3-Hydro­xy-2,4,6-tri­iodo­benz­aldehyde

The title compound, C₇H₃I₃O₂, crystallizes in space group P2₁2₁2₁ with a different molecular packing from the tri­bromo derivative (space group Pca2₁). The mol­ecules are linked in chains, running parallel to the c axis through weak O—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.011 Å
• R factor = 0.032
• wR factor = 0.104
• Data-to-parameter ratio = 26.8

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

General Notes



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           29.97
         From the CIF: _reflns_number_total               2951
         Count of symmetry unique reflns         1755
         Completeness (_total/calc)            168.15%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured      1196
         Fraction of Friedel pairs measured     0.681
         Are heavy atom types Z>Si present          yes
          Please check that the estimate of the number of Friedel pairs is
          correct. If it is not, please give the correct count in the
          _publ_section_exptl_refinement section of the submitted CIF.

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Computing details

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: HELENA (Spek, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2002); software used to prepare material for publication: SHELXL97.

3-Hydroxy-2,4,6-triiodobenzaldehyde

Crystal data

C7H3I3O2	Dx = 3.247 Mg m^−3
Mr = 499.79	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P212121	Cell parameters from 25 reflections
a = 4.3347 (7) Å	θ = 10.0–14.3°
b = 13.858 (3) Å	µ = 9.13 mm^−1
c = 17.019 (3) Å	T = 293 K
V = 1022.3 (3) Å^3	Prism, dark yellow
Z = 4	0.37 × 0.15 × 0.15 mm
F(000) = 880

Data collection

Enraf-Nonius CAD-4 diffractometer	2280 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.022
Graphite monochromator	θmax = 30.0°, θmin = 3.2°
profile data from w–2θ scans	h = 0→6
Absorption correction: ψ scan (North et al., 1968)	k = 0→19
Tmin = 0.201, Tmax = 0.254	l = −23→23
3402 measured reflections	3 standard reflections every 180 min
2951 independent reflections	intensity decay: 1.3%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.032	H-atom parameters constrained
wR(F^2) = 0.104	w = 1/[σ^2(Fo^2) + (0.0663P)^2 + 4.7049P] where P = (Fo^2 + 2Fc^2)/3
S = 0.90	(Δ/σ)max = 0.001
2951 reflections	Δρmax = 1.43 e Å^−3
110 parameters	Δρmin = −0.79 e Å^−3
0 restraints	Absolute structure: Flack (1983), 1196 Friedel pairs [Please check]
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.05 (8)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
I1	−0.17440 (15)	0.12016 (5)	0.39529 (3)	0.05150 (16)
I2	−0.10739 (14)	0.18627 (5)	0.73705 (3)	0.05037 (16)
I3	0.50807 (15)	−0.16694 (4)	0.60749 (5)	0.05674 (18)
O1	0.104 (2)	−0.0878 (7)	0.3890 (5)	0.079 (2)
O2	0.298 (2)	−0.0117 (6)	0.7241 (4)	0.066 (2)
H2	0.2046	0.0174	0.7585	0.098*
C1	0.1701 (18)	−0.0123 (6)	0.5127 (4)	0.0346 (15)
C2	−0.007 (2)	0.0699 (5)	0.5034 (4)	0.0363 (15)
C3	−0.081 (2)	0.1258 (6)	0.5674 (4)	0.0388 (16)
H3	−0.1992	0.1812	0.5606	0.047*
C4	0.019 (2)	0.1001 (6)	0.6423 (4)	0.0400 (17)
C5	0.1978 (19)	0.0178 (6)	0.6528 (4)	0.0395 (17)
C6	0.276 (2)	−0.0376 (6)	0.5879 (4)	0.0386 (17)
C7	0.260 (2)	−0.0728 (7)	0.4436 (5)	0.048 (2)
H7	0.4559	−0.1005	0.4440	0.057*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.0572 (3)	0.0620 (3)	0.0353 (2)	−0.0006 (3)	−0.0051 (3)	0.0100 (3)
I2	0.0511 (3)	0.0646 (4)	0.0354 (2)	0.0052 (3)	0.0040 (2)	−0.0092 (2)
I3	0.0530 (3)	0.0435 (3)	0.0737 (4)	0.0112 (3)	0.0116 (3)	0.0191 (3)
O1	0.070 (5)	0.100 (6)	0.068 (5)	0.008 (5)	−0.012 (5)	−0.045 (4)
O2	0.085 (6)	0.066 (5)	0.046 (3)	0.008 (4)	−0.005 (4)	0.012 (3)
C1	0.031 (4)	0.037 (4)	0.036 (3)	−0.004 (3)	0.003 (3)	−0.004 (3)
C2	0.038 (4)	0.036 (3)	0.035 (3)	−0.001 (3)	−0.002 (3)	0.003 (3)
C3	0.044 (4)	0.034 (3)	0.038 (4)	0.001 (3)	0.000 (3)	0.001 (3)
C4	0.043 (4)	0.048 (4)	0.029 (3)	0.000 (4)	0.004 (3)	−0.001 (3)
C5	0.038 (4)	0.044 (4)	0.036 (4)	−0.003 (3)	0.003 (3)	0.010 (3)
C6	0.044 (4)	0.034 (4)	0.037 (4)	−0.009 (3)	0.004 (3)	0.007 (3)
C7	0.054 (5)	0.047 (5)	0.042 (4)	−0.002 (4)	0.004 (4)	−0.004 (4)

