Syntheses, Structures, and Luminescent Properties of Silver(I

ARTICLE pubs.acs.org/crystal

Syntheses, Structures, and Luminescent Properties of Silver(I) Complexes Constructed from ortho-Hydroxyl Arenesulfonic Acids Zhao-Peng Deng, Li-Hua Huo, Ming-Shuai Li, Li-Wei Zhang, Zhi-Biao Zhu,* Hui Zhao, and Shan Gao* Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, Heilongjiang University, Harbin 150080, People's Republic of China

bS Supporting Information ABSTRACT: Eight novel silver(I) complexes constructed from ortho-hydroxyl arenesulfonic acids, [Ag(NH3)2] 3 (HL1) (1), [Ag2(L1)]n (2), [Ag2(HL2)(H2O)3]n (3), [Ag(HL3)(MeCN)2]n (4), [Ag2(HL3)2]n (5), [Ag2(HL4)(H2O)3]n (6), {(NH4)2 3 [Ag(NH3)2]2} 3 2(H2L5) 3 5H2O (7), and [Ag(H2L5)0.5]n (8) (H2L1 = 2-hydroxyl-5methyl-benzenesulfonic acid; H3L2 = 2-hydroxyl-5-methyl-1,3-benzenedisulfonic acid; H2L3 = 2-hydroxyl-5-bromo-benzenesulfonic acid; H3L4 = 2-hydroxyl-5-bromo-1,3benzenedisulfonic acid; H4L5 = 2,4-dihydroxyl-1,5-benzenedisulfonic acid), have been synthesized and characterized by elemental analysis, infrared, thermogravimetric analysis, UV
vis, photoluminescence (PL), powder and single-crystal X-ray diffraction. Complex 1 has a three-dimensional (3-D) supramolecular framework containing right-handed helical channels through the hydrogen-bonding interactions. Complex 2 exhibits a wavelike “inorgano-organic” layer structure, in which the inorganic substructures consist of Ag1 polyhedral chains linked through Ag2 dimers by sharing two vertexes and two edges. Complex 3 presents the 3-D pillared layered structure, and the inorganic layer substructures are formed by sulfonate tetrahedra bridging Ag
O chains through two vertexes. The sulfonate group in complex 4 bridges adjacent Ag(I) ions to generate a one-dimensional chain structure. Complex 5 exhibits a planar “inorgano-organic” layer structure, in which the inorganic substructures consist of chains of vertex-sharing Ag1 polyhedra and edge-sharing Ag2 polyhedra interlinked by sharing edges. Complex 6 shows a similar 3-D pillared layered structure with complex 3. In complex 7, the free water molecules, ammonium cations, and sulfonate groups form a 3-D hydrogen-bonding host network which encapsulates the [Ag(NH3)2]þ cations as guests. Complex 8 also displays a 3-D pillared layered structure with a two-dimensional (2-D) inorganic substructure formed by Ag(I) polyhedral chains interlinked by sharing edges. The structural diversities and evolutions can be attributed to the different ligands and the coordination modes of the sulfonate groups which are influenced by the hydroxyl groups. The solid-state luminescent properties have also been investigated at room temperature.

’ INTRODUCTION Crystal engineering and coordination chemistry of silver(I)sulfonates have been an active research field1
5 owing to their potential applications in the area of intercalation chemistry, photochemistry, and porous materials and intriguing structural diversities that stem from the following reasons: (a) The sulfonate, RSO3
, bears a strong structural analogy to the phosphonate (RPO32
), and the
SO3 group can achieve multiple bridging modes as illustrated in Chart 1. Consequently, some chemists described the
SO3 group as a “ball of Velcro”.6 (b) Ag(I) ion is noted for its rather pliant coordination sphere due mainly to a d10 electronic configuration.7 Coordination numbers from two to eight have been reported (taking no account of the Ag 3 3 3 Ag interaction).8 Furthermore, along with its soft Lewis acidic properties, the Ag(I) ion is a particularly good match for the flexible coordinative tendencies of sulfonate anions. (c) Silver(I)-sulfonates often exhibit intercalation of guest molecules,4a fluorescent properties,4g and intriguing selective and reversible guest inclusion properties.4i However, even though sulfonates form more aggregated structures with Ag(I) ions, and some silver(I)-sulfonates with a zero-dimensional (0-D) separated structure,2 one-dimensional (1-D) columnar structure,3 r 2011 American Chemical Society

two-dimensional (2-D) layered structure,4 and three-dimensional (3-D) pillared layered5 frameworks have been reported, it is still a tempting challenge to design and synthesize silver(I)sulfonates with attractive structures and properties. Recently, research has indicated that the carbonyl group at the ortho-position of the
SO3 group in the 4(1H)-pyridone-3sulfonic acid can enrich the coordination modes of the
SO3 group and construct novel architectures.9 A CSD search (version 5.27 with 16 updates)10 reveals that only one report on mixedligand silver(I)-sulfonates containing ortho-hydroxy-5-nitro1,3-benzenedisulfonic acid and nitrogen-containing secondary ligands has been documented.11 Hence, in order to investigate the influence of the hydroxyl groups at the ortho-position on the coordination modes of the
SO3 group and the variations of the final architectures, we designed five new ortho-hydroxyl arenesulfonic acids and reported in this article the syntheses, structures, and luminescent properties of eight new complexes, Received: March 22, 2011 Revised: April 22, 2011 Published: May 12, 2011 3090

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Chart 1. Versatile Coordination Modes of
SO3 Group to Silver(I) Ion (A, B, C, D, E, and F Denote that
SO3 Group Acted as μ1, μ2, μ3, μ4, μ5, and μ6 Connector, Respectively)

namely, [Ag(NH3)2] 3 (HL1) (1), [Ag2(L1)]n (2), [Ag2(HL2)(H2O)3]n (3), [Ag(HL3)(MeCN)2]n (4), [Ag2(HL3)2]n (5), [Ag2(HL4)(H2O)3]n (6), {(NH4)2 3 [Ag(NH3)2]2} 3 2(H2L5) 3 5H2O (7), and [Ag(H2L5)0.5]n (8) (H2L1 = 2-hydroxyl-5methyl-benzenesulfonic acid; H3L2 = 2-hydroxyl-5-methyl-1,3benzenedisulfonic acid; H2L3 = 2-hydroxyl-5-bromo-benzenesulfonic acid; H3L4 = 2-hydroxyl-5-bromo-1,3-benzenedisulfonic acid; H4L5 = 2,4-dihydroxyl-1,5-benzenedisulfonic acid). Complex 1 exhibits rare right-handed helical 3-D supramolecular network, while complex 7 is novel host
guest supramolecular network. Complex 4 presents a 1-D ladder chain structure. Complexes 2 and 5 are both an “inorgano-organic” layer structure. Complexes 3, 6, and 8 are a 3-D pillared layered structure. The difference of the ligands and the coordination modes of the
SO3 group influenced by the hydroxyl groups plays a crucial role in the structural diversities and evolutions. Moreover, as illustrated in Chart 1, the coordination mode of the
SO3 group in complex 2 is reported for the first time in silver(I)-sulfonates (F2).

