Cooperative metal-ligand-induced properties of heteroleptic copper(I) xanthate/dithiocarbamate PPh3 complexes

Article abstract of DOI:10.1002/ejic.201200307

Four new heteroleptic mononuclear complexes, [Cu(PPh₃) ₂L¹](1) {L¹ = (C₉H ₁₁O₂CS₂^-), [2-(4-methoxyphenyl) ethyl]xanthate}, [Cu(PPh₃)₂L

Full text of DOI:10.1002/ejic.201200307

Job/Unit: I20307
/KAP1
Date: 12-07-12 16:06:35
Pages: 8
FULL PAPER
DOI: 10.1002/ejic.201200307
Cooperative Metal–Ligand-Induced Properties of Heteroleptic Copper(I)
Xanthate/Dithiocarbamate PPh3 Complexes
Gunjan Rajput,[a] Vikram Singh,[a] Santosh K. Singh,[a] Lal B. Prasad,[a]
Michael G. B. Drew,[b] and Nanhai Singh*[a]
Keywords: Xanthate / S ligands / Phosphane ligands / Copper / Photoluminescence / Semiconductivity
Four new heteroleptic mononuclear complexes, [Cu(PPh3)2L1] and X-ray crystallography; their photoluminescent behaviour
(1) {L1
=
(C9H11O2CS2–), [2-(4-methoxyphenyl)ethyl]-
and molecular electrical conductivity have been investi-
gated. CuI possesses four-coordinate distorted tetrahedral
geometry in all the complexes. All are weakly conducting
and exhibit semiconductor behaviour in the studied 303–
363 K temperature range. Complex 4 shows striking lumines-
cent behaviour emitting bluish green light at 480 nm in
CH2Cl2 solution at room temperature.
xanthate}, [Cu(PPh3)2L2] (2) [L2 = (C6H7OCS2–), benzyl-
xanthate], [Cu(PPh3)2L3] (3) [L3 (C5H9OCS2–), (cyclo-
=
butylmethyl)xanthate] and [Cu(PPh3)2L4] (4) [L4
=
(NC13H13NCS2–), N-benzyl-N-(4-pyridylmethyl)dithiocarb-
amate], have been synthesized and characterized by using
microanalysis, IR, UV/Vis, 1H, 13C and 31P NMR spectroscopy
properties, in transition metal coordination spheres is im-
portant in tuning their physical properties because of the
unique energetic stability and reactivity related to the
metal–phosphorus bond. Also, this framework provides a
rigid environment around copper(I) facilitating the weaken-
ing of nonradiative deactivation pathways and also pre-
cludes solvent interactions, which promote the quenching
of CuI complexes.
The chemistry and properties of metal dithiocarbamate
and xanthate complexes have been extensively reported.[1]
In spite of their synthetic versatility and practical utility,
studies on the heteroleptic complexes of CuI with xanthate
or dithiocarbamate/dithiocarbimate and phosphane ligands
are scarce.[13–21,33] The monoanionic 1,1-dithiocarbamate
resembles the dianionic dithiocarbimate ligand that led to
the formation of a heteroleptic dinuclear CuI phosphane
complex with unprecedented bonding behaviour.[34] Al-
though monoanionic xanthate and dithiocarbamate ligands
have some common features, they differ significantly in
their coordination behaviour owing to the dominant contri-
bution of the resonance structures they exhibit in their com-
plexes (Figure 1). In general, the xanthate and phosphane
ligands reduce CuII to CuI, whereas the dithiocarbamates
stabilize the +2 oxidation state of copper in their complexes.
Influenced by these facts, it was considered worthwhile to
Introduction
Over more than two decades dithio transition metal com-
plexes have been studied in detail because of their exciting
molecular conducting, magnetic and optical properties that
provide a myriad of technological applications.[1–12] Despite
their structural simplicity, heteroleptic mono- and dinuclear
copper(I) complexes with phosphanes as a coligand have
exhibited interesting photoluminescent properties with pos-
sible applications as sensors, biological imaging probes,
electrochemical devices and as dyes for solar energy conver-
sion.[13–32] Complexes of the type [CuI(dithio)PR3]2 (R =
OMe, Me, Et; dithio = xanthate, dithiocarbamate) have di-
meric structures.[14] Homo- and heteronuclear CuI clusters
with xanthate, dithiocarbamate and dithiophosphate li-
gands have also been reported.[35–37] Copper(I) with a 3d10
configuration has no low-energy ligand-field transitions
and so makes available low-energy charge-transfer excited
states, which is an important property for luminescent ma-
terials. The coordination sphere of the copper(I) ion can be
closely controlled by the use of bidentate sulfur or nitrogen
ligands in conjunction with bulky phosphane ligands that
reinforce the likelihood of a tetrahedral environment.
