supplementary materials


Acta Cryst. (2007). E63, m2402    [ doi:10.1107/S1600536807040421 ]

Di-[mu]-iodido-bis[([eta]4-cycloocta-1,5-diene)iridium(I)]

T. Yamagata, M. Nagata, K. Mashima and K. Tani

Abstract top

The molecular structure of the title compound, [Ir2I2(C8H12)2], has C2 symmetry. The dinuclear structure features two bridging I atoms and a bent geometry for the Ir2([mu]-I)2 core, with a hinge angle of 95.26 (1)°.

Comment top

Crystal data for binuclear complexes of d8 transition metals of the type [L2M(µ-X)]2 (M= Rh or Ir; X = halide) and their theoretical analyses have been reported (Aullón et al., 1998; Cotton, et al., 1999). However, their iodide analogues are fairly rare. Among the known complexes, cyclooctadiene derivatives of the Group 8 transition metals, i.e. [M(µ-Cl)(COD)]2 (M = IrI or RhI; cod = cis,cis-1,5-cyclooctadiene), have been used as key starting materials for the preparation of various kinds of IrI or RhI complexes, that are efficient catalyst precursors. For example, the molecular structure of [Ir(µ-Cl){(R)-binap}]2 has been reported (Yamagata et al., 1997), which was prepared from the reaction of [Ir(µ-Cl)(cod)]2 with two equivalents of (R)-binap, where (R)-binap is (R)-(+)-2,2'-bis(diphenylphosphanyl)-1,1'-binaphthyl, as well as its use as an efficient catalyst for the asymmetric hydrogenation of prochiral imines (Tani et al., 1995).

The catalytic asymmetric olefin hydroamination with [Ir(µ-Cl)(diphosphine)]2 and the structure of [Ir(µ-Cl){(R)-binap}]2 have also been investigated by Togni and co-workers (Dorta et al., 1997). Although [Rh(µ-Cl)(cod)]2 (De Ridder & Imhoff, 1994) has an almost planar structure (the hinge angle is 169.1 (3)°), [Ir(µ-Br)(cod)]2 (Yamagata et al., 2007), [Ir(µ-Cl)(cod)]2 (Cotton et al., 1986), and [Rh(µ-Br)(cod)]2 (Pettinari et al., 2002) show bent structures; with hinge angles of 101.58 (3)°, 109.4 (3)°, and 148.7 (3)°, respectively. Thus, it was thought of interest to examine the structure of [Ir(µ-I)(cod)]2, (I), Fig. 1 & Table 1. The structure of (I) resembles those of the aforementioned [M(µ-X)(cod)]2 structures, indeed the structures are isomorphous. In (I), the Ir2(µ-I)2 core shows a bent geometry with the hinge angle of 95.26 (1)°. The M···M distances in (I), [Ir(µ-Br)(cod)]2, [Ir(µ-Cl)(cod)]2, and [Rh(µ-Br)(cod)]2 are 2.9228 (6), 2.9034 (5), 2.910 (1), and 3.565 Å, respectively. The degree of bending is Ir > Rh and I > Br > Cl. These tendencies can be explained by the differences in diffuseness of the metal's d orbitals and by analyzing the <pz2/dz2> and <dz2/dz2> overlap integrals between the Slater orbitals (EH calculations) (Aullón et al., 1998).

Related literature top

For related literature, see: Aullón et al. (1998); Cotton et al. (1986, 1999); Dorta et al. (1997); Pettinari et al. (2002); De Ridder & Imhoff (1994); Tani et al. (1995); Yamagata et al. (1997, 2007).

Experimental top

In a Schlenk flask with ether (50 ml) were added [Ir(µ-Cl)(cod)]2 (0.429 g, 0.639 mmol) and NaI (1.33 g, 8.86 mmol). The mixture was stirred at ambient temperature for 12 h. All volatiles were removed under reduced pressure and the residual washed with five portions of water (15 ml). The washings were monitored using aqueous silver nitrate. The resulting solid was washed with ethanol (10 ml) and dried in vacuo to yield [Ir(µ-I)(cod)]2 as a deep-red solid (0.441 g, 81%). Recrystallization from THF afforded an analytically pure product; m.pt. 522–527 K (dec.). 1H NMR (CDCl3, 308 K, 300 MHz, δ, p.p.m.): 4.43–4.44 (m, 8H, =CH), 2.10–2.14 (m, 8H, –CHH–), 1.13–1.36 (m, 8H, –CHH–). Analysis found: C 22.82, H 2.86%; C16H24I2Ir2 requires: C 22.49, H 2.83%.

