научная статья по теме SYNTHESIS, STRUCTURE, AND PHOTOLUMINESCENCE PROPERTIES OF A NOVEL 3D 3D–4F HETEROMETALLIC POLYMER: PR4(H2O)9CU3.5CL0.5(BPDC)6.5(OH)2 · 5H2O (H2BPDC = 2,2-BIPYRIDYL-5,5-DICARBOXYLIC ACID) Химия

Текст научной статьи на тему «SYNTHESIS, STRUCTURE, AND PHOTOLUMINESCENCE PROPERTIES OF A NOVEL 3D 3D–4F HETEROMETALLIC POLYMER: PR4(H2O)9CU3.5CL0.5(BPDC)6.5(OH)2 · 5H2O (H2BPDC = 2,2-BIPYRIDYL-5,5-DICARBOXYLIC ACID)»

КООРДИНАЦИОННАЯ ХИМИЯ, 2011, том 37, № 4, с. 298-304

УДК 541.49

SYNTHESIS, STRUCTURE, AND PHOTOLUMINESCENCE PROPERTIES OF A NOVEL 3D 3d-4f HETEROMETALLIC POLYMER:

Pr4(H2O)9Cu3.5ao.5(Bpdc)6.5(OH)2 • 5H2O (H2Bpdc = 2,2'-BIPYRIDYL-5,5-DICARBOXYLIC ACID)

© 2011 H. L. Cheng1, D. Y. Shi1, J. W. Zhao1, *, Z. D. Geng1, L. J. Chen1, 2,

P. T. Ma1, and J. Y. Niu1, *

1Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, P.R. China 2Basic Experiment Teaching Center, Henan University, Kaifeng, Henan 475004, P.R. China *E-mail: zhaojunwei@henu.edu.cn; jyniu@henu.edu.cn Received June 30, 2010

A novel 3D 3d-4fheterometallic polymer Pr4(H2O)9Cu3.5Cla5(Bpdc)6.5 (OH)2 ■ 5H2O (I) (H2Bpdc = 2,2'-bipyri-dyl-5,5'-dicarboxylic acid) has been hydrothermally synthesized by the reaction of CuCl2 ■ 2H2O, PrCl3, H2Bpdc, TAA (TAA = 1H-tetrazolyl-1-acetic acid) and glacial acetic acid and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Single-crystal structural analysis shows that I displays an interesting heterometallic 3D coordination framework constructed from 2D praseodymium—oxygen layers and [Cu(Bpdc)2]3- and [CuCl(Bpdc)]2- pillars. The photofluorescence properties of I have been investigated.

INTRODUCTION

In recent years, the design and synthesis oflanthanide-transition-metal heterometallic complexes have attracted increasing attention due to their versatile applications in catalysis, adsorption, separation, magnetism, optoelectronics, and molecular recognition, as well as their intriguing architectures and topologies [1, 2]. As we know, lanthanide metal cations have a strong affinity to O-do-nors, whereas transition metal cations prefer N-donors to O-donors according to the hard—soft acid base rule [3]. A fantastic strategy is to utilize the reaction of lanthanide cations and transition metal cations with N-/O-contain-ing ligands such as N-heterocyclic carboxylic ligands, to construct novel lanthanide-transition-metal heterome-tallic complexes [1]. Currently, the most commonly used N-heterocyclic carboxylic ligands mainly include pyridi-necarboxylic acids [4—6] and imidazolecarboxylic acids [7, 8]. To our knowledge, the investigation on 2,2'-bipy-ridyl-5,5'-dicarboxylic acid (H2Bpdc) as a multifunctional ligand remains less developed [9—14]. For example, in [9] authors isolated two copper—vanadium phosphates [{(Bpdc)Cu}2{V3O3(OH)2(H2O)}(O3PCH2PO3)2] ■ 2H2O and [Cu(HO3PCH2PO3H)(Bpdc)(H2O)]. Geary and coworkers prepared a platinum—H2Bpdc complex [Pt(H2Bpdc)(Tdt)] and its tetrabutylammonium salt [TBA]2[Pt(Bpdc)(Tdt)] (Tdt = 3,4-toluenedithiolate) and evaluated their performance in solar cell sensitizers [10]. C.J. Matthews and co-authors reported [Rh(HBpdc)3] ■ 6H2O and [Ru(HBpdc)2(H2Bpdc)] ■ ■ 2.5H2O and investigated the role of intermolecular hydrogen bonding and stacking interactions [11]. A robust

