Metal complexes of ditopic dithiophosphonate ligands built on a naphthalenediimide core Dedicated to the memory of Professor Ioan Silaghi-Dumitrescu

Article abstract of DOI:10.1016/j.ica.2013.02.037

Ditopic ligands consisting of two dithiophosphonate donor groups attached to a 1,4,5,8-naphthalenediimide core through ether spacers of different length have been synthesized and characterized. The NDI[(CH₂CH ₂O)_n(An)PS₂NH₄]₂ ligands (n = 1: 1a-[NH₄]₂; n = 2: 1b-[NH₄]₂; NDI = naphthalenediimide; An = anisole) react with Ph₃SnCl and (Ph₃P)₂CuNO₃ in a 1:2 ratio to yield bimetallic complexes (1a-[SnPh₃]₂ and 1a-[Cu(PPh₃) ₂]₂ for n = 1, and 1b-[SnPh₃]₂ and 1b-[Cu(PPh₃)₂]₂ for n = 2), and with Ph ₂SnCl₂ in a 1:1 ratio to form bimetallic ({1a-[SnPh ₂]}₂) and monometallic (1b-[SnPh₂]) macrocycles. Structural characterization of these compounds revealed monodentate and anisobidentate coordination modes of the dithiophosphonate group, as well as the presence of metal-sulfur secondary bonds. While the ditopic nature of the ligand does not have an influence over the coordination behavior of the individual -PS₂ groups, the length of the naphthalenediimide- dithiophosphonate linker lead to different solid-state supramolecular architectures. Cooperative π-π stacking and C-Ha?[?π interactions organize the supramolecular structures of these complexes, generating two-dimensional sheets (in the case of short-arm ligand: 1a-[SnPh₃]₂ and 1a-[Cu(PPh₃)₂] ₂) and mono-dimensional chains (in the case of long-arm ligand: 1b-[SnPh₃]₂). In the case of {1a-[SnPh ₂]}₂ and 1b-[SnPh₂] metallacycles, π-π stacking interactions between NDI central moieties produce infinite π-π stacked chains and discrete dimers, respectively.

Full text of DOI:10.1016/j.ica.2013.02.037

Inorganica Chimica Acta 400 (2013) 228–238
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Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Metal complexes of ditopic dithiophosphonate ligands built
on a naphthalenediimide core
a
a
a
b
Radu F. Semeniuc a, , Robert R. Baum , Jedidiah J. Veach , Kraig A. Wheeler , Perry J. Pellechia
⇑
a Department of Chemistry, Eastern Illinois University, Charleston, IL 61920, USA
b Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
Ditopic ligands consisting of two dithiophosphonate donor groups attached to a 1,4,5,8-naphthalenedii-
mide core through ether spacers of different length have been synthesized and characterized. The
NDI[(CH2CH2O)n(An)PS2NH4]2 ligands (n = 1: 1a-[NH4]2; n = 2: 1b-[NH4]2; NDI = naphthalenediimide;
An = anisole) react with Ph3SnCl and (Ph3P)2CuNO3 in a 1:2 ratio to yield bimetallic complexes (1a-
[SnPh3]2 and 1a-[Cu(PPh3)2]2 for n = 1, and 1b-[SnPh3]2 and 1b-[Cu(PPh3)2]2 for n = 2), and with Ph2-
SnCl2 in a 1:1 ratio to form bimetallic ({1a-[SnPh2]}2) and monometallic (1b-[SnPh2]) macrocycles.
Structural characterization of these compounds revealed monodentate and anisobidentate coordination
modes of the dithiophosphonate group, as well as the presence of metal-sulfur secondary bonds. While
the ditopic nature of the ligand does not have an influence over the coordination behavior of the individ-
ual –PS2 groups, the length of the naphthalenediimide-dithiophosphonate linker lead to different solid-
Received 29 November 2012
Received in revised form 26 February 2013
Accepted 26 February 2013
Available online 7 March 2013
Dedicated to the memory of Professor Ioan
Silaghi-Dumitrescu
Keywords:
Supramolecular chemistry
X-ray crystal structures
Phosphor-1,1-dithiolates
Tin complexes
state supramolecular architectures. Cooperative
supramolecular structures of these complexes, generating two-dimensional sheets (in the case of
p
–
p
stacking and C–HÁ Á Á
p interactions organize the
‘‘short-arm’’ ligand: 1a-[SnPh3]2 and 1a-[Cu(PPh3)2]2) and mono-dimensional chains (in the case of
Copper complexes
‘‘long-arm’’ ligand: 1b-[SnPh3]2). In the case of {1a-[SnPh2]}2 and 1b-[SnPh2] metallacycles,
p
–
p
stack-
ing interactions between NDI central moieties produce infinite
respectively.
p–p stacked chains and discrete dimers,
Ó 2013 Elsevier B.V. All rights reserved.
1. Introduction
Polytopic dithiocarbamates were also used in the synthesis of dior-
ganotin-based cavitands and capsules [8].
Investigations into the architecture of supramolecular metal
complexes formed by self-assembly processes have been undergo-
ing since the early 1990s. By using carefully designed polytopic li-
gands in combination with metallic centers having specific
stereochemical requirements, interesting and unusual molecular
architectures have been prepared and characterized [1–4]. Most
research in this area is based on oligopyridine [1] and oligocatech-
olate [2] ligands, although alkynyl- [3] and pyrazolyl-based [4]
ligands are also heavily employed in the synthesis of metal-
directed self-assembly of supramolecular architectures.
The incorporation of the soft 1,1-dithiolate donor set [5] into
polyfunctional systems represents a promising research field that
has not been yet exploited to its full potential. Only recently the
Beer group used the dithiocarbamate donor set to prepare supra-
molecular architectures such as macrocycles, cages, catenanes,
and resorcinarene-based assemblies [6]. Wilton-Ely prepared
piperazine-based ditopic dithiocarbamate ligands and used them
in the preparation of homo- and hetero polymetallic species [7].
Phosphor-1,1-dithiolates represent an important group of the
more general 1,1-dithiolate class of ligands, and include dithiophos-
phates [(RO)2PS2]À, dithiophosphinates [R2PS2]À, and dithiophosph-
onates [(RO)R’PS2]À. Usually, these ligands can coordinate to metal
atoms (Scheme 1) in a monodentate (a), isobidentate (b), or aniso-
bidentate (c) fashion. In some cases, bimetallic biconnective (d),
and bimetallic triconnective (e) bridging modes were observed. In
rare cases, phosphor-1,1-dithiolate ligands can bridge two metal
atoms through only one sulfur atom (f) and, in the case of Cu(I) clus-
ter compounds, the trimetallic triconnective (g) and tetrametallic
tetraconnective (h) coordination modes were also described [5a,b].
This rich coordination behavior stems from the presence of soft
Lewis acidic centers on these ligands, i.e. sulfur, thus opening the
possibility of supramolecular association in the crystalline phase
through secondary bonds.
Considering their well-documented and varied coordination
modes, as well as their availability, it is surprising that reports of
ditopic phosphor-1,1-dithiolates are extremely scarce. The dithio-
phosphonato ligand is the least studied member of the phosphor-
1,1-dithiolate family. While reports of their use (in combination
with pyridine-based ligands) in the synthesis of metal-directed
⇑
Corresponding author. Tel.: +1 217 581 5422.
E-mail address: rsemeniuc@eiu.edu (R.F. Semeniuc).
0020-1693/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.ica.2013.02.037

R.F. Semeniuc et al. / Inorganica Chimica Acta 400 (2013) 228–238
229
M
S
M
S
precipitated by passing a stream of dry gaseous NH3 through the
cold benzene solution of the dithiophosphonic acids. The ligands
were isolated in good yields as air and moisture stable orange pow-
ders, soluble in water and alcohols and insoluble in other common
organic solvents.
