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The title dinuclear Rh complex, [Rh2I2(CO)4], adopts a V-shape conformation with an intramolecular Rh...Rh distance of 3.385 (1) Å. The mol­ecules are connected in a zigzag fashion, with intermolecular Rh...Rh distances of 3.637 (2) Å.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536803005439/lh6043sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536803005439/lh6043Isup2.hkl
Contains datablock I

CCDC reference: 939443

Key indicators

  • Single-crystal X-ray study
  • T = 153 K
  • Mean [sigma](O-C) = 0.013 Å
  • R factor = 0.053
  • wR factor = 0.141
  • Data-to-parameter ratio = 18.0

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 1 O2 -C2 -RH1 -C1 -29.00 11.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 2 O2 -C2 -RH1 -I2 50.00 13.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 3 O2 -C2 -RH1 -I1 147.00 11.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 4 O1 -C1 -RH1 -C2 66.00 56.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 5 O1 -C1 -RH1 -I2 -108.00 56.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 6 O1 -C1 -RH1 -I1 -51.00 59.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 7 O4 -C4 -RH2 -C3 -35.00 21.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 8 O4 -C4 -RH2 -I1 149.00 21.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 9 O4 -C4 -RH2 -I2 169.00 11.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 10 O3 -C3 -RH2 -C4 125.00 73.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 11 O3 -C3 -RH2 -I1 -146.00 70.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 12 O3 -C3 -RH2 -I2 -56.00 73.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 14 C3 -RH2 -I1 -RH1 55.00 5.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 17 C1 -RH1 -I1 -RH2 -21.00 5.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 19 C2 -RH1 -I2 -RH2 62.00 3.00 1.555 1.555 1.555 1.555 PLAT_710 Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle # 22 C4 -RH2 -I2 -RH1 16.00 15.00 1.555 1.555 1.555 1.555 General Notes
ABSTM_02 When printed, the submitted absorption T values will be replaced by the scaled T values. Since the ratio of scaled T's is identical to the ratio of reported T values, the scaling does not imply a change to the absorption corrections used in the study. Ratio of Tmax expected/reported 0.134 Tmax scaled 0.061 Tmin scaled 0.017
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
16 Alert Level C = Please check

Comment top

[Rh2Cl2(CO)4] is used in catalysis for the carbonylation of methanol to give acetic acid (Paulik & Roth, 1968; Forster, 1976; Krzywicki & Marczewski, 1979; Thomas et al., 2002). It is one of the most important homogeneously catalysed industrial processes (Weissermel & Arpe, 1997). The catalytic reaction requires the use of iodide promoters (Parshall & Ittel, 1992), which convert methanol, prior to carbonylation, into the actual methyl iodide substrate. For this reason, the iodide analogue [Rh2I2(CO)4], (I), has been synthesized, with the hope of improve the catalytic activity for the carbonylation of methanol. The complex had already been observed in the reaction of [Rh2Cl2(CO)4] with KI under 1 atmosphere of CO pressure, but not structurally characterized (Fulford et al., 1990). We report here a modified synthesis and the single-crystal X-ray structure analysis of [Rh2I2(CO)4], the iodine analogue of [Rh2Cl2(CO)4].

Di-µ-chloro-bis[dicarbonylrhodium(I)] was structurally characterized for the first time by Dahl et al. (1961), then more recently by Walz & Scheer (1991). The molecular structure of di-µ-iodo-bis[dicarbonylrhodium(I)] is very similar, but the presence of bridging iodines instead of chlorines gives a less hindered complex. As for [Rh2Cl2(CO)4], the RhI atoms in (I) are both in a square-planar geometry, surrounded by two carbonyl groups and two bridging halogenated ligands. The dinuclear complex adopts a V-shape conformation, see Fig. 1, with intramolecular Rh···Rh distances of 3.385 (1) Å. The molecules are linked by metal–metal contacts, the intermolecular Rh···Rh distances being 3.637 (2) Å. These two Rh···Rh distances are longer then those observed for [Rh2Cl2(CO)4], where the values are 3.138 (1) (intramolecular) and 3.324 (1) Å (intermolecular). The same zigzag arrangement of molecules is observed in the solid state, see Fig. 2. The two RhI2(CO)2 moieties are planar, with a mean deviation of the fitted atoms of 0.0547 Å for Rh1 and 0.0394 Å for Rh2. The angle between the two planes is 59.1 (1)°.

Experimental top

Di-µ-iodo-bis[dicarbonylrhodium(I)] was prepared according to a previously described method (Powell & Shaw, 1968). Under 5 bar of carbon monoxide, a methanol solution (20 ml) of rhodium triiodide hydrate (500 mg) was refluxed (363 K) until the black solution turned red (48 h). After cooling to room temperature, the solution was evaporated to dryness. The dark-red residue was washed with hexane and filtered. 13C NMR (CD3CN): 203.21 p.p.m. IR (KBr, cm-1): 2078 (s), 2074 (s), 2040 (s), 2028 (s), 1390 (w), 578 (m). Red crystals suitable for X-ray diffraction analysis were grown by slow evaporation of a methanol solution.