’ EXPERIMENTAL SECTION General Procedures. All chemicals and solvents were of A. R. grade and used without further purification in the syntheses. Elemental analyses were carried out with a Vario MICRO from Elementar Analysensysteme GmbH, and the infrared spectra (IR) were recorded from KBr pellets in the range of 4000
400 cm
1 on a Bruker Equinox 55 FT-IR spectrometer. Powder X-ray diffraction (PXRD) patterns were measured at 293 K on a Bruker D8 diffractometer (Cu KR, λ = 1.54059 Å). The TG analysis was carried out on a Perkin-Elmer TG/DTA 6300 thermal analyzer under flowing N2 atmosphere, with a heating rate of 10 °C/min. The ultraviolet visible (UV
vis) spectra were measured on a Perkin-Elmer Lambda 900 spectrophotometer in aqueous solution. Luminescence spectra were measured on a Perkin-Elmer LS 55 luminance meter. Syntheses of Ligands. p-Methylphenol, p-bromophenol, and resorcin were slowly added to different amounts of 20% oleum with stirring, respectively. The mixture was left to react 2 h at 80 °C and then cooled to room temperature. The white solids were separated and recrystallized from hot water. For H2L1: yield: 83%. Mp: 59
62 °C. Elemental analysis calcd (%) for C7H8O4S: C 44.67, H 4.28; found: C 44.54, H 4.35. For H3L2: yield: 77%. Mp: 131
133 °C. Elemental 3091

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Table 1. Crystal Data and Structure Refinement Parameters of Complexes 1
8 complex

1

2

3

4 C10H10N2O4SBrAg

empirical formula

C7H13N2O4SAg

C7H6O4SAg2

C7H12O10S2Ag2

Mr

329.12

401.92

536.03

442.04

crystal system

orthorhombic

monoclinic

triclinic

orthorhombic

space group

P212121

P21/c

P1

Pbam

a/Å

6.5596(13)

11.734(2)

7.6464(15)

8.3619(17)

b/Å

8.3265(17)

11.878(2)

8.5086(17)

27.428(6)

c/Å

19.842(4)

6.2110(12)

11.210(2)

6.3036(13)

R/o β/o

90.00 90.00

90.00 91.18(3)

105.37(3) 102.62(3)

90.00 90.00

γ/o

90.00

90.00

91.43(3)

90.00

V/Å3

1083.7(4)

865.5(3)

683.5(2)

1445.7(5)

Z

4

4

2

4

Dc/mg m
3

2.017

3.085

2.604

2.031

μ/mm
1

2.048

4.745

3.218

4.311

θ range

3.19
27.43

3.43
27.43

3.54
27.43

3.23
27.48

reflections collected unique reflections

10651 2476

7764 1968

6740 3084

13286 1806

no. of parameter

158

128

212

117

F(000)

656

760

520

856

R1, wR2 [I > 2σ(I)]

0.0236, 0.0510

0.0484, 0.1202

0.0410, 0.1013

0.0577, 0.1326

GOF on F2

1.024

1.050

1.110

1.066

largest and hole/e 3 A
3

0.528,
0.520

0.796,
0.790

1.901,
1.239

0.920,
0.869

Flack parameter

0.00(4)

complex

5

6

7

8

empirical formula

C12H8O8S2Br2Ag2

C6H9O10S2BrAg2

C12H38N6O21S4Ag2

Mr

719.86

600.90

946.46

C3H2O4SAg 241.98

crystal system

monoclinic

triclinic

monoclinic

monoclinic

space group

P21/c

P1

C2/c

C2/c

a/Å

15.549(3)

7.6110(15)

24.720(5)

8.4020(17)

b/Å

5.6544(11)

8.6653(17)

10.960(2)

7.0556(14)

c/Å

19.612(4)

11.137(2)

24.730(5)

17.699(4)

R/o β/o

90.00 94.58(3)

103.60(3) 104.98(3)

90.00 98.46(3)

90.00 102.85(3)

γ/o

90.00

92.47(3)

90.00

90.00

V/Å3

1718.8(6)

685.4(2)

6627(2)

1022.9(4)

Z

4

2

8

8

Dc/mg m
3

2.782

2.912

1.897

3.142

μ/mm
1

7.211

6.123

1.522

4.268

θ range

3.22 to 25.00

3.49 to 27.48

3.11 to 27.45

3.81 to 27.43

reflections collected unique reflections

20849 3026

6743 3113

31563 7555

4785 1155

no. of parameter

242

199

496

86

F(000)

1360

572

3824

920 0.0250, 0.0596

R1, wR2 [I > 2σ(I)]

0.0346, 0.0683

0.0374, 0.0915

0.0349, 0.0992

GOF on F2

1.098

1.095

1.079

1.094

largest and hole/e 3 A
3

1.251,
0.997

1.279,
1.762

1.390,
0.828

0.918,
0.498

Flack parameter

analysis calcd (%) for C7H8O7S2: C 31.34, H 3.01; found: C 31.50, H 3.08. For H2L3: yield: 79%. Mp: 71
74 °C. Elemental analysis calcd (%) for C6H5O4SBr: C 28.48, H 1.99; found: C 28.45, H 1.96. For H3L4: yield: 78%. Mp: 111
114 °C. Elemental analysis calcd (%) for C7H5O7S2Br: C 24.36, H 1.46; found: C 24.63, H 1.51. For H4L5: yield:

72%. Mp: 168
170 °C. Elemental analysis calcd (%) for C6H6O8S2: C 26.67, H 2.24; found: C 26.65, H 2.26. Synthesis of [Ag(NH3)2](HL1) (1). Silver nitrate and H2L1 were mixed in 15 mL aqueous solution with a mole ratio of 2:1, and then the pH value was adjusted to ca. 6 with proper amount of ammonia. The 3092