S
P
S
P
S
P
S
P
M
S
M
S
R'
R'
M
R'
R'
R
R
R
R
a
b
c
d
The metathesis reaction of these ditopic dithiophosphonates
and Ph3SnCl or (Ph3P)2CuNO3 in a 1:2 ratio yielded the bimetallic
compounds 1a-[SnPh3]2 and 1a-[Cu(PPh3)2]2 for n = 1, and 1b-
[SnPh3]2 and 1b-[Cu(PPh3)2]2 for n = 2, in moderate to good yields,
Scheme 3, top. The reactions proceed easily in a CH2Cl2/H2O bipha-
sic setting and the completion of the reaction is indicated by the
loss of the color of the aqueous phase and the appearance of an or-
ange color in the organic phase. The same reaction performed in
the presence of one equivalent of Ph2SnCl2 afforded the bimetallic
{1a-[SnPh2]}2 and monometallic 1b-[SnPh2] macrocyclic com-
pounds, respectively, see Scheme 3 middle and bottom. The com-
pounds are orange solids, stable in air and in the presence of
moisture, soluble in chlorinated solvents and only sparingly solu-
ble in other organic solvents, such as acetone and acetonitrile.
Elemental analyses confirmed the bimetallic composition of 1a
and 1b type of compounds, as well as of the {1a-[SnPh2]}2 metal-
lacycle, and the presence of only one metallic center in the case of
M
M
S
M
S
M
M
S
M
M
S
P
S
S
P
S
M
S
M
M
P
P
R'
R'
R'
R'
R
R
R
R
M
e
f
g
h
Scheme 1. Coordination modes of phosphor-1,1-dithiolate ligands.
self-assembly of supramolecular architectures are known [9], to
date there are no significant studies on the synthesis of polytopic
dithiophosphonates and their use in coordination and supramolec-
ular chemistry [10].
We report here the preparation of ditopic ligands consisting of
two dithiophosphonate donor groups attached to a 1,4,5,8-naph-
thalenediimide core through ether spacers of different length and
the reactions of these ligands with metallic centers to form discrete
coordination compounds. Their molecular and supramolecular
structures and solution behavior are also discussed.
S
[M]
S
Me
P
n
O
2. Results and discussion
O
N
O
O
N
O
O
2.1. Synthesis and general characteristics of the ligands and their
complexes
O
S
n
O
P
Me
[M]
The ditopic dithiophosphonate ligands were synthesized
(Scheme 2) by the reaction of 1,4,5,8-naphthalenetetracarboxylic
dianhydride with two equivalents of either 2-aminoethanol or 2-
(2-aminoethoxy)ethanol in ethanol, followed by the reaction of
the resulting naphthalenediimide (NDI) based diols with the com-
mercially available 1,3,2,4-dithiadiphosphetane-2,4-bis(4-meth-
oxy-phenyl)-2,4-disulfide (Lawesson’s Reagent, L. R.) in refluxing
benzene. The ammonium salts NDI-[(CH2CH2O)n(An)-PS2NH4]2
(n = 1: 1a-[NH4]2; n = 2: 1b-[NH4]2; An = anisole) were then
S
n = 1: 1a-[SnPh3]2; 1a-[Cu(PPh3)2]2
n = 2: 1b-[SnPh3]2; 1b-[Cu(PPh3)2]2
O
N
O
O
N
O
O
O
P
P
O
O
O
O
S
S
S
S
S
S
Me
Me
Me
Me
O
O
O
O
O
O
Ph2Sn
SnPh2
S
P
S
P
i
O
O
O
N
O
O
N
O
H
n
O
N
O
O
N
O
O
{1a-[SnPh2]}2
O
n
H
P
Ph2
Sn
Me
Me
S
S
ii
S
S
O
O
S
H4NS
O
Me
P
P
P
n
O
O
N
O
O
N
O
O
O
O
O
O
O
N
O
O
N
O
n
O
n = 1: 1a-[NH4]2
n = 2: 1b-[NH4]2
Me
SNH4
S
1b-[SnPh2]
Scheme 2. Synthetic pathway toward the ditopic dithiophosphonate ligands: (i)
H2N(CH2CH2O)nOH (n = 1, 2), EtOH, reflux overnight; (ii) Lawesson’s Reagent,
benzene, reflux 2 h., then dry, gaseous NH3.
Scheme 3. Descriptive structures of the metal complexes described in this work;
[M] = SnPh3 and Cu(PPh3)2.

230
R.F. Semeniuc et al. / Inorganica Chimica Acta 400 (2013) 228–238
1b-[SnPh2]. The sharp and well defined peaks in the 1H NMR spec-
tra of {1a-[SnPh2]}2 and 1b-[SnPh2] suggests the presence of dis-
crete assemblies in solution, as opposed to mixtures of oligo- and/
or polymeric species, which usually show broad peaks. [1g–i] An
NMR comparative analysis of the free ligands with the metal com-
plexes described here was precluded by the difference in the solu-
bility of these compounds: while the ligands are soluble in water
and alcohols, the complexes show no solubility in these solvents.
1a-[SnPh3]2, together with selected bond lengths and angles, is
shown in Fig. 1, and consists of two –(An)PS2 moieties coordinated
to two -SnPh3 metallic centers in
(Scheme 1a).
a monodentate fashion
The overall geometry around the Sn(IV) center is distorted tet-
rahedral, with three practically equal carbon-tin bonds (Sn–C aver-
age 2.164 Å) and with one Sn–S bond of 2.450(4) Å. The second
sulfur atom of the dithiophosphonate group is also oriented to-
ward the Sn center. The Sn–S(1) separation of 3.7 Å is too long to
be considered a covalent bond, but is shorter than the sum of the
van der Waals radii of tin and sulfur atoms (3.97 Å) [11]. As such,
this interaction is best described as a secondary bond (dashed line
in Fig. 1) [12]. An important structural feature of 1a-[SnPh3]2 is the
trans orientation of the –(An)PS2SnPh3 groups with respect to the
central NDI moiety. The short –CH2CH2O– linker place the two
metallic regions in close proximity, with the –SnPh3 group on top
and below the naphthalenediimide plane. This orientation is only
a consequence of the length of the linker and is not supported by
any non-covalent interactions between the phenyl rings and NDI.
The crystal packing of 1a-[SnPh3]2 is based on a combination of
2.2. Crystallographic studies
Crystals suitable for X-ray diffraction studies were grown using
the layering technique: in a 15 cm test tube, approximately 50 mg
of each compound were dissolved in 20 mL CH2Cl2 and the solution
was carefully layered with about 80 mL hexanes. After several days
at room temperature single crystals of 1a-[SnPh3]2, 1a-
[Cu(PPh3)2]2, 1b-[SnPh3]2, {1a-[SnPh2]}2, and 1b-[SnPh2] were
obtained. Crystallographic details for these compounds are sum-
marized in Table 1.
p
–
p
stacking [13] and C–HÁ Á Á
p interactions [14] (Fig. 2). A phenyl
2.2.1. Molecular and crystal structure of 1a-[SnPh3]2
The asymmetric unit consists of half of a 1a-[SnPh3]2 molecule
situated about an inversion center. The molecular structure of
ring from one molecule (pictured in blue) is stacked above the
NDI core from a neighboring (orange) molecule, with a perpendic-
Table 1
Crystal data and structure refinement for 1a-[SnPh3]2, 1a-[Cu(PPh3)2]2, 1b-[SnPh3]2, {1a-[SnPh2]}2, and 1b-[SnPh2].