Furthermore, the incorporation of sterically encumbered
phosphane ligands, having strong σ-donor and π-acceptor
[a] Department of Chemistry, Faculty of Science, Banaras Hindu
University,
Varanasi 221005, India
Fax: +91-542-2386127
E-mail: nsingh@bhu.ac.in
nsinghbhu@gmail.com
[b] Department of Chemistry, University of Reading,
Whiteknights, Reading, RG6 6AD, UK
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201200307.
Figure 1. Dominant resonance structures of the dithioligands.
Eur. J. Inorg. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1

Job/Unit: I20307
/KAP1
Date: 12-07-12 16:06:35
Pages: 8
N. Singh et al.
FULL PAPER
undertake the synthesis, structural characterization and = 10–12 ppm) in the 13C NMR resonances for the CS2 car-
study of the conducting and photoluminescent properties bon atom in all the complexes compared to the free ligands,
of four new heteroleptic CuI complexes containing func- potassium xanthates and potassium dithiocarbamate sub-
tionalized xanthate/dithiocarbamate ligands together with stantiates M–S bonding in the complexes of CuI. The pres-
PPh3 as a coligand. The results of these investigations are ence of a sharp singlet in the δ = 0.17–0.80 ppm region in
presented here.
the 31P NMR spectra of all the compounds reveals the
equivalent nature of the PPh3 ligands bonded to the Cu
atom.
Results and Discussion
Complexes [Cu (PPh3)2L] (1–4) were synthesized by
treating a methanolic solution of the potassium salt KL
(L1–L4) of the ligands (Figure 2) with a dichloromethane
solution of the precursor [Cu(PPh3)2]NO3 in equimolar ra-
tios at room temperature. All the compounds are air-stable,
melt in the 140–160 °C range and are soluble in dichloro-
methane, chloroform, N,N-dimethylformamide (DMF) and
dimethyl sulfoxide (DMSO). The compounds were charac-
terized by elemental analysis, spectroscopy (IR, NMR, UV/
Vis) and single-crystal X-ray analysis; their photolumines-
cent behaviour, and solid-phase conductivities were also in-
vestigated (Scheme 1).
Crystal Structures
Single crystals of the complexes were grown by slow con-
centration of a dichloromethane/ethanol solution of the
crude product. The relevant crystallographic data and re-
finement details are listed in Table S1, and the molecular
dimensions are listed in Table 1. The structures are illus-
trated in Figures 3, 4, 5 and 6.
Table 1. Selected bond lengths and angles for 1, 2, 3 and 4.
Bond lengths [Å]
1 (X = O) 2 (X = O) 3 (X = O) 4 (X = N)
Cu(1)–P(1)
Cu(1)–P(2)
Cu(1)–S(11)
Cu(1)–S(13)
S(11)–C(12)
S(13)–C(12)
X(14)–C(12)
2.2407(13) 2.2357(9)
2.2521(14) 2.2647(8)
2.4263(16) 2.4405(8)
2.3809(15) 2.4157(8)
2.2559(11) 2.262(2)
2.2755(11) 2.274(2)
2.4728(12) 2.406(2)
2.3988(12) 2.417(2)
1.679(6)
1.653(7)
1.329(6)
1.686(3)
1.680(3)
1.347(4)
1.699(4)
1.689(5)
1.358(6)
1.725(6)
1.696(6)
1.354(7)
Bond angles [°]
P(1)–Cu(1)–P(2)
P(2)–Cu(1)–S(13)
P(1)–Cu(1)–S(13)
P(2)–Cu(1)–S(11)
S(13)–Cu(1)–S(11) 74.92(6)
P(1)–Cu(1)–S(11) 120.31(5)
S(13)–C(12)–S(11) 122.7(3)
C(12)–S(11)–Cu(1) 80.00(19)
C(12)–S(13)–Cu(1) 81.85(19)
127.05(5)
108.07(5)
110.49(6)
103.71(6)
118.27(3)
102.62(3)
123.96(3)
108.93(3)
74.50(3)
120.13(3)
121.66(18) 122.6(3)
81.12(11)
82.01(11)
126.22(4)
109.17(4)
116.31(4)
100.18(4)
74.57(4)
123.94(6)
105.02(6)
112.73(7)
117.66(6)
74.60(6)
111.45(7)
117.3(4)
83.7(2)
Figure 2. Structures of the ligands.
117.93(4)
80.03(15)
82.49(15)
84.0(2)
Scheme 1. L = [2-(4-methoxyphenyl)ethyl]xanthate (L1), benzyl-
xanthate (L2), (cyclobutylmethyl)xanthate (L3) and N-benzyl-N-(4-
pyridylmethyl)dithiocarbamate (L4).