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Figure 1. (a) Molecular structure of 1 with the weakly silver(I)-π interaction denoted by a dashed line. (b) Right-handed helical chain formed by [Ag(NH3)2]þ cations and sufonate groups. (c) Tubular layer structure of 1. (d) 3-D supramolecular framework showing the formation of right-handed helical channels with the toluene moieties omitted for clarity. mixture stirred at room temperature for 5 min followed by filtration. Colorless crystals of 1 were isolated from the filtrate after avoiding illumination for several days. Yield: 51% (based on Ag). Anal. Calcd for C7H13N2O4SAg: C 25.55, H 3.98, N 8.51%; Found: C 25.48, H 3.92, N 8.56%. Main IR (cm
1): 3412s, 3198s, 3025w, 2936w, 1606m, 1523m, 1384s, 1221s, 1183s, 1093m, 1026m, 823m, 712m, 632m, 535m. Synthesis of [Ag2(L1)]n (2). The procedure was similar with that for 1 by changing the ratio into 3:2 and adjusting the pH value to ca. 8 with the proper amount of ammonia. Red crystals of 2 were obtained from the solution after avoiding illumination for several days. Yield: 59% (based on Ag). Anal. Calcd for C7H6O4SAg2: C 20.92, H 1.50%; Found: C 20.86, H 1.43%. Main IR (cm
1): 3031w, 2932w, 1608m, 1510s, 1419m, 1366m, 1293m, 1218s, 1181s, 1136m, 1091s, 1027s, 818s, 706s, 634s, 536m. Synthesis of [Ag2(HL2)(H2O)3]n (3). Solid Ag2CO3 was added to an aqueous solution containing an equal amount of H3L2. The suspension was stirred for half an hour at room temperature and then filtered. The resulting clear solution was allowed to evaporate slowly at room temperature avoiding illumination for two weeks, and colorless crystals of 3 suitable for X-ray diffraction were isolated. Yield: 70% (based on Ag). Anal. Calcd for C7H12O10S2Ag2: C 15.69, H 2.26%; Found: C 15.74, H 2.31%. Main IR (cm
1): 3431m, 3031w, 2926w, 1592m, 1471m, 1417m, 1243m, 1201s, 1120m, 1039s, 809s, 740m, 632s, 593m, 534m. Synthesis of [Ag(HL3)(MeCN)2]n (4). Silver nitrate and H2L3 were mixed in 10 mL of MeCN with a mole ratio of 3:4, and then the mixture was stirred at room temperature for 5 min. After filtration, colorless crystals of 4 were isolated from the filtrate after avoiding illumination for five days. Yield: 62% (based on Ag). Anal. Calcd for C10H10N2O4SBrAg: C 27.17, H 2.28, N 6.34%; Found: C 27.23, H 2.23, N 6.31%. Main IR (cm
1): 3328 m, 3039w, 2928w, 2253m, 1606m, 1533s, 1446m, 1398m, 1351m, 1247m, 1218s, 1159m, 1045s, 898m, 765m, 700m, 624s, 538m. Synthesis of [Ag2(HL3)2]n (5). The procedure was similar to that for 2 by changing the H2L1 into H2L3. Colorless crystals of 5 suitable for X-ray diffraction were isolated. Yield: 57% (based on Ag). Anal. Calcd

Figure 2. (a) Perspective view of the asymmetric unit of 2 showing the coordination environments around the silver centers and the bridging modes of the ligand. (b) Ball-and-stick representation of the Ag
O layer, showing the vertex and edge oxygen atoms (black: Ag1 chain; blue: Ag2 dimer). (c) Polyhedral representation of the Ag
O layer formed by Ag1 chains (red polyhedra) and Ag2 dimers (green polyhedra).

for C12H8O8S2Br2Ag2: C 20.02, H 1.12%; Found: C 19.97, H 1.18%. Main IR (cm
1): 3339m, 3049w, 1589m, 1482s, 1398s, 1347m, 1251m, 1218s, 1180s, 1143s, 1093s, 1020s, 828m, 727m, 622s, 563m, 528m. Synthesis of [Ag2(HL4)(H2O)3]n (6). The procedure was similar with that for 3 by changing the H3L2 into H3L4. Colorless crystals of 6 suitable for X-ray diffraction were isolated. Yield: 66% (based on Ag). Anal. Calcd for C6H9O10BrS2Ag2: C 11.99, H 1.51%; Found: C 11.95, H 1.57%. Main IR (cm
1): 3436m, 3042w, 1601s, 1496m, 1415s, 1367m, 1253m, 1222s, 1166s, 1059s, 1027s, 830m, 742m, 624s, 528m. 3093

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Figure 3. (a) Perspective view of the asymmetric unit of 3 showing the coordination environments around the silver centers and the bridging modes of the ligand. (b) 1-D chain containing alternant Ag2O2 and Ag4O4 rings along the a-axis. (c) Polyhedral representation of the Ag
S
O layer formed by sulfonate groups linking adjacent chains (red polyhedra: Ag1; green polyhedra: Ag2; blue and orange polydedra: sulfonate groups). (d) Illustration of the 3-D pillared layered structure.

Synthesis of {(NH4)2 3 [Ag(NH3)2]2} 3 2(H2L5) 3 5H2O (7). The procedure was similar with that for 1 by changing the H2L1 into H4L5. Colorless crystals of 7 suitable for X-ray diffraction were isolated. Yield: 57% (based on Ag). Anal. Calcd for C12H38N6O21S4Ag2: C 15.23, H 4.05, N 8.88%; Found: C 15.18, H 4.09, N 8.90%. Main IR (cm
1): 3441s, 3203s, 3031w, 1608s, 1569m, 1524s, 1422m, 1371s, 1287m, 1220s, 1186m, 1139s, 1088m, 1027s, 815m, 742m, 680m, 538m. Synthesis of [Ag(H2L5)0.5]n (8). The procedure was similar to that for 3 by changing the H3L2 into H4L5. Colorless crystals of 8 suitable for X-ray diffraction were isolated. Yield: 64% (based on Ag). Anal. Calcd for C3H2O4SAg: C 14.89, H 0.83%; Found: C 14.93, H 0.89%. Main IR (cm
1): 3310s, 1600s, 1504m, 1427s, 1376s, 1284s, 1216s, 1166s, 1122s, 1064s, 1027s, 829s, 748m, 658m, 548m. X-ray Crystallographic Measurements. Table 1 provides a summary of the crystal data, data collection, and refinement parameters for complexes 1
8. All diffraction data were collected at 295 K on a RIGAKU RAXIS-RAPID diffractometer with graphite monochromatized Mo-KR (λ = 0.71073 Å) radiation in ω scan mode. All structures were solved by direct method and difference Fourier syntheses. All non-hydrogen atoms were refined by full-matrix least-squares techniques on F2 with anisotropic thermal parameters. The hydrogen atoms attached to carbons were placed in calculated positions with C
H = 0.93 Å (aromatic H atoms), 0.96 Å (methyl H atoms), and U (H) = 1.2Ueq (C) in the riding model approximation. The hydrogen atoms of hydroxyl groups in complexes 1, 3
8, water molecules in complexes 3, 6, 7, and ammonia molecules in complexes 1 and 7 were located in difference Fourier maps and refined in the riding model approximation, with O
H and N
H distances restraint (0.82(1) or 0.85(1) Å) and U(H) = 1.5Ueq (O, N) except that two water molecules in complex 6 and two water molecules in complex 7 were fixed by WINGX. All calculations were carried out with the SHELXL97 program.12 The CCDC reference numbers are 818132
818139 for complexes 1
8. Selected bond distances for all complexes and selected hydrogen bond para-