1a-[SnPh3]2
1a-[Cu(PPh3)2]2
1b-[SnPh3]2
{1a-[SnPh2]}2
1b-[SnPh2]
Formula
C
68H56N2O8P2S4Sn2 C104H86Cu2N2O8P6S4Á2(CH2Cl2) C72H64N2O10P2S4Sn2 C88H72N4O16P4S8Sn2Á2(CH2Cl2) C48H44N2O10P2S4SnÁ2(CH2Cl2)
Formula weight
1456.79
2102.74
1544.81
2229.21
1287.57
(g molÀ1
)
Crystal system
a (Å)
b (Å)
triclinic
9.1471(11)
13.3620(15)
14.7072(17)
75.808(5)
78.661(5)
87.864(5)
1
triclinic
9.2045(1)
11.5410(2)
23.4034(4)
85.150(1)
89.605(1)
75.421(1)
1
monoclinic
13.7321(2)
10.5102(2)
23.2601(3)
90.00
97.7400(10)
90.00
2
triclinic
10.9684(2)
12.3642(2)
17.6112(3)
87.540(1)
88.133(1)
71.074(1)
1
triclinic
12.3562(3)
13.0479(2)
18.2453(4)
91.4050(10)
105.8360(10)
105.2590(10)
2
c (Å)
a
(°)
b (°)
c
(°)
Z
V (Å)
T (K)
1708.6(3)
100(2)
2397.19(6)
173(2)
3326.48(9)
100(2)
2256.71(7)
100(2)
2715.40(10)
100(2)
Space group
P1
P1
Pc
P1
P1
R1 [I > 2
wR1 [I > 2
r
(I)]
(I)]
0.0990
0.2289
0.0408
0.0975
0.0371
0.0881
0.0268
0.0714
0.0450
0.1182
r
Fig. 1. Molecular structure of 1a-[SnPh3]2; selected bond lengths (Å) and angles (°): Sn1–S2 = 2.450(4); Sn1–C17 = 2.175(16); Sn1–C23 = 2.172(13); Sn1–C29 = 2.145(17);
S1–P1 = 1.938(7); S2–P1 = 2.080(4); P1–O3 = 1.587(12); P1–C10 = 1.772(15); S2–Sn1–C17 = 109.4(4); S2–Sn1–C23 = 97.8(4); S2–Sn1–C29 = 116.0(4); Sn1–S2–
P1 = 105.12(19); S1–P1–S2 = 115.2(2); color code: carbon-green; hydrogen-gray; phosphorus-orange; sulfur-yellow; tin-purple. (For interpretation of the references to
color in this figure legend, the reader is referred to the web version of this article.)

R.F. Semeniuc et al. / Inorganica Chimica Acta 400 (2013) 228–238
231
Fig. 2. Crystal packing of 1a-[SnPh3]2: the phenyl-NDI
p–p stacking interactions are shown between the blue and orange molecules and the sextuple phenyl embraces
between the orange and green molecules. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
Fig. 3. Molecular structure of 1a-[Cu(PPh3)2]2; selected bond lengths (Å) and angles (°): Cu1–S1 = 2.386(9); Cu1–S2 = 2.548(4); Cu1–P1 = 2.267(7); Cu1–P2 = 2.271(5); S1–
P5 = 1.995(8); S2–P5 = 1.985(0); P5–O3 = 1.614(9); P5–C10 = 1.808(0); S1–Cu1–S2 = 85.30; P1–Cu1–P2 = 124.12; S1–Cu1–P1 = 114.62; S1–Cu1–P2 = 112.69; S2–Cu1–
P1 = 101.19; S2–Cu1–P2 = 110.69; S1–P5–S2 = 114.39; O3–P5–C10 = 103.53; color code: carbon-green; hydrogen-gray; phosphorus-orange; sulfur-yellow; copper-purple.
(For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
ular distance between the rings of 3.5 Å. In a separate interaction,
each –SnPh3 group is involved in sextuple phenyl embraces [15]
with another molecule, as shown for the orange and green units.
This collection of interactions generates bi-dimensional
a

232
R.F. Semeniuc et al. / Inorganica Chimica Acta 400 (2013) 228–238
Fig. 4. Crystal packing of 1a-[Cu(PPh3)2]2: the sextuple phenyl embraces are pictured between the orange and green molecules; the blue unit interacts with both green and
orange molecules via C–HÁ Á Á interactions. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
p
Fig. 5. Molecular structure of 1b-[SnPh3]2; selected bond lengths (Å) and angles (°): Sn1–S7 = 2.440(2); Sn1–C37 = 2.109(8); Sn1–C43 = 2.113(6); Sn1–C49 = 2.143(7); Sn2–
S5 = 2.4326(17); Sn2–C55 = 2.138(7); Sn2–C61 = 2.123(6); Sn2–C67 = 2.156(7); S1–P2 = 1.929(3); S7–P2 = 2.077(2); S5–P1 = 2.085(2); S8–P1 = 1.934(2); P1–O8 = 1.597(5);
P1–C30 = 1.804(7); P2–O6 = 1.594(5); P2–C23 = 1.784(7); S7–Sn1–C37 = 109.0(2); S7–Sn1–C43 = 116.24(19); S7–Sn1–C49 = 96.0(2); Sn1–S7–P2 = 103.92(9); S1–P2–
S7 = 115.45(11); O6–P2–C23 = 99.9(3); S5–Sn2–C55 = 110.8(2); S5–Sn2–C61 = 115.78(19); S5–Sn2–C67 = 97.1(2); Sn2–S5–P1 = 102.22(8); S5–P1–S8 = 114.79(11); O8–P1–
C30 = 100.4(3); color code: carbon-green; hydrogen-gray; phosphorus-orange; sulfur-yellow; tin-purple. (For interpretation of the references to color in this figure legend,
the reader is referred to the web version of this article.)
supramolecular network running along the diagonal of the unit
cell.
–PPh3 groups coordinated to the Cu(I) atom (Fig. 4). Each end of
every molecule is involved in sextuple phenyl embraces, shown
in Fig. 4 between the orange and green units. In addition, a third
molecule (blue) interacts via C–HÁ Á Á
p interactions with both or-
ange and green neighbors, thus generating sheets in the bc plane
2.2.2. Molecular and crystal structure of 1a-[Cu(PPh3)2]2
The molecular structure of 1a-[Cu(PPh3)2]2 (Fig. 3) consists of
two –(An)PS2 moieties coordinated to two -Cu(PPh3)2 metallic cen-
ters in an anisobidentate fashion (Scheme 1c), with the Cu(1)–S(1)
and Cu(1)–S(2) distances of 2.386(9) and 2.548(4) Å respectively.
The 0.162 Å difference between the two bond lengths is indicative
of an anisobidentate coordination mode (Scheme 1c) of the dith-
iophosphonate ligand. In related isobidentate (Ph3P)2Cu com-
pounds [5], the copper(I)–sulfur distances are practically equal,
with a difference between the Cu–S bonds less than 0.015 Å. The
geometry about the copper(I) ion is distorted tetrahedral, with
the large distortions arising from the restricted ‘‘bite’’ angle of
the dithiophosphonate ligand, the S(1)–Cu(1)–S(2) and P(1)–
Cu(1)–P(2) angles being 85.30° and 124.12° respectively. As with
1a-[SnPh3]2, the compound adopts a trans orientation with respect
to the central NDI group and the short –CH2CH2O– linker place the
–(An)PS2(CuPPh3)2 group close to the core of the ligand. In contrast
to 1a-[SnPh3]2 where no interactions were found between the
metallic termini and the NDI group, in 1a-[Cu(PPh3)2]2 the anisole
of the unit cell.
