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Acta Cryst. (2007). E63, m2078    [ doi:10.1107/S1600536807032126 ]

(N,N'-Diethyldithiocarbamato-[kappa]2S,S')bis[2-(2-pyridyl)phenyl-[kappa]2C1,N]iridium(III)

L.-Q. Chen

Abstract top

In the title compound, [Ir(C11H8N)2(C5H10NS2)], the Ir center has a distorted octahedral environment. The N donors of the two chelating 2-(2-pyridyl)phenyl ligands are in trans positions with respect to each other and the two C atoms are in a cis configuration. The packing is partially facilitated by C-H...[pi] interactions between aromatic rings in neighboring molecules, connecting the molecules into infinite chains along the c axis of the unit cell. These chains are in turn connected by C-H...[pi] interactions between neighboring chains. A crystallographic twofold rotation axis passes through Ir and C,N of the dithiocarbamate ligand.

Comment top

Organic light-emitting diodes (OLEDs) have been actively investigated due to their potential applications in flat panel displays and light-emitting devices. Most recently, heavy metal complexes in OLEDs have attracted much attention as efficient phosphors because they can harvest both singlet and triplet excited states, and thus the OLEDs internal efficiency can theoretically reach 100% (Lamansky et al., 2001). Especially iridium (III) complexes with cyclometalated ligands show intense phosphorescence at room temperature and this behavior makes them very promising phosphor dyes in OLEDs (Baldo et al., 1998 & Lamansky et al., 2001). Also, metal complexes containing dithiolate ligands have been extensively studied. However, only relatively few iridium (III) dithiolate complexes have been described. The title compound, which emits green luminescence in both solid state and organic solution upon irradiation by UV-light at ambient temperature, may plays a very important role as a potential electrophosphorescent material.

In the crystal structure of the title molecule, the Ir center resides in a distorted octahedral environment. The nitrogen donors of the the two chelating 2-phenylpyridinato ligands are in trans posistion to each other, the two carbon atoms are in a cis configuration (Scheme 1). As expected, the Ir—C bonds (2.015 (4) Å) are shorter than the Ir—N bond distances (2.045 (4) Å). These values are very similar to those in similar complexes such as (ppy)2Ir(acac) (ppy: 2-phenylpyridine; acac: actylacetone)(Ir—C: 2.020 (2) Å; Ir—N: 2.090 (10) Å) (Garces et al., 1993). The similarity of the S—C bond lengths in the N,N'-diethyldithiocarbamate (Et2dtc) ligand indicates that the charge is delocalized over both sulfur atoms. The Et2dtc chelate angle (S1—Ir1—S1a) is 71.12 (5)°, and the phenyl and metalated pyridine rings in the same ppy ligand are coplanar (the dihedral angle between the two planes is 0.3 (1)°). Selected important bond distances and angles are given in the selected geomtetric parameters table.

The packing of compound (I) is partially facilitated by C—H···π interactions between aromatic rings in neighboring molecules, the two most prominent such interactions are given in the hydrogen bonding table (Cg1 represents the centroid of ring C6/C7/C8/C9/C10/C11, Cg2 that of N1/C1/C2/C3/C4/C5). The first of these interactions, which acts in centrosymmetric pairs between each two molecules, connects the molecules to infinite chains along the c axis of the unit cell. The second slightly weaker type of C—H···π interaction connects these chains with each other (Figures 2 and 3).

Related literature top

For related literature, see: Baldo et al. (1998); Garces et al. (1993); Lamansky et al. (2001); Watts et al. (1984).

