mer-Bis[3,5-difluoro-2-(2-pyrid­yl)phenyl-κ2 C 1,N]{5-(2-pyridyl-κN)-3-[3-(4-vinyl­benz­yloxy)phen­yl]-1,2,4-triazol-1-ido}iridium(III) methanol solvate

Peter G Jones; Marc Debeaux; Andreas Weinkauf; Henning Hopf; Wolfgang Kowalsky; Hans-Hermann Johannes

doi:10.1107/S1600536809052726

. 2009 Dec 16;66(Pt 1):m66–m67. doi: 10.1107/S1600536809052726

mer-Bis[3,5-difluoro-2-(2-pyridyl)phenyl-κ² C ¹,N]{5-(2-pyridyl-κN)-3-[3-(4-vinylbenzyloxy)phenyl]-1,2,4-triazol-1-ido}iridium(III) methanol solvate

Peter G Jones ^a,^*, Marc Debeaux ^b, Andreas Weinkauf ^a, Henning Hopf ^c, Wolfgang Kowalsky ^b, Hans-Hermann Johannes ^b

PMCID: PMC2980050 PMID: 21579961

Abstract

In the title compound, [Ir(C₁₁H₆F₂N)₂(C₂₂H₁₇N₄O)]·CH₃OH, the coordination at iridium is essentially octahedral, but with distortions associated with the bite angles of the ligands [76.25 (9)–80.71 (12)°] and the differing trans influences of C and N ligands [Ir—N = 2.04 Å (average) trans to N but 2.14 Å trans to C]. All three bidentate ligands have coordinating ring systems that are almost coplanar [interplanar angles = 1.7 (1)–3.8 (2)°]. The vinylbenzyl group is disordered over two positions with occupations of 0.653 (4) and 0.347 (4). The methanol solvent molecule is involved in a classical O—H⋯N hydrogen bond to a triazole N atom.

Related literature

For background to organic light-emitting diodes (OLEDs), see: Adachi et al. (2001 ▶); Baldo et al. (1998 ▶); Burroughes et al. (1990 ▶); Chang et al. (2007 ▶); Coppo et al. (2004 ▶); Dedeian et al. (1991 ▶); Dixon et al. (2000 ▶); Gong et al. (2002 ▶); Grushin et al. (2001 ▶); Lamansky et al. (2001 ▶); Schütz et al. (2008 ▶); Suzuki et al. (2005 ▶); Tang & VanSlyke (1987 ▶); You & Park (2005 ▶).

Experimental

Crystal data

[Ir(C₁₁H₆F₂N)₂(C₂₂H₁₇N₄O)]·CH₄O
M _r = 957.97
Triclinic,
a = 9.8934 (1) Å
b = 12.3039 (2) Å
c = 16.8933 (3) Å
α = 81.7429 (14)°
β = 83.2858 (11)°
γ = 69.9647 (14)°
V = 1906.82 (5) Å³
Z = 2
Mo Kα radiation
μ = 3.57 mm⁻¹
T = 100 K
0.20 × 0.15 × 0.10 mm

Data collection

Oxford Diffraction Xcalibur E diffractometer
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008 ▶) T _min = 0.848, T _max = 1.000
53102 measured reflections
10448 independent reflections
8442 reflections with I > 2σ(I)
R _int = 0.034

Refinement

R[F ² > 2σ(F ²)] = 0.029
wR(F ²) = 0.064
S = 0.93
10448 reflections
538 parameters
69 restraints
H-atom parameters constrained
Δρ_max = 2.18 e Å⁻³
Δρ_min = −0.84 e Å⁻³

Data collection: CrysAlis CCD (Oxford Diffraction, 2008 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2008 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP (Siemens, 1994 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809052726/tk2595sup1.cif

e-66-00m66-sup1.cif^{(41.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809052726/tk2595Isup2.hkl

e-66-00m66-Isup2.hkl^{(510.9KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

Ir—C11	2.010 (3)
Ir—C22	2.012 (3)
Ir—N1	2.033 (2)
Ir—N2	2.049 (2)
Ir—N4	2.118 (2)
Ir—N3	2.158 (2)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O99—H99⋯N6	0.84	2.04	2.853 (3)	164
C24—H24⋯O99	0.95	2.49	3.368 (4)	154
C31—H31⋯O99	0.95	2.66	3.587 (4)	164