2.2.3. Molecular and crystal structure of 1b-[SnPh3]2
The asymmetric unit of this compound consists of an entire 1b-
[SnPh3]2 molecule. As with its ‘‘shorter’’ counterpart 1a-[SnPh3]2,
the molecular structure of 1b-[SnPh3]2 comprises of two (An)PS2
moieties coordinated to two -SnPh3 metallic centers in a monoden-
tate fashion, see Fig. 5. The geometric parameters around the tin
atoms are virtually the same as in the case of 1a-[SnPh3]2, showing
that the coordination behavior of the –(An)PS2 moieties is indepen-
dent of the length of the side arms attached to the naphthalenedii-
mide group. The overall geometry around the Sn(IV) centers is
distorted tetrahedral. The Sn(1)–S(7) and Sn(2)–S(5) distances are
2.440(2) and 2.4326(17) Å, respectively. The secondary interac-
tions between the second sulfur atoms of the dithiophosphonate
donor sets and tin centers are 3.46 and 3.55 Å, respectively, and
are pictured as dashed lines in Fig. 5. The different relative orienta-
tion of the NDI and –(An)PS2SnPh3 regions (when compared to
1a-[SnPh3]2) is driven by the different length of the ether link of
the ligand: the longer side-arm place the metal-containing moie-
ties away from the center of the ligand, to the left and right sides
of the NDI plane.
groups are involved in intermolecular
p–p stacking interactions
with the aromatic core, several CAnisole– CNDI distances being be-
tween 3.4 and 3.6 Å.
The crystal packing of 1a-[Cu(PPh3)2]2 is driven by a similar
collection of
p–
p
stacking and C–HÁ Á Á
p interactions involving both

R.F. Semeniuc et al. / Inorganica Chimica Acta 400 (2013) 228–238
233
Fig. 6. Crystal packing of 1b-[SnPh3]2 supported by sextuple phenyl embraces.
Fig. 7. Molecular structure of {1a-[SnPh2]}2: left – the complete structural features; right – hydrogen atoms and phenyl groups removed for clarity; selected bond lengths (Å)
and angles (°): Sn1–C26 = 2.135(2); Sn1–C32 = 2.136(3); Sn1–S3 = 2.4996(6); Sn1–S2 = 2.5111(6); S1–P1 = 1.9370(9); S2–P1 = 2.0629(8); S3–P2 = 2.0507(9); S4–
P2 = 1.9703(9); P1–O5 = 1.6089(17); P1–C19 = 1.794(3); P2–O7 = 1.5909(18); P2–C38 = 1.792(3); C26–Sn1–C32 = 139.28(9); C26–Sn1–S3 = 109.11(7); C32–Sn1–
S3 = 106.16(7); C26–Sn1–S2 = 101.49(7); C32–Sn1–S2 = 101.74(7); S3–Sn1–S2 = 84.113(19); color code: carbon-green; hydrogen-gray; phosphorus-orange; sulfur-yellow;
tin-purple. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
The supramolecular structure of 1b-[SnPh3]2 is supported only
by sextuple phenyl embraces of the –SnPh3 groups (the blue and
orange molecules, Fig. 6). These interactions build up chains run-
ning along the diagonal of the unit cell, with the rest of the crystal
packing being driven by van der Waals forces. Importantly, the NDI
moiety is not involved in any supramolecular interaction, being
‘‘protected’’ by the position of the anisole groups, see Figs. 5 and 6.
consists of one dithiophosphonate ligand coordinated to one Sn(IV)
center, with the formation of a 25-member macrocycle. As with
{1a-[SnPh2]}2 above, the overall primary geometry around the
tin atom is distorted tetrahedral, with two practically equal Sn–C
(2.115 and 2.130 Å) and Sn–S (2.473 and 2.490 Å) bonds. In con-
trast to {1a-[SnPh2]}2 above, the other sulfur atoms of the dith-
iophosphonate group are situated at similar distances (3.175 and
3.285 Å), both suggesting secondary sulfur-tin interactions, and
making the geometry around the tin atom distorted octahedral.
As with {1a-[SnPh2]}2, the supramolecular structure of 1b-
2.2.4. Molecular and crystal structure of {1a-[SnPh2]}2
The asymmetric unit consists of half of a {1a-[SnPh2]}2 mole-
cule situated about an inversion center. The molecular structure
of {1a-[SnPh2]}2, together with selected bond lengths and angles,
[SnPh2] is driven by the
p–p stacking of the NDI regions of the
macrocycle. The perpendicular distance between the NDI rings is
3.4 Å, with several C–C distances around 3.5 Å. The rings are again
À
is shown in Fig. 7, and consists of two NDI-[CH2CH2O(An)PS2 li-
parallel (dihedral angle
a = 0.0°) and in an offset arrangement, with
gands coordinated to two Ph2Sn metallic centers, with the forma-
tion of a bimetallic 38-member macrocycle. The overall primary
geometry around the Sn(IV) center is again distorted tetrahedral,
with two equal Sn–C (2.135 Å) and Sn–S (2.505 Å) bonds. The other
sulfur atoms of the two dithiophosphonate groups are also ori-
ented toward the Sn center. However, there is a significant differ-
ence between these S–Sn distances: while the S(1)–Sn(1)
distance of 3.648 Å is indicative of a secondary sulfur-tin interac-
tion, the S(4)–Sn(1) distance of 2.980 Å suggests an anizobidentate
coordination of the PS2À donor set to the tin center. Taking in con-
sideration these non-covalent interactions, the geometry around
the tin atom can be described as highly distorted octahedral.
a slip angle b of 33.2°. However, these interactions built up only di-
mers (see Fig. 10), due to the fact that there is only one NDI group
present within the structure of each 1b-[SnPh2] macrocycle.
2.3. Solution studies
2.3.1. UV–Vis and fluorescence studies
Photophysical experiments were conducted at 293 K in H2O
solution for the anionic ligands and CH2Cl2 solution for the rest
of the compounds. The results are summarized in Table 2 and pre-
sented in Fig. 11.
The absorption spectra of the compounds show no significant
changes upon coordination of the ligands to the metallic centers.
Tin-based compounds undergo a decrease in absorption intensity
relative to their parent ligands, while the copper-based compounds
show an increase in absorption intensity.
The NDI cores of the macrocycles are involved in p–p stacking
interactions, with a perpendicular distance between the rings of
3.3 Å, with several C–C distances around 3.4 Å. The rings are paral-
lel (dihedral angle
a = 0.0°) and in an offset arrangement, with a
slip angle b of 22.9°. These interactions built up p-stacked chains,
shown in Fig. 8.
Upon excitation at kex = 345 nm, all compounds exhibit a struc-
tured fluorescence band (around 390 and 408 nm, see Table 2),
originating from the NDI core of the compounds, that can be as-
2.2.5. Molecular and crystal structure of 1b-[SnPh2]
The asymmetric unit of this compound consists of an entire 1b-
[SnPh2] molecule. The molecular structure of 1b-[SnPh2], together
with selected bond lengths and angles, is shown in Fig. 9, and
signed to a p–
p⁄ transition [16]. Again, the coordination of the 1a
and 1b ligands to the tin and copper centers does not cause signif-
icant changes in the emission properties of the NDI core.

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R.F. Semeniuc et al. / Inorganica Chimica Acta 400 (2013) 228–238
Fig. 8. Space filling representation of three
p
–p
stacked macrocycles of {1a-[SnPh2]}2; the different colors of the macrocycles are for clarity purposes only. (For interpretation
of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Fig. 9. Molecular structure of 1b-[SnPh2]: top – the complete structural features; bottom – hydrogen atoms and phenyl groups removed for clarity; selected bond lengths (Å)
and angles (°): Sn1–C43 = 2.114(4); Sn1–C37 = 2.129(5); Sn1–S1 = 2.4730(10); Sn1–S3 = 2.4904(10); S1 P1 2.0754(14); S2–P1 = 1.9424(15); S3–P2 = 2.0608(14); S4–
P2 = 1.9517(15); C43–Sn1–C37 = 127.94(18); C43–Sn1–S1 = 106.07(12); C37–Sn1–S1 = 109.09(13); C43–Sn1–S3 = 105.34(11); C37–Sn1–S3 = 115.48(13); S1–Sn1–
S3 = 83.74(3); S1–Sn1–S3 = 83.74(3); color code: carbon-green; hydrogen-gray; phosphorus-orange; sulfur-yellow; tin-purple. (For interpretation of the references to color
in this figure legend, the reader is referred to the web version of this article.)