meters for complexes 1 and 7 are presented in Tables S1 and S2, respectively (Supporting Information).

’ RESULTS AND DISCUSSION Structure of [Ag(NH3)2](HL1) (1). Single-crystal X-ray diffraction analysis reveals that complex 1 presents a 0-D discrete structure which crystallizes in the space group P212121. As illustrated in Figure 1a, the asymmetric unit of complex 1 consists of one [Ag(NH3)2]þ cation and one counteranion of HL1
. The Ag(I) ion displays a common linear geometry. The separation of 3.45 Å between silver(I) cation and phenyl ring of the HL1
is slightly beyond the reported range of Ag(I)-centroid distances of 2.89
3.37 Å and indicates the existence of weakly silver(I)
π interaction.13 Although the O atom is moderate in terms of its affinity toward the Ag(I) ion, in 1, the sulfonate and hydroxyl groups do not coordinate to Ag(I) and just are directed toward ammonia H atoms to form classic N
H 3 3 3 O hydrogen bonds which makes complex 1 an intriguing architecture. Adjacent [Ag(NH3)2]þ cations and sulfonate groups are linked into a right-handed helical chain parallel to the a-axis with a pitch of 6.6 Å through N
H 3 3 3 O hydrogen bonds (Figure 1b, Table S2, Supporting Information). Subsequently, such helical chains are interlinked by two other types of N
H 3 3 3 O hydrogen bonds into a tubular layer structure as shown in Figure 1c. Adjacent tubular layers are further packed into a 3-D supramolecular network through the residual N
H 3 3 3 O hydrogen bonds, which contains right-handed helical channels occupied by the toluene moieties (Figure 1d). Structure of 2-D Complexes [Ag2(L1)]n (2). In complex 2, there are two crystallographically independent Ag(I) ions and one L12
dianion in the asymmetric unit, and both of the two Ag(I) ions are five-coordinated with a distorted trigonal bipyramidal geometry 3094

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Figure 4. (a) Perspective view of the asymmetric unit of 4, showing the coordination environments around the silver center and the bridging mode of the ligand. (b) Illustration of the hydrogen-bonding double chain.

(Figure 2a). The Ag
C distance of 2.678(8) Å lies well within the limits from 2.337 to 3.069 Å observed in the reported silver(I)aromatic complexes14 and indicates the existence of a strong Ag
C interaction in a common η1 mode. Thus, the benzene moiety is best considered to involve the coordination sphere of the Ag1 ion. In turn, each L12
anion coordinates to eight Ag(I) ions, with the sulfonate group and deprotonated hydroxyl group adopting μ6 (k3O1, k2O2, k1O3) and μ3 bridging coordination modes. As we reported in our previous work,9 the O1 atom of the sulfonate group exhibits rare k3 coordination mode, whereas Shimizu has stated that the oxygen atoms of a sulfonate group will bridge a maximum to two metal ions more typically.6c Subsequently, adjacent Ag(I) ions are connected into a 2-D wavelike inorganic network substructure consisting of 1-D chains of vertex-sharing Ag1 trigonal bipyramidal linked through dimers of edge-sharing Ag2 trigonal bipyramidal by sharing two vertexes (O4) and two edges (O1 and O2) as illustrated in Figure 2b,c. The toluene moieties are protruded into the interlayer region in the direction of the a-axis (Figure S1, Supporting Information). The interlayer distance, defined as the perpendicular distance between planes of Ag(I) ions, is 11.73 Å, and the thickness of a single lamella, defined as the Ag
S
O layers, is 3.50 Å. Thus, the gallery height present in complex 2 is 8.23 Å, which is obviously shorter than that of silver p-toluenesulfonate (11.41 Å).4e The remarkable decrease of gallery height can be attribute to the

Figure 5. (a) Perspective view of the asymmetric unit of 5 showing the coordination environments around the silver centers and the bridging modes of the different ligands. (b) Ball-and-stick representation of the Ag
O layer, showing the edge oxygen atoms. (c) Polyhedral representation of the Ag
O layer formed by Ag1 (red polyhedra) and Ag2 (green polyhedra) chains.

coordination of the deprotonated hydroxyl groups and the formation of the Ag
C interactions which make the toluene moieties closer to the Ag
S
O layers. Structure of [Ag2(HL2)2(H2O)3]n (3). Decoration of H2L1 with another
SO3 group at the ortho-position of the hydroxyl group leads to the formation of the new ligand H3L2, and the reaction of Ag2CO3 with H3L2 gives rise to the 3-D pillared structure of complex 3. Figure 3a presents the asymmetric unit of complex 3 which contains two unique Ag(I) ions, one HL22
dianion, and three μ2-bridging water molecules. Ag1 displays a severely distorted square pyramidal geometry with the angles around the Ag(I) ion in the range of 71.11(2)
142.22(2)o, while Ag2 exhibits a slightly 3095

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Figure 6. (a) Perspective view of the asymmetric unit of 6 showing the coordination environments around the silver centers and the bridging mode of the ligand. (b) Illustration of the 3-D pillared layered structure.

distorted octahedron geometry with a weak Ag
O contact of 2.998(3) Å. Different from the deprotonated hydroxyl group in complex 2, the hydroxyl group in the present complex still remains the H atom and acts in monodentate mode. The two sulfonate groups adopt the same μ2 (k1O: k1O) bridging mode. In comparison with complex 2, the 2-D inorganic substructures in complex 3 present unique features. As shown in Figure 3b, two Ag(I) ions are bridged by two symmetry-related water molecules and form binuclear units, which are further joined by a pair of other Ag(I) “glue” to generate a 1-D Ag
O chain containing alternant Ag2O2 and Ag4O4 rings along the a-axis. One of the two sulfonate groups caps the two sides of the above-mentioned Ag4O4 rings, whereas the other sulfonate group links adjacent chains into a 2-D Ag
S
O layer by sharing two vertexes (Figure 3c). The toluene moieties in complex 3 bearing two sulfonate groups from different layers bridge the layers into a 3-D pillared layered framework as shown in Figure 3d. The gallery height of 6.24 Å (interlayer distance, 10.51 Å, the thickness of a single lamella, 4.27 Å) is obviously shorter