Refinement top

All residual electronic densities greater than 1 e Å-3 are observed around the I and Rh atoms.

Computing details top

Data collection: EXPOSE in IPDS Software (Stoe & Cie, 2000); cell refinement: CELL in IPDS Software; data reduction: INTEGRATE in IPDS Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The molecular structure of [Rh2I2(CO)4]. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. The zigzag arrangement of [Rh2I2(CO)4] molecules along the b axis.
Di-µ-iodo-bis[dicarbonylrhodium(I)] top
Crystal data top
[Rh2I2(CO)4]2F(000) = 1008
Mr = 571.66Dx = 3.742 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 9.4160 (13) ÅCell parameters from 6307 reflections
b = 9.589 (1) Åθ = 2.2–25.9°
c = 11.3024 (16) ŵ = 9.31 mm1
β = 96.091 (17)°T = 153 K
V = 1014.7 (2) Å3Block, red
Z = 40.7 × 0.3 × 0.3 mm
Data collection top
Stoe IPDS
diffractometer
1980 independent reflections
Radiation source: fine-focus sealed tube1774 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.089
Detector resolution: 0.81Å pixels mm-1θmax = 26.1°, θmin = 2.8°
ϕ oscillation scansh = 1111
Absorption correction: multi-scan
(Blessing, 1995)
k = 1111
Tmin = 0.127, Tmax = 0.458l = 1313
6101 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.053 w = 1/[σ2(Fo2) + (0.0974P)2 + 2.9244P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.141(Δ/σ)max < 0.001
S = 1.08Δρmax = 3.71 e Å3
1980 reflectionsΔρmin = 2.67 e Å3
110 parametersExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.0052 (6)
Crystal data top
[Rh2I2(CO)4]2V = 1014.7 (2) Å3
Mr = 571.66Z = 4
Monoclinic, P21/nMo Kα radiation
a = 9.4160 (13) ŵ = 9.31 mm1
b = 9.589 (1) ÅT = 153 K
c = 11.3024 (16) Å0.7 × 0.3 × 0.3 mm
β = 96.091 (17)°
Data collection top
Stoe IPDS
diffractometer
1980 independent reflections
Absorption correction: multi-scan
(Blessing, 1995)
1774 reflections with I > 2σ(I)
Tmin = 0.127, Tmax = 0.458Rint = 0.089
6101 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.053110 parameters
wR(F2) = 0.1410 restraints
S = 1.08Δρmax = 3.71 e Å3
1980 reflectionsΔρmin = 2.67 e Å3
Special details top

Experimental. A crystal was mounted at 153 K on a Stoe Image Plate Diffraction System (Stoe & Cie, 2000) using Mo Kα graphite monochromated radiation. Image plate distance 70 mm, ϕ oscillation scans 0 - 200°, step Δϕ = 2.0°, 1 minutes per frame.