porous material [Ni(Cyclam)(Bpdc)] • 5H2O (Cyclam = = 1,4,8,11-tetraazacyclotetradecane) was reported, which displays the reversible single-crystal to single-crystal transformations upon dehydration and rehydration [12]. In [13] authors discovered a thermally stable heterobime tallic metal-organic framework material [(Bpdc)PtCl2]3[Y(H2O)3]2 • 5H2O. K.S. Szeto and co-authors also reported another novel heterobime tallic metal-organic framework material {[(Bpdc)PtCl2]3(Gd(H2O)3)2} • 5H2O, which has been demonstrated to activate hydrocarbon C—H bonds in homogeneous systems [14]. As illustrated above, no 3d—4f heterometallic complex with H2Bpdc has been reported hitherto, which provides us an excellent opportunity for exploring the reaction of the first-row transition met-al/lanthanide cations with H2Bpdc. In this context, we have recently concentrated on this field with the aim of finding rational reaction conditions to obtain novel 3d—4fheterometallic complexes with H2Bpdc. Recently, we reported two novel 1D copper complexes [Cu"(HBpdc)2Cl2]2 • 2H2O and CuI(H2Bpdc)Cl by the one-pot hydrothermal reaction of H2Bpdc, CuCl2 • • 2H2O, PrCl3, and glacial acetic acid, however, no Pr3+cation was observed in the products [3]. Finally, by systematically changing the reaction conditions, a novel 3D 3d—4f heterometallic polymer Pr4(H2O)9Cu35Cl05(Bpdc)65(OH)2 • 5H2O (I) has fortunately been isolated. In the present paper, we report the synthesis, crystal structure, and characterization of I. Moreover, the fluorescence properties of I have also been investigated.

EXPERIMENTAL

Materials and methods. All reagents were purchased from commercial sources and used without further purification. Elemental analyses (C, H, and N) were performed on a PerkinElmer 240C elemental analyzer. The IR spectrum was recorded from a sample powder pelletized with KBr on a Nicolet FT-IR 360 spectrometer over a range of 4000—400 cm-1. The photoluminescence spectra were measured on an F-7000 fluorescence spectrophotometer.

Synthesis of I was carried out under hydrothermal conditions. A mixture of CuCl2 • 2H2O (0.085 g, 0.499 mmol), PrCl3 (0.133 g, 0.538 mmol), H2Bpdc (0.021 g, 0.086 mmol), TAA (0.032 g, 0.250 mmol), H2O (6 ml, 333 mmol), and glacial acetic acid (0.15 ml, 2.622 mmol) was stirred for 4 h, sealed in a Teflon-lined stainless steel autoclave (25 ml), kept 160°C for 8 days, and then cooled to room temperature. Black needle crystals of I were filtered, washed with distilled water, and dried in air at ambient temperature.

For C78H69N13O42Cl0.5Cu3.5Pr4

anal. calcd., %: C, 35.16; H, 2.61; N, 6.83.

Found, %: C, 35.34; H, 2.80; N, 6.64.

X-ray crystal determination. A high-quality single crystal was carefully selected under an optical microscope and glued at the tip of a thin glass fiber with cyanoacrylate adhesive. Intensity data were collected on a Bruker APEX-II CCD detector at 296(2) K with a Mo^ radiation (X = 0.71073 A). Corrections for Lp factors and empirical absorption were applied. The structure was solved by direct methods and refined by full-matrix least-squares techniques on F2 using the SHELXTL-97 package [15]. All of the non-hydrogen atoms were refined anisotropi-cally. All hydrogen atoms were placed in the idealized positions and refined with a riding model using default SHELXL parameters. The hydrogen atoms attached to lattice water molecules were not located. The weighting

detail: w = 1/ [a2 (Fo2) + (0.0891P )2 + 0.0000P ], where

P = (Fo2 + 2Fc2 )/3. The crystallographic data are listed in Table 1, and the selected bond lengths and bond angles are given in Table 2. The atomic coordinates and other parameters ofstructure I have been deposited with the Cambridge Crystallographic Data Centre (no. 782665; depos-it@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).

RESULTS AND DISCUSSION

X-ray single-crystal structural analysis reveals that I exhibits an interesting heterometallic 3D coordination framework constructed from 2D praseodymium-oxygen layers and [Cu(Bpdc)2]3- and [CuCl(Bpdc)]2- pillars. The asymetric molecular fragment of I is shown in Fig. 1. There exist 4 crystallographically unique Pr3+ cations, 3.5 Cu+ cations, 6.5 Bpdc2- anions, 0.5 Cl- anion, 2 OH-anions, 9 coordinated water molecules and 5 lattice water

Table 1. Crystallographic data and structure refinement summary for compound I

Parameter Vàlue

Formula weight 2664.22

Crystal system Monoclinic

Space group P21/n

a, A 17.3849(17)

b, A 21.0331(19)

c, A 23.409(2)

