Synthesis and structures of perthio- and polymeric metal complexes with the tetrathio- and dithioterephthalate ligands Dedicated to Prof. George Christou on the occasion of his 60th birthday.

Article abstract of DOI:10.1016/j.poly.2013.06.003

The thioterephthalate anions [1,4-(CS₂)₂C ₆H₄]^2-, TTT, (I); [1,4-(CS₂)(CO ₂)C₆H₄]^2-, DTT, (III); and, [1,4-(COS)(COS)C₆H₄]^2-, DCT, (IV) have been synthesized and isolated as tetraphenylphosphonium (Ph₄P)⁺ salts, (I, III, IV), tetra n-butylammonium (n-Bu₄N)₂TTT (II) and tetra-ethyl ammonium (Et₄N)₂TTT salts (IIa). I, IIa and IV have been characterized structurally. The S₂C-C ₆H₄ dihedral angles Φ vary from 7 to 44. The electronic spectra of the green Ph₄P⁺ (I) (Φ = 16) and the red Et₄N⁺ (IIa) (Φ = 44) salts in CH ₃CN solution are identical and indicate a low energy barrier to rotation about the S₂C-C₆H₄ bond. The (-CS ₂) groups in I and III react with either Cu(I)/S or with Cu(II) and undergo a sulfur addition reaction to give the "sulfur-rich" (-CS ₃)^- units that are coordinated to Cu(I) as bidentate chelates in the diamagnetic [ClCuS₃C-C₆H ₄-CS₃CuCl]^2-, (V) and [XCuS₃C-C ₆H₄-CO₂]^2-, (VI), (X = Cl ^-, Br^-) complexes. In the latter the Cu(I) ions are bound to halide ligands and display a distorted trigonal planar coordination. Generation of S^2-, or S22-, by cleavage of the C-S bonds, also occurs in the solid state synthesis of the unique [(n-BuS)₂Ni ₁₂(S)₈(S₂)₆]^2- cluster (IX), at 140 C, by the reaction of Ni(OAc)₂·4H₂O with II. The [Ni₁₂(S)₈(S₂)₆] core in IX is best described as a distorted S₈ cube with 12 Ni(II)S ₄ square planar units located at the centers of the cube edges. Six S22- ligands one on each of the six, S₈, cube faces, are quadruply bridging the Ni ions. Two n-Bu⁺ groups are bound, to two of the S^2- ligands that define one of the S₈ cube diagonals. A bridging mode of IV and III is found in {[Cu(DCT)(PPh₃)] ^-}_n, (X) and {Ni(DTT)₃Zn₂(DMSO) ₆}_n, (XI), respectively. In the polymeric X, the trigonal planar Cu(I) ions are bound to the S donors of two IV ligands and one PPh₃. In XI, the Ni(II) ion is octahedrally coordinated by three CS₂ groups from two "bridging" and one "terminal" type DTT ligands. The CO₂ groups of the "bridging" ligands are bound in a mono-dentate bridging fashion to one of the four-coordinate Zn(II) ions and the "terminal ligand" is coordinated in a bi-dentate fashion to a non-bridging six-coordinate Zn(II) ion. Dimethylsulfoxide molecules complete the coordination spheres around the Zn(II) ions.

Full text of DOI:10.1016/j.poly.2013.06.003

Polyhedron 64 (2013) 328–338
Contents lists available at SciVerse ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Synthesis and structures of perthio- and polymeric metal complexes
with the tetrathio- and dithioterephthalate ligands
⇑
Alok R. Paital, Jiangjun Zhan, Rory (Heeyeon) Kim, Jeff Kampf, Patrick Collins, Dimitri Coucouvanis
Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States
a r t i c l e i n f o
a b s t r a c t
The thioterephthalate anions [1,4-(CS2)2C6H4]2ꢀ, TTT, (I); [1,4-(CS2)(CO2)C6H4]2ꢀ, DTT, (III); and,
[1,4-(COS)(COS)C6H4]2ꢀ, DCT, (IV) have been synthesized and isolated as tetraphenylphosphonium
(Ph4P)+ salts, (I, III, IV), tetra n-butylammonium (n-Bu4N)2TTT (II) and tetra-ethyl ammonium (Et4N)2TTT
Article history:
Received 3 April 2013
Accepted 4 June 2013
Available online 22 June 2013
salts (IIa). I, IIa and IV have been characterized structurally. The S2C–C6H4 dihedral angles
U vary from 7°
to 44°. The electronic spectra of the green Ph4P+ (I) ( = 16) and the red Et4N+ (IIa) (
U
U
= 44) salts in CH3CN
Dedicated to Prof. George Christou on the
occasion of his 60th birthday.
solution are identical and indicate a low energy barrier to rotation about the S2C–C6H4 bond. The (–CS2)
groups in I and III react with either Cu(I)/S or with Cu(II) and undergo a sulfur addition reaction to give
the ‘‘sulfur-rich’’ (–CS3)ꢀ units that are coordinated to Cu(I) as bidentate chelates in the diamagnetic
[ClCuS3C–C6H4–CS3CuCl]2ꢀ, (V) and [XCuS3C–C6H4–CO2]2ꢀ, (VI), (X = Clꢀ, Brꢀ) complexes. In the latter
the Cu(I) ions are bound to halide ligands and display a distorted trigonal planar coordination. Generation
of S2ꢀ, or S22ꢀ, by cleavage of the C–S bonds, also occurs in the solid state synthesis of the unique [(n-BuS)2-
Ni12(S)8(S2)6]2ꢀ cluster (IX), at 140 °C, by the reaction of Ni(OAc)2ꢁ4H2O with II. The [Ni12(S)8(S2)6] core in
IX is best described as a distorted S8 cube with 12 Ni(II)S4 square planar units located at the centers of the
cube edges. Six S22ꢀ ligands one on each of the six, S8, cube faces, are quadruply bridging the Ni ions. Two
n-Bu+ groups are bound, to two of the S2ꢀ ligands that define one of the S8 cube diagonals. A bridging
mode of IV and III is found in {[Cu(DCT)(PPh3)]ꢀ}n, (X) and {Ni(DTT)3Zn2(DMSO)6}n, (XI), respectively.
In the polymeric X, the trigonal planar Cu(I) ions are bound to the S donors of two IV ligands and one
PPh3. In XI, the Ni(II) ion is octahedrally coordinated by three CS2 groups from two ‘‘bridging’’ and one
‘‘terminal’’ type DTT ligands. The CO2 groups of the ‘‘bridging’’ ligands are bound in a mono-dentate
bridging fashion to one of the four-coordinate Zn(II) ions and the ‘‘terminal ligand’’ is coordinated in a
bi-dentate fashion to a non-bridging six-coordinate Zn(II) ion. Dimethylsulfoxide molecules complete
the coordination spheres around the Zn(II) ions.
Keywords:
Synthesis
Structures
Thioterephthalates
Complexes
Polymers
Clusters
Ó 2013 Elsevier Ltd. All rights reserved.
1. Introduction
they have been found effective in the storage of small molecules
such as N2, CO2 CH4 and H2 [3]. The storage of H2 is of particular
Crystalline, microporous, solids obtained by connecting metal
clusters with multifunctional bridging ligands have received great
attention in recent years. The basic Zn acetate core Zn4O or the
dinuclear L2Cu2 unit, are found in the acetate cluster Zn4O(OAc)6
and in L2Cu2(OAc)4. The carboxylate groups in these
compounds, as well as in other carboxylate clusters, such as
interest given the potential use of H2 as a fuel. The interactions
of relatively inert guest molecules within the MOF lattice voids
determine the strength of physi-sorption and the temperatures at
which these materials can be effective as storage media. A
DH of
adsorption between 15 and 20 kJ molꢀ1 is desirable for effective
H2 storage at room temperature [4].