Refinement top

All H-atoms were included in the riding model approximation with C—H distances in the range 0.95–0.99 Å, and with Uiso(H) = 1.2Ueq(C) [or 1.5Ueq(C) for methyl groups]. The final difference Fourier map gave a maximum peak of 5.91 e Å−3 2.58 Å from the Ir atom and 2.35 Å from the I atom. The minimum hole of −5.04 e Å−3 was 0.66 Å from the Ir atom.

Computing details top

Data collection: RAPID-AUTO (Rigaku, 1998); cell refinement: RAPID-AUTO; data reduction: TEXSAN (Rigaku/MSC, 2004); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97; molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level. The carbon-bound H-atoms have been omitted for clarity. Symmetry code: (i) 1 − x, y, 3/2 − z.
Di-µ-iodido-bis[(η4-cycloocta-1,5-diene)iridium(I)] top
Crystal data top
[Ir2I2(C8H12)2]F000 = 1520
Mr = 854.56Dx = 3.280 Mg m3
Monoclinic, C2/cMo Kα radiation
λ = 0.71075 Å
Hall symbol: -C 2ycCell parameters from 41734 reflections
a = 12.3438 (4) Åθ = 3.1–31.9º
b = 11.8161 (4) ŵ = 18.92 mm1
c = 11.9435 (3) ÅT = 100 (1) K
β = 96.6568 (14)ºPlatelet, red
V = 1730.28 (10) Å30.39 × 0.28 × 0.22 mm
Z = 4
Data collection top
Rigaku R-AXIS RAPID imaging-plate
diffractometer
2909 independent reflections
Radiation source: normal-focus sealed tube2909 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.095
Detector resolution: 10.00 pixels mm-1θmax = 31.6º
T = 100(1) Kθmin = 3.1º
ω scansh = 18→18
Absorption correction: numerical
(NUMABS; Higashi, 1999)
k = 17→17
Tmin = 0.018, Tmax = 0.200l = 17→17
27799 measured reflections
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)] = 0.042H-atom parameters constrained
wR(F2) = 0.102  w = 1/[σ2(Fo2) + (0.0244P)2 + 97.8696P]
where P = (Fo2 + 2Fc2)/3
S = 1.19(Δ/σ)max = 0.001
2909 reflectionsΔρmax = 5.91 e Å3
91 parametersΔρmin = 5.04 e Å3
Primary atom site location: structure-invariant direct methodsExtinction correction: none
Crystal data top
[Ir2I2(C8H12)2]V = 1730.28 (10) Å3
Mr = 854.56Z = 4
Monoclinic, C2/cMo Kα
a = 12.3438 (4) ŵ = 18.92 mm1
b = 11.8161 (4) ÅT = 100 (1) K
c = 11.9435 (3) Å0.39 × 0.28 × 0.22 mm
β = 96.6568 (14)º
Data collection top
Rigaku R-AXIS RAPID imaging-plate
diffractometer
2909 independent reflections
Absorption correction: numerical
(NUMABS; Higashi, 1999)
2909 reflections with I > 2σ(I)
Tmin = 0.018, Tmax = 0.200Rint = 0.095
27799 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.042H-atom parameters constrained
wR(F2) = 0.102  w = 1/[σ2(Fo2) + (0.0244P)2 + 97.8696P]
where P = (Fo2 + 2Fc2)/3
S = 1.19Δρmax = 5.91 e Å3
2909 reflectionsΔρmin = 5.04 e Å3
91 parameters
Special details top

Experimental. Indexing was performed from 3 oscillations which were exposed for 2.0 minutes. The camera radius was 127.40 mm. Readout performed in the 0.100 mm pixel mode. #1 Phi=0.0, chi=55.0, omega=80.0 to 260.0 with 2.0deg step #2 Phi=180.0, chi=45.0, omega=0.0 to 180.0 with 2.0deg step #3 Phi=90.0, chi=20.0, omega=0.0 to 120.0 with 2.0deg step #4 Phi=180.0, chi= −5.0, omega=0.0 to 120.0 with 2.0deg step A total of 300 images, corresponding to 600.0 °. Osillation angles were collected with 4 different goniometer setting. Exposure time was 2.0 minutes per degree. The camera radius was 127.40 mm. Readout was performed in the 0.100 mm pixel mode.

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.