R.F. Semeniuc et al. / Inorganica Chimica Acta 400 (2013) 228–238
235
Fig. 10. Space filling representation of two
p
–p
stacked macrocycles 1b-[SnPh2].
Table 2
Absorption and emission data for 1a-[NH4]2, 1b-[NH4]2, 1a-[SnPh3]2, 1a-
[Cu(PPh3)2]2, 1b-[SnPh3]2, 1b-[Cu(PPh3)2]2, {1a-[SnPh2]}2, and 1b-[SnPh2].
Absorption (kmax/nm) (
e
/MÀ1cmÀ1
)
Emission
(kem/nm)
1a-[NH4]2
1b-[NH4]2
384 (1443); 365 (1333); 345 (838)
384 (1468); 364 (1355); 345, sh (873)
381 (1463); 361 (1235); 342 (753)
380 (2310); 360 (2050); 343 (1325)
381 (1358); 361 (1148); 342 (690)
381 (2828); 361 (2445); 343 (1585)
381 (1090); 361 (960); 343 (600)
381 (1010); 361 (875); 343 (543)
389, 411
392, 433
386, 407
388, 408
386, 406
389, 407
388, 410
387, 408
1a-[SnPh3]2
1a-[Cu(PPh3)2]2
1b-[SnPh3]2
1b-[Cu(PPh3)2]2
{1a-[SnPh2]}2
1b-[SnPh2]
Fig. 11. Absorption spectra of 1a-[NH4]2 and 1b-[NH4]2 (H2O), and 1a-[SnPh3]2, 1a-
[Cu(PPh3)2]2, 1b-[SnPh3]2, 1b-[Cu(PPh3)2]2, {1a-[SnPh2]}2, and 1b-[SnPh2] (CH2-
Cl2) at 293 K.
2.3.2. NMR studies
Having observed supramolecular assemblies of these com-
pounds in solid state, association of these complexes in solution
phase was investigated by DOSY-NMR. This technique provides
an indirect measure of molecular size by allowing the determina-
tion of the diffusion coefficient of a given species in solution. Sub-
sequent application of the Stokes–Einstein equation then yields the
hydrodynamic radius, rH, which typically falls within ca. 20% of the
determined crystallographic radius. This technique has been used
successfully in a number of different applications, including estab-
lishing the presence or absence of dimeric species in solution [17].
Nevertheless, the above structures are not spherical, and thus a
straightforward application of the Stokes–Einstein equation is
precluded.
As such, we have turned our attention to Graham’s law of diffu-
sion, which relates the diffusion rate of a given species in solution
at a specific temperature to its molecular mass: D = K(T/m)1/2
(where D = diffusion rate, T = temperature, m = molecular mass,
and K = a constant depending on several factors). By comparing
the diffusion rate of a supramolecular species with the observed
value of the solvent, and assuming that both K and T are the same
for all the species present, it is possible to estimate the molecular
mass of the former by applying the following equation: MWB =
MWA(DA/DB)2 (where MWB = molecular weight of the species,
MWA = molecular weight of the solvent, DA = diffusion rate of the
solvent and DB = diffusion rate of the species). While this method
does not yield a precise value for the molecular mass of a species,
it is accurate enough to offer the possibility to distinguish between
associated and non-associated species: indeed, this method has
been used to investigate the presence or absence of supramolecu-
lar association in solution in several cases [18].
In our case, the only compound showing supramolecular associ-
ation in CDCl3 solution is 1b-[SnPh2]. The diffusion rates retrieved
from the DOSY experiment (expressed in logm2/s) are À8.63 for
CDCl3 and À9.25 for 1b-[SnPh2]. Based on these values, the calcu-
lated MW of the complex is 2074.58 Daltons, very close to the the-
oretical value for the MW of the dimer (2235.58 Daltons), a less
than 10% difference. For comparison, in the case of {1a-[SnPh2]}2,
the diffusion rates are À8.63 for CDCl3 and À9.27 for the macrocy-
cle. As such, the calculated MW is 2274.74 Daltons, value which
this time falls very close (again with a difference of about 10%)
to the theoretical value for the non-associated species, 2059.37
Daltons. These results suggest that the asymmetric nature of 1b-
[SnPh2] (only one NDI group, as opposed to two NDI moieties in
the case of {1a-[SnPh2]}2) might be responsible for the observed
association of these molecular species in solution. DOSY-NMR data
also suggest that while the phenyl embraces interactions are capa-
ble to support supramolecular associations of the remaining bime-
tallic 1a and 1b compounds in the solid state, they are not strong
enough to promote aggregation of these species in solution phase.
From a structural point of view, this study provided several key
findings. First, the ditopic nature of the ligand does not have an
influence over the coordination behavior of the individual –PS2
groups: the structural features around the metallic center in these
compounds are similar to those observed with ‘‘regular’’ monotop-
ic dithiophosphonates. This observation suggests that using these
or other polytopic dithiophosphonate ligands with different topol-
ogies in combination with various metallic centers we can expect
to implement the observed rich coordination pattern of the –PS2

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R.F. Semeniuc et al. / Inorganica Chimica Acta 400 (2013) 228–238
groups (see Scheme 1) into the structural features of more complex
polymetallic inorganic–organic hybrid materials.
EtOH. To this mixture was added, under stirring, a solution of 2-
aminoethanol (1.222 g, 0.02 mol) in 50 mL EtOH. The mixture
was stirred overnight under reflux. After cooling at room tempera-
ture, the mixture was poured into 600 mL ice cold water and the
resulting precipitate was filtered, washed with water (100 mL),
ethanol (75 mL) and diethyl ether (75 mL), to afford the desired
product (3.21 g, 90.6%) as a pink powder. 1H NMR (400 MHz,
DMSO-d6): d = 8.68 (s, 4H, NDI), 4.86 (t, J = 6.3 Hz, 2H, –OH), 4.18
(t, J = 6.2 Hz, 4H, –CH2–), 3.68–3.65 (m, 4H, –CH2–).
A second important result of this work is that the different
length of the ligand’s side-arms is responsible for the different rel-
ative position of the –(An)PS2[M] groups with respect to the cen-
tral NDI moiety: in 1a-[SnPh3]2 and 1a-[Cu(PPh3)2]2 they
virtually surround the NDI group, while in 1b-[SnPh3]2 they are
positioned away from the NDI moiety. This has a direct conse-
quence on the supramolecular structures of these compounds.
Comparing the supramolecular association of 1a-[SnPh3]2 with
1b-[SnPh3]2, where the only difference between the compounds
consist in the length of the side-arms, it can be easily observed that
only in the case of 1a-[SnPh3]2 the NDI group is involved in the
supramolecular architecture of the metal complex by participating
4.3. Synthesis of NDI-[CH2CH2OCH2CH2OH]2
This compound was prepared as described above for NDI-[CH2-
CH2OH]2, using 1,4,5,8-naphthalenetetracarboxylic dianhydride
(2.682 g, 0.01 mol) and 2-(2-aminoethoxy)ethanol (2.103 g,
0.02 mol). The compound (3.94 g, 89.1%) was isolated as a pale
pink powder. 1H NMR (400 MHz, DMSO-d6): d = 8.66 (s, 4H, NDI),
4.57 (t, J = 5.3 Hz, 2H, –OH), 4.27–4.25 (m, 4H, –CH2–), 3.70–3.67
(m, 4H, –CH2–), 3.49–3.46 (m, 8H, –CH2–).
in
p–p stacking interactions with neighboring molecules. In the
case of {1a-[SnPh2]}2 and 1b-[SnPh2], the same difference in the
length of the linker also accounts for the mono/bimetallic compo-
sition of the macrocycles. The two side-arms of 1a are not long en-
ough to coordinate to only one metallic center, hence the need of
two ligands and two tin centers for the formation of the macrocycle.