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than that of complex 2, owing to the coordination of the HL22
dianions to the Ag(I) ions in the adjacent layers. Structure of [Ag(HL3)(MeCN)2]n (4). As illustrated in Figure 4a, the asymmetric unit of complex 4 contains one Ag(I) ion, one HL3
monoanion, and two coordinated MeCN molecules. The Ag(I) ion is a distorted tetrahedral geometry. The sulfonate group is deprotonated and bridges adjacent Ag(I) ions in bis-monodentate mode to generate a 1-D chain with a Ag 3 3 3 Ag distance of 6.304 Å (Figure 4b). Additionally, the uncoordinated hydroxyl groups form hydrogen bonds with the uncoordinated O2 atom of sulfonate groups and generate a hydrogen-bonding ladder chain incorporating a R22(4) ring (Figure 4b). The shortest Ag 3 3 Ag separation between the single chain is 7.478 Å. Structure of [Ag2(HL3)2]n (5). The asymmetric unit comprises of two Ag(I) ions and two HL3
monoanions (Figure 5a). The coordination sphere about Ag1 is a distorted trigonal bipyramidal geometry, while Ag2 has a distorted trigonal prism. Different from complex 2, both the H atoms are not removed in the two hydroxyl groups which exhibit diverse coordination behavior with O1 bridging two Ag(I) ions and O5 being free. The two sulfonate groups also show a completely distinct coordination mode of μ5 (k2O2, kO3, k2O4) and μ4 (k2O6, k2O7) in comparison with complex 2. Such complicated coordination modes of the HL3
monoanion bridge adjacent Ag(I) ions into the 2-D infinite inorganic network substructure as illustrated in Figure 5b,c, which consists of chains of vertex-sharing Ag1 polyhedra and edge-sharing Ag2 polyhedra interlinked by sharing edges (O4 and O6 from HL3
). The Ag 3 3 3 Ag distance of 3.122 Å in Ag1 chains indicates the argentophilic interaction, while the Ag 3 3 3 Ag distance of 3.825 Å in Ag2 chains is significantly longer than the summed van der Waals radii of two silver atoms (3.44 Å).15 The bromophenyl moieties from the sulfonates are protruded into the interlayer region in the direction of the a-axis (Figure S2, Supporting Information). The difference of 11.37 Å between the interlayer distance (15.50 Å) and the thickness of a single lamella (4.13 Å) constitutes the gallery height, which is very close to that of the aforementioned silver p-toluenesulfonate but obviously longer than that of complex 2. Such differences reconfirm that the formation of the Ag
C interactions can remarkably influence the gallery height of classic “inorgano-organic” layer structures. Structure of [Ag2(HL4)(H2O)3]n (6). Decoration of H2L3 with another
SO3 group at the ortho-position of the hydroxyl group leads to the formation of the new ligand of H3L4 which reacts with Ag2CO3 to generate a similar 3-D pillared structure of complex 6. As observed in complex 3, the asymmetric unit of complex 6 in Figure 6a contains two unique Ag(I) ions, one HL42
dianion, and three μ2-bridging water molecules. The hydroxyl group does not remove the H atom and acts in monodentate mode, and the two sulfonate groups adopt the same μ2 (k1O: k1O) bridging mode as detected in complex 3. However, different from complex 3, both the two Ag(I) ions exist in distorted octahedron geometry, in which one of them is coordinated by an additional Br atom with the Ag
Br distance being 2.9499(13) Å. The gallery height of 5.93 Å in complex 6 (interlayer distance, 10.40 Å, the thickness of a single lamella, 4.47 Å) is somewhat shorter than that of complex 3 owing to the formation of Ag
Br bonds (Figure 6b). Moreover, such a value is obviously shorter than that of complex 5, owing to the coordination of the HL42
dianions to the Ag(I) ions in the adjacent layers. Structure of {(NH4)2 3 [Ag(NH3)2]2} 3 2(H2L5) 3 5(H2O) (7). As illustrated in Figure 7a, the asymmetric unit of complex 7 consists of two [Ag(NH3)2]þ cations, two ammonium cations, two 3096

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Figure 7. (a) Molecular structure of 7 with the hydrogen-bonding interactions denoted by dash lines. (b) 1-D Hydrogen-bonding tape formed by sulfonate groups and water molecules incorporating two types ring. (c) Single ring B decorated by two additional symmetrical arms and two ammonium cations. (d) Schematic representation of the 2-D hydrogen-bonding layer involving N5 ammonium cations. Sulfonate groups and water molecules are denoted as yellow and red balls for clarity. (e) 3-D Host
guest supramolecular network with the [Ag(NH3)2]þ cations encapsulated in the channels.

counter-anions of H2L52-, and five water molecules. The two hydroxyl groups in both the two counter-anions remain the H atoms. Owing to the existence of extensive hydrogen-bonding donors and acceptors, complex 7 exhibits an intricate 3-D supramolecular network, which can be understood in the following manner. First, the sulfonate groups form hydrogen bonds with water molecules and generate 1-D hydrogen-bonding tape incorporating two types rings (Figure 7b). Ring A, R88(24), is constructed from two pairs of sulfonate groups and two pairs of water molecules while ring B, R10 12(32), is constructed from three pairs of sulfonate groups and three pairs of water molecules. It should be noted that ring B is decorated by two additional symmetrical arms formed by a sulfonate group involving S1 and O3w which are further fixed by two ammonium cations involving N6 atom in tetrapod donors mode (Figure 7c). Subsequently, the other ammonium cation involving N5 atom also acts as

tetrapod donors and bridges the aforementioned tape into a 2-D hydrogen-bonding layer in the ab plane (Figure 7d). Finally, the ammonia molecules (N3 and N4) of the Ag2 containing [Ag(NH3)2]þ cations form hydrogen bonds with adjacent 2-D layer, thus giving rise to the 3-D host
guest supramolecular network with the [Ag(NH3)2]þ cations encapsulated in the channels (Figure 7e). Structure of [Ag(H2L5)0.5]n (8). X-ray structural analysis reveals that complex 8 also exhibits a 3-D pillared layered framework. The asymmetric unit contains one Ag(I) ion and one H2L52
dianion which locate on a 2-fold axis (Figure 8a). Ag1 is coordinated by six O atoms from four different H2L52
dianions. As observed in complexes 3 and 6, the two hydroxyl groups of the H2L52
dianion retain the H atoms but act in bidentate mode to bridge adjacent Ag(I) ions, giving rise to a four-membered ring, Ag2O2, in which the distance between Agii and Agv of 3.308 Å indicates the existence of 3097

