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An interesting case of `halogen-bonding-promoted' crystal structure architecture is presented. The two title compounds, C8H8Br2O2 and C8H8I2O2, have almost indistinguishable mol­ecular structures but very different spatial organization, and this is mainly due to differences in the halogen-bonding inter­actions in which the different species present, i.e. Br and I, take part. The dibromo structure exhibits a [pi]-bonded columnar array involving all four independent mol­ecules in the asymmetric unit, with inter­columnar inter­actions governed by C-Br...Br-C links and with no C-Br...O/N inter­actions present. In the diiodo structure, instead, the C-I...O synthon prevails, defining linear chains, in turn inter­linked by C-I...I-C inter­actions.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S010827010803309X/uk3001sup1.cif
Contains datablocks global, I, II

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S010827010803309X/uk3001Isup2.hkl
Contains datablock I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S010827010803309X/uk3001IIsup3.hkl
Contains datablock II

CCDC references: 710755; 710756

Comment top

For many years, interest in the study of noncovalent interactions has been monopolized almost entirely by hydrogen bonding and, more recently, ππ and C—H···π interactions. The driving force for this interest was (and still is) the fundamental role these interactions play in molecular recognition, a chemical process basic to life itself but nowadays also closely related to many frontier technology enterprises. In the past few years, however, a different (though closely related) type of noncovalent interactions has begun to attract the scientist's attention, the so called `halogen bond', where the main actor is a highly polarized halogen species. Under this wide umbrella, however, shelter a large variety of interactions of different aspects and behaviours; since only some of these will be used in the present work we will briefly introduce them here, directing the interested reader to more specific and qualified literature (e.g. Metrangolo et al., 2007).

In particular, we shall deal with interactions of the C—X···O/N and C—X···X—C type (where X is a halogen). The main aspects of the former type are quite in tune with the conventional hydrogen bond, and accordingly its most conspicuous geometrical characteristics are (a) a rather large C—X···O/N angle (> 150°) and (b) an X···O distance shorter than the sum of the van der Waals radii. The second type is rather more complex from a descriptive point of view, but the main aspects could be summarized as follows: If we denote the larger of the two C—X···X angles as θ1, and the smaller as θ2, then two types of C—X···X—C interactions can be envisaged (Desiraju & Parthasarathy, 1989): the (so-called) I1 interactions, which have θ1 = θ2, and the I2 interactions, which have θ1 180 ° and θ2 90 °. In both cases, the X···X distance is shorter than the sum of the van der Waals radii.

The structures reported herein correspond to some of the simplest systems where this type of interaction can take place: a couple of dihalogenated aryl derivatives, namely 1,2-dibromo-4,5-dimethoxybenzene, C8H8Br2O2, (I) (or dibromo veratrole), and 1,2-diiodo-4,5-dimethoxybenzene, C8H8I2O2, (II) (or diiodo veratrole). Diiodo veratrole is a versatile starting point in many chemical reactions, including the synthesis of electron-rich phtalocyanines, conductive polymers (Bhongale et al., 2006) and cathecol-based ligands (Kinder & Youngs, 1996). It belongs to the same family of diiodobenzene, but the methoxy substituents makes this compound more electron-rich, thus rendering it more reactive towards electrophiles. The crystal structures of these closely related compounds are governed by a variety of nonbonding interactions, but the leading organizing forces are the above-mentioned `halogen bonds', which differences we will discuss in detail.

The asymmetric unit of (I) is composed of four identical, though non-equivalent, C8H8Br2O2 molecules (AD, Fig. 1), disposed one on top of the other in an almost perfect 41 arrangement, with a relative rotation of ~π/2 and a graphitic translation shift (range \sim 3.64–3.80 Å; Table 1) when going from one to the next. This almost perfect columnar disposition is maintained by the fact that the array is continued via two inversion operations with their centres in the column axis, at (0, 1, 1/2) and (1/2, 0, 0) (marked as x and y in Fig. 2).

This preserves the alignment along the [121] columnar direction of the π-bonded chain, while disrupting the pseudo 41 piling sequence, turning it into a ···ABCDDCBAABCD··· array (Fig. 2) with DD and AA related by inversion operations, and at a slightly longer than typical center-to-center distance [4.061 (1) and 4.227 (1) Å, respectively; Table 1]. The columnar alignment seems to be the consequence of both ππ and dipolar C—O—C interactions: the dipole of the C3/O1/C7 ether group is almost aligned with that of the C4/O2/C8 group of the adjacent molecule, but with opposite sense (see Fig. 1).

Besides these ππ interactions connecting aromatic rings in a columnar-like array, the structure presents some other nonbonding interactions at nearly right angles to the column direction, of which the most important are the C—Br···Br—C (type I2) halogen-bond contacts linking molecules with their nearest neighbours. The most relevant of these contacts (d < 3.9 Å) are shown in Fig. 1 and Table 2, all of them fulfilling the above-mentioned conditions for an I2 interaction (first four entries) and for an I1 interaction (last two entries). There are in addition a couple of nonconventional C—H···O bonds, presented in Table 3. All these interactions link neighbouring chains together into a densely connected three-dimensional structure (Fig. 3).

At a molecular level, (II) (Fig. 4) is almost identical to its Br analogue (I).

The main interactions in the structure are mediated by the halogen atoms, and in this respect the situation is highly asymmetric, atom I2 being much more active than I1. The strongest interaction is the head-to-tail link in which I2 makes a bifurcated contact with atoms O1 and O2 in a neighbouring molecule (Table 4 and Fig. 4), thus defining a wavy chain running along the b-axis direction. These chains, in turn, are linked by a halogen–halogen contact (Table 5), into an, also wavy, two-dimensional structure parallel to (100). Both interactions are illustrated as broken lines in Fig. 4, where the two-dimensional array is shown; Fig. 5, in turn, exemplifies though a side view of the latter the wavy nature of the chain juxtaposition. Piling of these two-dimensional elements promotes a couple of π interactions of different type, viz. a ππ contact (Table 6) and a C—H···π hydrogen bond (Table 7), which link the two-dimensional structures into a three-dimensional one.