Experimental top

Iridium trichloride hydrate and 2-phenylpyridine were purchased and used without further purification. The synthesis of the target product involves two steps. First, iridium trichloride hydrate (0.352 g, 1.0 mmol) was combined with 2.5 equiv of the cyclometalating ligand, 2-phenylpyridine (0.385 g, 2.5 mmol), was dissolved in a mixture of 2-ethoxyethanol (30 ml) and water (10 ml), and then refluxed for 24 h. The solution was cooled to room temperature, and the yellow precipitate was collected on a glass filter frit. After drying, the crude product was directly used for the next step without further purification (Watts et al., 1984). In the second step, the product (0.075 mmol), sodium N,N'-diethyldithio-carbamate (NaEt2dtc) (0.25 mmol) and anhydrous sodium carbonate (Na2CO3, 1.0 mmol) were dissolved in 2-ethoxyethanol (10 ml). The mixture was refluxed under argon for 18 h. After cooling to room temperature, a small quantity of water was added. The resulting red precipitate was collected by filtration, washed with water, ethanol and hexane, and dried in vacuum. The crude product was purified by column chromatography on silica gel with CH2Cl2/petroleum ether (1:3) as the eluent. The residue was dried under vacuum and recrystallized from dichloromethane/hexane (1:1, v/v). Yield: 0.215 g (65.2%), 1H NMR (CDCl3, 300 MHz, p.p.m.) 1.20–1.25 (t, J = 7.5 Hz, 6H), 3.46–3.53 (m, 2H), 3.73–3.80 (m, 2H), 6.28 (d, J = 7.8 Hz, 2H), 6.60 (dd, J = 7.2 Hz, 2H), 6.76 (dd, J = 8.1 Hz, 2H), 7.14–7.21 (m, 2H), 7.50 (d, J = 8.4 Hz, 2H) 7.66 (dd, J = 6.9 Hz, 2H) 7.81 (d, J = 7.2 Hz, 2H) 9.57 (d, J = 8.7 Hz, 2H). Calcd for C27H26N3S2Ir: C, 49.98; H, 4.04; N, 6.48%, Found: C, 50.23; H, 4.10; N, 6.21%. MS (FAB): m/e, 649 (M+).

Refinement top

All H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C—H distances in the range 0.93–0.98 Å, and with Uiso(H) = 1.2U eq for aryl H atoms and 1.5Ueq for the methyl H atoms. Methyl H atoms were allowed to rotate to best fit the experimental electron density.