Spectroscopy
In their IR spectra, 1–3 show ν(CS2) and ν(C–O) bands
near 1090 and 1150 cm–1, respectively, diagnostic of S,S co-
ordination of the xanthate ligands.[1] The dithiocarbamate
complex 4 exhibits a band at 1388 cm–1 characteristic of a
ν(C–N) vibration. A perceptible enhancement in the ν(C–
N) frequency in 4 in comparison with the free dithio-
carbamate ligand indicates symmetrical bidentate behav-
iour of the dithiocarbamate ligand due to a significant con-
tribution of resonance form II (Figure 1). The NMR spec-
tra of all the compounds elucidate their composition, purity
1
and diamagnetic nature. The presence of sharp H NMR
resonances in all four compounds correlates well with the
corresponding hydrogen atoms. A noticeable upfield shift (δ Figure 3. ORTEP diagram for 1 at 30% probability level.
2
www.eurjic.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 0000, 0–0

Job/Unit: I20307
/KAP1
Date: 12-07-12 16:06:35
Pages: 8
Heteroleptic Copper(I) Xanthate/Dithiocarbamate PPh3 Complexes
xanthate complexes 1, 2 and 3, the Cu(1)–S(11) and Cu(1)–
S(13) distances differ significantly with the Cu(1)–S(11)
bond lengths consistently longer at 2.4263(16), 2.4405(8)
and 2.4728(12) Å than the Cu(1)–S(13) bond lengths at
2.3809(15), 2.4157(8) and 2.3988(12) Å.
However, there are no significant differences in the C–S
bond lengths. By contrast with this asymmetrical S,S bond-
ing behaviour of the xanthate ligands, in the dithiocarb-
amate complex 4, the Cu(1)–S(11) and Cu(1)–S(13) dis-
tances are equivalent at 2.410(2) and 2.412(2) Å, thereby
indicating symmetrical S,S bidentate behaviour.
In all four complexes, the geometry around the metal
atom is distorted tetrahedral as is evident from the angles
shown in Table 1. The distortion from ideal geometry oc-
curs primarily as a result of the small S(11)–Cu(1)–S(13)
bite angles, which range from 74.50(3) to 75.00(7)°. How-
ever, there are significant differences in the remaining
angles. The angles in 1 and 3 are similar with P(1)–Cu(1)–
P(2) being 127.05(5) and 126.22(4)° and P–Cu(1)–S angles
ranging from 103.71(6) to 120.31(5)° and 100.18(4) to
117.93(4)°, respectively. In contrast, in 2 the P(1)–Cu(1)–
P(2) angle is much smaller at 118.27(3)°, and this disparity
could be due to the disposition of the phenyl rings, as look-
ing along the P···P vector it is apparent that the rings in
2 have a staggered conformation rather than the eclipsed
conformation found in 1, 3 and 4. The corresponding angle
in 4 is 123.94(6)°.
Figure 4. ORTEP diagram for 2 at 30% probability level.
The angle between the two least-square planes formed by
Cu(1), S(11), S(13) and C(12) and by P(1), Cu(1) and P(2)
are 84.74(7), 85.09(4), 84.19(5) and 83.67(7)°, respectively,
for 1–4, thus indicating that the two planes are approxi-
mately perpendicular to each other. The root mean square
(r.m.s.) deviations from the planarity of atoms Cu(1), S(11),
S(13) and C(12), defining the chelate ring, are 0.044, 0.049,
0.075 and 0.033 Å, respectively.
Figure 5. ORTEP diagram for 3 at 30% probability level.
The Cu–S and Cu–P distances (Table 1) are typical of
those found in analogous CuI complexes.[13,20,32] The
C(12)–N(14) bond length of 1.354(7) Å in 4 is intermediate
between the C–N (1.47 Å) and C=N (1.28 Å) bond lengths,
which confirms the significant contribution of resonance
form II (Figure 1) of the dithiocarbamate ligand, thereby
indicating the partial double-bond character of the C–N
bond. The C–S bonds of 1.653(7)–1.699(4) Å in xanthate
complexes 1–3 are significantly smaller than that of 1.725(6)
and 1.696(6) Å in the dithiocarbamate complex 4, though
both are considerably shorter than the C–S single bond (ca.
1.81 Å) due to π delocalization over the CS2 unit. Although
packing diagrams are not shown here, it is obvious that the
presence of the bulky triphenylphosphane ligands preclude
any possible S···S intermolecular stacking involving the
xanthate or dithiocarbamate ligands, a mode of packing
often found in their complexes.[34]
Figure 6. ORTEP diagram for 4 at 30% probability level.
In each complex, the geometry about CuI is four-coordi-
nate with the Cu atoms bonded to two phosphorus atoms
of the PPh3 moieties together with two sulfur atoms of the
Electronic Absorption and Photoluminescent Spectra
The electronic absorption spectra of complexes 1–4 in
bidentate xanthate or dithiocarbamate ligand. For the CH2Cl2 solution are given in Figure 7. The free xanthate
Eur. J. Inorg. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
3

Job/Unit: I20307
/KAP1
Date: 12-07-12 16:06:35
Pages: 8
N. Singh et al.
FULL PAPER
ligands (L1–L3) display two strong absorptions near 225 nm transfer transitions. The lowest excited state at 325 nm (ε =
(ε = 92000–122000 m–1 cm–1) and 305 nm (ε = 59000– 8000–10000 m–1 cm–1) present in 2 and 4 may be ascribed to
76000 m–1 cm–1), dithiocarbamate at 258 nm (ε
=
an IL charge-transfer transition with some admixture of a
105000 m–1 cm–1) and 295 nm (75000 m–1 cm–1) and PPh3 at metal-to-ligand charge-transfer transition (MLCT).