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Acknowledgments

The authors thank the Bundesministerium für Bildung und Forschung (BMBF 01 BD 0687) for financial support.

supplementary crystallographic information

Comment

Since Tang and VanSlyke (1987) reported on the first organic light-emitting diode (OLED) based on the electroluminescence of tris(8-hydroxyquinoline)aluminium, and Burroughes et al. (1990) discovered a device with an electroluminescent organic polymer (PLED), OLEDs have attracted much attention because of their application in flat-panel and large-area displays (Burroughes et al., 1990; Tang & VanSlyke, 1987). By incorporation of phosphorescent organometallic complexes of transition metals with a strong spin-orbit coupling, electroluminescent quantum efficiencies up to 100% can be achieved (Baldo et al., 1998; Gong et al., 2002). Among these heavy metals, iridium(III)-based complexes are especially attractive because of their highly tunable emission colors and relatively short phosphorescence lifetimes (Dixon et al., 2000; Lamansky et al., 2001).

Homo- and heteroleptic iridium(III) complexes are versatile and readily available. The emission colour of heteroleptic complexes can be tuned by varying the two monoanionic cyclometalating ligands (Dedeian et al., 1991; Grushin et al., 2001) and/or the third ligand (Chang et al., 2007; You et al., 2005). For example, the replacement of the picolinate by a triazolylpyridine ligand in the well known "blue" emitting FIrpic leads to a hypsochromically shifted phosphorescence (Adachi et al., 2001; Coppo et al., 2004).

In terms of large scale fabrication, the easiness and inexpensiveness of wet processes such as spin coating, dip coating or ink-jet printing of PLEDs represent important advantages over vacuum techniques. Chemically attaching emitter moieties to the polymer matrix can prevent degradation processes clearly caused by phase separation (Suzuki et al., 2005). Furthermore, the covalent attachment also prevents cascading energy transfer through steric shielding (Schütz et al., 2008).

In this contribution, we report the structure of a styrene-functionalized, cyan-emitting complex that can be incorporated in an ambipolar polymer approach (Suzuki et al., 2005). The structure of the title complex, which crystallizes as a methanol solvate, is shown in Fig. 1. The vinylbenzyl group is disordered over two positions with occupations 0.653 (4), 0.347 (4); this is shown in Fig. 2. The coordination at iridium is essentially octahedral, but with some distortions associated with the restricted bite of the bidentate ligands; C11—Ir—N1 80.20 (11), C22—Ir —N2 80.71 (12), and N4—Ir—N3 76.25 (9)°. All five-membered chelate rings are planar (max. r.m.s.d. 0.019 Å) and mutually perpendicular (max. deviation 3°). Interplanar angles between the coordinating rings of each ligand are small: 3.8 (2)° in the ligand based on N1/C11, 3.4 (2)° for N2/C22, and 1.7 (1)° for N3/N4.

The bond lengths, Table 1, at Ir reflect the different trans influences of C and N ligands, although the significant difference between the two Ir—N bond lengths trans to C has no obvious explanation.

Hydrogen bonds are listed in Table 2. The methanol molecule is linked to an N atom of the triazole ring via a classical H bond. The contacts H24···O99 and H31···O99 may also be interpreted as weak H bonds within the asymmetric unit, but are not drawn explicitly in Fig. 1.

Experimental

A suspension of bis[3,5-difluoro-2-(pyridin-2-yl-κN)phenyl]-[3-(3-hydroxyphenyl)-5-(pyridin-2-yl-κN)-1,2,4-triazol-1-yl]-iridium(III) (400 mg, 494 µmol) in dry DMF (5 ml) was treated with sodium hydride (60% dispersion in mineral oil, 40 mg, 988 µmol) and stirred for 30 min at room temperature. 1-(Chloromethyl)-4-vinylbenzene (151 mg, 988 µmol) was added and stirred for 1 d at room temperature. The solvent was removed under reduced pressure at 373 K. The product was isolated from the residue by flash chromatography on silica gel (dichloromethane/acetone 4:1; R_f = 0.40) as a yellow solid (255 mg, 56%). Single crystals were grown from dichloromethane/methanol solution. Elemental analysis: calculated for C₄₄H₂₉F₄IrN₆O: C 57.07, H 3.16, N 9.08%; found: C 57.06, H 3.04, N 8.82%.