Thus, we have described two compounds that present almost indistinguishable molecular structures but which, in spite of the molecular similarities, give rise to absolutely different packing arrangements, and this seems to be a result of the different strengths of the C—X···O and C—X···X—C interactions as a result of the change in the corresponding halogen species involved. In this respect, the C—Br···Br—C interaction appears to be much more feasible than C—Br···O [not a single example of the latter interaction is present in (I)]; conversely, the main synthon in (II), which leads to the formation of the chains, is constructed out of the C—I···O link, the C—I···I—C interaction appearing as second order and serving as an interchain linkage.

It is to be expected that these types of interactions will become more fully recognized and their incidence in crystal architectures will be analyzed in more detail, so that better and more efficient ab initio molecular designs can be achieved through their statistical rationalization.

Related literature top

For related literature, see: Bhongale et al. (2006); Desiraju & Parthasarathy (1989); Kinder & Youngs (1996); Metrangolo et al. (2007).

Experimental top

Both compounds were prepared by direct halogenation of dimethoxybenzene, using Br2 and ICl for the dibromo and diiodo compounds, respectively.

For the synthesis of (I), in a three-necked 250 ml flask equipped with a thermometer and a pressure-compensated addition funnel were placed veratrole (10.141 g) and dichloromethane (125 ml) with a magnetic stirring bar. The flask was placed in an ice-bath, and while the mixture cooled to 278 K, a hose with a funnel was attached to the remaining neck. The funnel was carefully placed facing down just over the surface of an Na2CO3 solution, in such a way that the acid vapours generated would be neutralized by the carbonate. A solution of Br2 (8 ml) in CH2Cl2 (20 ml) was loaded on the addition funnel and added dropwise with continuous stirring for a period of 1 h. The ice-bath was removed and the solution was stirred overnight. The contents of the flask were carefully poured into a separation funnel containing a solution of sodium bisulphite. The organic phase was washed with water, Na2CO3 and water again, dried over MgSO4, and evaporated. The crude product was recrystallized from ethanol until no traces of the monobrominated product were detected by thin-layer chromatography, yielding 20.96 g (96%) of white [colourless according to CIF] crystals (m.p. 362–364 K).

The diiodo compound was prepared in a similar fashion to the brominated analogue. Namely, veratrole (9.106 g), dichloromethane (125 ml) and a magnetic stirring bar were placed in a 250 ml three-necked flask. The mixture was cooled to 278 K using an ice-bath, and a pressure-compensated addition funnel and a system for the evacuation of the generated acidic vapours similar to that used in the synthesis of the dibromo compound were attached to the flask. A solution of ICl (22.5 g) in CH2Cl2 (20 ml) was loaded into the addition funnel and then added slowly dropwise (0.2 ml min-1), with continuous stirring. The cold bath was removed, and after 1 h of stirring at room temperature, the solution was poured into a separation funnel containing sodium bisulphite. The organic phase was separated, washed with water, Na2CO3 and then water again, and dried over MgSO4. The solvent was evaporated and the purple tar obtained was passed quickly through a fritted disc funnel filled with a short column of silica, eluting with a mixture of dichloromethane and cyclohexane. The almost colourless solution was evaporated and the white solid was recrystallized several times from ethanol, yielding 18.22 g (70.9%) of white needles [colourless blocks according to CIF] (m.p. 404–405 K).

Crystals of both compounds were obtained by slow evaporation of an ethanol solution of the corresponding dihalodimethoxybenzene. Depending on the speed of evaporation, crystals with dimensions ranging from less than a millimeter up to a centimeter were obtained. Both compounds showed 1H NMR spectra consistent on two singlets, one corresponding to the aromatic H atoms (at 7.06 and 7.23 p.p.m. for the dibromo and diiodo compounds) and one corresponding to the methoxy H atoms at 3.83 p.p.m. Elemental analysis: expected (calculated) for C8H8O2Br2: C 32.6 (32.47), H 2.7 (2.72)%; for C8H8O2I2: C 24.8 (24.64), H 2.1 (2.07)%.

Refinement top

H atoms were placed at calculated positions [C—H = 0.93 Å (aromatic) and 0.96 Å (methyl)] and allowed to ride; methyl groups were allowed to rotate as well. Uiso(H) values were taken as xUeq(host) [x = 1.2 (aromatic) and 1.5 (methyl)].