Computing details top

Data collection: SMART (Siemens, 1996); cell refinement: SMART; data reduction: SAINT (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. The structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level (-x, y, 0.5 - z).
[Figure 2] Fig. 2. Packing Diagram of (I), view down the b axis showing the infinite chains created by the C—H···π interactions between C4—H4 and the ring C6/C7/C8/C9/C10/C11.
[Figure 3] Fig. 3. Packing Diagram of (I), view down the c axis along the infinite chains shown in Figure 2. Red dashed lines: C—H···π interactions of C4—H4 to ring C6/C7/C8/C9/C10/C11 forming the infinite chains. Blue: C8—H8 to ring N1/C1/C2/C3/C4/C5 connecting these chains.
(N,N'-Diethyldithiocarbamato-κ2S,S')bis[2-(2-pyridyl)phenyl- κ2C1,N]iridium(III) top
Crystal data top
[Ir(C11H8N)2(C5H10NS2)]F(000) = 1272
Mr = 648.83Dx = 1.718 Mg m−3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 2854 reflections
a = 16.401 (3) Åθ = 4–27.5°
b = 11.436 (2) ŵ = 5.51 mm−1
c = 13.540 (3) ÅT = 293 K
β = 99.00 (3)°Block, red
V = 2508.2 (9) Å30.10 × 0.10 × 0.10 mm
Z = 4
Data collection top
Siemens SMART CCD area-detector
diffractometer		2852 independent reflections
Radiation source: fine-focus sealed tube2597 reflections with I > 2σ(I)
graphiteRint = 0.0000
φ and ω scansθmax = 27.4°, θmin = 2.2°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		h = 0→21
Tmin = 0.576, Tmax = 0.582k = 0→14
2852 measured reflectionsl = −17→17
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.023H-atom parameters constrained
wR(F2) = 0.071 w = 1/[σ2(Fo2) + (0.0376P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.15(Δ/σ)max = 0.001
2852 reflectionsΔρmax = 0.87 e Å−3
153 parametersΔρmin = −1.12 e Å−3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997a), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0046 (2)
Crystal data top
[Ir(C11H8N)2(C5H10NS2)]V = 2508.2 (9) Å3
Mr = 648.83Z = 4
Monoclinic, C2/cMo Kα radiation
a = 16.401 (3) ŵ = 5.51 mm−1
b = 11.436 (2) ÅT = 293 K
c = 13.540 (3) Å0.10 × 0.10 × 0.10 mm
β = 99.00 (3)°
Data collection top
Siemens SMART CCD area-detector
diffractometer		2852 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		2597 reflections with I > 2σ(I)
Tmin = 0.576, Tmax = 0.582Rint = 0.0000
2852 measured reflectionsθmax = 27.4°
Refinement top
R[F2 > 2σ(F2)] = 0.023H-atom parameters constrained
wR(F2) = 0.071Δρmax = 0.87 e Å−3
S = 1.15Δρmin = −1.12 e Å−3
2852 reflectionsAbsolute structure: ?
153 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C1−0.1615 (2)−0.1270 (4)0.1595 (3)0.0431 (9)
C2−0.2324 (3)−0.1397 (4)0.0889 (4)0.0536 (11)
H2−0.2740−0.18990.10200.064*
C3−0.2418 (3)−0.0792 (5)0.0005 (4)0.0594 (12)
H3−0.2889−0.0891−0.04690.071*
C4−0.1801 (3)−0.0031 (5)−0.0171 (4)0.0566 (11)
H4−0.18510.0395−0.07630.068*
C5−0.1117 (3)0.0082 (5)0.0544 (3)0.0476 (10)
H5−0.07040.05970.04250.057*
C60.1429 (3)−0.1884 (4)0.2456 (3)0.0459 (9)
C70.1972 (3)−0.2661 (4)0.2101 (4)0.0649 (14)