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

8.2950 (0.0021) x − 8.7297 (0.0018) y − 1.5346 (0.0022) z = 0.3948 (0.0020)

* 0.0000 (0.0000) Ir * 0.0000 (0.0000) I * 0.0000 (0.0000) I_$1

Rms deviation of fitted atoms = 0.0000

8.2950 (0.0021) x + 8.7297 (0.0019) y − 1.5346 (0.0022) z = 5.5983 (0.0018)

Angle to previous plane (with approximate e.s.d.) = 84.74 (0.01)

* 0.0000 (0.0000) Ir_$1 * 0.0000 (0.0000) I * 0.0000 (0.0000) I_$1

Rms deviation of fitted atoms = 0.0000

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
Ir0.38310 (2)0.18522 (2)0.75987 (2)0.01168 (9)
I0.52845 (4)0.29804 (4)0.90380 (4)0.01538 (11)
C10.3674 (7)0.0519 (7)0.8752 (7)0.0168 (13)
H10.44220.06490.90020.020*
C20.2902 (6)0.1384 (7)0.8903 (7)0.0167 (13)
H20.31610.20620.92690.020*
C30.1697 (7)0.1290 (8)0.8517 (8)0.0223 (16)
H3A0.13380.20180.86540.027*
H3B0.13750.07000.89660.027*
C40.1472 (7)0.0988 (8)0.7252 (7)0.0214 (15)
H4A0.13570.01610.71760.026*
H4B0.07930.13680.69280.026*
C50.2387 (6)0.1330 (7)0.6594 (7)0.0179 (14)
H50.23830.20690.62800.021*
C60.3252 (7)0.0589 (7)0.6427 (7)0.0180 (14)
H60.37890.08440.59770.022*
C70.3372 (8)0.0590 (8)0.6926 (8)0.0255 (17)
H7A0.40740.09150.67580.031*
H7B0.27790.10740.65600.031*
C80.3333 (8)0.0612 (7)0.8202 (8)0.0223 (16)
H8A0.25830.07970.83580.027*
H8B0.38250.12140.85390.027*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ir0.01187 (13)0.01351 (13)0.00961 (13)0.00130 (8)0.00106 (9)0.00053 (8)
I0.0146 (2)0.0182 (2)0.0131 (2)0.00157 (16)0.00073 (16)0.00549 (16)
C10.017 (3)0.016 (3)0.018 (3)0.002 (3)0.003 (3)0.003 (3)
C20.015 (3)0.019 (3)0.018 (3)0.006 (3)0.007 (3)0.003 (3)
C30.022 (4)0.021 (4)0.025 (4)0.001 (3)0.004 (3)0.004 (3)
C40.013 (3)0.028 (4)0.023 (4)0.005 (3)0.004 (3)0.004 (3)
C50.012 (3)0.023 (4)0.018 (3)0.000 (3)0.002 (3)0.003 (3)
C60.016 (3)0.023 (4)0.015 (3)0.004 (3)0.002 (3)0.003 (3)
C70.024 (4)0.022 (4)0.032 (5)0.002 (3)0.006 (3)0.011 (3)
C80.023 (4)0.017 (3)0.028 (4)0.003 (3)0.006 (3)0.000 (3)
Geometric parameters (Å, °) top
Ir—C12.116 (8)C3—H3A0.9900
Ir—C22.112 (7)C3—H3B0.9900
Ir—C52.122 (8)C4—C51.504 (12)
Ir—C62.113 (8)C4—H4A0.9900
Ir—I2.6901 (5)C4—H4B0.9900
Ir—Ii2.6991 (6)C5—C61.413 (12)
Ir—Iri2.9228 (6)C5—H50.9500
I—Iri2.6991 (5)C6—C71.516 (13)
C1—C21.422 (11)C6—H60.9500
C1—C81.527 (12)C7—C81.529 (14)
C1—H10.9500C7—H7A0.9900
C2—C31.511 (12)C7—H7B0.9900
C2—H20.9500C8—H8A0.9900
C3—C41.545 (12)C8—H8B0.9900
C2—Ir—C697.6 (3)C2—C3—H3A109.2
C2—Ir—C139.3 (3)C4—C3—H3A109.2
C6—Ir—C181.7 (3)C2—C3—H3B109.2
C2—Ir—C581.3 (3)C4—C3—H3B109.2
C6—Ir—C539.0 (3)H3A—C3—H3B107.9
C1—Ir—C591.0 (3)C5—C4—C3112.9 (7)
C2—Ir—I92.1 (2)C5—C4—H4A109.0