Computing details top

Data collection: SMART (Bruker, 2001) for (I); MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1988) for (II). Cell refinement: SAINT (Bruker, 2002) for (I); MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1988) for (II). Data reduction: SAINT (Bruker, 2002) for (I); MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1988) for (II). For both compounds, 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 (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. The asymmetric unit of (I), showing the four independent molecules (labelled AD), with displacement ellipsoids drawn at the 40% probability level. Unlabelled atoms follow the same label sequence as molecule A. ππ bonds are represented by dashed lines connecting ring centres and Br···Br interactions by double-dashed lines. [Symmetry codes: (i) -x + 1, -y + 2, -z + 1; (ii) -x, -y +1, -z + 1; (iii) -x, -y, -z; (iv) -x + 1, -y + 1, -z; (v) -x + 1, -y + 1, -z + 1; (vi) -x, -y +1, -z.]
[Figure 2] Fig. 2. A view of the packing (I), showing the way in which a column is formed (see text).
[Figure 3] Fig. 3. A view of the packing (I), projected down [121], the column direction, and showing the way in which parallel chains interact to form a three-dimensional structure.
[Figure 4] Fig. 4. The two-dimensional structure in (II), parallel to (100), with displacement ellipsoids drawn at the 40% probability level. [Symmetry codes: (i) -x + 1/2, -y + 1, z + 1/2, (ii) -x + 1/2, y - 1/2, z.]
[Figure 5] Fig. 5. The same two-dimensional structure as in Fig. 4, viewed at right angles and revealing its `wavy' character.
(I) 1,2-Dibromo-4,5-dimethoxybenzene top
Crystal data top
C8H8Br2O2Z = 8
Mr = 295.96F(000) = 1136
Triclinic, P1Dx = 2.020 Mg m3
Hall symbol: -P 1Melting point: 363(1) K
a = 10.1172 (5) ÅMo Kα radiation, λ = 0.71073 Å
b = 10.2052 (5) ÅCell parameters from 6539 reflections
c = 20.2764 (10) Åθ = 2.5–24.7°
α = 104.1710 (12)°µ = 8.29 mm1
β = 98.9405 (10)°T = 294 K
γ = 101.0630 (12)°Blocks, colourless
V = 1946.46 (17) Å30.16 × 0.14 × 0.14 mm
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
8656 independent reflections
Radiation source: fine-focus sealed tube5046 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.033
phi and ω scansθmax = 27.9°, θmin = 2.1°
Absorption correction: multi-scan
(SADABS; Bruker, 2002)
h = 1313
Tmin = 0.28, Tmax = 0.32k = 1313
30774 measured reflectionsl = 2626
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)] = 0.036Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.097H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.038P)2 + 0.6302P]
where P = (Fo2 + 2Fc2)/3
8656 reflections(Δ/σ)max = 0.001
441 parametersΔρmax = 0.44 e Å3
0 restraintsΔρmin = 0.46 e Å3
Crystal data top
C8H8Br2O2γ = 101.0630 (12)°
Mr = 295.96V = 1946.46 (17) Å3
Triclinic, P1Z = 8
a = 10.1172 (5) ÅMo Kα radiation
b = 10.2052 (5) ŵ = 8.29 mm1
c = 20.2764 (10) ÅT = 294 K
α = 104.1710 (12)°0.16 × 0.14 × 0.14 mm
β = 98.9405 (10)°
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
8656 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2002)
5046 reflections with I > 2σ(I)
Tmin = 0.28, Tmax = 0.32Rint = 0.033
30774 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0360 restraints
wR(F2) = 0.097H-atom parameters constrained
S = 1.02Δρmax = 0.44 e Å3
8656 reflectionsΔρmin = 0.46 e Å3
441 parameters
Special details top

Experimental. Characterization was performed by NMR (Bruker Avance300 using CDCl3 as solvent and its residual peak as internal reference at 7.26 p.p.m.) and elemental analysis (Carlo Erba CHNS-O EA1108 at the Servicio de Microanálisis of Inquimae).