262 nm[43] arising from intraligand (IL) charge-transfer
Upon excitation at 250 nm in CH2Cl2 solution at room
transitions (Figures S2–S5). The features of the absorption temperature, the xanthate complexes 1, 2 and 3 give rise to
bands of all the heteroleptic CuI complexes are virtually a medium broad emission band and a shoulder emission
alike, encompassing strong absorptions near 240 nm (ε = band at about 300 and 350 nm, respectively, arising from
16000–25000 m–1 cm–1) and 267 nm (ε
=
14000– intraligand π–π* charge-transfer transitions (Figure 8a).
25000 m–1 cm–1) and showing considerable redshifts that can The excitation spectrum for the emission (λemmax) in a
be assigned to metal-perturbed π–π* intraligand charge- CH2Cl2 solution of 4 is shown in Figure 8b. Unlike the xan-
thate complexes, 4 shows an unstructured emission at
480 nm upon excitation at 300 nm, emitting bluish green
light with a pronounced Stokes shift of 180 nm, which ema-
nates from the π–π* IL states in the perturbed coordination
environment about the metal atom (Figure 8). The remark-
able luminescent behaviour of 4 seems to arise, because the
presence of the pyridine substituent on the dithiocarbamate
enhances conjugation. An additional factor may be that
only minimal changes are found in the structure of the com-
plex in the excited state compared to the ground state, be-
cause the geometry around the metal atom is fixed by the
sterically demanding PPh3 ligands.
Figure 7. Electronic absorption spectra for 1–4 in CH2Cl2.
Pressed-Pellet Conductivity
The pressed-pellet conductivity of all the complexes was
measured with a Keithley 236 source measure unit using
the conventional two-probe technique. Complexes 1–4 are
weakly conducting with σrt values of the order 10–13 Scm–1.
Their lower conductivities may be attributed to the lack of
S···S intermolecular stacking (vide supra in the crystallogra-
phy section), which is prevented by the bulky PPh3 ligands.
A plot of logσ vs. T–1 in the 303–363 K range with band
gaps of 0.81, 0.75, 0.77 and 0.71 eV for 1–4, respectively,
shows their semiconducting behaviour (Figure 9). An in-
crease in σ values at higher temperature is due to the ther-
mal activation of electrons.
Figure 8. (a) Emission spectra for 1–3. (b) Excitation and emission
(λemis = 480 nm) spectra for 4 in CH2Cl2.
Figure 9. Pressed-pellet conductivity for 1–4.
4
www.eurjic.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 0000, 0–0

Job/Unit: I20307
/KAP1
Date: 12-07-12 16:06:35
Pages: 8
Heteroleptic Copper(I) Xanthate/Dithiocarbamate PPh3 Complexes
[Cu(PPh3)2L1] (1): A solution of Cu(PPh3)2NO3 (0.665 g, 1 mmol)
in CH2Cl2 (5 mL) was added gradually to a stirred solution of KL1
(0.227 g, 1 mmol) in methanol (25 mL). A yellowish brown solid
was formed within a short time, and the reaction mixture was
stirred for 1 h. The solid was collected by filtration and washed
with methanol followed by diethyl ether. The product thus obtained
was recrystallized from a dichloromethane/ethanol mixture, yield-
ing block-shaped crystals. Yield 0.676 g, 82%; m.p. 135 °C.
C46H41CuOP2S2 (824.40): calcd. C 68.51, H 4.83, S 8.31; found C
Conclusions
Four new mononuclear heteroleptic CuI complexes con-
taining xanthate/dithiocarbamate and PPh3 ligands have
been synthesized and fully characterized by spectroscopic
and X-ray crystallographic techniques. It is worth men-
tioning that all the bis(phosphane) complexes 1–4 involving
the bulky PPh3 ligand are mononuclear in comparison to
those of the analogous monophosphane dimeric complexes
formed with less bulky phosphane ligands such as [(CuIdi-
thio)PR3]2 (R = OMe, Me, Et; dithio = xanthate, dithio-
carbamate).[14] The xanthate complexes 1, 2 and 3, despite
variation in functionalities, are weakly luminescent in the
UV region, whereas the dithiocarbamate complex 4 strik-
ingly emits observable bluish green light in the visible re-
gion. The interesting photoluminescent behaviour of this
complex probably stems from the presence of a pyridine
substituent on the dithiocarbamate moiety with a lone pair
of electrons on the nitrogen atom, which causes greater con-
jugation in the molecule. This widens the scope for the syn-
thesis and study of luminescent properties of heteroleptic
dithio complexes with enhanced delocalization in the mole-
cule. All the complexes are weakly conducting because of
the absence of any significant S···S intermolecular contacts,
no doubt because any stacking is inhibited by the bulky
PPh3 molecules. It is worth mentioning that in contrast to
the dinuclear dithiocarbimate CuI–PPh3 complex,[34] the
CuI dithiocarbamate PPh3 complex is mononuclear, though
both ligands are quite similar.