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Figure 8. (a) Perspective view of the asymmetric unit of 8 showing the coordination environments around the silver center and the bridging mode of the ligand. (b) 2-D Ag
O layer with a [Ag6] core denoted as green balls. (c) Illustration of the 3-D pillared layered structure.

weak Ag 3 3 3 Ag interactions (Figure 8b). The two sulfonate groups adopt the same μ4 (k2O1, k2O3) bridging mode and also bridge adjacent Ag(I) ions to generate two four-membered Ag2O2 rings as shown in Figure 6b. The Ag 3 3 3 Ag distance of 3.530 (Ag1 3 3 3 Agii) and 3.753 Å (Ag1iii 3 3 3 Agv) are longer than the summed van der Waals radii of two silver atoms (3.44 Å), which proves that no argentophilic interactions exist in these Ag2O2 rings. It should be noted that a pair of the aforementioned three types Ag2O2 rings links together to form a [Ag6] core. A repetition of the [Ag6] core in

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the ab plane results in the formation of the 2-D inorganic layer structure. Figure 8c exhibits the 3-D pillared layered framework of complex 8, in which the phenyl rings act as the pillars. The gallery height of 4.93 Å (interlayer distance, 8.63 Å, the thickness of a single lamella, 3.70 Å) is shorter than that of complexes 3 and 6, which is probably caused by the coordination of the additional hydroxyl groups to the Ag(I) ions and subsequently shortens the distance between the adjacent layers. The Influencing Factor of the Structural Evolutions. It can be concluded from the aforementioned structural descriptions that the evolution of the structures are influenced by the synthetic methods, different ligands, and coordination modes of the sulfonate group induced by the hydroxyl groups. During the synthesis process with AgNO3 and monosulfonate ligand, when the pH value was adjusted to ca. 6, two 0-D structures of 1 and 7 were obtained, in which the two ligands of HL1
and H2L52
exist as counteranions. Moreover, the introduction of the alkalescent MeCN solvent leads to a 1-D chain structure of 4 owing to the terminal coordination of MeCN molecules. As the pH value increases to 8, two 2-D layer structures of 2 and 5 were obtained. After the metal salt was changed to Ag2CO3, three 3-D networks of 3, 6, and 8 with disulfonate ligands were obtained. In a more elaborate analysis, the form (deprotonated or not) and behavior of the ortho-hydroxyl groups directly affect the coordination modes of the sulfonate group, which subsequently generate different networks. The hydroxyl group, when remains the H atom, exhibits three states, namely, uncoordinated (complexes 1, 4, 5, and 7), monodentate (complexes 3 and 6), and μ2-bridging (complexes 5 and 8) modes, whereas the deprotonated hydroxyl group exhibits rare μ3-bridging mode (complex 2) as observed in our previous work.9 Accordingly, the sulfonate groups exhibit increasingly coordination modes with the changes of hydroxyl groups. In complexes 1, 4, and 7, the sulfonate groups exhibit uncoordinated and simple μ2 (k1O: k1O) mode, respectively, which lead to the formation of 0-D and 1-D complexes. In complexes 3 and 6, the sulfonate groups exhibit μ2 (k1O: k1O) mode, which lead to the formation of 3-D frameworks. However, if only one sulfonate group involved, the dimensionality of the two complexes will decrease to 1-D. The μ2-bridging modes of hydroxyl groups in complexes 5 and 8 make the sulfonate groups exhibit the μ5 (k2O: k2O: kO) and μ4 (k2O: k2O) fashions, thus giving rise to 2-D layer structures by considering only one sulfonate group of complex 8. Actually, complex 5 contains another ligand with an uncoordinated hydroxyl group and μ4 (k2O: k2O) sulfonate group. Without considering it, adjacent Ag(I) ions only prolongated into a 1-D chain structure. Deprotonated and μ3bridging hydroxyl group in complex 2 generates a 2-D layer structure with the novel μ6 (k3O: k2O: k1O) fashion which is reported for the first time in silver(I)-sulfonates as shown in Chart 1 (F2). On the basis of the above description and our previous results, the deprotonated hydroxyl group can form a novel μ3-bridging mode and result in complicated coordination modes of the sulfonate group. Thus, it can be foreseen that removing the H atom of hydroxyl group and increasing the number of sulfonate groups can create a large tendency to form high dimensionalities, which, in turn, affects the topological structure of the framework. Luminescent Property. Complexes with d10 metal centers and organic ligands are promising candidates for photoluminescent materials.16 The luminescent properties of complexes 1
8 and five free ligands in the solid state at room temperature were investigated. 3098

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emission is probably attributed to the π*
π transitions. Under a similar excitation, no clear emissions for complexes 7 and 8 were detected, which can be attributed to the heavy atom effect of the Ag atom.9,18 Heavy atoms, such as Ag and Br atom here, in the fluorophore or in close contact to it increase the rate of intersystem crossing (ISC) by strengthening spin
orbit coupling.21 Thus, the decrease of fluorescence yield (radiative transition S1 f S0) is in most cases explained by an increase in the probability of the competing S1 f Tn radiationless transition of the fluorophore. However, the heavy atom effect is not always dominant in silver(I) complexes. Some luminescent silver(I) complexes have been reported as the present complexes 2 and 3,15b owing to the intricate influence factor of luminescence.

Figure 9. (a) Emission spectra of complex 2 and ligand H2L1 in the solid state at room temperature. (b) Emission spectra of complex 3 and ligand H3L2 in the solid state at room temperature.