C6—Ir—I157.3 (2)C3—C4—H4A109.0
C1—Ir—I93.3 (2)C5—C4—H4B109.0
C5—Ir—I163.7 (2)C3—C4—H4B109.0
C2—Ir—Ii164.4 (2)H4A—C4—H4B107.8
C6—Ir—Ii90.2 (2)C6—C5—C4122.1 (8)
C1—Ir—Ii156.1 (2)C6—C5—Ir70.2 (4)
C5—Ir—Ii96.8 (2)C4—C5—Ir114.5 (5)
I—Ir—Ii85.54 (2)C6—C5—H5118.9
C2—Ir—Iri133.2 (2)C4—C5—H5118.9
C6—Ir—Iri102.0 (2)Ir—C5—H585.5
C1—Ir—Iri102.6 (2)C5—C6—C7123.7 (8)
C5—Ir—Iri136.6 (2)C5—C6—Ir70.9 (5)
I—Ir—Iri57.305 (13)C7—C6—Ir112.3 (6)
Ii—Ir—Iri57.008 (13)C5—C6—H6118.1
Ir—I—Iri65.687 (15)C7—C6—H6118.1
C2—C1—C8121.9 (7)Ir—C6—H686.9
C2—C1—Ir70.2 (4)C6—C7—C8113.2 (7)
C8—C1—Ir114.3 (6)C6—C7—H7A108.9
C2—C1—H1119.0C8—C7—H7A108.9
C8—C1—H1119.0C6—C7—H7B108.9
Ir—C1—H185.7C8—C7—H7B108.9
C1—C2—C3124.0 (7)H7A—C7—H7B107.7
C1—C2—Ir70.5 (4)C1—C8—C7112.1 (7)
C3—C2—Ir113.2 (6)C1—C8—H8A109.2
C1—C2—H2118.0C7—C8—H8A109.2
C3—C2—H2118.0C1—C8—H8B109.2
Ir—C2—H286.3C7—C8—H8B109.2
C2—C3—C4112.0 (7)H8A—C8—H8B107.9
C2—Ir—I—Iri142.2 (2)C3—C4—C5—C691.6 (10)
C6—Ir—I—Iri26.6 (6)C3—C4—C5—Ir10.4 (10)
C1—Ir—I—Iri102.9 (2)C2—Ir—C5—C6113.7 (5)
C5—Ir—I—Iri152.1 (8)C1—Ir—C5—C675.5 (5)
Ii—Ir—I—Iri53.207 (18)I—Ir—C5—C6179.2 (6)
C6—Ir—C1—C2112.9 (5)Ii—Ir—C5—C681.9 (5)
C5—Ir—C1—C274.9 (5)Iri—Ir—C5—C634.2 (6)
I—Ir—C1—C289.3 (4)C2—Ir—C5—C43.5 (6)
Ii—Ir—C1—C2175.8 (4)C6—Ir—C5—C4117.2 (9)
Iri—Ir—C1—C2146.5 (4)C1—Ir—C5—C441.7 (7)
C2—Ir—C1—C8117.0 (8)I—Ir—C5—C463.6 (12)
C6—Ir—C1—C84.1 (6)Ii—Ir—C5—C4160.9 (6)
C5—Ir—C1—C842.0 (6)Iri—Ir—C5—C4151.4 (5)
I—Ir—C1—C8153.7 (6)C4—C5—C6—C72.6 (12)
Ii—Ir—C1—C867.3 (9)Ir—C5—C6—C7104.5 (8)
Iri—Ir—C1—C896.5 (6)C4—C5—C6—Ir107.1 (7)
C8—C1—C2—C31.6 (12)C2—Ir—C6—C566.0 (5)
Ir—C1—C2—C3105.4 (8)C1—Ir—C6—C5102.0 (5)
C8—C1—C2—Ir107.0 (7)I—Ir—C6—C5179.4 (5)
C6—Ir—C2—C166.9 (5)Ii—Ir—C6—C5100.5 (5)
C5—Ir—C2—C1102.4 (5)Iri—Ir—C6—C5156.7 (4)
I—Ir—C2—C192.6 (4)C2—Ir—C6—C753.6 (6)
Ii—Ir—C2—C1173.6 (6)C1—Ir—C6—C717.5 (6)
Iri—Ir—C2—C147.6 (5)C5—Ir—C6—C7119.5 (8)
C6—Ir—C2—C352.7 (6)I—Ir—C6—C761.1 (9)
C1—Ir—C2—C3119.5 (8)Ii—Ir—C6—C7139.9 (6)
C5—Ir—C2—C317.1 (6)Iri—Ir—C6—C783.7 (6)
I—Ir—C2—C3147.9 (6)C5—C6—C7—C853.0 (11)
Ii—Ir—C2—C366.9 (11)Ir—C6—C7—C828.2 (9)
Iri—Ir—C2—C3167.1 (4)C2—C1—C8—C791.0 (10)
C1—C2—C3—C454.0 (11)Ir—C1—C8—C710.0 (9)
Ir—C2—C3—C427.4 (9)C6—C7—C8—C124.7 (11)
C2—C3—C4—C524.4 (11)
Symmetry codes: (i) −x+1, y, −z+3/2.
Table 1
Selected geometric parameters (Å, °)
top
Ir—C12.116 (8)Ir—I2.6901 (5)
Ir—C22.112 (7)Ir—Ii2.6991 (6)
Ir—C52.122 (8)Ir—Iri2.9228 (6)
Ir—C62.113 (8)
I—Ir—Ii85.54 (2)Ir—I—Iri65.687 (15)
Symmetry codes: (i) −x+1, y, −z+3/2.
Acknowledgements top

This research was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan.

references
References top

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