68.13, H 4.69, S 7.79. IR (KBr): ν = 1154 (νC–O), 1094 (νC–S) cm–1.
˜
1H NMR (300.40 MHz, CDCl3): δ = 7.75–6.81 (m, 34 H, Ar-H),
4.51 (t, J = 7.2 Hz, 2 H, OCH2), 3.00 (t, J = 14.7 Hz, 2 H, CH2Ar),
3.78 (s, 3 H, OCH3) ppm. 13C NMR (75.45 MHz, CDCl3): δ =
226.88 (CS2), 55.25 (OCH3), 73.66 (OCH2), 34.08 (CH2Ar), 158.18,
113.84, 128.57, 129.43 (C6H5), 131.51, 129.93, 128.57, 128.34
(CPPh3) ppm. 31P NMR (121.50 MHz, CDCl3): δ = 0.753 ppm.
[Cu(PPh3)2L2] (2): The light yellow complex 2 was synthesized and
isolated by adopting the same method as described for 1 and using
KL2 (0.171 g, 1 mmol). Yield 0.663 g, 86%; m.p. 160 °C.
C44H37CuOP2S2 (771.34): calcd. C 67.32, H 5.25, S 8.56; found C
67.02, H 5.33, S 8.23. IR (KBr): ν = 1148 (νC–O), 1093 (νC–S) cm–1.
˜
1H NMR (300.40 MHz, CDCl3): δ = 7.37–7.16 (m, 35 H, ArH),
5.29 (s, 2 H, CH2O) ppm. 13C NMR (75.45 MHz, CDCl3): δ =
226.66 (CS2), 74.41 (OCH2), 141.21, 136.16, 133.67, 129.46,
(C6H5), 128.37, 128.31, 128.22, 127.86 (CPPh3) ppm. 31P NMR
(121.50 MHz, CDCl3): δ = 0.803 ppm.
[Cu(PPh3)2L3] (3): The pale yellow complex 3 was prepared and
isolated by adopting the same method as described for 1 and using
KL3 (0.161 g, 1 mmol). Yield 0.636 g, 85%; m.p. 160 °C.
C42H39CuOP2S2 (749.33): calcd. C 69.11, H 5.17, S 8.02; found C
68.84, H 5.09, S 7.76. IR (KBr): ν = 1141 (νC–O), 1092 (νC–S) cm–1.
˜
1H NMR (300.40 MHz, CDCl3): δ = 7.33–7.16 (m, 30 H, PPh3),
2.76–1.54 (m, 6 H, C6H7), 3.95 (s, 1 H, C6H7), 4.35 (d, J = 6.6 Hz,
2 H, OCH2) ppm. 13C NMR (75.45 MHz, CDCl3): δ = 227.41
(CS2), 34.08–18.50 (C4H7), 59.71 (OCH2), 133.65, 129.41, 129.57,
128.32 (CPPh3) ppm. 31P NMR (121.50 MHz, CDCl3): δ =
0.778 ppm.
Experimental Section
[Cu(PPh3)2L4] (4): A solution of Cu(PPh3)2NO3 (0.665 g, 1 mmol)
in CH2Cl2 (5 mL) was added dropwise to a stirred solution of
KL4 (0.31 g, 1 mmol) in methanol (15 mL). The reaction mixture
was stirred overnight, and the solvent was removed to obtain a
light yellow solid. Yield 0.852 g, 87%; m.p. 140–142 °C.
C50H43CuN2P2S2 (861.52): calcd. C 69.71, H 5.03, N 3.25, S 7.44;
Materials and Reagents: All reactions were performed in air at am-
bient temperature. The solvents dichloromethane, diethyl ether,
methanol and carbon disulfide were purchased from commercial
sources and – where necessary – were purified by standard pro-
cedures prior to their use. The starting compound [Cu(PPh3)2]NO3
was obtained by using a literature method.[39] Potassium salts of
the anionic ligands [2-(4-methoxyphenyl)ethyl]xanthate (L1), benz-
ylxanthate (L2), (cyclobutylmethyl)xanthate (L3), N-benzyl-N-(4-
pyridylmethyl)dithiocarbamate (L4) were synthesized by treating
the appropriate alcohol or secondary amine with KOH and CS2
according to a previously reported procedure,[38] and characterized
found C 69.28, H 4.92, N 3.15, S 6.90. IR (KBr): ν = 1388 (νC–N),
˜
1
1091 (νC–S) cm–1. H NMR (300.40 MHz, CDCl3): δ = 8.51 (m, 2
H, C5H4N), 7.37–7.11 (s, 30 H, C6H5), 5.29 (s, CH2NC5H4) ppm.