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
C10.0671 (11)0.1228 (10)0.2588 (9)0.025 (2)
C20.1481 (10)0.0689 (10)0.4197 (9)0.023 (2)
C30.0004 (11)0.6917 (11)0.3562 (9)0.028 (2)
C40.2285 (10)0.6430 (9)0.5029 (10)0.026 (2)
O10.1714 (8)0.0686 (8)0.2273 (7)0.0351 (18)
O20.1667 (7)0.0209 (8)0.4861 (7)0.0308 (16)
O30.0874 (8)0.7743 (8)0.3476 (6)0.0334 (17)
O40.2806 (9)0.7013 (8)0.5849 (7)0.0372 (18)
Rh10.10268 (7)0.21200 (7)0.31263 (6)0.0186 (3)
Rh20.14210 (7)0.55721 (7)0.36825 (6)0.0206 (3)
I10.33573 (6)0.35428 (6)0.39488 (5)0.0222 (3)
I20.01971 (6)0.42736 (6)0.17457 (5)0.0229 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.030 (5)0.016 (4)0.030 (5)0.008 (4)0.009 (4)0.001 (4)
C20.021 (4)0.024 (5)0.026 (5)0.004 (3)0.007 (4)0.001 (4)
C30.029 (5)0.027 (5)0.028 (5)0.006 (4)0.004 (4)0.003 (4)
C40.025 (5)0.018 (4)0.034 (6)0.007 (3)0.001 (4)0.001 (4)
O10.030 (4)0.035 (4)0.039 (4)0.015 (3)0.003 (3)0.000 (3)
O20.029 (4)0.026 (4)0.038 (4)0.005 (3)0.008 (3)0.007 (3)
O30.039 (4)0.030 (4)0.030 (4)0.011 (3)0.000 (3)0.001 (3)
O40.042 (4)0.037 (4)0.031 (4)0.002 (3)0.009 (3)0.001 (3)
Rh10.0214 (4)0.0154 (4)0.0200 (4)0.0008 (2)0.0067 (3)0.0011 (2)
Rh20.0237 (4)0.0155 (4)0.0228 (5)0.0020 (2)0.0039 (3)0.0001 (3)
I10.0199 (4)0.0186 (4)0.0286 (4)0.00146 (19)0.0050 (3)0.0005 (2)
I20.0274 (4)0.0195 (4)0.0216 (4)0.0007 (2)0.0023 (3)0.0020 (2)
Geometric parameters (Å, º) top
C1—O11.134 (12)C4—O41.147 (13)
C1—Rh11.858 (10)C4—Rh21.842 (10)
C2—O21.144 (12)Rh1—I22.6554 (9)
C2—Rh11.849 (9)Rh1—I12.6661 (9)
C3—O31.136 (12)Rh2—I12.6617 (9)
C3—Rh21.856 (10)Rh2—I22.6712 (10)
O1—C1—Rh1179.1 (9)I2—Rh1—I189.25 (3)
O2—C2—Rh1175.5 (9)C4—Rh2—C390.1 (4)
O3—C3—Rh2179.2 (10)C4—Rh2—I189.8 (3)
O4—C4—Rh2177.3 (9)C3—Rh2—I1176.1 (3)
C2—Rh1—C190.2 (4)C4—Rh2—I2178.7 (3)
C2—Rh1—I2174.1 (3)C3—Rh2—I291.0 (3)
C1—Rh1—I288.6 (3)I1—Rh2—I289.01 (3)
C2—Rh1—I191.6 (3)Rh2—I1—Rh178.82 (3)
C1—Rh1—I1176.1 (3)Rh1—I2—Rh278.84 (3)
O2—C2—Rh1—C129 (11)C4—Rh2—I1—Rh1143.7 (3)
O2—C2—Rh1—I250 (13)C3—Rh2—I1—Rh155 (5)
O2—C2—Rh1—I1147 (11)I2—Rh2—I1—Rh135.83 (3)
O1—C1—Rh1—C266 (56)C2—Rh1—I1—Rh2138.1 (3)
O1—C1—Rh1—I2108 (56)C1—Rh1—I1—Rh221 (5)
O1—C1—Rh1—I151 (59)I2—Rh1—I1—Rh236.08 (3)
O4—C4—Rh2—C335 (21)C2—Rh1—I2—Rh262 (3)
O4—C4—Rh2—I1149 (21)C1—Rh1—I2—Rh2140.8 (3)
O4—C4—Rh2—I2169 (11)I1—Rh1—I2—Rh235.93 (3)
O3—C3—Rh2—C4125 (73)C4—Rh2—I2—Rh116 (15)
O3—C3—Rh2—I1146 (70)C3—Rh2—I2—Rh1140.1 (3)
O3—C3—Rh2—I256 (73)I1—Rh2—I2—Rh136.00 (3)

Experimental details

Crystal data
Chemical formula[Rh2I2(CO)4]2
Mr571.66
Crystal system, space groupMonoclinic, P21/n
Temperature (K)153
a, b, c (Å)9.4160 (13), 9.589 (1), 11.3024 (16)
β (°) 96.091 (17)
V3)1014.7 (2)
Z4
Radiation typeMo Kα
µ (mm1)9.31
Crystal size (mm)0.7 × 0.3 × 0.3
Data collection
DiffractometerStoe IPDS
diffractometer
Absorption correctionMulti-scan
(Blessing, 1995)
Tmin, Tmax0.127, 0.458
No. of measured, independent and
observed [I > 2σ(I)] reflections
6101, 1980, 1774
Rint0.089
(sin θ/λ)max1)0.618
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.053, 0.141, 1.08
No. of reflections1980
No. of parameters110
Δρmax, Δρmin (e Å3)3.71, 2.67

Computer programs: EXPOSE in IPDS Software (Stoe & Cie, 2000), CELL in IPDS Software, INTEGRATE in IPDS Software, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997), SHELXL97.

Selected geometric parameters (Å, º) top
Rh1—I22.6554 (9)Rh2—I12.6617 (9)
Rh1—I12.6661 (9)Rh2—I22.6712 (10)
C2—Rh1—C190.2 (4)I1—Rh2—I289.01 (3)
I2—Rh1—I189.25 (3)Rh2—I1—Rh178.82 (3)
C4—Rh2—C390.1 (4)Rh1—I2—Rh278.84 (3)
 

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