As shown in Figure 9a, upon excitation at 243 nm, free ligand H2L1 exhibits an emission maximum at 324 nm which is probably attributed to the π*
π transitions. In contrast to the emission of the free ligand H2L1, the strong purple fluorescent emission band at 373 nm for complex 2 (ex = 323 nm) can probably be assigned to the intraligand (IL) π
π* transitions because of the resemblance of the emission spectra in comparison with free ligands.17 However, under a similar excitation, no obvious emissions for complex 1 were detected, which can be attributed to the weak silver(I)-π interaction originating from the heavy atom effect of the Ag atom.9,18 Figure 9b presents the emission spectra of free ligand H3L2 and complex 3. Upon excitation at 243 nm, free ligand H3L2 exhibits an emission maximum at 370 nm which is also probably attributed to the π*
π transitions. By contrast, the strong purple fluorescent emission band at 383 nm for complex 3 (ex = 325 nm) can probably be assigned to the intraligand (IL) π
π* transitions because of the resemblance of the emission spectra in comparison with free ligands.17 The shifts of the emission peaks in complexes 2 and 3 are probably attributable to the differences of ligands and the coordination environment around Ag(I) ions.19 Unfortunately, no obvious emissions for free ligands H2L3, H3L4, and complexes 4
6 were detected, which can be attributed to the heavy atom quenching effect of bromide.20 The emission spectrum of free ligand H4L5 was illustrated in Figure S3, Supporting Information, in which free ligand H4L5 exhibits emission maximum at 313 nm upon excitation at 260 nm. The

’ CONCLUSIONS In summary, self-assembly of five ortho-hydroxyl benzenesulfonic acids and silver(I) salts leads to the formation of a series of complexes, which exhibit structure diversities and evolutions of 0-D discrete motif, 1-D linear chain, 2-D “inorgano-organic” layers, and 3-D pillared layered networks. The structural diversities and evolutions can be attributed to the different ligands and the coordination modes of the sulfonate groups which are influenced by the hydroxyl groups. Moreover, complexes 2 and 3 exhibit strong purple-light emissions at room temperature. This study clearly demonstrates that the introduction of the hydroxyl group at the ortho-position of
SO3 group can enrich the coordination modes of the
SO3 group and modulate the final topological structures of silver(I)-sulfonates. Further syntheses, structures, and properties studies of the silver(I)-sulfonates with other ortho-hydroxyl arenesulfonic acids are also underway in our laboratory. ’ ASSOCIATED CONTENT

bS Supporting Information. Additional figures, PXRD patterns, TG curves, UV
vis spectra, selected bond distances for all complexes, selected hydrogen bond parameters for complexes 1 and 7, and the X-ray crystallographic files in CIF format. This material is available free of charge via the Internet at http://pubs. acs.org. ’ AUTHOR INFORMATION Corresponding Author

*E-mail: [email protected] (S.G.). E-mail: zhuzhibiao@ hlju.edu.cn (Z.B.Z.).

’ ACKNOWLEDGMENT This work is financial supported by the Key Project of Natural Science Foundation of Heilongjiang Province (No. ZD200903), Key Project of Education bureau of Heilongjiang Province (No. 12511z023, No. 2011CJHB006), the Innovation team of Education bureau of Heilongjiang Province (No. 2010td03) and Program for New Century Excellent Talents in University (NCET-06-0349). We thank the University of Heilongjiang (Hdtd2010-04, yjscx2010-015hlju) for supporting this study. ’ REFERENCES (1) (a) Smith, G.; Thomasson, J. H.; White, J. M. Aust. J. Chem. 1999, 52, 317. (b) Shimizu, G. K. H.; Enright, G. D.; Ratcliffe, C. I.; 3099