In contrast, the length of the (–CH2CH2O–)2 ether link in 1b is suffi-
cient to coordinate to one Ph2Sn moiety. The consequence of these
molecular structural features is the different supramolecular associ-
ation of these compounds in solid state, where we note a change
4.4. Synthesis of NDI-[CH2CH2O(An)PS2NH4]2 (1a-[NH4]2)
Under a nitrogen atmosphere, a 250 mL flask was charged with
a stirring bar, NDI-[CH2CH2OH]2 (1.771 g, 5.0 mmol), 1,3,2,4-dithi-
adiphosphetane-2,4-bis(4-methoxyphenyl)-2,4-disulfide (Lawes-
son’s Reagent, L.R.) (2.022 g, 5.0 mmol) and 150 mL dry benzene.
The mixture was stirred under inert atmosphere for 90 min. at
80 °C, and allowed to cool at room temperature. Then, dry NH3
gas (prepared from NH4OH dropped onto solid NaOH and dried
by passing it through a tower filled with powdered NaOH) was
bubbled through the cold solution. The resulting voluminous pre-
cipitate was filtered, washed with cold benzene (50 mL) and then
ether (2 Â 50 mL) to afford an orange product (3.08 g, 77.7%), iden-
tified as NDI-[CH2CH2O(An)PS2NH4]2Á Á Á1/2 C6H6. 1H NMR
(400 MHz, Acetone-d6/D2O 5:0.6 v/v): d = 8.67 (s, 4H, NDI), 7.85–
7.82 (m, 4H, MeO–C6H4–-P), 7.33 (s, 3H, C6H6), 6.45–6.42 (m, 4H,
MeO–C6H4–P), 4.39 (t, J = 6.9 Hz, 4H, –CH2–), 4.16–4.13 (m, 4H, –
CH2–), 3.58 (s, 6H, –O–CH3); Anal. Calc. for C35H37N4O8P2S4: C,
50.53; H, 4.48; N, 6.73. Found: C, 50.26, H, 4.46, N, 6.69%.
from infinite
p–p stacked chains to discrete dimeric species.
3. Conclusions
A series of new metal complexes based on ligands having two
dithiophosphonate donor groups linked to a 1,4,5,8-naphthalene-
diimide core through ether spacers of different length have been
prepared and characterized in both solution and solid state. The
crystal structures described above represent the first structurally
characterized compounds consisting of metallic centers coordi-
nated by ligands based on linking two dithiophosphonate groups
within the same molecule. This study shows how changes in the
length of the linker, while keeping the same donor set and topol-
ogy of the ligand, can lead to different solid-state supramolecular
architectures. We are currently exploring the potential of these
ditopic dithiophosphonate ligands in the synthesis of novel supra-
molecular architectures using other metallic systems, capable of
accommodating a greater number of –PS2 donor groups. We are
also investigating the use of other spacers to link two or more dith-
iophosphonate donor sets in the same ligand; these results will be
reported in due course.
4.5. Synthesis of NDI-[CH2CH2OCH2CH2O(An)PS2NH4]2 (1b-[NH4]2)
This compound was prepared as described above for 1a-[NH4]2,
using NDI-[CH2CH2OCH2CH2OH]2 (2.212 g, 5 mmol), L.R. (2.022 g,
5.0 mmol) and 150 mL benzene. The procedure afforded an orange
product (3.28 g, 74.5%), identified as NDI-[CH2CH2OCH2CH2-
O(An)PS2NH4]2. 1H NMR (400 MHz, Acetone-d6/D2O 5:0.6 v/v):
d = 8.72 (s, 4H, NDI), 7.97–7.94 (m, 4H, MeO–C6H4–P), 6.77–6.74
(m, 4H, MeO–C6H4–P), 4.36 (t, J = 6.8 Hz, 4H, –CH2–), 3.92–3.89
(m, 4H, –CH2–), 3.76–3.72 (m, 10H, 4H –CH2– overlap with 6H –
O–CH3), 3.67–3.64 (m, 4H, –CH2–); Anal. Calc. for C36H42N4O10P2S4:
C, 49.08; H, 4.81; N, 6.36. Found: C, 48.82; H, 5.00; N, 6.20%.
4. Experimental
4.1. General considerations
Unless otherwise noted, all operations were carried out in open
air. Operations requiring inert (nitrogen) atmosphere were carried
out using standard Schlenk techniques. Solvents were dried by
conventional methods and distilled under a dry N2 atmosphere
immediately prior to use. Elemental analyses were performed by
Robertson Microlit Laboratories, NJ. NMR spectra were recorded
by using a 400 MHz Bruker Avance FT-NMR Spectrometer and a
Varian Mercury/VX 400 Spectrometer. (Ph3P)2CuNO3 was prepared
according to published procedures [19]. All other reagents are
commercially available (Sigma–Aldrich) and were used without
further purification.
4.6. Synthesis of NDI-[CH2CH2O(An)PS2(SnPh3)2]2 (1a-[SnPh3]2)
A 250 mL flask was charged with a stirring bar and a solution of
Ph3SnCl (0.0964 g, 0.25 mmol) in DCM (75 mL). To this colorless
solution was added, under vigorous stirring, an orange aqueous
solution of 1a-[NH4]2 (0.0991 g, 0.125 mmol) in 75 mL water, and
the mixture was stirred overnight. The completion of the reaction
was indicated by the loss of the color of the aqueous phase and the
appearance of an orange color in the organic phase. The organic
phase was separated, and the aqueous phase extracted with DCM
(3 Â 10 mL). The combined organic phases were dried over anhy-
drous Na2SO4 and volatiles were removed under reduced pressure,
to afford the title compound as an orange solid (0.1192 g, 65.5%).
4.2. Synthesis of NDI-[CH2CH2OH]2
A 250 mL flask was charged with a stirring bar, 1,4,5,8-naphtha-
lenetetracarboxylic dianhydride (2.682 g, 0.01 mol) and 100 mL

R.F. Semeniuc et al. / Inorganica Chimica Acta 400 (2013) 228–238
237
1H NMR (400 MHz, CDCl3): d = 8.58 (s, 4H, NDI), 7.60–7.52 (m, 16H,
4H MeO–C6H4–P overlap with 12H, Sn-(C6H5)3), 7.37–7.33 (m, 18H,
Sn-(C6H5)3), 6.68–6.65 (m, 4H, MeO–C6H4–P), 4.51–4.47 (m, 4H, –
CH2–), 4.33–4.30 (m, 4H, –CH2–), 3.76 (s, 6H, –O–CH3). Anal. Calc.
for C68H56N2O8P2S4Sn2: C, 56.06; H, 3.87; N, 1.92. Found: C,
55.74, H, 3.69, N, 1.91%.
(3 Â 10 mL). The combined organic phases were dried over anhy-
drous Na2SO4 and volatiles were removed under reduced pressure,
to afford the title compound as an orange solid (0.1042 g, 80.9%).