[M3(l
3-O)(O2CR)6, (M = Cr+3, Fe+3, Al+3 etc.), the linear M3(O2CR)6,
4-O)((O2CR)8 with a square planar M4O core
The use of MOFs based on metal carboxylate clusters with mul-
tifunctional carboxylate bridges (such as terephthalates), as H2
storage materials, often is characterized by weak interactions and
consequently these materials function best at cryogenic tempera-
tures [4]. As a result of M–O bonding between oxophilic metal ions
and the carboxylate ligands, the porous framework products, in
terephthalate-based MOFs, potentially may be susceptible to
hydrolysis. Hydrolysis would have an adverse effect in the utility
of these extended frameworks as materials for the storage of gases.
the oxo-centered, M4(
l
and others [1] can be replaced by the carboxylate units in multi-
carboxylate phenyl ligands to form polymeric materials. Many of
these, often low density, metal organic frameworks, MOFs, contain
solvent molecules within the lattice voids [2]. Upon desolvation
⇑
Corresponding author.
E-mail address: dcouc@umich.edu (D. Coucouvanis).
An increase in the
DH of adsorption of H2 may be expected for
0277-5387/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.poly.2013.06.003

A.R. Paital et al. / Polyhedron 64 (2013) 328–338
329
materials that contain coordinatively unsaturated metal centers
within the organic linkers [4].
operated at 1.2 kW power (40 kV, 30 mA). The X-ray intensities
for XI were measured at 85(1) K with the detector placed at a
distance 42.00 mm from the crystal or on a Bruker SMART APEX
CCD-based X-ray diffractometer equipped with a low temperature
device and fine focus Mo-target X-ray tube (k = 0.71073 Å) oper-
ated at 1500 W power (50 kV, 30 mA).
We suggest that a class of bridging connectors that may satisfy
some of the requirements for optimal adsorption of H2 are those that
contain Ni+2, Cu+2, Rh+ or Pt+2 complexes of S,S coordinated, multi-
topic thiocarboxylate ligands that may serve as terephthalic acid
substitutes in MOFs. The conductivity, doping and redox chemistry
of a dithiolene based metal organic framework has been reported
[4b]. The effective use of the TTT dianion as a bridging connector
has been reported in the synthesis of the isomorphous polymeric
M(TTT)(DMF) 2 complexes M = Zn(II), Mn(II)). The structure of the
Zn complex consists of one dimensional ‘‘zig-zag’’ chains [5].
Our interest in the design of extended frameworks with thio-
carboxylate complexes as bridging ligands has led us to a struc-
tural/synthetic study of the tetrathioterephthalate, TTT, (Fig. 1, I)
[6], dithioterephthalate, DTT, (Fig. 1, III) [7], and the 1,4-thioacyl
benzene, DCT, (Fig. 1, IV) [8], ligands, their chelating properties
and their ability to serve as ditopic linkers. The TTT, DTT, and
DCT, ligands (pKa’s of the dithiobenzoic, thiobenzoic and benzoic
acid at 1.92, 2.48 and 4.20 respectively [9]) were prepared by mod-
ified procedures of the previously reported syntheses [6–8]. In this
paper we report on certain unique reactivity characteristics of the
thioterephthalate ligands. The latter include: (a) facile C–S bond
cleavage with generation of elemental sulfur and subsequent for-
mation of ‘‘sulfur-rich’’ thiocarboxylates and also of sulfido and
polysulfido ligands. (b) The ability of the thio-carboxylate ligands
to serve bi-functionally as homo-metallic or hetero-metallic
bridges.
Yellow needles of {[Cu(CDT)(PPh3)ꢁ(Ph4P)ꢁEt2O]}n,
X were
grown from a diethyl-ether solution of the compound at 23 °C. A
crystal of dimensions 0.28 ꢂ 0.09 ꢂ 0.02 mm was mounted. A total
of 3542 images were collected with an oscillation width of 1.0° in
x
. The exposure time was 2 s. for the low angle images, 8 s. for
high angle. The integration of the data yielded a total of 56650
reflections to a maximum 2h value of 136.48° of which 8322 were
independent and 6850 were greater than 2r(I). The final cell
ꢀ
constants Table 1 ) were based on, using the space group P1 with
Z = 2 for the formula C52H45.5O3.25P2S2Cu. Full matrix
least-squares refinement based on F2 converged at R1 = 0.0755
and wR2 = 0.2304 [based on I > 2r(I)], R1 = 0.0835 and
wR2 = 0.2442 for all data. Additional details are presented in Table 1
and are given as Supporting information in a CIF file. Acknowledge-
ment is made for funding from NSF grant CHE-0840456 for X-ray
instrumentation.
Red-brown needles of {Ni(DTT)3Zn2(DMSO)6}n, XI, were grown
from a dimethylsulfoxide solution at 23 °C. A crystal of dimensions
0.13 ꢂ 0.09 ꢂ 0.03 mm was mounted. The X-ray intensities were
measured at 85(1) K; the detector was placed at a distance
5.055 cm from the crystal. A total of 2966 frames were collected
with a scan width of 0.5° in w and 0.45° in phi with an exposure
time of 80 s/frame. The crystal was determined to be a non-mero-
hedral twin with indexing preformed with CELL_NOW. Reflections
from the primary component were used as the basis of an HKLF 4
input file. The integration of the data yielded a total of 28359
reflections to a maximum 2h value of 37.84° of which 4695 were
Herein we report on the syntheses and structural characteriza-
tion of the ‘‘sulfur-rich’’ (PPh4)2[ClCu(SDTT)] and (PPh4)2
[ClCu(STTTS)CuCl] complexes, (Fig. 2, V, VI) the polymeric
{[Cu(DCT)(PPh3)](Ph4P).Et2O}n (Fig. 2, X) and {Ni(DTT)3Zn2
(DMSO)6}n (Fig. 2, XI) complexes. The solvo-thermally obtained,
n-Bu4N+ salt, of the [(n-BuS)2Ni12(S)8(S2)6]2ꢀ cluster (Fig. 2, IX) also
was the product of the reaction between Ni(OAc)2ꢁ4H2O and II and
was structurally characterized.
independent and 3781 were greater than 2
stants (Table 1) were based on the xyz centroids of 5981 reflections
above 10 (I). Analysis of the data showed negligible decay during
r(I). The final cell con-
r
data collection; the data were processed with TWINABS (CELL_-
NOW: SHELDRICK, G. v.2008/2, Program For Indexing Twins) and cor-
rected for absorption. The structure was solved and refined with
the Bruker SHELXTL (version 2008/4) software package (Sheldrick,
G.M. SHELXTL, v. 2008/4; Bruker Analytical X-ray, Madison, WI,
2. Experimental
All reactions have been performed under aerobic conditions. Li-
gands TTT [6] DTT [7] and DCT [8] were prepared by modified
procedures.
ꢀ
2008.) using the space group P1 with Z = 2 for the formula
C35H45O12S12NiZn2. Disordered lattice solvates, presumably
DMSO and possibly water were treated as contributing to diffuse
scatter by the SQUEEZE subroutine of the PLATON program suite, (A.L.
Spek (2008) PLATON, A Multipurpose Crystallographic Tool, Utrecht
University, Utrecht, The Netherlands).
IR spectra were obtained on a Perkin Elmer BX FT-IR spectrom-
eter (mid-IR) and a Nicolet 740 FT-IR spectrometer (Far-IR) in KBr
pellets. Mass spectra were collected on a Micromass LCT Time-of-
Flight mass spectrometer.
All non-hydrogen atoms were refined anisotropically with the
hydrogen atoms placed in idealized positions. Full matrix least-
squares refinement based on F2 converged at R1 = 0.1910 and
wR2 = 0.4654 [based on I > 2r(I)], R1 = 0.2062 and wR2 = 0.4737
for all data. Additional details are presented in Table 1 and are
2.1. Crystallography
Single crystal X-ray diffraction data for all compounds except XI
were collected on a Rigaku AFC10K Saturn 944+ CCD-based X-ray
diffractometer equipped with a low temperature device and Micro-
max-007HF Cu-target micro-focus rotating anode (k = 1.54187 Å)
given as Supporting information in a CIF file.
Fig. 1. Structures of the thioterephthalate salts. I, (Ph4P)2(TTT); III, (Ph4P)2(DTT); IV, (Ph4P)2(DCT).

