temperature. One single crystal
of 0.10ϫ0.10ϫ0.50 mm3 was mounted using a glass fiber at 198(2)
K on the goniometer. Data were collected on an Enraf–Nonius
CAD-4 automatic diffractometer at the Université de Sherbrooke
using ω scans. The DIFRAC[32] program was used for centering,
indexing, and data collection. One standard reflection was mea-
sured every 100 reflections, no intensity decay was observed during
data collection. The data were corrected for absorption by empiri-
cal methods based on psi scans and reduced with the NRCVAX[32]
programs. They were solved using SHELXS-97[33] and refined by
full-matrix least-squares on F2 with SHELXL-97.[34] The non-hy-
drogen atoms were refined anisotropically. The hydrogen atoms
were placed at idealized calculated geometric position and refined
(br., 1 H, Ar), 7.32 (m, 3 H, Ar), 7.16 (m, 6 H, Ar), 7.10 (m, 3 H,
Ar), 7.02 (br., 15 H, Ar), 6.74 (br., 1 H, Ar), 6.36 (br., 4 H, Ar),
3.49 (m, 4 H, CH2), 3.25 (s, 12 H, OCH3), 2.15–1.50 (m, 36 H,
dmb) ppm. 13C{1H} NMR (CDCl3): δ = 142.9 (CN), 141.1 (Carom),
138.0–135.1 (br. m, Carom), 133.5 (Carom) 125.9 (br., Carom), 116.9
(Carom), 66.1 (Cq), 60.7 (Cq), 60.3 (OCH3), 46.3 (CH), 40.8 (CH2),
31.6 (CH2), 27.5 (CH3), 27.2 (PCH2P), 26.4 (CH3) ppm. 31P{1H}
NMR (CDCl3): δ = –2.1 (br), –9.3 (br), –13.69 (br) ppm.
(C39H44BCuF4N2O2P2)n: calcd. C 59.62, H 5.61, O 4.08, N 3.57;
found C 59.47, H 5.44, O 4.19, N 3.34.
{[Cu2(23)2(dmb)2](BF4)2}n: Yield 67% (82 mg), m.p. 172 °C. [α]2D0
=
–3.5 (c = 0.19, CHCl ). IR (solid): ν = 2178, 1627, 1451, 1476,
˜
3
1316, 1174, 1095, 1062 cm–1. 1H NMR (CD3CN): δ = 7.24 (br., 12
H, Ar), 7.12 (br., 10 H, Ar), 6.87 (br., 10 H, Ar), 3.28 (br., 4 H, isotropically using a riding model. The absolute structure[35] was
CH2), 2.12 (s, 24 H, CH3), 1.47 (br., 36 H, dmb) ppm. 13C{1H}
assigned by anomalous dispersion effects.
2608
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© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 2597–2609

P-Stereogenic 1D Coordination Polymers
[14] É. Fournier, F. Lebrun, M. Drouin, A. Decken, P. D. Harvey,
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for fundings. Dr. Pierre Lavigne (Faculté de Médecine of the Uni-
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Received: February 16, 2011
Published Online: April 7, 2011
Eur. J. Inorg. Chem. 2011, 2597–2609
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2609