1H NMR (400 MHz, CDCl3): d = 8.57 (s, 8H, NDI), 7.71–7.68 (m,
8H, MeO–C6H4–P), 7.62–7.57 (m, 8H, Sn–(C6H5)3), 7.51–7.48 (m,
12H, Sn–(C6H5)3), 6.69–6.65 (m, 8H, MeO–C6H4–-P), 4.48 (t,
J = 5.7 Hz, 8H, –CH2–), 4.33–4.28 (m, 8H, –CH2–), 3.76 (s, 6H, –O–
CH3). Anal. Calc. for C88H72N4O16P4S8Sn2: C, 51.32; H, 3.52; N,
2.72. Found: C, 51.56; H, 3.48; N, 2.89%.
4.7. Synthesis of NDI-[CH2CH2O(An)PS2(Cu(PPh3)2]2 (1a-
[Cu(PPh3)2]2)
This compound was prepared as described above for 1a-
[SnPh3]2, using (Ph3P)2CuNO3 (0.1625 g, 0.25 mmol) and 1a-
[NH4]2 (0.0991 g, 0.125 mmol), to afford the title compound as a
dark orange solid (0.1922 g, 79.5%). 1H NMR (400 MHz, CDCl3):
d = 8.59 (s, 4H, NDI), 7.78–7.75 (m, 4H, MeO–C6H4–P), 7.34–7.29
(m, 36H, –P(C6H5)3), 7.19–7.16 (m, 24H, –P(C6H5)3), 6.67–6.63
(m, 4H, MeO–C6H4–P), 4.47–4.45 (m, 4H, –CH2–), 4.22–4.20 (m,
4H, –CH2–), 3.73 (s, 6H, –O–CH3). Anal. Calc. for C104H86Cu2N2O8P6-
S4: C, 64.62; H, 4.48; N, 1.45. Found: C, 64.38; H, 4.35; N, 1.57%.
4.11. Synthesis of NDI-[CH2CH2OCH2CH2O(An)PS2]2(SnPh2) (1b-
[SnPh2])
This compound was prepared as described above for {1a-
[SnPh2]}2, using Ph2SnCl2 (0.0429 g, 0.125 mmol) and 1b-[NH4]2
(0.110 g, 0.125 mmol) to afford the title compound as an orange
solid (0. 1091 g, 78.1%). 1H NMR (400 MHz, CDCl3): d = 8.59 (s,
4H, NDI), 7.61–7.59 (m, 4H, MeO–C6H4––P), 7.51–7.44 (m, 4H,
Sn–(C6H5)3), 7.35–7.30 (m, 6H, Sn–(C6H5)3), 6.94–6.91 (m, 4H,
MeO–C6H4–P), 4.42 (t, J = 4.7 Hz, 4H, –CH2–), 3.99–3.97 (m, 4H, –
CH2–), 3.92 (s, 6H, –O–CH3), 3.65–3.63 (m, 4H, –CH2–), 3.54–3.52
(m, 4H, –CH2–). Anal. Calc. for C48H44N2O10P2S4Sn: C, 51.58; H,
3.97; N, 2.51. Found: C, 51.36; H, 3.48; N, 2.72%.
4.8. Synthesis of NDI-[CH2CH2OCH2CH2O(An)PS2(SnPh3)2]2 (1b-
[SnPh3]2)
A 250 mL flask was charged with a stirring bar and a solution of
Ph3SnCl (0.0964 g, 0.25 mmol) in DCM (75 mL). To this colorless
solution was added, under vigorous stirring, an orange aqueous
solution of 1b-[NH4]2 (0.110 g, 0.125 mmol) in 75 mL water, and
the mixture was stirred overnight. The completion of the reaction
was indicated by the loss of the color of the aqueous phase and the
appearance of an orange color in the organic phase. The organic
phase was separated, and the aqueous phase extracted with DCM
(3 Â 10 mL). The combined organic phases were dried over anhy-
drous Na2SO4 and volatiles were removed under reduced pressure,
to afford the title compound as an orange solid (0.1427 g, 73.9%).
1H NMR (400 MHz, CDCl3): d = 8.61 (s, 4H, NDI), 7.71–7.57 (m,
16H, 12H Sn–(C6H5)3 overlap with 4H, MeO–C6H4–P), 7.42–7.39
(m, 18H, Sn–(C6H5)3), 6.68–6.65 (m, 4H, MeO–C6H4–P), 4.43–4.41
(m, 4H, –CH2–), 3.97–3.95 (m, 4H, –CH2–), 3.82–3.76 (m, 10H,
6H, –O–CH3 overlap with 4H, –CH2–), 3.57–3.55 (m, 4H, –CH2–).
Anal. Calc. for C72H64N2O10P2S4Sn2: C, 55.98; H, 4.18; N, 1.81.
Found: C, 55.59; H, 3.90; N, 1.99%.
4.12. Crystallographic studies
The X-ray data were collected at 100 K on a Bruker SMART
APEXII CCD diffractomer equipped with Cu K
a radiation. Intensi-
ties were collected using phi and omega scans and were corrected
for Lorentz polarizatrion and absorption effects. The X-SEED soft-
ware platform [20], equipped with SHELXS and SHELXL modules on a
PC computer [21], was used for all structure solution and refine-
ment calculations and molecular graphics. The structure was
solved by direct methods, and refined by anisotropic full-matrix
least-squares for all non-hydrogen atoms. All hydrogen atoms
were placed in calculated positions and refined using a riding mod-
el with fixed thermal parameters.
Acknowledgments
Acknowledgment is made to the Donors of the American Chem-
ical Society Petroleum Research Fund for support of this research
(grant 48039-GB3); the Single Crystal Diffractometer at EIU was
purchased using funds provided by the NSF (CHE-0722547).
4.9. Synthesis of NDI-[CH2CH2OCH2CH2O(An)PS2(Cu(PPh3)2]2 (1b-
[Cu(PPh3)2]2)
This compound was prepared as described above for 1b-
[SnPh3]2, using (Ph3P)2CuNO3 (0.1625 g, 0.25 mmol) and 1b-
[NH4]2 (0.110 g, 0.125 mmol), to afford the title compound as a
dark orange solid (0.2011 g, 79.6%). 1H NMR (400 MHz, CDCl3):
d = 8.57 (s, 4H, NDI), 7.66–7.64 (m, 4H, MeO–C6H4–P), 7.35–7.31
(m, 36H, –P(C6H5)3), 7.24–7.22 (m, 24H, –P(C6H5)3), 6.69–6.67
(m, 4H, MeO–C6H4–P), 4.48–4.45 (m, 4H, –CH2–), 3.85–3.79 (m,
14H, 8H –CH2– overlap with 6H –O–CH3), 3.57–3.54 (m, 4H, –
CH2–). Anal. Calc. for C108H94Cu2N2O10P6S4: C, 64.18; H, 4.69; N,
1.39. Found: C, 63.85; H, 4.34; N, 1.62%.
Appendix A. Supplementary material
CCDC 773639, 773642, 900068, 900069, and 900070 contain
the supplementary crystallographic data for this paper. These data
can be obtained free of charge from The Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.ica.2013.02.037.