330
A.R. Paital et al. / Polyhedron 64 (2013) 328–338
Fig. 2. Structures of the thioterephthalate derivatives. (Ph4P)2[ClCuS3C–C6H4–CS3CuCl] V, the positionally disordered (Ph4P)2[XCuS3C–C6H4–CO2]
VI, (n-Bu4N)2[(n-BuS)2Ni12(S)8(S2)6] IX, {[Cu(DCT)(PPh3)] (Ph4P)ꢁEt2O}n X, and {Ni(DTT)3Zn2(DMSO)6}n XI.
2.2. Syntheses
for C56H44P2S4: (I) M.W. = 907.16. C, 74.14; H, 4.89. Found: C,
73.22; H, 5.29%. IR (cmꢀ1) 3432(m), 3050(w), 3004(w), 1584(m),
1437(vs), 1433(vs), 1393(w), 1376(w), 1335(w), 1310(w),
1184(m), 1106(vs), 1009(s), 996(s), 888(m), 858(m), 752(m),
722(vs), 688(s), 608(w), 526(vs). FAR-IR. UV–visible spectrum
(DMF): kmax(nm), 521, 330. NMR(CD3CN): d7.9–7.6(br, 44H);
3.6(q, 2H); 1.1(t, 3H). MS: (ESI+) m/z 339.1; MS: (ESIꢀ) m/z 227.8.
2.2.1. Bis-tetraphenylphosphonium tetrathioterephthalate, (I, Ia)
2.2.1.1. [Ph4P]2[1,4-(CS2)2C6H4]; [Ph4P]2(TTT). To
a solution of
sodium methoxide (10.8 g, 0.20 mol) in 300 ml of dry methanol,
sulfur (6.40 g, 0.20 mol) was added and refluxed for 3 h. Then
p-xylyl chloride, (H3C–C6H4–CH2Cl) (8.75 g, 0.05 mol) was added
in small portions for 1.5 h and refluxed overnight. The solution
was filtered and the solvent was partially evaporated to give a
dark-brown residue which was treated with a large excess of dilute
HCl to give a green precipitate of the tetrathio acid (5.5 g). The
above precipitate was isolated and dissolved in 150 ml of 10%
NaOH solution and then added to 150 ml of a hot aqueous solution
of tetraphenyl phosphonium bromide (20 g, 0.047 mol).
2.2.2. Bis-tetrabutylammonium tetrathioterephthalate, II
2.2.2.1. (n-Bu4N)2 [1,4-(CS2)2C6H4]; (n-Bu4N)2TTT. It was prepared
following the above procedure by using tetrabutyl ammonium
chloride (13.06 g, 0.047 mol) instead of tetraphenyl phosphonium
bromide. The color of this compound is pink-red. Yield (15 g,
42%). mp 68–69 °C. Anal. Calc. for C40H76N2S4: M.W. = 713.31. C,
67.35; H, 10.74; N, 3.93. Found: C, 66.88; H, 9.82; N, 3.24%.
IR(cmꢀ1): 3432(m), 2960(vs), 2934(m), 2873(m), 1483(s),
1462(m), 1379(m), 1219(w), 1150(w), 1100(w), 1013(vs), 890(s),
The dark red-brown precipitate was recrystallized either from
methanol–water or from hot ethanol to give the desired compound
with water or ethanol as solvent of crystallization.
The methanol–water recrystallized product, (I), is red in the so-
lid state whereas the ethanol recrystallized product (Ia) is green in
the solid state. Yield for I, (22 g, 48.5%). mp: 160–162 °C. Anal. Calc.
834(s), 798(s), 738(s), 496(s). NMR(CD3CN):
3.1(t, 16H); 1.62(m, 16H); 1.35(m, 16H); 0.96(t, 24H). MS: (ESI+)
m/z 242.3; MS: (ESIꢀ) m/z 227.8.
d 8(s, 4H);

A.R. Paital et al. / Polyhedron 64 (2013) 328–338
331
Table 1
Crystallographic and refinement data.
I
Ia
III
V
VI
(PPh4)2TTT
green
(PPh4)2TTTꢁ2EtOH
brown
(PPh4)2DTTꢁ2EtOH
red
(PPh4)2[Cu2TTT)Cl2
(PPh4)2[CuDTT)Cl]
Color
Size (mm)
Formula
Weight
Space group
Unit Cell dimensions
a (Å)
0.34 ꢂ 0.24 ꢂ 0.2
0.40 ꢂ 0.10 ꢂ 0.07
C60H56O2P2S4
999.23
0.28 ꢂ 0.16 ꢂ 0.14
C60H56O4P2S2
967.11
0.16 ꢂ 0.12 ꢂ 0.035
C56H44Cl2P2S6Cu2
1169.29
0.41 ꢂ 0.14 ꢂ 0.12
C56H44ClO2P2S3Cu
1006.09
C56H44P2S4
907.16
P21/n
ꢀ
ꢀ
P21/n
Pc
P1
P1
10.0469(7)
15.7502(11)
14.6751(10)
90.00
90.412(1)
90.00
12.6773(9)
15.9314(11)
14.225(1)
90.00
112.892(1)
90.00
12.7345(8)
15.3061(10)
13.4780(9)
90.00
108.377(1)
90.00
9.3608(6)
9.6370(6)
15.4408(10)
105.067(1)
102.685(1)
93.993(1)
1300.27(14)
2
9.1629(6)
9.2845(6)
15.4553(10)
78.1250(10)
73.6810(10)
89.1180(10)
1233.59(14)
1
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
V (Å3)
2322.1(3)
4
2646.8(3)
2
2493.1(3)
2
Z
T (K)
85(2)
293(2)
85(2)
85(2)
85(2)
Absorption coefficient
F(000)
0.312
948
0.282
1052
0.220
1020
h range (°)
Reflections
R1
wR2 [I > 2r(I)]
R1
1.90–28.35
5805
1.83–19.24
2211
169–28.4
12414
6489
6182
0.0516
0.1357
0.0662
0.1467
1.057
0.0492
0.1241
0.0662
0.1367
1.021
0.0388
0.0999
0.0409
0.1014
1.033
0.0264
0.0718
0.0304
0.0792
1.112
0.0413
0.1096
0.0501
0.1153
1.090
wR2 (all data)
Goodness-of-fit (GOF) (F2)
Table 1
Crystallographic and refinement data (continued).
IV
X
IX
XI
(PPh4)2DCT
[Cu(DCT)(PPh3)]ꢀ(Ph4P).(Et2O)1.5
0.28 ꢂ 0.09 ꢂ 0.02
C52H45.5O3.25P2S2Cu
911.98
[Ni12S18(n-BuS)2]2ꢀ [Bu4N]2
0.21 ꢂ 0.18 ꢂ 0.18
C41H51C12N2S20Ni12
1988.46
Ni(DTT)3Zn2(DMSO)6
0.13 ꢂ 0.09 ꢂ 0.03
C35H45O12S12NiZn2
1231.88
Size (mm)
Formula
Weight
0.20 ꢂ 0.11 ꢂ 0.23
C56H44O2P2S2
875.03
ꢀ
ꢀ
ꢀ
ꢀ
Space group
P1
P1
P1
P1
k (Å)
1.54178
1.54178
1.54178
0.71073
Unit cell dimension
a (Å)
b (Å)
9.0494(6)
9.5133(7)
14.0642(10)
75.137(1)
71.765(1)
80.838(1)
1107.4(1)
1
10.3820(2)
12.2861(2)
19.461(1)
74.927(5)
86.02(6)
74.435(5)
2309.06(18)
2
13.7145(3)
14.2809(3)
19.462(1)
84.909(6)
79.705(6)
73.947(5)
3601.0(3)
2
12.478(3)
15.366(4)
17.808(5)
113.841(4)
100.781(4)
98.954(4)
2964(7)
2
c (Å)
a
(°)
b (°)
c
(°)
V (Å3)
Z
T (K)
85.2
85.2
85.2
85.2
Absorption coefficient
F(000)
0.237
458
0.250
949
2002
1262
h range (°)
Reflections
Limit. indices
1.56–29.65
12449
ꢀ12 < h<12
ꢀ13 < k < 13
ꢀ19 < l < 19
0.0336
6.59–68.24
8322
ꢀ12 < h < 12
ꢀ14 < k < 14
ꢀ23 < l < 23
0.0755
2.31–50.43
2211
ꢀ13 < h < 13
ꢀ14 < k < 14
ꢀ19 < l < 19
0.0839
2.25–18.92
4695
ꢀ11 < h < 11
ꢀ13 < k < 13
ꢀ16 < l < 16
0.1910
R1
wR2, [I > 2
r
(I)]
0.0892
0.2304
0.2409
RI (all data)
0.0391
0.0940
1.046
0.0835
0.2442
1.207
0.0907
0.2480
1.035
0.2062
1.070
wR2 (all data)
Goodness-of-fit (GOOF) (F2)
2.2.3. Bis-tetraphenylphosphonium dithioterephthalate, III
0.0096 mol). A green precipitate formed, was isolated and was
recrystallized from ethanol-ether to give the desired product with
ethanol as solvent of crystallization.