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Crystal Growth & Design Ripmeester, J. A. Chem. Commun. 1999, 461. (c) Melcer, N. J.; Enright, G. D.; Ripmeester, J. A.; Shimizu, G. K. H. Inorg. Chem. 2001, 40, 4641. (d) Sun, D. F.; Cao, R.; Sun, Y. Q.; Bi, W. H.; Li, X.; Hong, M. C.; Zhao, Y. J. Eur. J. Inorg. Chem. 2003, 38. (e) Smith, G.; Cloutt, B. A.; Lynch, D. E.; Byriel, K. A.; Kennard, C. H. L. Inorg. Chem. 1998, 37, 3236. (f) Li, F. F.; Ma, J. F.; Song, S. Y.; Yang, J.; Liu, Y. Y.; Su, Z. M. Inorg. Chem. 2005, 44, 9374. (g) Jia, H. Q.; Hu, N. H. Cryst. Growth Des. 2006, 6, 209. (h) Liu, H. Y.; Wu, H.; Ma, J. F.; Song, S. Y.; Yang, J.; Liu, Y. Y.; Su, Z. M. Inorg. Chem. 2007, 46, 7299. (i) Lian, Z. X.; Cai, J. W.; Chen, C. H.; Luo, H. B. CrystEngComm 2007, 9, 319. (2) (a) Wulfsberg, G.; Parks, K. D.; Rutherford, R.; Jackson, D. J.; Jones, F. E.; Derrick, D.; Ilsley, W.; Strauss, S. H.; Miller, S. M.; Anderson, O. P.; Babushkina, T. A.; Gushchin, S. I.; Kravchenko, E. A.; Morgunov, V. G. Inorg. Chem. 2002, 41, 2032. (b) Downer, S. M.; Squattrito, P. J.; Bestaoui., N.; Clearfield, A. J. Chem. Cryst. 2006, 36, 487. (c) Wu, H.; Dong, X. W.; Ma, J. F. Acta Crystallogr. 2006, E62, m385. (d) Liu, H. Y.; Wu, H.; Ma, J. F. Acta Crystallogr. 2006, E62, m1036. (3) (a) Shimizu, G. K. H.; Enright, G. D.; Rego, G. S.; Ripmeester, J. A. Can. J. Chem. 1999, 77, 313. (b) Purdy, A. P.; Gilardi, R.; Luther, J.; Butcher, R. J. Polyhedron 2007, 26, 3930. (4) (a) Cote, A. P.; Ferguson, M. J.; Khan, K. A.; Enright, G. D.; Kulynych, A. D.; Dalrymple, S. A.; Shimizu, G. K. H. Inorg. Chem. 2002, 41, 287. (b) Gao, S.; Zhu, Z. B.; Huo, L. H.; Ng, S. W. Acta Crystallogr. 2005, E61, m279. (c) Gao, S.; Lu, Z. Z.; Huo, L. H.; Zhu, Z. B.; Zhao, H. Acta Crystallogr. 2005, C61, m22. (d) Shimizu, G. K. H.; Enright, G. D.; Preston, K. F.; Ratcliffe, C. I.; Reid, J. L.; Ripmeester, J. A. Chem. Commun. 1999, 1485. (e) Shimizu, G. K. H.; Enright, G. D.; Ratcliffe, C. I.; Rego, G. S.; Reid, J. L.; Ripmeester, J. A. Chem. Mater. 1998, 10, 3282. (f) Akhbari, K.; Morsali, A.; Rafiei, S.; Matthias, Z. J. Organomet. Chem. 2008, 693, 257. (g) Ma, J. F.; Yang, J.; Li, S. L.; Song, S. Y.; Zhang, H. J.; Wang, H. S.; Yang, K. Y. Cryst. Growth Des. 2005, 5, 807. (h) Cote, A. P.; Shimizu, G. K. H. Inorg. Chem. 2004, 43, 6663. (i) May, L. J.; Shimizu, G. K. H. Chem. Mater. 2005, 17, 217. (5) (a) Gao, S.; Zhu, Z. B.; Huo, L. H.; Ng, S. W. Acta Crystallogr. 2005, E61, m282. (b) Li, Q.; Liu, X.; Fu, M. L.; Guo, G. C.; Huang, J. S. Inorg. Chem. Acta. 2006, 359, 2147. (c) Sun, D. F.; Cao, R.; Liang, Y. C.; Hong, M. C. Chem. Lett. 2002, 198. (d) Hoffart, D. J.; Dalrymple, S. A.; Shimizu, G. K. H. Inorg. Chem. 2005, 44, 8868. (6) (a) Cote, A. P.; Shimizu, G. K. H. Chem.—Eur. J. 2003, 9, 5361. (b) Makinen, S. K.; Melcer, N. J.; Parvez, M.; Shimizu, G. K. H. Chem.— Eur. J. 2001, 7, 5176. (c) Cote, A. P.; Shimizu, G. K. H. Coord. Chem. Rev. 2003, 245, 49. (7) (a) Venkataraman, D.; Du, Y.; Wilson, S. R.; Zhang, P.; Hirsch, K.; Moore, J. S. J. Chem. Educ. 1997, 74, 915. (b) Khlobystov, A. N.; Blake, A. J.; Champness, N. R.; Lemenovskii, D. A.; Majouga, A. G.; Zyk, N. V.; Schr€oder, M. Coord. Chem. Rev. 2001, 222, 155. (c) Zheng, S. L.; Tong, M. L.; Chen, X. M. Coord. Chem. Rev. 2003, 246, 185. (d) Chen, C. L.; Kang, B. S.; Su, C. Y. Aust. J. Chem. 2006, 59, 3. (e) Steel, P. T.; Fitchett, C. M. Coord. Chem. Rev. 2008, 252, 990. (8) Young, A. G.; Hanton, L. R. Coord. Chem. Rev. 2008, 252, 1346. (9) (a) Deng, Z. P.; Zhu, Z. B.; Gao, S.; Huo, L.-H.; Zhao, H. Dalton Trans. 2009, 1290. (b) Deng, Z. P.; Zhu, Z. B.; Gao, S.; Huo, L.-H.; Zhao, H.; Ng, S. W. Dalton Trans. 2009, 6552. (10) Cambridge Structure Database search, CSD Version 5.27 (November 2005) with 16 updates (January 2006
Feb 2011). (11) Wu, H.; Dong, X.-W.; Ma, J.-F.; Liu, H.-Y.; Yang, J.; Bai, H.-Y. Dalton Trans. 2009, 3162. (12) Sheldrick, G. M. SHELXTL-97, Program for Crystal Structure Solution and Refinement; University of Gottingen: Germany, 1997. (13) Mascal, M.; Kerdelhue, J. L.; Blake, A. J.; Cooke, P. A.; Mortimer, R. J.; Teat, S. J. Eur. J. Inorg. Chem. 2000, 485. (14) (a) Munakata, M.; Wu, L. P.; Kuroda-Sowa, T.; Maekawa, M.; Suenaga, Y.; Sugimoto, K. Inorg. Chem. 1997, 36, 4903. (b) Munakata, M.; Wu, L. P.; Kuroda-Sowa, T.; Maekawa, M.; Suenaga, Y.; Ning, G. L.; Kojima, T. J. Am. Chem. Soc. 1998, 120, 8610. (c) Ning, G. L.; Wu, L. P.; Sugimoto, K.; Munakata, M.; Kuroda-Sowa, T.; Maekawa, M. J. Chem. Soc., Dalton Trans. 1999, 2529. (d) Zang, S.-Q.; Han, J.; Mak, T. C. W. Organometallics 2009, 28, 2677.

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(15) (a) Bondi, A. J. J. Phys. Chem. 1964, 68, 441. (b) Deng, Z.-P.; Huo, L.-H.; Zhu, L.-N.; Zhao, H.; Gao, S. Polyhedron 2010, 29, 3207. (16) (a) Wu, Q.; Esteghamatian, M.; Hu, N.-X.; Popovic, Z.; Enright, G.; Tao, Y.; D’Iorio, M.; Wang, S. Chem. Mater. 2000, 12, 79. (b) McGarrah, J. E.; Kim, Y.-J.; Hissler, M.; Eisenberg, R. Inorg. Chem. 2001, 40, 4510. (c) Santis, G. D.; Fabbrizzi, L.; Licchelli, M.; Poggi, A.; Taglietti, A. Angew. Chem., Int. Ed. 1996, 35, 202. (17) (a) Alcock, N. W.; Barker, P. R.; Haider, J. M.; Hannon, M. J.; Painting, C. L.; Pikramenon, Z.; Plummer, E. A.; Rissanen, K.; Saarenketo, P. J. Chem. Soc., Dalton Trans. 2000, 1447. (b) Collin, J. P.; Dixon, I. M.; Sauvage, J. P.; Williams, J. A. G.; Barigelletti, F.; Flamigni, L. J. Am. Chem. Soc. 1999, 121, 5009. (c) Xiong, R. G.; Zuo, J. L.; You, X. Z.; Fun, H. K.; Raj, S. S. S. Organometallics 2000, 19, 4183. (18) (a) Aragoni, M. C.; Arca, M.; Demartin, F.; Devillanova, F. A.; Isaia, F.; Garau, A.; Lippolis, V.; Jalali, F.; Papke, U.; Shamsipur, M.; Tei, L.; Yari, A.; Verani, G. Inorg. Chem. 2002, 41, 6623. (b) Seward, C.; Chan, J.; Song, D.; Wang, S. N. Inorg. Chem. 2003, 42, 1112. (19) Valeur, B. Molecular Fluorescence: Principles and Applications; Wiley-VCH: Weinheim, 2002. (20) Geddes, C. D.; Apperson, K.; Karolin, J.; Birch, D. J. S. Anal. Biochem. 2001, 293, 60. (21) (a) McClure, D. S. J. Chem. Phys. 1949, 17, 905. (b) Kasha, M. J. Chem. Phys. 1952, 20, 71.

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