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Br1A0.18852 (5)0.84633 (5)0.56347 (2)0.08861 (16)
Br2A0.11747 (5)0.62952 (5)0.47438 (2)0.08819 (15)
O1A0.1572 (3)1.0684 (3)0.35540 (14)0.0836 (8)
O2A0.0780 (3)0.9081 (3)0.29058 (14)0.0872 (9)
C1A0.0987 (4)0.8591 (4)0.47729 (18)0.0612 (9)
C2A0.1624 (4)0.9604 (4)0.44997 (19)0.0646 (10)
H2A0.24711.01930.47430.077*
C3A0.1027 (4)0.9747 (4)0.38795 (18)0.0645 (10)
C4A0.0254 (4)0.8857 (4)0.35145 (18)0.0657 (10)
C5A0.0879 (4)0.7858 (4)0.37868 (19)0.0668 (10)
H5A0.17270.72690.35460.080*
C6A0.0262 (4)0.7716 (4)0.44160 (18)0.0618 (9)
C7A0.2883 (4)1.1603 (5)0.3899 (2)0.0869 (13)
H7AA0.31521.22150.36260.130*
H7AB0.35561.10690.39540.130*
H7AC0.28211.21410.43480.130*
C8A0.2073 (4)0.8181 (6)0.2512 (2)0.1095 (18)
H8AA0.23200.84160.20860.164*
H8AB0.27700.82920.27790.164*
H8AC0.19970.72320.24070.164*
Br1B0.51028 (5)0.84947 (5)0.39054 (2)0.09023 (16)
Br2B0.40577 (5)0.60365 (5)0.46979 (2)0.08438 (15)
O1B0.0405 (3)0.6253 (3)0.21122 (14)0.0760 (8)
O2B0.0379 (3)0.4381 (3)0.27175 (14)0.0773 (7)
C1B0.3397 (4)0.7172 (4)0.35633 (19)0.0602 (9)
C2B0.2559 (4)0.7211 (4)0.29605 (19)0.0640 (10)
H2B0.28540.78740.27380.077*
C3B0.1298 (4)0.6281 (4)0.26885 (18)0.0587 (9)
C4B0.0868 (4)0.5265 (4)0.30234 (19)0.0594 (9)
C5B0.1704 (4)0.5233 (4)0.36135 (18)0.0604 (9)
H5B0.14210.45640.38350.073*
C6B0.2966 (4)0.6177 (4)0.38877 (18)0.0599 (9)
C7B0.0833 (5)0.7271 (5)0.1756 (2)0.0865 (13)
H7BA0.01200.71630.13610.130*
H7BB0.16610.71380.16030.130*
H7BC0.10030.81890.20680.130*
C8B0.0872 (4)0.3350 (4)0.3047 (2)0.0772 (11)
H8BA0.17490.27790.27770.116*
H8BB0.09710.38000.35050.116*
H8BC0.02260.27800.30810.116*
Br1C0.15911 (5)0.45176 (5)0.02682 (2)0.09230 (17)
Br2C0.47373 (5)0.65530 (5)0.11271 (2)0.08761 (16)
O1C0.1936 (3)0.2113 (3)0.22690 (13)0.0698 (7)
O2C0.4349 (3)0.3628 (3)0.29126 (13)0.0693 (7)
C1C0.2523 (4)0.4309 (4)0.11005 (18)0.0610 (9)
C2C0.1871 (4)0.3281 (4)0.13655 (19)0.0619 (9)
H2C0.10050.27250.11290.074*
C3C0.2494 (4)0.3082 (4)0.19688 (18)0.0572 (9)
C4C0.3800 (4)0.3909 (4)0.23244 (17)0.0559 (9)
C5C0.4440 (4)0.4937 (4)0.20656 (18)0.0585 (9)
H5C0.53030.55020.23020.070*
C6C0.3789 (4)0.5125 (4)0.14515 (19)0.0595 (9)
C7C0.0615 (4)0.1217 (4)0.1909 (2)0.0764 (11)
H7CA0.02940.06320.21850.115*
H7CB0.06960.06480.14700.115*
H7CC0.00280.17710.18300.115*
C8C0.5725 (4)0.4376 (5)0.3258 (2)0.0782 (12)
H8CA0.60080.40560.36520.117*
H8CB0.57610.53520.34110.117*
H8CC0.63310.42220.29410.117*
Br1D0.13475 (5)0.12779 (5)0.02042 (2)0.08027 (14)
Br2D0.26373 (5)0.09162 (5)0.06800 (2)0.08695 (15)
O1D0.5780 (3)0.1239 (3)0.21456 (13)0.0792 (8)
O2D0.6751 (3)0.2925 (3)0.14934 (13)0.0783 (8)
C1D0.3045 (4)0.0067 (4)0.05654 (18)0.0573 (9)
C2D0.3764 (4)0.0138 (4)0.12185 (18)0.0602 (9)
H2D0.34110.04680.14590.072*
C3D0.4984 (4)0.1094 (4)0.15087 (18)0.0608 (9)
C4D0.5534 (4)0.2009 (4)0.11520 (18)0.0618 (9)
C5D0.4818 (4)0.1936 (4)0.05073 (18)0.0620 (9)
H5D0.51710.25380.02650.074*
C6D0.3564 (4)0.0962 (4)0.02122 (18)0.0596 (9)
C7D0.5192 (5)0.0460 (5)0.2567 (2)0.0939 (15)
H7DA0.58170.06830.30080.141*
H7DB0.50260.05170.23380.141*
H7DC0.43380.06880.26380.141*
C8D0.7344 (4)0.3886 (4)0.1158 (2)0.0839 (12)
H8DA0.81990.44640.14500.126*
H8DB0.67230.44570.10710.126*
H8DC0.75120.33870.07240.126*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br1A0.0960 (3)0.0955 (3)0.0719 (3)0.0127 (3)0.0071 (2)0.0427 (2)
Br2A0.1043 (4)0.0785 (3)0.0778 (3)0.0019 (3)0.0137 (3)0.0368 (2)
O1A0.0754 (19)0.102 (2)0.0684 (17)0.0081 (16)0.0056 (14)0.0438 (16)
O2A0.0713 (18)0.124 (2)0.0612 (16)0.0050 (17)0.0042 (14)0.0500 (16)
C1A0.070 (3)0.070 (2)0.0483 (19)0.024 (2)0.0111 (18)0.0212 (18)
