Aqua­(benzamidato-κN)bis­[3,5-difluoro-2-(pyridin-2-yl)phenyl-κC 1]iridium(III) methanol monosolvate

Songlin Zhang; Feng Wu; Yuqiang Ding

doi:10.1107/S1600536812005922

. 2012 Feb 17;68(Pt 3):m310. doi: 10.1107/S1600536812005922

Aqua(benzamidato-κN)bis[3,5-difluoro-2-(pyridin-2-yl)phenyl-κC ¹]iridium(III) methanol monosolvate

Songlin Zhang ^a, Feng Wu ^a, Yuqiang Ding ^a,^*

PMCID: PMC3297261 PMID: 22412451

Abstract

In the title compound, [Ir(C₁₁H₆F₂N)₂(C₇H₆NO)(H₂O)]·CH₃OH, the Ir^III ion adopts an octahedral geometry, and is coordinated by two 3,5-difluoro-2-(pyridin-2-yl)phenyl ligands, one molecule of water and one benzamidate anion. The two 2-(4,6-difluorophenyl)pyridyl ligands are arranged in a cis-C,C′ and trans-N,N′ fashion. Additionally, there is a bystanding methanol molecule outside the coordination sphere of the Ir^III ion. In the crystal, molecules of the title compound are linked by O—H⋯O and O—H⋯N hydrogen bonds. One F atom of each ligand is equally disordered over two sites. The C atom of the solvent molecule is likewise disordered over two sites in a 0.589 (11):0.411 (11) ratio.

Related literature

For related cyclometallated Ir^III complexes containing a κ ²-bound benzaminate anion, see: Yang et al. (2011 ▶); Wang et al. (2008 ▶); Zhang et al. (2011 ▶). For the coordination geometry of some homoleptic meridional and heteroleptic iridium(III) complexes, see: Tamayo et al. (2003 ▶); Yang et al. (2007 ▶); You & Park (2005 ▶); Zhang et al. (2011 ▶). For the general procedure of preparing a chloride-bridged Ir^III dimer, see: Nonoyama (1974 ▶).

Experimental

Crystal data

[Ir(C₁₁H₆F₂N)₂(C₇H₆NO)(H₂O)]·CH₄O
M _r = 742.74
Monoclinic,
a = 29.544 (4) Å
b = 11.6258 (12) Å
c = 20.247 (3) Å
β = 129.391 (2)°
V = 5374.5 (12) Å³
Z = 8
Mo Kα radiation
μ = 5.04 mm⁻¹
T = 223 K
0.34 × 0.25 × 0.24 mm

Data collection

Rigaku Saturn diffractometer
Absorption correction: multi-scan (REQAB; Jacobson, 1998 ▶) T _min = 0.279, T _max = 0.378
14977 measured reflections
6122 independent reflections
5277 reflections with I > 2σ(I)
R _int = 0.031

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.101
S = 1.09
6122 reflections
392 parameters
4 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 1.20 e Å⁻³
Δρ_min = −1.18 e Å⁻³

Data collection: CrystalClear (Rigaku, 2007 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812005922/br2185sup1.cif

e-68-0m310-sup1.cif^{(22.8KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812005922/br2185Isup2.hkl

e-68-0m310-Isup2.hkl^{(299.8KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2B⋯N3	0.85 (1)	2.54 (6)	3.029 (7)	117 (6)
O2—H2B⋯O1	0.85 (1)	1.74 (3)	2.560 (6)	161 (7)
O2—H2A⋯N1	0.85 (1)	2.45 (6)	2.960 (6)	119 (6)
O2—H2A⋯O1ⁱ	0.85 (1)	1.97 (4)	2.700 (7)	142 (6)

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors thank the National Natural Science Foundation of China (NNSFC grant No. 20971058) and the Fundamental Research Funds for the Central Universities (grant No. JUSRP 11105) for financial support.

supplementary crystallographic information

Comment

The title compound was obtained unexpectedly during our study on the preparation of bis(2-(4,6-difluorophenyl)pyridyl)iridium(III) κ²-benzamidate complex. Ancillary κ²-amidate ligands have been shown to have a great influence on the photophysical and electrochemical properties of cyclometalated Ir(III) complexes (Yang et al., 2011; Wang et al., 2008). We have synthesized several such bis(2-(4,6-difluorophenyl)pyridyl)iridium(III) κ²-amidate complexes, in all of which, there is a substitutent on the amide nitrogen atom (Zhang et al., 2011). When benzamide lacking a substituent on the amide nitrogen atom was subjected to the reaction condition for the preparation of Ir(III) κ²-amidate complexes, an unexpected Ir(III) complex with a N-bound benzamidate ligand and an O-bound water ligand, i.e., the title compound, was obtained. As shown in Fig. 1, the iridium center adopts an octahedral geometry. The two 2-(4,6-difluorophenyl)pyridyl ligands are arranged in a cis-C, C' and trans-N, N' fashion, which have already been observed in some homoleptic meridional iridium(III) complexes (Tamayo et al., 2003) and also some heteroleptic iridium(III) complexes (Yang et al., 2007; You & Park, 2005; Zhang et al., 2011). The remaining two coordination sites were occupied by benzamidate nitrogen atom and water oxygen atom, respectively. The methanol molecule outside the coordination sphere of the Ir center should result from the deprotonation of the benzamide ligand by the intermediate Ir-OMe complex, which is generated by reaction of chloro-bridged Ir(III) dimer with sodium methoxide. However, there is still some uncertainties about the nature of the bystanding solvent molecule or how it is arranged. In the crystal, there should be intermolecular hydrogen bonds, such as O-H-O and N-H-O, as shown by Fig. 2.

Experimental

Into a Schlenk tube containing chloro-bridged bis(2-(4,6-difluorophenyl)pyridyl) Ir(III) dimer (1 eq.), benzamide (2.5 eq.) and sodium methoxide (10 eq.) was added dichloromethane solvent under dinitrogen. The chloro-bridged Ir(III) dimer was obtained by reaction of IrCl₃^.3H₂O with 2-(4,6-difluorophenyl)pyridine ligand in ethoxyethanol solvent under dinitrogen atmosphere according to the general procedure reported by Nonoyama (1974). The mixture was stirred for 48 h at room temperature, resulting in the formation of an orange solution. The CH₂Cl₂ solvent in the crude product mixture was then evaporated and the residue was then washed by dried ether. The crystal of the title compound was obtained by recrystallization of the solid in CH₂Cl₂/cyclohexane mixed solvent.