Yield (3.41 g, 39%). Anal. Calc. for C56H44O2P2S2: M.W. = 875.03.
C, 76.87; H, 5.07. Found: C, 75.92; H, 4.80%. mp 197–199 °C.
IR(cmꢀ1): 3399(m), 3051(w), 2954(w), 1581(s), 1543(m),
1482(m), 1437(vs), 1361(vs), 1312(m), 1185(m), 1108(vs),
1052(w), 1004(s), 993(s), 903(w), 878(w), 819(w), 793(m),
757(m), 722(vs), 689(vs), 614(w), 525(vs). kmax(nm) DMF MS: (ESIꢀ)
m/z 197.7.
2.2.3.1. [Ph4P]2[1,4-(CS2)(COS)C6H4]; [Ph4P]2 DTT. 1.17 g of
Potassium (0.03 mol) was dissolved in 100 ml dry ethanol. To this
solution 0.64 g of sulfur (0.02 mol) was added followed by 4-Bro-
momethylbenzoic acid (2.15 g, 0.01 mol) and the mixture was
refluxed overnight. The solution was filtered and the solvent was
evaporated to give a yellow-brown color precipitate of bis-potas-
sium dithioterephthalate. The precipitate was dissolved in 100 ml
of water and the solution was added to 100 ml of a hot aqueous
solution of tetraphenyl phosphonium bromide (4.02 g,

332
A.R. Paital et al. / Polyhedron 64 (2013) 328–338
2.2.4. Bis-tetraphenyl phosphonium 1,4-dithiocarboxybenzene, IV
2.2.4.1. [Ph4P]2[1,4-(COS)(COS)C6H4]; [Ph4P]2DCT. 2 g of terepthaloyl
chloride (9.85 mmol) was dissolved in 30 ml of dichloromethane.
To the above solution N,N0-dimethylthioformamide (1.75 ml,
20.2 mmol) was added dropwise under stirring. H2S gas was
passed in the solution at 25 °C, at a moderate rate, for 1 h. Then
the solvent was removed in a rotary evaporator to give a yellow so-
lid which was washed with dichloromethane and water (1.77 g,
8.96 mmol). The above acid was dissolved in 30 ml of 10% NaOH
solution and to it 2 equivalents of tetraphenyl phosphonium bro-
mide (7.5 g, 17.92 mmol) in hot water was added and the mixture
stirred for 30 min to give a dark yellow solid. Yield (6.97 g, 89%).
Anal. Calc. for C56H44O2P2S2: M.W. = 875.03. C, 76.87; H, 5.07.
Found: C, 76.02; H, 5.29%. IR (cmꢀ1) 3453(m), 3394(m), 3055(w),
1620(w), 1583(m), 1550(w), 1513(vs), 1480(m), 1432(vs),
1310(w), 1170(s), 1104(vs), 993(m), 927(s), 857(w), 750(m),
720(vs), 687(s), 669(m), 525(vs). Uv–Vis (DMF): 328 nm. NMR
(CDCl3): d 7.8–7.4(m, 52H). MS: (ESI+) m/z 339.1; MS: (ESIꢀ) m/z
195.8, 1178.9, 162.9.
2.2 mmol) was added to the above mixture and allowed to stir
for 2 h. The precipitate slowly dissolved to give a brown color solu-
tion along with a minor precipitate. The solution was filtered to
isolate a small amount of black precipitate and brown colored
filtrate was layered with ca. 150 ml ether, affording a brown pre-
cipitate. Yield, 60% based on ligand.
The insoluble black precipitate obtained is insoluble in organic
solvents.
The brown product shows the presence of tetraphenyl phospho-
nium cation in the FT-IR spectrum.
Elemental Anal. Calc. for C64H48S9P2Ni: C, 62.69, H, 4.08. Found:
C, 62.78, H, 4.61%.
2.2.8. (Ph4P)2 Ni(SDTT)2, VIII
To a DMF solution of (PPh4)2DTT (1 g, 1.14 mmol in 15 ml DMF)
a NiCl2ꢁ6H2O solution (0.135 g, 0.57 mmol in 5 ml DMF) was added
drop wise under stirring to give a brown precipitate. Elemental
Sulfur powder (0.037 g, 1.1 mmol) was added and the mixture
was allowed to stir for 2 h. The precipitate slowly dissolved to give
a violet color solution. The resulting solution was filtered and
layered with ca. 200 ml ether, affording a violet colored crystalline
material. Yield 0.77 mmol, 68% based on ligand. Elemental Anal.
Calc. for C64H54S6P2O7Ni: C, 61.59, H, 4.33. Found: C, 61.07, H,
2.2.5. (PPh4)2[ClCu(STTTS)CuCl], V
Method A: To a 10 ml DMF solution of the [Ph4P]2(TTT) ligand,
(0.5 g, 0.55 mmol), a CuCl2ꢁ2H2O solution (0.093 g, 0.55 mmol in
5 ml DMF) was added drop-wise under stirring and the stirring
continued for 2 h. The solution was filtered and layered with
75 ml of diethyl ether. Upon standing, brown colored crystals
formed. Yield (0.263 g, 41%). Anal. Calc. for C56H44Cl2P2S6Cu2:
M.W. = 1169.29. C, 57.52; H, 3.79. Found: C, 56.90; H, 3.42%.
IR(cmꢀ1): 3429(m), 3054(w), 1664(w), 1584(w), 1572(w),
1482(w), 1440(s), 1434(vs), 1400(w), 1338(w), 1313(w),
1234(w), 1184(w), 1163(w), 1107(vs), 1015(s), 1005(s), 996(s),
974(w), 895(vs), 842(m), 760(m), 750(m), 724(vs), 689(vs),
578(s), 561(s), 525(vs). kmax(nm) (DMF): 506, 382. NMR (DMSO): d
8–7.5(m, 44H). MS: (ESI+) m/z 339.1; MS: (ESIꢀ) m/z 390.9,
354.9,327, 290.9, 223.9, 134.9.
Method B: To a 10 ml DMF solution of the [Ph4P]2(TTT) ligand,
(0.5 g, 0.55 mmol), S powder (0.036 g, 1.1 mmol) was added and
was immediately followed by the addition of CuCl (0.108 g,
1.1 mmol) under stirring and the stirring continued for 2 h. A violet
color solution was obtained and was filtered. It was layered with
50 ml of diethyl ether and upon standing gave a red-brown crystal-
line product. Yield (0.39 g, 60%). The compound was found identi-
cal to that obtained by method A.
4.35%.
FT-IR:
3394(w),3052(w),
1583(w),
1480(w),
1436(s),1235(vs), 1107(vs), 1018(vs), 993(m), 761(m), 723(vs),
691(vs), 600(vs), 525(vs). kmax DMF: 485, 377 nm.
2.2.9. [Ni12(n-C4H9S)2(S)6(S2)6][(n-C4H9)4N]2ꢁCH2Cl2 IX
(n-Bu4N)2TTT (0.7 g) and Ni(OAc)2ꢁ4H2O (0.244 g), were inti-
mately mixed (in the air) and placed in a 5 mL glass ampoule.