H70.2485−0.28140.24790.078*
C80.1746 (4)−0.3200 (5)0.1191 (5)0.0761 (16)
H80.2115−0.36930.09400.091*
C90.0977 (4)−0.3010 (5)0.0653 (4)0.0711 (15)
H90.0821−0.33980.00500.085*
C100.0428 (3)−0.2244 (4)0.1000 (3)0.0557 (11)
H10−0.0091−0.21260.06270.067*
C110.0647 (3)−0.1648 (3)0.1901 (3)0.0405 (8)
C120.00000.2174 (5)0.25000.0392 (12)
C130.0614 (3)0.4009 (4)0.2065 (4)0.0583 (12)
H13A0.03500.46860.17200.070*
H13B0.08370.35320.15780.070*
C140.1303 (5)0.4405 (6)0.2859 (7)0.095 (2)
H14A0.10910.49380.33040.143*
H14B0.17190.47900.25510.143*
H14C0.15410.37390.32300.143*
Ir10.0000−0.040880 (17)0.25000.03458 (10)
N1−0.1011 (2)−0.0514 (3)0.1408 (3)0.0382 (7)
N20.00000.3332 (4)0.25000.0454 (11)
S10.06343 (6)0.13548 (9)0.18733 (8)0.0423 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.045 (2)0.0360 (19)0.050 (2)−0.0042 (17)0.0123 (16)−0.0108 (19)
C20.050 (2)0.047 (2)0.063 (3)−0.0046 (19)0.007 (2)−0.015 (2)
C30.057 (3)0.059 (3)0.058 (3)0.009 (2)−0.005 (2)−0.014 (3)
C40.062 (3)0.059 (3)0.048 (3)0.014 (2)0.004 (2)0.000 (2)
C50.050 (2)0.051 (2)0.042 (2)0.005 (2)0.0099 (18)0.005 (2)
C60.056 (2)0.036 (2)0.048 (2)0.0074 (18)0.0196 (18)0.0059 (19)
C70.069 (3)0.053 (3)0.077 (4)0.024 (2)0.022 (3)0.005 (3)
C80.096 (4)0.057 (3)0.082 (4)0.029 (3)0.036 (3)−0.008 (3)
C90.109 (4)0.054 (3)0.055 (3)0.013 (3)0.027 (3)−0.014 (3)
C100.074 (3)0.046 (2)0.050 (3)0.005 (2)0.018 (2)−0.002 (2)
C110.050 (2)0.0335 (19)0.040 (2)0.0012 (16)0.0147 (16)0.0005 (17)
C120.032 (2)0.045 (3)0.040 (3)0.0000.005 (2)0.000
C130.068 (3)0.040 (2)0.068 (3)−0.009 (2)0.015 (2)0.006 (2)
C140.080 (4)0.102 (5)0.104 (6)−0.041 (4)0.014 (4)−0.004 (4)
Ir10.03838 (14)0.03183 (13)0.03526 (14)0.0000.01116 (8)0.000
N10.0421 (17)0.0381 (17)0.0355 (17)0.0013 (13)0.0092 (13)−0.0024 (13)
N20.045 (3)0.034 (2)0.057 (3)0.0000.011 (2)0.000
S10.0413 (5)0.0386 (5)0.0504 (6)−0.0006 (4)0.0180 (4)0.0012 (5)
Geometric parameters (Å, °) top
C1—N11.367 (5)C10—C111.394 (6)
C1—C21.393 (6)C10—H100.9300
C1—C6i1.454 (6)C11—Ir12.015 (4)
C2—C31.370 (7)C12—N21.324 (8)
C2—H20.9300C12—S1i1.719 (3)
C3—C41.384 (9)C12—S11.719 (3)
C3—H30.9300C13—N21.465 (5)
C4—C51.369 (7)C13—C141.504 (9)
C4—H40.9300C13—H13A0.9700
C5—N11.342 (6)C13—H13B0.9700
C5—H50.9300C14—H14A0.9600
C6—C71.395 (6)C14—H14B0.9600
C6—C111.408 (6)C14—H14C0.9600
C6—C1i1.454 (6)Ir1—C11i2.015 (4)
C7—C81.376 (8)Ir1—N12.045 (4)
C7—H70.9300Ir1—N1i2.045 (4)
C8—C91.371 (8)Ir1—S12.4792 (11)
C8—H80.9300Ir1—S1i2.4792 (11)
C9—C101.389 (7)N2—C13i1.465 (5)
C9—H90.9300
N1—C1—C2119.3 (4)S1i—C12—S1114.0 (3)
N1—C1—C6i114.3 (4)N2—C13—C14111.0 (5)
C2—C1—C6i126.4 (4)N2—C13—H13A109.4
C3—C2—C1121.0 (4)C14—C13—H13A109.4
C3—C2—H2119.5N2—C13—H13B109.4
C1—C2—H2119.5C14—C13—H13B109.4
C2—C3—C4118.9 (4)H13A—C13—H13B108.0
C2—C3—H3120.6C13—C14—H14A109.5
C4—C3—H3120.6C13—C14—H14B109.5
C5—C4—C3118.6 (5)H14A—C14—H14B109.5
C5—C4—H4120.7C13—C14—H14C109.5
C3—C4—H4120.7H14A—C14—H14C109.5
N1—C5—C4123.3 (5)H14B—C14—H14C109.5
N1—C5—H5118.4C11i—Ir1—C1190.6 (2)