C2A0.059 (2)0.073 (3)0.057 (2)0.0090 (19)0.0055 (18)0.0204 (19)
C3A0.065 (2)0.075 (3)0.053 (2)0.006 (2)0.0108 (18)0.0265 (19)
C4A0.064 (2)0.084 (3)0.050 (2)0.009 (2)0.0092 (18)0.0277 (19)
C5A0.060 (2)0.078 (3)0.057 (2)0.005 (2)0.0086 (18)0.020 (2)
C6A0.071 (3)0.060 (2)0.057 (2)0.013 (2)0.0166 (19)0.0212 (18)
C7A0.075 (3)0.094 (3)0.086 (3)0.004 (2)0.011 (2)0.039 (3)
C8A0.072 (3)0.169 (5)0.075 (3)0.013 (3)0.009 (2)0.058 (3)
Br1B0.0765 (3)0.0857 (3)0.0943 (3)0.0094 (2)0.0129 (2)0.0412 (3)
Br2B0.0791 (3)0.1052 (3)0.0695 (3)0.0147 (3)0.0057 (2)0.0450 (2)
O1B0.0723 (18)0.0818 (18)0.0744 (17)0.0076 (14)0.0081 (14)0.0466 (15)
O2B0.0623 (17)0.0847 (19)0.0833 (18)0.0007 (15)0.0009 (14)0.0444 (15)
C1B0.055 (2)0.059 (2)0.062 (2)0.0094 (18)0.0004 (17)0.0202 (18)
C2B0.070 (3)0.063 (2)0.064 (2)0.015 (2)0.0088 (19)0.0334 (19)
C3B0.058 (2)0.064 (2)0.059 (2)0.0192 (19)0.0036 (18)0.0277 (18)
C4B0.054 (2)0.066 (2)0.062 (2)0.0144 (19)0.0083 (18)0.0278 (19)
C5B0.057 (2)0.069 (2)0.062 (2)0.0150 (19)0.0074 (18)0.0345 (19)
C6B0.062 (2)0.069 (2)0.054 (2)0.022 (2)0.0048 (17)0.0260 (18)
C7B0.091 (3)0.098 (3)0.078 (3)0.017 (3)0.001 (2)0.055 (3)
C8B0.068 (3)0.083 (3)0.086 (3)0.005 (2)0.018 (2)0.043 (2)
Br1C0.1027 (4)0.0917 (3)0.0714 (3)0.0022 (3)0.0193 (2)0.0430 (2)
Br2C0.0905 (3)0.0816 (3)0.0888 (3)0.0050 (2)0.0015 (2)0.0514 (2)
O1C0.0701 (17)0.0681 (16)0.0683 (16)0.0005 (14)0.0031 (13)0.0344 (13)
O2C0.0641 (17)0.0800 (18)0.0633 (15)0.0076 (14)0.0029 (13)0.0368 (13)
C1C0.067 (2)0.058 (2)0.057 (2)0.0122 (19)0.0017 (18)0.0249 (18)
C2C0.058 (2)0.058 (2)0.062 (2)0.0034 (18)0.0028 (18)0.0213 (18)
C3C0.061 (2)0.053 (2)0.057 (2)0.0108 (18)0.0065 (18)0.0224 (17)
C4C0.060 (2)0.055 (2)0.053 (2)0.0146 (18)0.0037 (17)0.0204 (17)
C5C0.055 (2)0.053 (2)0.064 (2)0.0069 (17)0.0008 (17)0.0212 (17)
C6C0.064 (2)0.054 (2)0.063 (2)0.0103 (18)0.0079 (19)0.0270 (17)
C7C0.076 (3)0.061 (2)0.085 (3)0.004 (2)0.015 (2)0.025 (2)
C8C0.064 (3)0.096 (3)0.069 (2)0.009 (2)0.010 (2)0.035 (2)
Br1D0.0746 (3)0.0780 (3)0.0734 (3)0.0069 (2)0.0003 (2)0.0236 (2)
Br2D0.0798 (3)0.1106 (4)0.0657 (3)0.0040 (3)0.0051 (2)0.0437 (2)
O1D0.086 (2)0.0850 (19)0.0561 (15)0.0008 (15)0.0084 (14)0.0320 (14)
O2D0.0746 (18)0.0818 (18)0.0661 (16)0.0087 (15)0.0006 (14)0.0292 (14)
C1D0.059 (2)0.053 (2)0.057 (2)0.0097 (17)0.0081 (17)0.0160 (17)
C2D0.067 (2)0.053 (2)0.060 (2)0.0079 (19)0.0086 (18)0.0238 (17)
C3D0.070 (3)0.060 (2)0.053 (2)0.015 (2)0.0076 (18)0.0212 (18)
C4D0.063 (2)0.063 (2)0.055 (2)0.0074 (19)0.0063 (18)0.0189 (18)
C5D0.065 (2)0.065 (2)0.059 (2)0.0070 (19)0.0103 (18)0.0311 (18)
C6D0.061 (2)0.064 (2)0.054 (2)0.0149 (19)0.0061 (18)0.0210 (18)
C7D0.121 (4)0.093 (3)0.060 (2)0.000 (3)0.005 (2)0.043 (2)
C8D0.074 (3)0.083 (3)0.088 (3)0.004 (2)0.008 (2)0.035 (2)
Geometric parameters (Å, º) top
Br1A—C1A1.887 (3)Br1C—C1C1.881 (3)
Br2A—C6A1.883 (4)Br2C—C6C1.899 (4)
O1A—C3A1.369 (4)O1C—C3C1.361 (4)
O1A—C7A1.429 (5)O1C—C7C1.434 (4)
O2A—C4A1.356 (4)O2C—C4C1.355 (4)
O2A—C8A1.431 (5)O2C—C8C1.428 (4)
C1A—C6A1.373 (5)C1C—C6C1.363 (5)
C1A—C2A1.388 (5)C1C—C2C1.395 (5)
C2A—C3A1.362 (5)C2C—C3C1.366 (5)
C2A—H2A0.9300C2C—H2C0.9300
C3A—C4A1.405 (5)C3C—C4C1.398 (5)
C4A—C5A1.371 (5)C4C—C5C1.383 (5)
C5A—C6A1.384 (5)C5C—C6C1.389 (5)
C5A—H5A0.9300C5C—H5C0.9300
C7A—H7AA0.9600C7C—H7CA0.9600
C7A—H7AB0.9600C7C—H7CB0.9600
C7A—H7AC0.9600C7C—H7CC0.9600
C8A—H8AA0.9600C8C—H8CA0.9600
C8A—H8AB0.9600C8C—H8CB0.9600
C8A—H8AC0.9600C8C—H8CC0.9600
Br1B—C1B1.886 (4)Br1D—C1D1.893 (4)
Br2B—C6B1.885 (3)Br2D—C6D1.889 (3)
O1B—C3B1.352 (4)O1D—C3D1.369 (4)
O1B—C7B1.442 (5)O1D—C7D1.423 (5)
O2B—C4B1.355 (4)O2D—C4D1.358 (4)
O2B—C8B1.431 (4)O2D—C8D1.420 (5)
C1B—C6B1.379 (5)C1D—C6D1.370 (5)