The ampoule was evacuated, sealed and heated in an oven to
140 °C for 3 days. A brown-black oil formed. The oil was dissolved
in 10 mL of CH2Cl2 the solution filtered and layered with 15 mL of
diethyl ether. Upon cooling to 3 °C for 5 days (or until fully dif-
fused) a small amount of dark green crystals formed on the wall
of the crystallization test tube. The experiment was repeated suc-
cessfully three times. The small amounts of this compound did not
allow for an elemental analysis but a crystal gave a satisfactory
Ni:S ratio of 3:5 by microprobe analysis. MS: (ESI+) m/z 242.2;
MS: (ESIꢀ) m/z 1699.7, 1457.4, 671.5, 639.5, 325.2. FT-IR:
2956.0(s), 2926.2(s) 2868.4(m), 1635.6(w), 1458.4(m), 1383.1(m),
1262.5(w), 1166.8(w), 1106.1(w), 1032.6(w), 881.7(w), 741.7 (m)
509.0(w).
2.2.6. (PPh4)2[Cu(SDTT)Cl], VI
2.2.10. {[Cu(DCT)(PPh3)]ꢀ[Ph4P] Et2O}n
Method A: To a 10 ml DMF solution of the [Ph4P]2(DTT) ligand,
(0.5 g, 0.55 mmol), a CuCl2ꢁ2H2O solution (0.050 g, 0.28 mmol in
5 ml DMF) was added slowly with stirring and the stirring contin-
ued for 2 h. The solution was filtered and layered with 75 ml of
diethyl ether to give red colored crystals. Yield (0.229 g, 40%). Anal.
Calc. for C56H44ClO2P2S3Cu: M.W. = 1006.09. C, 66.85; H, 4.41.
Found: C, 66.12; H, 4.18%. IR (cmꢀ1): 3417(m), 3051(w),
2324(m), 1687(s0, 1584(w0, 1482(w), 1434(vs), 1400(w),
1374(w0, 1312(w), 1224(s0, 1178(w), 1108(vs), 1004(m), 994(s),
864(w), 776(m), 754(m), 722(vs), 689(vs), 667(w), 559(w),
To a 12 mL CH3CN solution of (Ph4P)2(DCT), (0.36 g, 0.44 mmol)
was added a 5 mL solution of Cu(CH3CN)4PF6 (0.28 g, 0.44 mmol).
An insoluble red-orange precipitate formed instantly suspended
in an essentially colorless solution. The precipitate was filtered,
washed with diethyl-ether, Et2O, and dried. It was suspended in
20 mL of dimethylformamide, DMF, and Ph3P was added (2.6 g,
10 mmol). The red-orange solid dissolved rapidly and a yellow
solution was obtained. A layer of Et2O (20 mL) was carefully depos-
ited on top of the DMF solution. Upon standing for 24 h. at room
temperature, yellow crystals formed. Microprobe analysis showed
a S:Cu:P ratio of 2:1:1. The reaction was reproducible (as estab-
lished by single crystal X-ray diffraction), however the quantity
of 373(w), 340(w). kmax(nm) DMSO: 291, 356 these crystals was
insufficient for elemental analysis.
526(vs), 456(vs). kmax(nm) DMF: 491, 356. NMR (DMSO):
d
8–7.7(m, 44H). MS: (ESI+) m/z 339; MS: (ESIꢀ) m/z 326.9, 291,
263, 247, 134.9.
Method B: The same compound is obtained from S/CuCl as de-
scribd above for the synthesis of V.
2.2.11. {Ni(DTT)3Zn2(DMSO)6ꢁCH2Cl2}n XI
2.2.7. (Ph4P)2 [(TTT)Ni(STTT], VII
Method A (from preformed (Ph4P)2[Ni(DTT)2]); see synthesis of VIII
above): An amount of (Ni(CH3CN)6)(BF4)2 (0.1 g, 0.21 mmol) in
15 mL of CH3CN was added dropwise to 20 mL of a CH3CN solution
of (Ph4P)2DTT (0.37 g, 0.42 mmol). A precipitate formed immedi-
ately and the suspension was stirred for 10 min. The brown solid
Procedure: To a DMF solution of the (PPh4)2TTT ligand (1 g,
1.1 mmol in 20 ml DMF), a [Ni(MeCN)6](BF4)2 solution (0.263 g,
0.55 mmol in 5 ml DMF) was added drop wise under stirring to
give
a brown precipitate. Elemental Sulfur powder (0.070 g,

A.R. Paital et al. / Polyhedron 64 (2013) 328–338
333
Table 2
Structures of the thioterephthalate ligands.
(Et4N)2TTT IIa
(Ph4P)2TTT I
(Ph4P)2TTT Ia – 2EtOH
(Ph4P)2DCT IV
(Ph4P)2DTT III 2EtOH
Color of crystals
red
43.96°
green
23.11°
brown
16.08°
yellow
25.07°
yellow-brownc
Ua
28.85d; 28.33e; 7.12d; 8.47e
S–C–S/Ph
S–C–O/Ph
O–C–O/Ph
a
b
c
1.688(1)
1.683(1)
1.496(4)
1.684(3)
1.640(3)
1.501(6)
1.617(6)
1.659(6)b
1.497(9)
1.721(1)
1.510(5)
1.395(5)
1.395(6)
1.385(4)
1.238(4)
1.691(1); 1.692e
1.679(1): 1.677e
1.490(4)
1.521(4)
1.397(4)
1.386(4)
1.401(4)
1.394(4)
1.384(4)
d
e
f
1.399(4)
1.397(4)
1.389(4)
1.397(6)
1.400(6)
1.385(6)
1.391(8)
1.382(9)
1.362(9)
1.390(4)
g
h
i
1.250(2); 1.249e
1.261(2);1.271e
124.3(4(11)
S–C–S
S–C–O
O–C–O
124.96(7)°
123.4(1)°
122.6(4)°
124.74(8)
126.64(16)
a
b
c
The dihedral angle between the SCX unit and the phenyl ring.
Sulfur H-bonded to EtOH.
Themolecule occupies the site in two orientations, differering by 180°, at occupancies of 79% and 21%.
For the ligand at the 79% orientation.
d
e
For the ligand at the 21% orientation.
was filtered and washed with CH3CN, diethyl-ether and air dried.
(yield 0.19 g, 80% of (Ph4P)2[Ni(DTT)2]). This solid (0.19 g) was
added to 20 mL of dimethylsulfoxide, DMSO, and the suspension
was stirred slowly until most of the solid had dissolved. The solu-
tion was filtered to remove a small amount of undissolved solid
and to it was added 1.399 g of Zn(NO3)2ꢁ6H2O. The mixture was
stirred for 10 min to give a homogeneous brow red solution. Two
mL portions of the solution were placed into a wide-mouth jar that
contained 15 mL of chloro-benzene and 0.2 mL of NEt3. The jar was
capped and allowed to stand at room temperature. After 2 days a
small amount of red crystals formed, were filtered washed with
acetone and air dried. Microprobe analysis, qualitatively showed:
S, Ni, and Zn in a 8:1:2 ratio. FT-IR spectra: 3419(m), 2962(w)
1652(m) 1616(m) 1539(m), 1495(w), 1402(vs), 1380(vs),
1306(w), 1265(m), 1224(m), 1170(w), 1133(w), 1100(w),
1016(vs), 989(s), 949(m), 933(m), 838(m), 785(m), 701(w),
665(w), 580(w), 527(w), 508(w), 417(w).
Method B: An amount of Zn(NO3)2ꢁ6H2O (0.219 g, 0.74 mmol)
and (Ph4P)2DTT) (0.215 g, 0.25 mmol) were dissolved n 10 mL
DMSO to give a red solution. To this solution, a solution of
(Ni(CH3CN)6)(BF4)2 (0.1 g, 0.21 mmol) in 5 mL DMSO was added
and the color changed to a deep red-brown. 1 mL of this solution
was layered with 2 mL of CH3CN. Upon standing overnight, at room
temperature, a small amount of red crystals formed. The IR spectra
and microprobe analysis data show these crystals to be the same as
those obtained by method A. Due to the poor quality of the best
crystals obtained, the determined structure of XI was of unsatisfac-
tory precision and is reported herein only to support the stoichi-
ometry and atomic connectivity.