References
4.10. Synthesis of {NDI-[CH2CH2O(An)PS2]2(SnPh2)}2 ({1a-[SnPh2]}2)
[1] (a) M. Yoshizawa, J.K. Klosterman, M. Fujita, Angew. Chem., Int. Ed. 48 (2009)
3418;
A 250 mL flask was charged with a stirring bar and a solution of
Ph2SnCl2 (0.0429 g, 0.125 mmol) in DCM (75 mL). To this colorless
solution was added, under vigorous stirring, an orange aqueous
solution of 1a-[NH4]2 (0.0991 g, 0.125 mmol) in 75 mL water, and
the mixture was stirred overnight. The completion of the reaction
was indicated by the loss of the color of the aqueous phase and the
appearance of an orange color in the organic phase. The organic
phase was separated, and the aqueous phase extracted with DCM
(b) Y. Inokuma, M. Kawano, M. Fujita, Nat. Chem. 3 (2011) 349;
(c) R. Chakrabarty, P.S. Mukherjee, P.J. Stang, Chem. Rev. 111 (2011) 6810;
(d) B.H. Northrop, Y.-R. Zheng, K.-W. Chi, P.J. Stang, Acc. Chem. Res. 42 (2009)
1554;
(e) G.F. Swiegers, T.J. Malefetse, Chem. Rev. 100 (2000) 3483;
(f) L. Brammer, Chem. Soc. Rev. 33 (2004) 476;
(g) H.-B. Yang, K. Ghosh, B.H. Northrop, P.J. Stang, Org. Lett. 9 (2007) 1561;
(h) A. Sautter, D.G. Schmid, G. Jung, J. Am. Chem. Soc. 123 (2001) 5424;
(i) D. Schultz, J.R. Nitschke, Angew. Chem. 118 (2006) 2513.

238
[2] (a) M. Albrecht, Chem. Rev. 101 (2001) 3457;
R.F. Semeniuc et al. / Inorganica Chimica Acta 400 (2013) 228–238
(c) M.C. Aragoni, M. Arca, M. Crespo, F.A. Devillanova, M.B. Hursthouse, S.L.
(b) M. Albrecht, Chem. Soc. Rev. 27 (1998) 281.
Huth, F. Isaia, V. Lippolis, G. Verani, Dalton Trans. (2009) 2510.
[10] (a) M. Karakus, H. Yilmaz, E. Bulak, Russ. J. Coord. Chem. 31 (2005) 316;
(b) A.R. Gataulina, D.A. Safin, T.R. Gimadiev, M.V. Pinus, Transition Met. Chem.
33 (2008) 921.
[3] (a) K.M.-C. Wong, V.W.-W. Yam, Acc. Chem. Res. 44 (2011) 424;
(b) V.W.-W. Yam, K.M.-C. Wong, Chem. Commun. 47 (2011) 11579.
[4] (a) C. Pettinari, R. Pettinari, Coord. Chem. Rev. 249 (2005) 525;
(b) C. Pettinari, R. Pettinari, Coord. Chem. Rev. 249 (2005) 663.
[5] (a) I. Haiduc, D.B. Sowerby, S.F. Lu, Polyhedron 14 (1995) 3389;
(b) I. Haiduc, D.B. Sowerby, Polyhedron 15 (1996) 2469;
(c) I. Haiduc, in: F. Devillanova (Ed.), Handbook of Chalcogen Chemistry. New
Perspectives in Sulfur, Selenium and Tellurium, RSC Publishing, The Royal
Society of Chemistry, London, 2007, pp. 593–643;
[11] (a) A. Bondi, J. Phys. Chem. 68 (1964) 441;
(b) R.S. Rowland, R. Taylor, J. Phys. Chem. 100 (1996) 7384.
[12] (a) N.W. Alcock, Adv. Inorg. Chem. Radiochem. 15 (1972) 1;
(b) N.W. Alcock, R.M. Countryman, J. Chem. Soc., Dalton Trans. (1977) 217;
(c) I. Haiduc, Appl. Organomet. Chem. 21 (2007) 476;
(d) I. Haiduc, Coord. Chem. Rev. 158 (1997) 325;
(d) E.R.T. Tiekink, J. Zukerman-Schpector, Coord. Chem. Rev. 254 (2010) 46;
(e) E.R.T. Tiekink, CrystEngComm 8 (2006) 104;
(f) E.R.T. Tiekink, Met. Chem. 15 (1992) 161.
(e) E.R.T. Tiekink, CrystEngComm 5 (2003) 101.
[13] (a) C.A. Hunter, J.K.M. Sanders, J. Am. Chem. Soc. 120 (1990) 5525;
(b) C. Janiak, J. Chem. Soc., Dalton Trans. (2000) 3885 (and references therein).
[6] (a) M.E. Padilla-Tosta, O.D. Fox, M.G.B. Drew, P.D. Beer, Angew. Chem., Int. Ed.
40 (2001) 4235;
[14] (a) M. Nishio, M. Hirota, Y. Umezawa, The CH/
p Interaction: Evidence, Nature
and Consequences, Wiley–VCH, New-York, 1998;
(b) P.D. Beer, N. Berry, M.G.B. Drew, O.D. Fox, M.E. Padilla-Tosta, S. Patell,
Chem. Commun. (2001) 199;
(b) W.B. Jennings, B.M. Farrell, J.F. Malone, Acc. Chem. Res. 34 (2001) 885;
(c) M. Nishio, CrystEngComm 6 (2004) 130.
(c) P.D. Beer, A.G. Cheetham, M.G.B. Drew, O.D. Fox, E.J. Hayes, T.D. Rolls,
Dalton Trans. (2003) 603;
(d) W.W.H. Wong, D. Curiel, A.R. Cowley, P.D. Beer, Dalton Trans. (2005) 359;
(e) W.W.H. Wong, D. Curiel, S.-W. Lai, M.G.B. Drew, P.D. Beer, Dalton Trans.
(2005) 774;
[15] (a) I.G. Dance, M.L. Scudder, J. Chem. Soc., Chem. Commun. (1995) 1039;
(b) I.G. Dance, M.L. Scudder, J. Chem. Soc., Dalton Trans. (1998) 1341;
(c) V. Russel, M.L. Scudder, I.G. Dance, J. Chem. Soc., Dalton Trans. (2001) 789;
(d) I.G. Dance, CrystEngComm 5 (2003) 208.
[16] (a) D.G. Hamilton, J.E. Davies, L. Prodi, J.K.M. Sanders, Chem. Eur. J. 4 (1998)
608;
(f) J. Cookson, P.D. Beer, Dalton Trans. (2007) 1459.
[7] (a) M.J. Macgregor, G. Hogarth, A.L. Thompson, J.D.E.T. Wilton-Ely,
Organometallics 28 (2009) 197;
(b) D.G. Hamilton, M. Montalti, L. Prodi, M. Fontani, P. Zanello, J.K.M. Sanders,
Chem. Eur. J. 6 (2000) 608.
(b) S. Naeem, A.J.P. White, G. Hogarth, J.D.E.T. Wilton-Ely, Organometallics 29
(2010) 2547.
[17] P.S. Pregosin, P.G.A. Kumar, I. Fernandez, Chem. Rev. 105 (2005) 2977 (and
references therein).
[8] R. Reyes-Martínez, P. García y García, M. López-Cardoso, H. Höpfl, H. Tlahuext,
Dalton Trans. (2008) 6624.
[18] (a) J. Fielden, D. Long, A.M.Z. Slawin, P. Ko1gerler, L. Cronin, Inorg. Chem. 46
(2007) 9090;
[9] (a) M.C. Aragoni, M. Arca, N.R. Champness, A.V. Chernikov, F.A. Devillanova, F.
Isaia, V. Lippolis, N.S. Oxtoby, G. Verani, S.Z. Vatsadze, C. Wilson, Eur. J. Inorg.
Chem. (2004) 2008;
(b) G. Consiglio, S. Failla, P. Finocchiaro, I.P. Oliveri, R. Purrello, S.D. Bella, Inorg.
Chem. 49 (2010) 5134.
[19] F.A. Cotton, D.M.L. Goodgame, J. Chem. Soc. (1960) 5267.
[20] L.J. Barbour, Supramol. Chem. 1 (2001) 189.
(b) M.C. Aragoni, M. Arca, M. Crespo, F.A. Devillanova, M.B. Hursthouse, S.L.
Huth, F. Isaia, V. Lippolis, G. Verani, CrystEngComm 9 (2007) 873;
[21] G.M. Sheldrick, Acta Crystallogr., Sect. A 64 (2008) 112.