C4—C5—H5118.4C11i—Ir1—N180.27 (16)
C7—C6—C11121.0 (4)C11—Ir1—N194.94 (15)
C7—C6—C1i123.7 (4)C11i—Ir1—N1i94.94 (15)
C11—C6—C1i115.3 (3)C11—Ir1—N1i80.27 (16)
C8—C7—C6119.8 (5)N1—Ir1—N1i173.25 (17)
C8—C7—H7120.1C11i—Ir1—S1170.21 (11)
C6—C7—H7120.1C11—Ir1—S199.15 (12)
C9—C8—C7120.1 (5)N1—Ir1—S197.86 (10)
C9—C8—H8120.0N1i—Ir1—S187.65 (9)
C7—C8—H8120.0C11i—Ir1—S1i99.15 (12)
C8—C9—C10120.7 (5)C11—Ir1—S1i170.21 (11)
C8—C9—H9119.7N1—Ir1—S1i87.65 (9)
C10—C9—H9119.6N1i—Ir1—S1i97.86 (10)
C9—C10—C11120.9 (5)S1—Ir1—S1i71.12 (5)
C9—C10—H10119.6C5—N1—C1119.0 (4)
C11—C10—H10119.6C5—N1—Ir1125.4 (3)
C10—C11—C6117.5 (4)C1—N1—Ir1115.6 (3)
C10—C11—Ir1128.1 (3)C12—N2—C13121.9 (3)
C6—C11—Ir1114.4 (3)C12—N2—C13i121.9 (3)
N2—C12—S1i123.02 (17)C13—N2—C13i116.2 (5)
N2—C12—S1123.02 (17)C12—S1—Ir187.46 (17)
N1—C1—C2—C31.2 (7)C4—C5—N1—Ir1179.1 (4)
C6i—C1—C2—C3−178.0 (4)C2—C1—N1—C5−0.4 (6)
C1—C2—C3—C4−1.2 (7)C6i—C1—N1—C5178.9 (4)
C2—C3—C4—C50.5 (8)C2—C1—N1—Ir1−179.9 (3)
C3—C4—C5—N10.3 (8)C6i—C1—N1—Ir1−0.5 (4)
C11—C6—C7—C80.6 (7)C11i—Ir1—N1—C5−177.0 (4)
C1i—C6—C7—C8−179.7 (5)C11—Ir1—N1—C5−87.2 (4)
C6—C7—C8—C9−2.6 (9)S1—Ir1—N1—C512.7 (4)
C7—C8—C9—C102.2 (9)S1i—Ir1—N1—C583.3 (3)
C8—C9—C10—C110.2 (8)C11i—Ir1—N1—C12.4 (3)
C9—C10—C11—C6−2.1 (6)C11—Ir1—N1—C192.2 (3)
C9—C10—C11—Ir1174.7 (4)S1—Ir1—N1—C1−167.8 (3)
C7—C6—C11—C101.7 (6)S1i—Ir1—N1—C1−97.3 (3)
C1i—C6—C11—C10−178.0 (4)S1i—C12—N2—C13172.4 (3)
C7—C6—C11—Ir1−175.5 (3)S1—C12—N2—C13−7.6 (3)
C1i—C6—C11—Ir14.8 (5)S1i—C12—N2—C13i−7.6 (3)
C10—C11—Ir1—C11i84.4 (4)S1—C12—N2—C13i172.4 (3)
C6—C11—Ir1—C11i−98.8 (3)C14—C13—N2—C12−98.1 (5)
C10—C11—Ir1—N14.1 (4)C14—C13—N2—C13i81.9 (5)
C6—C11—Ir1—N1−179.1 (3)N2—C12—S1—Ir1180.0
C10—C11—Ir1—N1i179.3 (4)S1i—C12—S1—Ir10.0
C6—C11—Ir1—N1i−3.9 (3)C11—Ir1—S1—C12−178.88 (12)
C10—C11—Ir1—S1−94.7 (4)N1—Ir1—S1—C1284.78 (10)
C6—C11—Ir1—S182.1 (3)N1i—Ir1—S1—C12−99.14 (10)
C4—C5—N1—C1−0.3 (7)S1i—Ir1—S1—C120.0
Symmetry codes: (i) −x, y, −z+1/2.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C4—H4···Cg1ii0.932.853.610 (6)140
C8—H8···Cg2iii0.933.003.897 (7)163
Symmetry codes: (ii) x+1/2, y+1/2, z; (iii) −x, −y−1, −z.
Table 1
Selected geometric parameters (Å, °) top
C11—Ir12.015 (4)Ir1—N1i2.045 (4)
Ir1—C11i2.015 (4)Ir1—S12.4792 (11)
Ir1—N12.045 (4)Ir1—S1i2.4792 (11)
C11i—Ir1—C1190.6 (2)C11i—Ir1—S1i99.15 (12)
N1—Ir1—N1i173.25 (17)C11—Ir1—S1i170.21 (11)
C11i—Ir1—S1170.21 (11)N1—Ir1—S1i87.65 (9)
C11—Ir1—S199.15 (12)N1i—Ir1—S1i97.86 (10)
N1—Ir1—S197.86 (10)S1—Ir1—S1i71.12 (5)
N1i—Ir1—S187.65 (9)
Symmetry codes: (i) −x, y, −z+1/2.
Table 2
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C4—H4···Cg1ii0.932.853.610 (6)140
C8—H8···Cg2iii0.933.003.897 (7)163
Symmetry codes: (ii) x+1/2, y+1/2, z; (iii) −x, −y−1, −z.
Acknowledgements top

The author thanks the Natural Science Foundation of South-Central University for Nationalities (grant No. YZZ07007) for financial support.

references
References top

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