3. Discussion
3.1. The thioterephthalate ligands
The structures of the TTT, DTT and DCT ligands (Fig. 1) have
been determined (Tables 1 and 2).
In TTT (Fig. 1, I) the planar dithio groups make different dihedral
angles with the central phenyl rings at (156.89°, 163.92° and,
136.04° in the (Ph4P+)2 (Fig. 1, I) (Ph4P+)22EtOH, and (Et4N+)2 salts,
respectively. The S@C–S bond angles are in the range of 122.7(4)–
124.95(7)°. The IR spectra of the free TTT ligands show character-
istic C@S stretches around 1009 cmꢀ.
Single crystals of the (PPh4)2DTTꢁ2EtOH ligand (Fig. 1, III) were
obtained from EtOH-Ether. The anionic ligand is positionally disor-
dered. The C@S and C–S bond distances are 1.679(2) and
1.691(2) Å, whereas the C@O and C–O bond distances are
1.250(2) and 1.261(2) Å respectively. The S@C–S and O@C–O bond
angles are 124.34(11)° and 126.64(16)°. The S@C–S group makes a
dihedral angle of 151.28° whereas the O@C–O group makes a dihe-
dral angle of 172.19° with the central phenyl ring indicating that
the O@C–O unit is almost planar with the phenyl ring but the
S@C–S is unit is non planar. The solvent of crystallization, EtOH,
forms hydrogen bonding interaction with the ligand carboxylate
ends, (H–OH, 1.45, 1.50 Å). The dithioterephthalate ligand shows
the C@O stretching vibration at 1543 cmꢀ1 and the C–O vibration
at 1361 cmꢀ1. The C@S stretch appears at 1004 cmꢀ1
Single crystals of (PPh4)2DCT (Fig. 1, IV) were obtained from
EtOH-Ether. The C–S bond distances are 1.720(2) whereas the
C@O bond distances are 1.238(2) Å. The O@C–S bond angles are
.

334
A.R. Paital et al. / Polyhedron 64 (2013) 328–338
124.74(10)°. The dihedral angle between the O@C–S groups and
central phenyl ring is 153.75°.
[S–Cu–S: 99.838(16)°; S–Cu–Cl: 121.087(18)° and 139.050(18)°].
The S@C–S bond angle is 126.26(9)°. The Cu(I) can be best de-
scribed as having a distorted trigonal planar coordination.
The oxidative generation of aromatic perthiocarboxylates from
dithiobenzoate and dithiotoluate ligands has been observed previ-
ously with the bis Ni(II) [10] bis Zn(II) [11] and tris Fe(III) [12] com-
plexes of these ligands.
Crystal and structural details are presented in Tables 1 and 2.
3.2. Sulfur-rich’’ Cu(I) complexes with the TTT and DTT ligands, V and
VI, respectively
The structure of V demonstrates the utility of the STTT ligand as
a bridge for thiophilic ions. We anticipate that the additional sulfur
in the STTT ligand would be easily removed by Ph3P. This reaction
has been established in 1,1-dithiolate chemistry [13] and also with
‘‘sulfur-rich’’ dithio-benzoate ligands.
3.2.1. The Cu(I) complexes
The TTT dianion reacts readily with CuCl2 to give the neutral CuI
complex (STTT)(CuCl)2,V (Fig. 2, V; Scheme 1) which can be iso-
lated in crystalline form as a tetraphenyl phosphonium salt. The
additional S is generated from the TTT ligand. V also is obtained
in the reaction of TTT with CuCl and elemental S (Scheme 1).
A procedure, similar to the one used in the synthesis of V
(scheme 1), was used to obtain the (PPh4)2[Cu(SDTT)Cl] complex.
VI, (scheme 2).
Single crystals of VI were obtained from DMF-Ether. The dian-
ion in VI (Fig. 1, VI, Tables 1 and 3) is positionally disordered and
also contains a ‘‘sulfur-rich’’ dithioterephthalate ligand which
binds one Cu(I) at the dithiolate end, as the carboxylate end re-
mains free. The geometry around Cu(I) can be best described as
distorted trigonal planar with bond lengths around the Cu(I) at
[Cu–S(C@S): 2.2008(11) Å; Cu–S(C–S): 2.2382(19) Å and Cu–Cl:
2.2790(8) Å]. The C@S and C–S bonds in the ligand are 1.554(3)
and 1.668(2) Å respectively whereas the C@O and C–O bond dis-
tances are 1.205(8) and 1.325(6) Å. The bond angles around the
Cu(I) are [S–Cu–S: 99.56(6); S–Cu–Cl: 118.67(6) and 141.68(4)].
The S@C–S and O@C–O bond angles are 138.2(2)° and 125.3(5)°
respectively. The unusually long Cu–Cl bond in VI at 2.279 Å is
0.1 Å longer than the Cu–Cl bond in V but still shorter than the
The incorporation of the extra sulfur in the Cu(I)-coordinated
TTT and DTT ligands at present is difficult to understand. We can
only speculate that the apparent stability of the Cu(I)SSCS five-
member ring, promotes oxidation of the TTT and DTT, Cu(I)-coordi-
nated, ligands and subsequent reductive cleavage of the C–S bond.
The identification of ligand-dissociation by-products will be neces-
sary to determine the validity of this speculation.
The dicopper complex of the STTT ligand shows the characteris-
tic S–S vibration at 561 cmꢀ1. Mass spectrum shows no molecular
ion peak but at 390.9(–CuCl), 354.9(–Cl), 327(–S), 290.9(per-tetra-
thio ligand only), 223.9, 134.9.
Cu–Br bond length in [CuLEt(Br), 2.316(2) Å [14]]; [[PPh4]2[( 5-C5-
g
Me5)MoS3Cu3Br3]2, 2.291 Å [15] and in [(t-BuNC)4Mo(
l-t-BuS)2-
Single crystals of (PPh4)2[Cu2(STTTS)Cl2]ꢁV, can be obtained
from dimethylformamide-diethyl-ether mixtures and the crystal
structure of V was determined by X-ray diffraction (Fig. 1, V,
Table 3). The complex dianion contains two per-tetrathioterepht-
halte ligands which bind two Cu(I) ions, one each, at the two ends
of the ligand. Two chlorides serve as Cu-bound terminal ligands.
The bonds around the Cu(I) are [Cu–S(C@S): 2.2046(5) Å;
Cu–S(C–S): 2.2387(5) Å and Cu–Cl: 2.1790(4) Å]. The C@S and
C–S bonds are 1.6811(16) and 1.6964(16) Å respectively. The
S–S bond is 1.9989(5) Å. The bond angles around the Cu(I) are
CuBr, 2.317 Å [16] (see Table 4)
Table 4
Structural Details of the [Ni12(n-C4H9S)2(S)6(S2)6]2ꢀ, IX, cluster.
Distancea
Range
[Ni12(S)8(S2)6][Et4N]3
b
Distances (#)
Ni–Ni
2.794(7,12)
2.754 (2)–
2.825(2)
2.821 2.763(2)–
2.915(2)
Ni–S (24)
2.181(5,24)
2.139(3)–
2.219(3)
Ni–S2 (24)
Ni–SnBu (6)
Ni–S (all, 54)
2.173(4,24)
2.200(6,6)
2.179(3,54)
2.137–2.205
2.185–2.211
2.137(3)–
2.219(3)
4.302(8)–
4.376(8)
2.190(2) 2.142(3)–
2.244(3)
S2–S2ꢀ (cube,
12)
S–S S22ꢀ, 6)
4.343(11,12)
2.105(8,6)
2.069(8)–
2.128(8)
Scheme 1.
C–S
Ni–S–Nicorners
1.821; 1.848
74.4(5)–112.7
(5)
c
77–106
a
The first number in parenthesis represents the larger of the individual standard
deviations or the standard deviation from the mean
r
= [Ri=1N(xi ꢀ x)2N(N ꢀ 1)]1/2
,
the second represents the number of chemically equivalent bonds averaged out.
b
From Ref. [15].
