A photoluminescent polymeric chain complex: Synthesis and structure of [(PPh3)2Cu2(μ-I)2(μ-4, 4′-bpy)]n

Article abstract of DOI:10.1016/S1387-7003(03)00170-9

The synthesis and crystal structure of a new one-dimensional mixed-ligand Cu(I) coordination polymer, [(PPh₃)₂Cu₂(μ-I)₂(μ-4, 4′bpy)]_n (4,4′-bpy = 4,4′-bipydine) are reported. The neutral polymer consists of (PPh₃)₂Cu₂(μ-I)₂(μ-4, 4′-bpy) units bridged by 4,4′-bpy to construct an infinite chain architecture. Crystal data: C₂₃H₁₉CuINP, M_r = 530.80, Triclinic space group (P1, No. 2), a = 9.2279(8) A?, b = 9.4014(8) A?, c = 13.3663(12) A?, α = 107.445(2)°, β = 106.707(2)°, γ = 93.479(2)°, V = 1045.8(2) A?³, D_calc = 1.686 g m^-3, Z = 2. The solid state of the complex is luminescent with a peak maximum at 535 nm, upon excitation at 300-400 nm at room temperature. The emission is assigned to Copper(I) to 4,4′-bpy charge transfer (MLCT).

Full text of DOI:10.1016/S1387-7003(03)00170-9

Inorganic Chemistry Communications 6 (2003) 1017–1019
www.elsevier.com/locate/inoche
A photoluminescent polymeric chain complex: synthesis and
structure of [(PPh3)2Cu2(l-I)2(l-4,40-bpy)]n
a
a,
a
b
Rong-Zhen Li , Dan Li *, Xiao-Chun Huang a,b, Zhi-Yu Qi , Xiao-Ming Chen
a
Department of Chemistry, Shantou University, Shantou, Guangdong 515063, China
b
School of Chemistry and Chemical Engineering, Sun Yat-Sen (Zhongshan) University, Guangzhou 510275, China
Received 22 March 2003; accepted 27 April 2003
Published online: 11 June 2003
Abstract
The synthesis and crystal structure of a new one-dimensional mixed-ligand Cu(I) coordination polymer, [(PPh3)2Cu2(l-I)2(l-4,40-
bpy)]n (4,40-bpy ¼ 4,40-bipydine) are reported. The neutral polymer consists of (PPh3)2Cu2(l-I)2(l-4,40-bpy) units bridged by 4,40-
bpy to construct an infinite chain architecture. Crystal data: C23H19CuINP, Mr ¼ 530:80, Triclinic space group (P1, No. 2),
3
ꢀ
ꢀ
ꢀ
ꢀ
a ¼ 9:2279ð8Þ A, b ¼ 9:4014ð8Þ A, c ¼ 13:3663ð12Þ A, a ¼ 107:445ð2Þ°, b ¼ 106:707ð2Þ°, c ¼ 93:479ð2Þ°, V ¼ 1045:8ð2Þ A ,
Dcalc ¼ 1:686 g mꢀ3, Z ¼ 2. The solid state of the complex is luminescent with a peak maximum at 535 nm, upon excitation at 300–
400 nm at room temperature. The emission is assigned to Copper(I) to 4,40-bpy charge transfer (MLCT).
Ó 2003 Elsevier Science B.V. All rights reserved.
Keywords: Copper(I); Coordination polymer; Structure; 4,40-Bipyridine; Photoluminescence
1. Introduction
2. Experimental
The self-assembly of large inorganic architectures has
rapidly become one of the most exciting area in supra-
molecular chemistry. The crystal engineering of coor-
dination polymers is becoming an increasing popular
field of research, and offers the promise of deliberately
designing new materials with novel electronic, optical,
magnetic and catalytic properties [1–6]. While a larger
number of copper(I) complexes have been found to be
photoluminescence with different emitting excited state
[7,8], luminescent Cu(I) polymers are less common
[9,10]. 4,40-Bipyridine (4,40-bpy) is well-known used as a
linear ligand to bridge metal centers to form one-, two-
and three-dimensional polymeric networks. [11–15] We
report herein the synthesis and crystal structure of a
new one dimensional mixed-ligand Cu(I) complex
[(PPh3)2Cu2(l-I)2(l-4,40-bpy)]n with photoluminescent
properties.
2.1. General
The chemicals and reagents for syntheses were ob-
tained commercially and used without further purifi-
cation. Infrared spectra were recorded in the range of
4000–400 cmꢀ1 on a Nicolet Magna 750 spectrometer.
Elemental analyses were carried out using a Perkin–
Elmer 2400C instrument. Ultraviolet and photolumi-
nescence analyses were performed on a UV-1100
spectrometer and a Perkin–Elmer LS 55 luminescence
Spectrometer, respectively.
2.2. Preparation of [(PPh3)2Cu2(l-I)2(l-4,40-bpy)]n
Crystals of the title complex were prepared by multi-
layer diffusion method. To a dichloromethane solution
(10 ml) of [CuIPPh3]4 (0.45 g, 0.25 mmol) in a glass tube
was carefully added a buffer layer of THF/CH2Cl2 (20
ml). A solution of 4,40-bipyridine (0.23 g, 1.2 mmol) in
THF (10 ml) was introduced dropwise to form a third
layer. Yellow block crystals suitable for X-ray diffrac-
* Corresponding author. Tel: +86-754-290-3154; fax: +86-754-251-
0505.
E-mail address: dli@stu.edu.cn (D. Li).
1387-7003/$ - see front matter Ó 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S1387-7003(03)00170-9