P, deg 91.978(2)

V, A3 8554.7(14)

Z 4

Pcalcc^ g cm-3 2.069

p., mm-1 3.209

F(000) 5240

Crystal size, mm 0.41 x 0.19 x 0.17

Limiting indices -19 < h < 20, -24 < k < 24

-27 < l < 25

9 range for data collection, deg 1.77 to 25.00

Type of scan 9 and ro scan

Number of reflections, I > 2ct(D 9569

Number of parameters refined 1301

Reflections collected/unique 42997/14843 (Rint = 0.0719)

Goodness-of-fit on F2 1.056

Final R indices (I > 2ct(I)) R1 = 0.0651, wR2 = 0.1623

R indices (all data) Rx = 0.1068, wR2 = 0.1805

^Pmax/^Pmin e A-3 3.103/-1.926

molecules in the asymmetric molecular fragment of I. The Pr(1), Pr(2), Pr(3), and Pr(4) centers are all eight-coordinated and all adopt the bicapped trigonal prism geometry (Fig. 2). In the coordination sphere of Pr(1) and Pr(2) cations (Figs. 2a and 2b), five oxygen atoms from five Bpdc2- ligands (Pr-O 2.396-2.526 A) and one coordinated water oxygen atom (Pr-O 2.523-2.540 A) constitute two bottom planes of the trigonal prism, and one oxygen atom from one Bpdc2- ligand (Pr-O 2.428-2.465 A) and one coordinated water oxygen atom occupy two "cap" positions (Pr-O 2.571-2.644 A). In the coordination sphere ofPr(3) cation (Fig. 2c), two bottom planes of the trigonal prism are defined by six oxygen atoms from six Bpdc2- ligands (Pr-O 2.423-2.491 A), while two "cap"

300

CHENG et al.

Table 2. The selected bond lengths and bond angles in compound I*

Bond d, Â Bond d, Â Bond d, Â

Pr(1)-O(2)#1 2.397(8) Pr(2)-O(3w) 2.572(8) Pr(4)-O(9 w) 2.543(7)

Pr(1)-O(19) 2.436(7) Pr(3)-O(24) 2.423(7) Pr(4)-O(7w) 2.779(6)

Pr(1)-O(7)#1 2.441(7) Pr(3)-O(26) 2.430(7) Cu(1)-N(4) 2.034(8)

Pr(1)-O(12)#1 2.457(7) Pr(3)-O(5) 2.440(7) Cu(1)-N(2) 2.060(8)

Pr(1)-O(17)#2 2.466(7) Pr(3)-O(16) 2.449(6) Cu(1)-N(3) 2.157(8)

Pr(1)-O(3)#3 2.528(7) Pr(3)-O(15)#4 2.456(6) Cu(1)-N(1) 2.165(8)

Pr(1)-O(2w) 2.539(9) Pr(3)-O(9) 2.481(7) Cu(2)-N(8) 2.028(8)

Pr(1)-O(1w) 2.644(8) Pr(3)-O(23)#4 2.492(7) Cu(2)-N(6) 2.034(8)

Pr(2)-O(4)#3 2.397(7) Pr(3)-O(5w) 2.591(7) Cu(2)-N(5) 2.045(8)

Pr(2)-O(13) 2.427(7) Pr(4)-O(25) 2.351(8) Cu(2)-N(7) 2.080(8)

Pr(2)-O(21) 2.438(7) Pr(4)-O(14)#5 2.387(7) Cu(3)-N(11) 2.032(9)

Pr(2)-O(20) 2.451(7) Pr(4)-O(10) 2.389(7) Cu(3)-N(9) 2.069(8)

Pr(2)-O(8)#! 2.452(7) Pr(4)-O(6w) 2.394(16) Cu(3)-N(10) 2.084(8)

Pr(2)-O(11)#! 2.483(7) Pr(4)-O(18) 2.455(8) Cu(3)-N(12) 2.119(8)

Pr(2)-O(4w) 2.523(8) Pr(4)-O(8w) 2.521(8) Cu(4)-N(13) 1.861(12)

Angle ro, deg Angle ro, deg Angle ro, deg

N(4)Cu(1)N(2) 157.4(3) N(8)Cu(2)N(6) 153.7(3) N(11)Cu(3)N(9) 153.6(3)

N(4

Для дальнейшего прочтения статьи необходимо приобрести полный текст. Статьи высылаются в формате PDF на указанную при оплате почту. Время доставки составляет менее 10 минут. Стоимость одной статьи — 150 рублей.

Показать целиком