C1B—C2B1.389 (5)C1D—C2D1.386 (5)
C2B—C3B1.376 (5)C2D—C3D1.362 (5)
C2B—H2B0.9300C2D—H2D0.9300
C3B—C4B1.410 (5)C3D—C4D1.401 (5)
C4B—C5B1.365 (5)C4D—C5D1.369 (5)
C5B—C6B1.383 (5)C5D—C6D1.394 (5)
C5B—H5B0.9300C5D—H5D0.9300
C7B—H7BA0.9600C7D—H7DA0.9600
C7B—H7BB0.9600C7D—H7DB0.9600
C7B—H7BC0.9600C7D—H7DC0.9600
C8B—H8BA0.9600C8D—H8DA0.9600
C8B—H8BB0.9600C8D—H8DB0.9600
C8B—H8BC0.9600C8D—H8DC0.9600
C3A—O1A—C7A117.0 (3)C3C—O1C—C7C116.9 (3)
C4A—O2A—C8A117.1 (3)C4C—O2C—C8C117.4 (3)
C6A—C1A—C2A119.9 (3)C6C—C1C—C2C119.4 (3)
C6A—C1A—Br1A121.9 (3)C6C—C1C—Br1C122.7 (3)
C2A—C1A—Br1A118.2 (3)C2C—C1C—Br1C117.9 (3)
C3A—C2A—C1A120.9 (4)C3C—C2C—C1C120.6 (3)
C3A—C2A—H2A119.5C3C—C2C—H2C119.7
C1A—C2A—H2A119.5C1C—C2C—H2C119.7
C2A—C3A—O1A126.0 (4)O1C—C3C—C2C124.8 (3)
C2A—C3A—C4A119.3 (4)O1C—C3C—C4C115.2 (3)
O1A—C3A—C4A114.7 (3)C2C—C3C—C4C120.0 (3)
O2A—C4A—C5A125.1 (4)O2C—C4C—C5C124.5 (3)
O2A—C4A—C3A115.4 (3)O2C—C4C—C3C116.0 (3)
C5A—C4A—C3A119.5 (3)C5C—C4C—C3C119.5 (3)
C4A—C5A—C6A120.8 (4)C4C—C5C—C6C119.7 (3)
C4A—C5A—H5A119.6C4C—C5C—H5C120.1
C6A—C5A—H5A119.6C6C—C5C—H5C120.1
C1A—C6A—C5A119.5 (4)C1C—C6C—C5C120.9 (3)
C1A—C6A—Br2A122.4 (3)C1C—C6C—Br2C121.9 (3)
C5A—C6A—Br2A118.1 (3)C5C—C6C—Br2C117.3 (3)
O1A—C7A—H7AA109.5O1C—C7C—H7CA109.5
O1A—C7A—H7AB109.5O1C—C7C—H7CB109.5
H7AA—C7A—H7AB109.5H7CA—C7C—H7CB109.5
O1A—C7A—H7AC109.5O1C—C7C—H7CC109.5
H7AA—C7A—H7AC109.5H7CA—C7C—H7CC109.5
H7AB—C7A—H7AC109.5H7CB—C7C—H7CC109.5
O2A—C8A—H8AA109.5O2C—C8C—H8CA109.5
O2A—C8A—H8AB109.5O2C—C8C—H8CB109.5
H8AA—C8A—H8AB109.5H8CA—C8C—H8CB109.5
O2A—C8A—H8AC109.5O2C—C8C—H8CC109.5
H8AA—C8A—H8AC109.5H8CA—C8C—H8CC109.5
H8AB—C8A—H8AC109.5H8CB—C8C—H8CC109.5
C3B—O1B—C7B116.7 (3)C3D—O1D—C7D116.8 (3)
C4B—O2B—C8B117.4 (3)C4D—O2D—C8D117.8 (3)
C6B—C1B—C2B119.5 (3)C6D—C1D—C2D119.9 (3)
C6B—C1B—Br1B122.4 (3)C6D—C1D—Br1D122.7 (3)
C2B—C1B—Br1B118.1 (3)C2D—C1D—Br1D117.4 (3)
C3B—C2B—C1B120.9 (3)C3D—C2D—C1D120.1 (3)
C3B—C2B—H2B119.6C3D—C2D—H2D119.9
C1B—C2B—H2B119.6C1D—C2D—H2D119.9
O1B—C3B—C2B125.0 (3)C2D—C3D—O1D124.7 (3)
O1B—C3B—C4B115.8 (3)C2D—C3D—C4D120.7 (3)
C2B—C3B—C4B119.2 (3)O1D—C3D—C4D114.6 (3)
O2B—C4B—C5B125.2 (3)O2D—C4D—C5D125.5 (4)
O2B—C4B—C3B115.4 (3)O2D—C4D—C3D115.6 (3)
C5B—C4B—C3B119.4 (3)C5D—C4D—C3D118.9 (3)
C4B—C5B—C6B121.1 (3)C4D—C5D—C6D120.4 (3)
C4B—C5B—H5B119.4C4D—C5D—H5D119.8
C6B—C5B—H5B119.4C6D—C5D—H5D119.8
C1B—C6B—C5B119.9 (3)C1D—C6D—C5D120.0 (3)
C1B—C6B—Br2B122.0 (3)C1D—C6D—Br2D121.9 (3)
C5B—C6B—Br2B118.1 (3)C5D—C6D—Br2D118.0 (3)
O1B—C7B—H7BA109.5O1D—C7D—H7DA109.5
O1B—C7B—H7BB109.5O1D—C7D—H7DB109.5
H7BA—C7B—H7BB109.5H7DA—C7D—H7DB109.5
O1B—C7B—H7BC109.5O1D—C7D—H7DC109.5
H7BA—C7B—H7BC109.5H7DA—C7D—H7DC109.5
H7BB—C7B—H7BC109.5H7DB—C7D—H7DC109.5
O2B—C8B—H8BA109.5O2D—C8D—H8DA109.5
O2B—C8B—H8BB109.5O2D—C8D—H8DB109.5
H8BA—C8B—H8BB109.5H8DA—C8D—H8DB109.5
O2B—C8B—H8BC109.5O2D—C8D—H8DC109.5
H8BA—C8B—H8BC109.5H8DA—C8D—H8DC109.5
H8BB—C8B—H8BC109.5H8DB—C8D—H8DC109.5
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C7A—H7AA···O2Ci0.962.563.498 (5)167
C8D—H8DA···O1Bii0.962.533.485 (5)171
Symmetry codes: (i) x, y+1, z; (ii) x+1, y, z.
(II) 1,2-Diiodo-4,5-dimethoxybenzene top
Crystal data top
C8H8I2O2Dx = 2.514 Mg m3
Mr = 389.94Melting point: 404(1) K
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 25 reflections
a = 8.993 (4) Åθ = 7.5–17.5°
b = 13.882 (9) ŵ = 6.07 mm1
c = 16.506 (4) ÅT = 294 K
V = 2060.7 (17) Å3Blocks, colourless
Z = 80.32 × 0.26 × 0.16 mm
F(000) = 1424
Data collection top
Rigaku AFC6 difractometer
diffractometer
1441 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.039
Graphite monochromatorθmax = 26.0°, θmin = 2.5°
ω/2θ scansh = 111
Absorption correction: ψ scan