Geometric parameters (Å, º)

I1—C2	2.097 (8)	C1—C7	1.496 (11)
I2—C4	2.081 (8)	C2—C3	1.373 (11)
I3—C6	2.082 (8)	C3—C4	1.393 (11)
O1—C7	1.170 (12)	C3—H3	0.9300
O2—C5	1.352 (10)	C4—C5	1.390 (12)
O2—H2	0.8200	C5—C6	1.387 (11)
C1—C2	1.384 (11)	C7—H7	0.9300
C1—C6	1.404 (11)
C5—O2—H2	109.5	C3—C4—I2	118.7 (6)
C2—C1—C6	119.4 (7)	C5—C4—I2	121.2 (6)
C2—C1—C7	121.2 (7)	O2—C5—C6	117.9 (8)
C6—C1—C7	119.4 (8)	O2—C5—C4	122.9 (8)
C3—C2—C1	120.3 (7)	C6—C5—C4	119.1 (7)
C3—C2—I1	115.3 (6)	C5—C6—C1	120.5 (7)
C1—C2—I1	124.4 (6)	C5—C6—I3	117.8 (6)
C2—C3—C4	120.5 (7)	C1—C6—I3	121.3 (6)
C2—C3—H3	119.7	O1—C7—C1	124.8 (9)
C4—C3—H3	119.7	O1—C7—H7	117.6
C3—C4—C5	120.2 (7)	C1—C7—H7	117.6
C6—C1—C2—C3	−0.4 (12)	I2—C4—C5—C6	179.8 (6)
C7—C1—C2—C3	−178.3 (8)	O2—C5—C6—C1	178.0 (8)
C6—C1—C2—I1	178.4 (6)	C4—C5—C6—C1	−1.4 (12)
C7—C1—C2—I1	0.5 (11)	O2—C5—C6—I3	5.0 (11)
C1—C2—C3—C4	−0.5 (13)	C4—C5—C6—I3	−174.4 (6)
I1—C2—C3—C4	−179.5 (7)	C2—C1—C6—C5	1.4 (12)
C2—C3—C4—C5	0.5 (14)	C7—C1—C6—C5	179.3 (8)
C2—C3—C4—I2	−178.8 (7)	C2—C1—C6—I3	174.2 (6)
C3—C4—C5—O2	−179.0 (9)	C7—C1—C6—I3	−7.9 (10)
I2—C4—C5—O2	0.4 (12)	C2—C1—C7—O1	−36.8 (14)
C3—C4—C5—C6	0.4 (13)	C6—C1—C7—O1	145.3 (11)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O1^i	0.82	2.56	3.157 (13)	130
O2—H2···I2	0.82	2.73	3.266 (8)	125

Symmetry code: (i) −x+1/2, −y, z+1/2.