1018
R.-Z. Li et al. / Inorganic Chemistry Communications 6 (2003) 1017–1019
tion analysis were obtained on interdiffusion of the
reactants in weeks. Polycrystalline [(PPh3)2Cu2
2
(l-I)2(l-4,40-bpy)]n was synthesized by the direct reac-
tion of CuI with PPh3 and 4,40-bpy. To a suspension of
CuI (0.19 g, 1 mmol) in 10 ml CH2Cl2 were added PPh3
(0.53 g, 2 mmol) and 0.20 g 4,40-bpy (1 mmol). Yellow
precipitates were formed rapidly. Solid [(PPh3)Cu(l-I)2
(l-4,40-bpy)]n was obtained by filtration after washing
with diethyl ether and dried in vacuo. Anal. Calcd for
C23H19CuINP: C, 52.12%; H, 3.40%; N, 2.60%. Found:
C, 52.04%; H, 3.61%; N, 2.64%. IR(KBr pellets), m/
cmꢀ1: 519s, 694vs, 749vs, 1093s, 1433vs, 1481s (PPh3);
810s, 1000m, 1047w, 1219s, 1406s, 1599s (4,40-bpy).
Fig. 2. View of the infinite chain architecture.
Table 1
0
ꢀ
Selected bond lengths (A) and angles (°) for [(PPh3)2Cu2(l-I)2(l-4,4 -
bpy)]n
Cu(1)–N(1)
Cu(1)–P(1)
Cu(1)–I(1A)
Cu(1)–I(1)
I(1)–Cu(1A)
2.079(2)
2.2434(8)
2.6650(5)
2.7393(5)
2.6650(5)
2.3. X-ray structure determination
A yellow crystal (0.43 mm ꢁ 0.34 mm ꢁ 0.13 mm) was
chosen for X-ray crystallography determination. Crystal
data: C23H19CuINP, Mr ¼ 530:80, Triclinic space
N(1)–Cu(1)–P(1)
N(1)–Cu(1)–I(1A)
P(1)–Cu(1)–I(1A)
N(1)–Cu(1)–I(1)
P(1)–Cu(1)–I(1)
I(1A)–Cu(1)–I(1)
Cu(1A)–I(1)–Cu(1)
120.04(7)
103.75(7)
114.74(2)
101.15(7)
107.13(2)
108.91(1)
71.10(1)
ꢀ
ꢀ
group (P1, No. 2), a ¼ 9:2279ð8ÞA; b ¼ 9:4014ð8ÞA;
ꢀ
c ¼ 13:3663ð12Þ A, a ¼ 107:445ð2Þ°, b ¼ 106:707ð2Þ°,
3
c ¼ 93:479ð2Þ°, V ¼ 1045:8ð2Þ A , Dcalc ¼ 1:686 g mꢀ3
,
ꢀ
Z ¼ 2; 6637 reflections collected, 4988 unique, (Rint
¼
0:0219), Final
R
indices [I ꢂ 2rðIÞ] R1 ¼ 0:0325,
wR2 ¼ 0:0935. Data collections (4:43 < h < 28:28) were
performed at 293 K on a Siemens R3m diffractometer
ꢀ
bond distances and angles are listed in Table 1. It is
compared well with its chloride analogues [(PPh3)2
Cu2(l-Cl)2(l-4,40-bpy)]n and[(PPh3)2Cu2(l-Cl)2(l-pyz)]n
(pyz ¼ pyrazine) reported by Lu et al. [15] and Henary
et al. [9], respectively, as well as a Ag(I) analogue
[(PPh3)2Ag2(l-I)2(l-4,40-bpy)]n by Vittal et al. [17]. The
two pyridine rings in the title complex are almost co-
planar, similar to those in [(PPh3)2Cu2(l-Cl)2(l-pyz)]n
[9]. The four-coordination Cu(I) was completed by one
N from 4,40-bpy, one P from triphenylphosphine and