(North et al., 1968)
k = 117
Tmin = 0.18, Tmax = 0.38l = 120
2652 measured reflections3 standard reflections every 150 reflections
2023 independent reflections intensity decay: <2%
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) = 0.108 w = 1/[σ2(Fo2) + (0.0345P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.41(Δ/σ)max = 0.001
2023 reflectionsΔρmax = 0.82 e Å3
112 parametersΔρmin = 0.76 e Å3
0 restraintsExtinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0159 (6)
Crystal data top
C8H8I2O2V = 2060.7 (17) Å3
Mr = 389.94Z = 8
Orthorhombic, PbcaMo Kα radiation
a = 8.993 (4) ŵ = 6.07 mm1
b = 13.882 (9) ÅT = 294 K
c = 16.506 (4) Å0.32 × 0.26 × 0.16 mm
Data collection top
Rigaku AFC6 difractometer
diffractometer
1441 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.039
Tmin = 0.18, Tmax = 0.383 standard reflections every 150 reflections
2652 measured reflections intensity decay: <2%
2023 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0420 restraints
wR(F2) = 0.108H-atom parameters constrained
S = 1.41Δρmax = 0.82 e Å3
2023 reflectionsΔρmin = 0.76 e Å3
112 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
I10.08039 (8)0.74558 (4)0.55011 (4)0.0553 (3)
I20.31872 (6)0.53741 (4)0.59939 (3)0.0433 (2)
O10.0021 (6)0.5609 (4)0.2648 (3)0.0420 (13)
O20.1706 (6)0.4178 (4)0.2970 (3)0.0437 (13)
C10.1135 (8)0.6290 (5)0.4722 (4)0.0305 (16)
C20.0389 (8)0.6337 (5)0.3974 (4)0.0343 (16)
H20.02460.68490.38620.041*
C30.0605 (7)0.5616 (6)0.3403 (4)0.0334 (16)
C40.1547 (8)0.4835 (5)0.3572 (4)0.0305 (16)
C50.2286 (8)0.4803 (5)0.4318 (4)0.0334 (17)
H50.29280.42950.44310.040*
C60.2070 (8)0.5521 (6)0.4891 (4)0.0342 (17)
C70.0979 (9)0.6405 (6)0.2433 (5)0.049 (2)
H7A0.13160.63260.18850.074*
H7B0.04360.69980.24790.074*
H7C0.18190.64190.27910.074*
C80.2883 (10)0.3511 (6)0.3043 (5)0.049 (2)
H8A0.29030.31010.25750.073*
H8B0.27380.31260.35200.073*
H8C0.38090.38510.30850.073*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
I10.0778 (5)0.0460 (4)0.0419 (4)0.0067 (3)0.0007 (3)0.0115 (3)
I20.0490 (4)0.0532 (4)0.0277 (3)0.0079 (3)0.0105 (2)0.0019 (2)
O10.044 (3)0.053 (3)0.028 (2)0.004 (3)0.008 (2)0.004 (2)
O20.052 (3)0.050 (3)0.029 (3)0.008 (3)0.006 (2)0.012 (3)
C10.030 (4)0.030 (3)0.032 (4)0.007 (3)0.001 (3)0.001 (3)
C20.033 (4)0.036 (4)0.033 (4)0.005 (3)0.003 (3)0.001 (3)
C30.027 (3)0.051 (4)0.022 (3)0.008 (3)0.004 (3)0.007 (3)
C40.035 (4)0.032 (4)0.025 (3)0.002 (3)0.002 (3)0.004 (3)
C50.037 (4)0.038 (4)0.025 (4)0.003 (3)0.004 (3)0.002 (3)
C60.039 (4)0.044 (4)0.020 (3)0.009 (3)0.003 (3)0.003 (3)
C70.046 (5)0.055 (5)0.047 (5)0.011 (4)0.011 (4)0.016 (4)
C80.058 (5)0.046 (5)0.043 (4)0.014 (4)0.001 (4)0.010 (4)
Geometric parameters (Å, º) top
I1—C12.089 (7)C3—C41.404 (10)
I2—C62.090 (7)C4—C51.401 (10)
O1—C31.366 (8)C5—C61.387 (11)
O1—C71.446 (10)C5—H50.9300
O2—C41.356 (9)C7—H7A0.9600
O2—C81.412 (9)C7—H7B0.9600
C1—C61.387 (10)C7—H7C0.9600
C1—C21.408 (10)C8—H8A0.9600
C2—C31.389 (10)C8—H8B0.9600
C2—H20.9300C8—H8C0.9600
C3—O1—C7117.7 (6)C4—C5—H5119.7
C4—O2—C8117.2 (6)C1—C6—C5120.1 (7)
C6—C1—C2120.1 (6)C1—C6—I2122.7 (5)
C6—C1—I1124.0 (5)C5—C6—I2117.1 (5)
C2—C1—I1115.8 (5)O1—C7—H7A109.5
C3—C2—C1119.7 (6)O1—C7—H7B109.5
C3—C2—H2120.2H7A—C7—H7B109.5
C1—C2—H2120.2O1—C7—H7C109.5
O1—C3—C2124.5 (7)H7A—C7—H7C109.5
O1—C3—C4115.1 (6)H7B—C7—H7C109.5
C2—C3—C4120.4 (6)O2—C8—H8A109.5
O2—C4—C5124.9 (6)O2—C8—H8B109.5
O2—C4—C3115.9 (6)H8A—C8—H8B109.5
C5—C4—C3119.1 (6)O2—C8—H8C109.5
C6—C5—C4120.6 (7)H8A—C8—H8C109.5
C6—C5—H5119.7H8B—C8—H8C109.5
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C7—H7A···Cg1i0.962.903.747 (8)147
Symmetry code: (i) x1/2, y, z+1/2.