13C NMR (75.45 MHz, CDCl3): δ = 216.7 (CS2), 153.8, 149.3
(NC5H4), 138.6, 137.0, 134.4, 129.0, 128.8, 128.7, 128.5, 128.4,
128.3, 127.8, 122.2 (C5H4N, C5H5), 58.0 (CH2C6H5N), 54.0
(CH2Ar) ppm. 31P (121.50 MHz, CDCl3): δ = 0.17 ppm.
1
by elemental analysis, IR, H and 13C NMR spectra.
Physical Measurements: The melting points of the complexes were
determined in open capillaries with a Gallenkamp apparatus and
are uncorrected. Elemental analyses (C, H, N and S) were per-
Structure Determination: Single-crystal X-ray data, space group,
unit-cell dimensions and intensity data for 1, 2, 3 and 4 were col-
formed with a CE-440 CHN analyzer. IR spectra were recorded as lected with an Oxford Diffraction X-calibur CCD diffractometer
1
KBr discs with a Varian 3100 FTIR instrument; H, 13C{1H} and
31P NMR spectra in CDCl3 were recorded with a JEOL AL300
FTNMR spectrometer. Chemical shifts are quoted in parts per mil-
lion with TMS as an internal standard for 1H and 13C, and PCl3
as an external standard (δ = 220 ppm) for 31P NMR spectra. The
electronic absorption and emission spectra of the ligands in meth-
anol and the complexes in CH2Cl2 solution were collected at room
at 150 K (1–3) and 293 K (4) using Mo-Kα radiation (for 1, 3, 4)
and Cu-Kα radiation (for 2). Data reduction for 1–4 was carried out
by the CrysAlis program.[40] The structures were solved by direct
methods using SHELXS-97[41] and refined on F2 by full-matrix
least-squares technique using SHELXL-97.[41] Non-hydrogen
atoms were refined anisotropically, and hydrogen atoms were geo-
metrically fixed with thermal parameters equivalent to 1.2 times
temperature with Shimadzu UV-1700 Pharma Spec UV/Vis and that of the atom to which they are bonded. Two water molecules
Varian Cary Eclipse Fluorescence spectrophotometers, respectively. were located in 1 and refined with 0.25 occupancy, but their hydro-
Eur. J. Inorg. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
5

Job/Unit: I20307
/KAP1
Date: 12-07-12 16:06:35
Pages: 8
N. Singh et al.
FULL PAPER
[5] A. T. Coomber, D. Beljonne, R. H. Friend, J. L. Bredas, A.
Charlton, N. Robertson, A. E. Underhill, M. Kurmoo, P. Day,
Nature 1996, 380, 144–146.
gen atoms could not be located. In 3, some atoms in the cyclobutyl
ring showed high thermal motion, and disordered models were in-
vestigated. One model was chosen in which one atom was disor-
dered over two sites with occupation factors x and 1 – x with x
refining to 0.54(2). Four solvent water molecules were located in 4
and refined with reduced occupancies. The hydrogen atoms could
not be located. Diagrams for all complexes were prepared using
ORTEP.[42] CCDC-803645 (for 1), -870133 (for 2), -803643 (for 3)
and -881935 (for 4) contain the supplementary crystallographic
data for this paper. These data can be obtained free of charge from
The Cambridge Crystallographic Data Centre via www.ccdc.cam.
ac.uk/data_request/cif.
[6] N. Robertson, L. Cronin, Coord. Chem. Rev. 2002, 227, 93–
127.
[7] S. Rabaça, M. Almeida, Coord. Chem. Rev. 2010, 254, 1493–
1508.
[8] J. Cookson, P. D. Beer, Dalton Trans. 2007, 1459–1472.
[9] G. Hogarth, Prog. Inorg. Chem. 2005, 53, 71–561.
[10] K. Oliver, A. J. P. White, G. Hogarth, J. D. E. T. Wilton-Ely,
Dalton Trans. 2011, 40, 5852–5864.
[11] K. Diwan, B. Singh, S. K. Singh, M. G. B. Drew, N. Singh,
Dalton Trans. 2012, 41, 367–369.
[12] A. Kumar, R. Chauhan, K. C. Molloy, G. Kociok-Kohn, L.
Bahadur, N. Singh, Chem. Eur. J. 2010, 16, 4307–4314.
[13] C. Bianchini, C. A. Ghilardi, A. Meli, S. Midollini, A. Orland-
ini, Inorg. Chem. 1985, 24, 932–939.