See footnote of Fig. 5 above.
c
Scheme 2.
Table 3
Cu(I) complexes of the STTT and SDTT ligands.
(Ph4P)2[ClCu(STTTS)CuCl]
(Ph4P)2Cu(SDTT)X
Cu–S
Cu–Cl
2.2046(5); 2.3875(5)
2.1790(4)
2.201(1); 2.238(2)
2.2790(8)a
S–Cu–S
S–Cu–Cl
99.84(2)°
121.09(2); 139.05(2)
99.56(6)
118.67(6); 141.68(4)
S–S
1.9989(5)
1.999(2)
C–S
C–O
S–C–S
O–C–O
1.681(2); 1.696(2)
1.554(3); 1.668(2)
1.205(8); 1.325(6)
138.2(2)a
126.3(1)a
125.3(5)
a
Dihedral angle between the CuS2CS and phenyl ring: 32.04o.
Fig. 3. The [Ni12(n-C4H9S)2(S)6(S2)6]2ꢀ, IX, Cluster.

A.R. Paital et al. / Polyhedron 64 (2013) 328–338
335
3.2.2. [Ni12(n-C4H9S)2(S)6(S2)6][(n-C4H9)4N]2, IX
The synthesis of IX was accomplished by the reaction of Ni ace-
tate tetrahydrate and II in a sealed tube at 140° for 3 days. The
molten II served as a solvent for the reaction and also as a source
for n-Bu+ that adds to S2ꢀ to form the n-BuSꢀ ligands. The forma-
tion of the S2ꢀ and S22ꢀ anions from the decomposition of the coor-
dinated TTT ligand demonstrates the propensity of the dithioaryl
group to undergo reductive cleavage of the C–S bond. This reaction
in the synthesis of IX undoubtedly is promoted by the thermody-
namic stability of the Ni-S cluster.
The cuboctahedral Ni12(n-BuS)2(S)6(S2)6]2ꢀ core in IX (Figs. 5–7)
is structurally similar to the [Ni12(S)8(S2)6]3ꢀ core in the [Ni12(S)8(-
S2)6][Et4N]3 cluster [17], XII.
Fig. 4. The Ni12S20 framework. The yellow spheres are the S22ꢀ and the Orange
Spheres the S2ꢀ Ligands.
The latter was obtained by a lengthy hydrothermal reaction be-
tween GeS2, Ni(OAc)2ꢁ4H2O, and Et4HCO3 in a 10:1:17 ratio. In this
cluster the S2 ligands are related by three mutually perpenticular
2-fold axes (D2 symmetry) and the overall charge suggests a
Ni(II)11(Ni(III) formulation. By comparison, the S2 ligands in
IX (described as a Ni(12) cluster are related by a center of symmetry.
The electronic description of XII was chosen on the basis of spectro-
scopic evidense for an intravalence charge transfer absorption. The
addition of two n-Bu+ groups to S2ꢀ ligands and formation of two
n-BuSꢀ ligands, in the synthesis of IX, may support the presence
of an SHꢀ ligand in XII. The distortion of the [Ni12(S2)6S8]3ꢀ
framework in XII can be seen in the range of Ni–S–Ni bond angles,
77.0–105.8°, that define the S8 corners. In IX the Ni–S–Ni range is
Refinement with Brꢀ present at the same site as Clꢀ, converged
to a Brꢀ occupation of 60% The presence of Brꢀ also was qualita-
tively verified by microprobe analysis. The structure of VI demon-
strates that, with a ‘‘free’’ carboxylate unit, the SDTT ligand may
serve as a bridge between thiophilic and oxophilic metal ions,
and VI conceptually may be considered a functionalized benzoate
ligand.
The ‘‘sulfur-rich’’ complexes (Ph4P)2[(TTT)Ni(STTT], VII and
(Ph4P)2Ni(SDTT)2, VIII, also can be obtained (see experimental)
by the reactions of (PPh4)2TTT and (PPh4)2DTT with [Ni(MeCN)6]
(BF4)2 or NiCl2ꢁ6H2O and elemental sulfur in DMF solution.
Fig. 5. Two Views of the Ni12S8 Core. Three sets of Ni–S–Ni angles define the S8 distortion. (Left) Six Ni–SR–Ni angles around: S6, S4, range: 110–113°. (Right) Six Ni–S–Ni
angles around: S1, S2, S3, S7, S8, S5, range: 95–103° (Right) 12 Ni–S–Ni angles around: S1, S2, S3, S7, S8, S5 range: 74–82°.
Fig. 6. The {[Cu(DCT)(PPh3)]ꢀ1
} polymer.
n

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A.R. Paital et al. / Polyhedron 64 (2013) 328–338
Fig. 7. Packing of the {[Cu(DCT)(PPh3)](Ph4P)}n chains parallel to the y–z plane.
found in XII. They are approximately 0.30 Å longer than the aver-
Table 5
Structural data for the {Cu(DCT)(PPh3)ꢀ1
} polymer.
n
age Ni-Ni distance in metallic nicke1 [18], 0.02 Å shorter than
found in millerite [19] and 0.27 Å longer than the Ni–Ni distance
in hazelwoodite [20]. The Ni–S distances range from 2.137(3) to
2.219(3) Å with an average of 2.179 Å as opposed to averages of
2.272 and 2.306 Å in hazelwoodite and millerite, respectively.
The Ni12S8 core in IX is similar to the M/S cores in [Cu12S8]4ꢀ
[21] and [NaAu12S8]3ꢀ [22]. The latter do not contain the bridging
S22ꢀ ligands. (Figs. 3 and 4).
Distances
Angles
Cu–S
Cu–P
Cu–Cuinter
Cu–Cuintra
S–O
2.2417(11); 2.2425(13)
2.2204(12)
21.7690(1)
17.8012(1)
2.607(3); 2.610(3)
3.211(2); 3.267(2)
S–Cu–S
S–Cu–P
S–Cu–P
120.20(5)
120.87(4)
118.62(5)
Cu–O
3.2.3. {[Cu(CDT)(PPh3)](Ph4P)ꢁEt2O}n, X
74.4(5)–112.7°. The larger of these angles are the Ni-n-BuS-Ni
angles that range from 110° to 112.6°.
The reaction of (Ph4P)2DCT with Cu(CH3CN)4PF6 in CH3CN solu-
tion in a 1:1 M ratio is fast and complete. The orange-red precipi-
tate that forms is insoluble in most solvents and most likely a
polymer. The analytical data support the 1:1 formulation. The
structure of this compound is not known but the polymer reacts
with Ph3P to give the neutral X (Fig. 6) which is now soluble, and
crystallizes from DMF. The polymer chains stack in the y-z plane
The
l3-S-n-Bu ligands in IX are located on the S8 cube body
diagonal and as a result the Ni12S20 cube is compressed along this
diagonal.
The Ni–Ni distances in IX range from 2.754(2) to 2.825(2) Å,
with an average value of 2.794(7) Å and are comparable to values
Fig. 8. The polymeric structure of the {Ni(DTT)3Zn2(DMSO)6}n complex. The methyl groups in the Zn-bound DMSO ligands have been omitted for clarity.

A.R. Paital et al. / Polyhedron 64 (2013) 328–338
337
Fig. 9. The coordination environments of A: the Ni Site, B: the ‘‘terminal’’ Zn Site and C: the ‘‘bridging’’ Zn site.
Table 6
Structural details in the {Ni(DTT)3Zn2(DMSO)6}n complex.
The ‘‘bridging’’ DTT ligands (Fig. 9C) are bound as monoden-
tate ligands to the Zn(II) ions which complete their coordination
sphere binding to two DMSO molecules. The Zn(II) ions on the
‘‘terminal’’ ligands show a distorted octahedral geometry, O–O
bound to a bidentate DTT ligand, and four DMSO molecules
(Fig. 9B). In the solid the polymeric assembly inter-digitizes
to give sheets which stack. The stacked sheets are shown in
the supplementary material. Structural details are shown in
Table 6.
