Synthesis, crystal structures and luminescence properties of {[Cu(μ-PhPPy2)(CH3CN)]ClO4}2 dimer and monodimensional polymer [Cu2(μ-PhPPy2) 2(μ-SO4)]∞ (PhPPy2</sub

Article abstract of DOI:10.1016/j.inoche.2005.10.012

A new binuclear complex, {[Cu(μ-PhPPy₂)(CH ₃CN)]ClO₄}₂ (1) is synthesized by a direct reaction of [Cu(CH₃CN)₄]ClO₄ with PhPPy ₂. Dimeric cation of 1, [Cu(μ-PhPPy2)(CH3

Full text of DOI:10.1016/j.inoche.2005.10.012

Inorganic Chemistry Communications 9 (2006) 72–74
www.elsevier.com/locate/inoche
Synthesis, crystal structures and luminescence properties of
{[Cu(l-PhPPy2)(CH3CN)]ClO4}2 dimer and monodimensional
polymer [Cu2(l-PhPPy2)2(l-SO4)]1
(PhPPy2 = bis(2-pyridyl)phenylphosphine)
a,
a
a
b
Tianle Zhang *, Chunguang Chen , Yu Qin , Xianggao Meng
a
Department of Chemistry, Huazhong University of Science and Technology, 1037 Luoyu, Wuhan, Hubei 430074, PR China
b
Department of Chemistry, Central China Normal University, Wuhan, Hubei 430079, PR China
Received 21 September 2005; accepted 9 October 2005
Available online 18 November 2005
Abstract
A new binuclear complex, {[Cu(l-PhPPy2)(CH3CN)]ClO4}2 (1) is synthesized by a direct reaction of [Cu(CH3CN)4]ClO4 with
PhPPy2. Dimeric cation of 1, ½Cuðl-PhPPy ÞðCH3CNÞꢀ2þ, can be utilized as building block precursor to construct coordination polymer
2
2
[Cu2(l-PhPPy2)2(l-SO4)] (2) by replacement of coordinated acetonitrile molecules with bridging ligand ðSO2ꢁÞ. Both 1 and 2 exhibit
1
4
strong green emissions in solid state at room temperature. Crystal structures of 1 and 2 have been determined by single crystal X-ray
diffraction.
Ó 2005 Elsevier B.V. All rights reserved.
Keywords: Binuclear copper(I) complex; Polymer; Bis(2-pyridyl)phenylphosphine; Luminescence
There is a great interest in construction of supramolecu-
lar assemblies or polymers [1]. Recently, incorporation of
bi- or polynuclear units, such as Mo42þ [2a], Rh24þ [2a],
Ru52þ [2b,2c], and Cu4I4 [3], into extended frameworks
becomes a new area of supramolecular chemistry and
material science, in which way synthetic materials may pos-
ses some novel properties due to metal–metal interactions
and rigidity of dimeric or cluster units [3,4]. 2-pyridylphos-
phine ligands, especially Ph2PPy ((2-pyridyl)diphenylphos-
phine), have been extensively used to synthesize homo- or
heterobinuclear complexes to study metal–metal bonding,
due to their abilities to lock two metals together to enhance
metal–metal interaction and stabilize metals at low oxida-
tion states [5]. We are interested in utilization of 2-pyridyl-
phosphines to prepare bi- or polynuclear low-valent
transition metal complexes as building block precursors
to construct supramolecular assemblies or polymeric mate-
rials exhibiting catalytic and photoluminescence properties.
Although compared to Ph2PPy, the coordination modes of
PhPPy2 are complicated, not only as monodentate [6], but
also bidentate [7] and tridentate [6,8], leading to bi- or poly-
nuclear complexes [6a,9], our previous results revealed that
PhPPy2 could be a suitable ligand to bond to transition
metals adopting tetrahedral or square-planar geometry to
form rigid binuclear complexes [9b]. In this paper, synthe-
sis, crystal structures and luminescence properties of a
binuclear copper(I) complex 1 and related polymer 2 are
reported.
A direct reaction of PhPPy2 with [Cu(CH3CN)4]ClO4
quantitatively affords an air- and light-stable binuclear
Cu(I) complex, {[Cu(l-PhPPy2)(CH3CN)]ClO4}2 (1). Sin-
gle crystal X-ray crystallographic studies show that in solid
state, two copper atoms are bridged by two cis-PhPPy2
ligands (Fig. 1) [10]. Each copper atom adopts a distorted
tetrahedral geometry, coordinated by one P and three N
*
Corresponding author. Fax: +86 27 87543632.
E-mail address: tlzhang@mail.hust.edu.cn (T. Zhang).
1387-7003/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.inoche.2005.10.012