Crystal Data for 1: C46H42CuO2.50P2S2, formula mass 824.40, tri-
¯
clinic space group P1, a = 12.3315(14), b = 13.0377(11), c =
15.0501(16) Å, α = 92.123(8), β = 92.225(9), γ = 115.574(10)°, V =
2177.1(4) Å3, Z = 2, dcalcd. = 1.258 gcm–3, F(000) = 858, reflections
collected 11173, independent reflections 6720, final indices
[14] M. Afzal, C. L. Rosenberg, M. A. Malik, A. J. P. White, P.
O’Brien, New J. Chem. 2011, 35, 2773–2780.
[15] L. I. Victoriano, H. B. Cortes, J. Coord. Chem. 1996, 39, 231–
[IϾ2σ(I)] R1 = 0.0640, wR2 = 0.1639, R indices (all data) R1
0.1064, wR2 = 0.1833, GOF 1.038.
=
239.
[16] L. Z. Xu, J. H. Lin, S. S. Zhang, K. Jiao, F. F. Jian, Pol. J.
Chem. 2001, 75, 755.
Crystal Data for 2: C44H37CuOP2S2, formula mass 771.34, mono-
clinic space group P21/c, a = 10.9581(3), b = 19.8423(4), c =
[17] C. Bianchini, C. A. Ghilardi, A. Meli, S. Midollini, A. Orland-
ini, J. Organomet. Chem. 1983, 255, C27–C30.
[18] T. Shono, Y. Fuji, K. Shinra, Chem. Lett. 1972, 163–164.
[19] C. Kowala, J. M. Swan, Aust. J. Chem. 1966, 19, 555–559.
[20] I. Haiduc, R. Cea-Olivares, R. A. Toscano, C. Silvestru, Poly-
hedron 1995, 14, 1067–1071.
[21] L. M. Nguyen, M. E. Dellinger, J. T. Lee, R. A. Quinlan, A. L.
Rheingold, R. D. Pike, Inorg. Chim. Acta 2005, 358, 1331–
1336.
[22] a) A. Tsuboyama, K. Kuge, M. Furugori, S. Okada, M. Hosh-
ino, K. Ueno, Inorg. Chem. 2007, 46, 1992–2001; b) R. Czerwi-
enic, J. Yu, H. Yersin, Inorg. Chem. 2011, 50, 8293–8301.
[23] C. A. Bignozzi, R. Argazzi, C. Kleverlaan, J. Chem. Soc. Rev.
2000, 29, 87–96.
[24] E. S. Smirnova, A. A. Milikhova, V. V. Gurzhiy, D. V. Krup-
enya, I. O. Koshevoy, S. P. Tunik, Z. Anorg. Allg. Chem. 2012,
638, 415–422.
[25] C. Kutal, Coord. Chem. Rev. 1990, 99, 213–252.
[26] a) D. G. Cutell, S. Kuang, P. E. Fanwick, D. R. McMillin,
R. A. Walton, J. Am. Chem. Soc. 2002, 124, 6–7; b) S. Kuang,
D. G. Cutell, D. R. McMillin, P. E. Fanwick, R. A. Walton, In-
org. Chem. 2002, 41, 3313–3322.
[27] P. Aslanidis, P. J. Cox, S. Divanidis, A. C. Tsipis, Inorg. Chem.
2002, 41, 6875–6866.
17.7195(5) Å, β = 106.248(3)°, V = 3698.97(16) Å3, Z = 4, dcalcd.
=
1.385 gcm–3, F(000) = 1600, reflections collected 15346, indepen-
dent reflections 5226, final indices [IϾ2σ(I)] R1 = 0.0449, wR2 =
0.1222, R indices (all data) R1 = 0.0540, wR2 = 0.1327, GOF 0.978.
Crystal Data for 3: C42H39CuOP2S2, formula mass 749.33, triclinic
¯
space group P1, a = 10.3928(15), b = 13.1640(15), c = 14.4155(17)
Å, α = 92.082(9), β = 105.993(12), γ = 100.309(11)°, V = 1857.6(4)
Å3, Z = 2, dcalcd. = 1.340 gcm–3, F(000) = 780.0, reflections col-
lected 16764, independent reflections 5102, final indices [IϾ2σ(I)]
R1 = 0.0598, wR2 = 0.1786, R indices (all data) R1 = 0.0637, wR2
= 0.1835, GOF 1.056.
Crystal Data for 4: C50H47CuO2N2P2S2, formula mass 897.50, tri-
¯
clinic space group P1, a = 12.6418(12), b = 13.0045(513), c =
16.5164(718) Å, α = 109.887(10), β = 92.126(8), γ = 114.519(10)°,
V = 2272.1(4) Å3, Z = 2, dcalcd. = 1.312 gcm–3, F(000) = 936, reflec-
tions collected 19914, independent reflections 10024, final indices
[IϾ2σ(I)] R1 = 0.0894, wR2 = 0.1843, R indices (all data) R1
0.2021, wR2 = 0.2177, GOF 1.007.
=
Supporting Information (see footnote on the first page of this arti-
cle): UV/Vis spectra of ligands and crystallographic data and struc-
ture refinement parameters.