Distance (#)
Range
Mean⁄
Distance
Ni–S (6)
2.41–2.43
1.92–2.20
2.23; 2.21
2.03; 2.03
1.93–1.98
2.42(1,6)
2.06(13,4)
Ni-Zn2 11.08(1)
Ni–Zn1 11.12(1)
Ni–Ni 18.22(1)
Zn1–Zn1 18.22(1)
Zn1–Zn2 19.83(1)
Zn2–ODMSO (4)
Zn2–ODTT (2)
Zn1–ODMSO (2)
Zn1–ODTT (2)
The first number in parenthesis represents the standard deviation from the mean
r
= [Ri=1N(xi ꢀ x)2N(N ꢀ 1)]1/2, the second represents the number of chemically
equivalent bonds averaged out.
4. Conclusions
(Fig. 7). The properties of X in solution are under study. Structural
details of X are presented in Table 5.
This preliminary synthetic study of the tetrathioterephthalate,
TTT, dithio-terephthalate, DTT, and the 1,4-thioacyl benzene,
DCT, ligands, demonstrates unique reactivity characteristics and
their ability to serve as ditopic linkers. The TTT ligands show a fac-
ile C–S bond cleavage with generation of elemental sulfur and sub-
sequent formation of ‘‘sulfur-rich’’ thiocarboxylates and also of
sulfido and polysulfido ligands that subsequently form thiolate
clusters. The general scope of these reactions will be investigated
further. The DTT and DCT thio-carboxylate ligands serve bi-func-
tionally as homo-metallic or hetero-metallic bridges and can be
considered as functionalized carboxylate ligands. The SS-coordi-
nated DTT ligands with thiophilic metal ions are metal functional-
ized terephthalates and their use as precursors for the synthesis of
specific, highly porous, metal organic frameworks are presently
under investigation.
3.2.4. {Ni(DTT)3Zn2(DMSO)6}n, XI
The bifunctional DTT ligand is ideally suited to bind to both
thio-philic and oxo-philic ions. The reaction of III with both Ni(II)
and Zn(II) ions in solution, gives the S–S–Ni and O–O–Zn bridging
mode not unexpected for the thiophilic Ni(II) and the oxophilic
Zn(II) ions.
The structure of Ni(DTT)3Zn2(DMSO) (Fig. 8) shows a polymeric
array of six-coordinate Ni ions, S-bound to three DTT ligands
(Fig. 9A) in a distorted octahedral geometry (N–S, 2.41(1) Å).
Octahedral coordination by 1,1-dithio-ligands is rare, and to our
knowledge is only known for the tris-ethyl-xanthato nickelate
[Ni(Et-xanth)3]ꢀ anion [23].

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A.R. Paital et al. / Polyhedron 64 (2013) 328–338
Chem. Commun. (2003) 2976;
Acknowledgements
(e) A. Wang, H. Furukawa, M. O’Keeffe, O.M. Yaghi, Nature 453 (2008) 207;
(f) D. Britt, D. Tranchemontagne, O.M. Yaghi, Proc. Natl. Acad. Sci. USA 105
(2008) 11623.
The award of a Camille and Henry Dreyfus Foundation, Inc.
undergraduate student mentoring grant to D.C is gratefully
acknowledged.
[4] (a) M. Dinca, J.R. Long, Angew. Chem., Int. Ed. 47 (2008) 6766;
(b) Y. Kobayashi, B. Jacobs, M.D. Allendorf, J.R. Long, Chem. Mater. 22 (2010)
4120;
(c) K. Sumida, D. Stuck, L. Mino, J.-Da Chai, E.D. Bloch, O. Zavorotynska, L.J.
Murray, M. Dinca, S. Shavan, S. Bordiga, M. Head-Gordon, J.R. Long, J. Am.
Chem. Soc. 135 (2013) 1083.
Appendix A. Supplementary data
[5] E. Neofotistou, C. Maliakas, P.N. Trikalitis, Inorg. Chem. 46 (2007) 8487.
[6] J.E. Mulvaney, Francisco R. Figueroa, J. Polym. Sci. Polym. Chem. Ed. 24 (1)
(1986) 147.
[7] U. Mikloweit, R. Mattes, Z. Anorg. Allg. Chem. 532 (1986) 145.
[8] Y. Kobayashi, K. Itabashi, Synthesis 6–7 (1985) 671.
[9] O. Niyomura, S. Kato, Top. Curr. Chem. 251 (2005) 1.
[10] (a) D. Coucouvanis, J.P. Fackler, J. Am. Chem. Soc. 89 (1967) 1346;
(b) J.P. Fackler, D. Coucouvanis, J. Am. Chem. Soc. 89 (1967) 1745;
(c) J.P. Fackler, D. Coucouvanis, J.A. Fetchin, W.C. Seidel, J. Am. Chem. Soc. 90
(1968) 2784.
CCDC 940488-940494; 940519, 940520; contains the supple-
mentary crystallographic data for I, Ia, III, IV, V, VI, IX, XI. These
data can be obtained free of charge via http://www.ccdc.cam.a-
c.uk/conts/retrieving.html, or from the Cambridge Crystallographic
Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44)
1223-336-033; or e-mail: deposit@ccdc.cam.ac.uk.
[11] (a) J.P. Fackler, J.A. Fetchin, D.C. Fries, J. Am. Chem. Soc. 94 (1972) 7323;
(b) D.C. Fries, J.P. Fackler Jr., Chem. Commun. (1971) 276.
[12] D. Coucouvanis, S.J. Lippard, J. Am. Chem. Soc. 90 (1968) 3281.
[13] D. Coucouvanis, Prog. Inorg. Chem. 11 (1969) 567.
[14] L.I. Victoriano, M.T. Garland, A. Vega, C. Lopez, J. Chem. Soc., Dalton Trans.
(1998) 1127.
References
[1] O.M. Yaghi, H. Li, C. Davis, D. Richardson, T.L. Groy, Acc. Chem. Res. 31 (1998)
474.
[2] (a) M. Eddaoudi, D.B. Moler, H. Li, B. Chen, T.M. Reineke, M. O’Keeffe, O.M.
Yaghi, Acc. Chem. Res. 34 (2001) 319;
[15] J.-P. Lang, H. Kawaguchi, S. Ohnishi, K. Tatsumi, Inorg. Chim. Acta 283 (1998)
136.
(b) H. Li, M. Eddaoudi, M. O’Keeffe, O.M. Yaghi, Nature 402 (1999) 276;
(c) N.W. Ockwig, O. Delgado-Friedrichs, M. O’Keeffe, O.M. Yaghi, Acc. Chem.
Res. 38 (2005) 176.
[16] N.C. Payne, N. Okura, S. Otsuka, J. Am. Chem. Soc. 105 (1983) 245.
[17] C.L. Cahil1, K. Tan, R. Novosellerc, J.B. Parise, Chem. Commun. (1996) 1678.
[18] B.J. Wuensch, Rev. Mineral. Sulfide Mineral. 1 (1976) 21.
[19] V. Rajamani, C.T. Prewitt, Can. Mineral. 112 (1974) 248.
[20] J.B. Parise, Acta Crystallogr., Sect. B 36 (1980) 1179.
[21] P. Betz, B. Krebs, G. Henkel, Angew. Chem., Int. Ed. Engl. 23 (1984) 311.
[22] S.-P. Huang, M.G. Kanatzidis, Angew. Chem., Int. Ed. Engl. 31 (1992) 787.
[23] D. Coucouvanis, J.P. Fackler Jr., Inorg. Chem. 6 (1967) 2047.
[3] (a) B. Chen, D.S. Contreras, N. Ockwig, O.M. Yaghi, Angew. Chem., Int. Ed. 44
(2005) 4745;
(b) M. Dinca, A. Dailly, Y. Liu, C.M. Brown, D.A. Newmann, J.R. Long, J. Am.
Chem. Soc. 128 (2006) 16876;
(c) X.B. Zhao, B. Xiao, A.J. Fletcher, K.M. Thomas, D. Bradshaw, M.J. Rosseinsky,
Science 306 (2004) 1012;
(d) G. Ferey, M. Latroche, C. Serre, F. Millange, T. Loiseau, A. Percheron-Guegan,