T. Zhang et al. / Inorganic Chemistry Communications 9 (2006) 72–74
73
While adding CuSO4 in methanol to a solution of 1 in ace-
tonitrile, a deep blue-green solution was obtained, from
which polymer 2 crystallized as a pale green-yellow blocks
in moderate yield (62.5%). Polymer 2 is not soluble in com-
mon organic solvents, such as dichloromethane, acetoni-
trile and methanol. IR data indicated that anion
metathesis reaction occurred and the bands for coordi-
nated acetonitrile molecules disappeared. X-ray diffraction
studies confirm this, and reveal that the dimeric cations,
½Cuðl-PhPPy2Þꢀ2þ, are connected by sulfate anions to form
2
a zigzag chain (Fig. 2) [12]. The angle of S–O–Cu is
177.1(10)°, just slightly deviated from perfect linearity
[13]. Two copper centers are still collinear with two oxygen
atoms from coordinated sulfate anions.
Mono- or polynuclear copper(I) complexes and poly-
mers have been extensively studied due to their fascinating
luminescence properties [3,14,15]. At room temperature,
both 1 and 2 exhibit intense green emissions with bands
around 531 and 535 nm in solid state, respectively. The
spectra of polymer 2 is shown in Fig. 3. It is unreasonable
to assign the observed luminescence to intraligand PhPPy2
p ! p*, as the energy gap between the two emission max-
Fig. 1. Molecular structure of 1. ClOꢁ4 anions are omitted for clarity.
Selected bond lengths (A) and angles (°) Cu(1)–P(1) 2.1908(9), Cu(1)–N(1)
2.073(3), Cu(1)–N(2) 2.047(3), Cu(1)–N(3) 2.026(3), N(1)–Cu(1)–N(3)
100.70(13), N(1)–Cu(1)–N(2) 94.38(11), N(2)–Cu(1)–N(3) 104.31(13),
P(1)–Cu(1)–N(1) 118.25(8), P(1)–Cu(1)–N(2) 115.94(9), P(1)–Cu(1)–N(3)
119.36(9).
˚
ima is on the order of 7480 cmꢁ1 (kemi ¼ 380 nm for free
atoms, two of which are from pyridyl groups of another
PhPPy2 ligand, and one from acetonitrile molecule. This
coordination mode of PhPPy2 is similar to that observed
in [(PhPPy2)2PdCuCl2]ClO4 [9b]. Bond lengths of Cu–P
and Cu–N (from pyridyl groups), and related bond angles
are normal. A distance of Cu–N (from acetonitrile) is
max
PhPPy2). This emission band might be assigned as metal
to ligand charge transfer (MLCT), mainly arising from
˚
2.026(3) A, shorter than that found in [Cu3(dpmp)2(CH3-
˚
CN)2(l-Cl)2]ClO4 (2.13(1) A) [11]. The Cu. . .Cu distance
˚
is 3.691 A. At this value, no Cu. . .Cu interaction is
expected. Interestingly, two copper atoms are collinear
with two coordinated acetonitrile molecules.
In our synthetic strategy to coordination polymers and
supramolecular assemblies with controllable structures,
bridging ligands with specific geometries are chosen as link-
ers to connect bi- or polynuclear units. In {[Cu(l-
PhPPy2)(CH3CN)]ClO4}2 molecule, PhPPy2 groups are
non-labile, while coordinated acetonitrile molecules are
possibly easy to be exchanged by various linkers, which
could allow the construction of high-order architectures.
Fig. 3. Excitation and emission spectra of 2 in solid state at room
temperature: emission spectrum (kmax = 531 nm); excitation spectrum
(kmax = 375 nm).
˚
Fig. 2. Crystal structure of 2. Selected bond lengths (A) and angles (°): Cu(1)–P(1) 2.1792(17), Cu(1)–N(1) 2.084(6), Cu(1)–N(2) 2.059(6), Cu(1)–O(4)
2.024(7), N(1)–Cu(1)–P(1) 123.30(15), N(2)–Cu(1)–P(1) 120.50(17), N(2)–Cu(1)–N(1) 92.7(2), O(4)–Cu(1)–N(1) 101.8(4), O(4)–Cu(1)–N(2) 98.2(4), O(4)–
Cu(1)–P(1) 115.4(3), S(1)–O(4)–Cu(1) 177.1(10), O(4)–S(1)–O(1) 114.3(9), O(3)–S(1)–O(2) 103.5(16).

74
T. Zhang et al. / Inorganic Chemistry Communications 9 (2006) 72–74
(c) G.F. Zhang, J. Zhao, G.R. Sieber, E. Herdtweck, F.E. Kuhn,
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¨
Cu(I) ! PhPPy2 as no noticeable change was observed
while the replacement of coordinated acetonitrile molecules
by sulfate anions occurred [14a].
Upon to date, there have been a number of Cu(I) poly-
mers reported [16], but synthetic strategies to coordination
polymers, especially low-dimensional polymers with
designed architectures, and structure–property relationship
of polymers still remain to be further investigated. Due to
the rigidity and linear geometry for 1, {Cu(l-PhPPy2)
(CH3CN)ClO4}2, could be an excellent building block pre-
cursor for the construction of supramolecular assemblies
or coordination polymers. Work in this area is in progress.
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[10] Dimer 1: UV–Vis(CH3CN) k, nm: 211, 235, 310; IR(KBr disk), m,
cmꢁ1 2020(CH3CN), 1145, 1086, 626(ClOꢁ4 ); Anal. Calcd. for
:
C18H16N3O4PClCu: C, 46.17; H, 3.44; N, 8.97, Found: C, 46.03; H,
3.51; N, 9.02. Crystal data for 1 at 292 K: Monoclinic, P21/n,
˚
˚
˚
a = 8.7492(8) A, b = 9.8287(8) A, c = 23.0359(19) A, b = 91.540(2)°,
3
V = 1980.2(3) A ,
Z = 4,
q = 1.571 Mg/mꢁ3
h
,
abs.
coeff. =
˚
1.348 mmꢁ1
,
F(000) = 952,
range: 1.77–26.00°, R1 = 0.0473,
wR2 = 0.1336 [I > 2r(I)]; R1 = 0.0564, wR2 = 0.1410 (all data),
S = 1.036.
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