[28] H. Xu, Z. Chen, S. Ishizaka, N. Kitamura, J. Wu, Chem. Com-
mun. 2002, 1934–1935.
[29] E. Fournier, F. Lebrun, M. Drouin, A. Decken, P. D. Harvey,
Inorg. Chem. 2004, 43, 3127–3135.
[30] S. B. Harkins, J. C. Peters, J. Am. Chem. Soc. 2005, 127, 2030–
2031.
Acknowledgments
[31] Y.-G. Ma, W. H. Chan, X.-M. Zhou, C.-M. Che, New J. Chem.
1999, 23, 263; S. Sakaki, T. Kuroki, T. Hamada, J. Chem. Soc.,
Dalton Trans. 2002, 840.
[32] N. Sutin, C. Creutz, Pure Appl. Chem. 1980, 52, 2717–2738.
[33] A. Kumar, H. Meyer-Figge, W. S. Sheldrick, N. Singh, Eur. J.
Inorg. Chem. 2009, 2720–2725.
We gratefully acknowledge the Council of Scientific and Industrial
Research (CSIR), New Delhi for funding [Project no. 01(2290)/09/
EMR-II], the Banaras Hindu University for funds for the CCD
diffractometer used in the data collection of 4, the Engineering
and Physical Sciences Research Council (EPSRC) (UK) and the
University of Reading for funds for the CCD diffractometer used
in the data collection of 1, 2 and 3.
[34]
[35]
[36]
[37]
[38]
[39]
B. Singh, M. G. B. Drew, G. Kociok-Kohn, K. C. Molloy, N.
Singh, Dalton Trans. 2011, 40, 623–631.
F. Sabin, C. K. Ryu, P. C. Ford, A. Vogler, Inorg. Chem. 1992,
31, 1941–1945.
J. P. Fackler Jr., R. J. Staples, C. W. Liu, R. T. Stubbs, C. Lo-
pez, J. T. Pitts, Pure Appl. Chem. 1998, 70, 839–844.
N. Zhu, S. Du, P. Chen, X. Wu, J. Cluster Sci. 1992, 3, 201–
218.
V. Singh, A. Kumar, R. Prasad, G. Rajput, M. G. B. Drew, N.
Singh, Cryst. Eng. Commun. 2011, 13, 6817–6827.
G. G. Messmer, G. J. Palenik, Inorg. Chem. 1969, 8, 2750.
[1] D. Coucouvanis, Prog. Inorg. Chem. 1979, 26, 301–469.
[2] P. I. Clemenson, Coord. Chem. Rev. 1990, 106, 171–203.
[3] P. Cassoux, L. Valade, Inorganic Materials, John Wiley and
Sons, Chichester, 1996.
[4] M. Bousseau, L. Valade, J. P. Legros, P. Cassoux, M. Gar-
boukas, L. V. Interrante, J. Am. Chem. Soc. 1986, 108, 1908–
1916.
6
www.eurjic.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 0000, 0–0

Job/Unit: I20307
/KAP1
Date: 12-07-12 16:06:35
Pages: 8
Heteroleptic Copper(I) Xanthate/Dithiocarbamate PPh3 Complexes
[40] CrysAlis RED program, Oxford Diffraction, Abingdon, 2008.
[41] SHELXS97 and SHELXl97, Programs for Crystallographic
Solution and Refinement: G. M. Sheldrick, Acta Crystallogr.,
Sect. A 2008, 64, 112.
[42] M. N. Burnett, C. K. Johnson, ORTEP-III, Oak Ridge Ther-
mal Ellipsoid Plot Program for Crystal Structure Illustrations,
Report ORNL-6895, Oak Ridge National Laboratory, Oak
Ridge, USA, 1996.
H. Kunkley, A. Vogler, J. Am. Chem. Soc. 1995, 117, 540–541.
Received: March 26, 2012
[43]
Published Online: ᭿
Eur. J. Inorg. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
7

Job/Unit: I20307
/KAP1
Date: 12-07-12 16:06:35
Pages: 8
N. Singh et al.
FULL PAPER
Heteroleptic Cu(I) Complexes
Heteroleptic CuI dithiocarbamate/xanthate
PPh3 complexes are synthesized and struc-
turally characterized. Their conductivity
and photoluminescence are investigated.
The dithiocarbamate complex bearing the
pyridine substituent exhibited bluish green
light in the visible region. The semicon-
ductor behaviour of the complexes was as-
cribed to the lack of intermolecular S···S
contacts in the solid state.
G. Rajput, V. Singh, S. K. Singh,
L. B. Prasad, M. G. B. Drew,
N. Singh* .......................................... 1–8
Cooperative
Metal–Ligand-Induced
Properties of Heteroleptic Copper(I) Xan-
thate/Dithiocarbamate PPh3 Complexes
Keywords: Xanthate / S ligands / Phos-
phane ligands / Copper / Photolumin-
escence / Semiconductivity
8
www.eurjic.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 0000, 0–0