Experimental details

(I)(II)
Crystal data
Chemical formulaC8H8Br2O2C8H8I2O2
Mr295.96389.94
Crystal system, space groupTriclinic, P1Orthorhombic, Pbca
Temperature (K)294294
a, b, c (Å)10.1172 (5), 10.2052 (5), 20.2764 (10)8.993 (4), 13.882 (9), 16.506 (4)
α, β, γ (°)104.1710 (12), 98.9405 (10), 101.0630 (12)90, 90, 90
V3)1946.46 (17)2060.7 (17)
Z88
Radiation typeMo KαMo Kα
µ (mm1)8.296.07
Crystal size (mm)0.16 × 0.14 × 0.140.32 × 0.26 × 0.16
Data collection
DiffractometerBruker SMART APEX CCD area-detector
diffractometer
Rigaku AFC6 difractometer
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2002)
ψ scan
(North et al., 1968)
Tmin, Tmax0.28, 0.320.18, 0.38
No. of measured, independent and
observed [I > 2σ(I)] reflections
30774, 8656, 5046 2652, 2023, 1441
Rint0.0330.039
(sin θ/λ)max1)0.6590.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.036, 0.097, 1.02 0.042, 0.108, 1.41
No. of reflections86562023
No. of parameters441112
H-atom treatmentH-atom parameters constrainedH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.44, 0.460.82, 0.76

Computer programs: SMART (Bruker, 2001), MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1988), SAINT (Bruker, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) for (I) top
D—H···AD—HH···AD···AD—H···A
C7A—H7AA···O2Ci0.962.563.498 (5)167.2
C8D—H8DA···O1Bii0.962.533.485 (5)171.0
Symmetry codes: (i) x, y+1, z; (ii) x+1, y, z.
Table 1. π-π interactions (Å, °) for (I) top
Group 1/Group 2ccd(Å)sa(°)ipd(Å)
Cg1/Cg1i4.061 (2)25.(1)3.66 (1)
Cg1/Cg23.639 (2)4.(2)3.62 (2)
Cg2/Cg33.802 (2)21.(1)3.55 (4)
Cg3/Cg43.670 (2)13.(1)3.58 (1)
Cg4/Cg4ii4.227 (2)28.(1)3.71 (1)
Symmetry codes: (i) -x,-y+2,-z+1; (ii) -x+1,-y,-z. Cg1: C1A–C6A; Cg2: C1B–C6B; Cg3: C1C–C6C; Cg4: C1D–C6D. ccd: center-to-center distance (distance between ring centroids); sa: mean slippage angle (angle subtended by the intercentroid vector to the plane normal); ipd: mean interplanar distance (distance from one plane to the neighbouring centroid) [for details, see Janiak (2000)].
Table 2. C-Br···Br-C interactions (Å, °) for (I) top
C'-X'···X"-C"C'-X'C"-X"X'···X"θ1θ2
C1A-Br1A···(Br1B-C1B)i1.887 (3)1.886 (4)3.7231 (7)100.44 (13)167.87 (11)
C6B-Br2B···(Br2A-C6A)ii1.885 (4)1.883 (4)3.8901 (6)97.45 (12)160.75 (12)
C1C-Br1C···(Br1D-C1D)iii1.881 (4)1.893 (4)3.8051 (6)98.06 (12)165.23 (11)
C6D-Br2D···(Br2C-C6C)iv1.889 (4)1.899 (4)3.7161 (6)100.38 (12)165.64 (11)
C6B-Br2B···(Br2B-C6B)v1.885 (4)1.885 (4)3.4210 (9)142.59 (11)142.59 (11)
C1C-Br1C···(Br1C-C1C)vi1.881 (4)1.881 (4)3.6291 (10)135.24 (12)135.24 (12)
Symmetry codes: (i) -x+1, -y+2, -z+1; (ii) -x, -y+1, -z+1; (iii) -x, -y, -z; (iv) -x+1, -y+1, -z; (v) -x+1, -y+1, -z+1; (vi) -x, -y+1, -z. θ1: C'-X'···X", the smallest of the two XB angles; θ2: X'···X"-C", the largest of the two XB angles; expected values: θ1 ~ 90° and θ2 ~ 180° (for I2 interactions), or θ1 ~ θ2 (for I1 interactions) [for details, see Desiraju & Parthasarathy (1989)].
Hydrogen-bond geometry (Å, º) for (II) top
D—H···AD—HH···AD···AD—H···A
C7—H7A···Cg1i0.962.903.747 (8)147.2
Symmetry code: (i) x1/2, y, z+1/2.
Table 6. ππ interactions (Å, °) for (II) top
Group 1/Group 2ccd(Å)ipd(Å)sa(°)
Cg1/Cg1iv4.036 (4)3.75 (1)22.(1)
Symmetry code: (iv) -x,-y+1,-z+1. Cg1: C1–C6; ccd: center-to-center distance (distance between ring centroids); sa: mean slippage angle (angle subtended by the intercentroid vector to the plane normal); ipd: mean interplanar distance (distance from one plane to the neighbouring centroid) [for details, see Janiak (2000)].
Table 5. C-I···I-C interactions (Å, °) for (II) top
C'-X'···X"-C"C'-X'C"-X"X'···X"θ1θ2
C6-I2···(I1-C1)ii2.090 (7)2.089 (7)4.231 (3)91.7 (2)146.1 (2)
Symmetry codes: (i) -x+1/2, -y+1, z+1/2, (ii) -x+1/2, y-1/2, z. θ1: C1-X1···X2, the smallest of the two XB angles; θ2: X1···X2-C2, the largest of the two XB angles; expected values: θ1 ~ 90° and θ2 ~ 180°, or θ1 ~θ2 . [for details, see Desiraju & Parthasarathy (1989)].
Table 4. C–I···O interactions (Å, °) for (II) top
C-X···OC-XX···OC-X···O
C6—I2···O1i2.090 (7)3.470 (5)162.3 (2)
C6—I2···O2i2.090 (7)3.321 (5)148.3 (2)
Symmetry codes: (i) -x+1/2, -y+1, z+1/2 [for details, see Desiraju & Parthasarathy (1989)].
 

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