two iodine atoms to form a distorted tetrahedron ge-
ometry. Unlike the short Cu–Cu distances of 2.65–2.88
with graphite-monochromated Mo-Ka (k ¼ 0:71073 A)
radiation. The structure was solved with direct methods
and refined by full matrix least squares (SHELXTL)
[16].
3. Results and discussion
Single crystal crystallography has revealed the title
complex is a neutral compound that consists of
(PPh3)2Cu2(l-I)2 units (Fig. 1) bridging by 4,40-bpy to
construct an infinite chain architecture (Fig. 2). Selected
ꢀ
A in Cu4I4L4 (L ¼ nitrogen containing heterocyclic li-
gands) cubic clusters [8], the Cuꢃ ꢃ ꢃCu distance in the title
ꢀ
polymer is 3.143 A indicating no Cu–Cu interaction
existing.
The N(1)–Cu(1)–P(1) and averaging values of N(1)–
Cu(1)–I are 120.04(7)° and 102.45°. The P(1)–Cu(1)–I(1)
and P(1)–Cu(1)–I(1A) are 107.13(2) and 114.74(2), re-
ꢀ
spectively. The Cu(1)–N(1) distances of 2.079(2) A and
ꢀ
Cu(1)–P(1) of 2.2434(8) A are comparable with those in
its chloride analogues [14,16]. The Cu–I distances of
ꢀ
2.6650(5)–2.7393(5) A are slightly longer than those of
ꢀ
2.499(3)–2.565(3) A in the related chain complex
[Cu2I2(PPh3)2(C4H5N3)]n (C4H5N3 ¼ 2-aminopyrimi-
dine) [18].
The solid state of the polymer is luminescent upon
excited with UV light. Fig. 3 illustrates the emission
spectrum of the complex with a peak maximum at 535
nm, upon excitation at 300–400 nm at room tempera-
em
max
Fig. 1. Illustration of (PPh3)2Cu2(l-I)2(l-4,40-bpy) unit of the polymer.
ture. We have reported that the emission (k
¼ 483

R.-Z. Li et al. / Inorganic Chemistry Communications 6 (2003) 1017–1019
1019
Data Centre with the deposition number of CCDC
200365. Copies of this information may be obtained
free of charge from The Director, CCDC, 12 Union
Road, Cambridge, CB2 1EZ, UK (fax: +44-1223-
336033; e-mail: deposit@ccdc.cam.ac.uk or http://
www.ccdc.cam.ac.uk) or from the corresponding au-
thor on request.
Acknowledgements
D. Li is grateful to the National Natural Science
Foundation of China (29901004, 20271031) and Natural
Science Foundation of Guangdong Province of China
(021240) for financial support.
Fig. 3. Emission spectrum excited at 350 nm of the solid polymer at
room temperature.
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Crystallographic data for the title complex have
been deposited at the Cambridge Crystallographic