1
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P. G. Jones et al. · Bromo- and/or Bromomethyl-substituted Benzenes
Table 3. Br···Br contacts (
A˚
Comp. C–Br···Br–C
Br···Br
C–Br···Br
Br···Br–C Operator
1
C7–Br1···Br3–C9
3.7593(4)
3.8322(3)
3.9102(3)
3.9355(3)
3.9720(3)
3.5291(5)
3.5360(5)
3.8359(7)
3.6111(7)
3.7204(8)
3.9211(7)
4.0374(8)
4.0511(8)
3.9784(6)
3.7119(6)
3.8562(6)
3.6065(5)
3.8989(5)
3.7487(3)
3.9662(3)
3.9760(3)
3.5717(3)
3.7924(3)
3.8345(3)
3.7743(3)
84.53(6)
154.28(5)
133.98(6)
103.99(5)
72.93(5)
167.03(8)
149.84(7)
75.58(9)
113.5(2)
162.8(2)
139.1(2)
88.5(2)
139.56(5) −x+3/2, y+1/2, −z+1/2
and deg).
C8–Br2···Br3–C9
C7–Br1···Br2–C8
C7–Br1···Br2–C8
C7–Br1···Br3–C9
C1–Br1···Br3–C8
C7–Br2···Br3–C8
C8–Br3···Br3–C8
C1–Br1···Br3–C8
C7–Br2···Br3–C8
C1–Br1···Br3–C8
C1–Br1···Br2–C7
C7–Br2···Br3–C8
C2–Br1···Br2–C5
C2–Br1···Br2–C5
C2–Br1···Br3–C8
C1–Br1···Br2–C7
C1–Br1···Br2–C7
C8–Br3···Br3–C8
C1–Br1···Br3–C8
C1–Br1···Br3–C8
C1–Br1···Br2–C4
C1–Br1···Br2–C4
C1–Br1···Br2–C4
C4–Br2···Br3–C7
157.71(5) x, y+1, z
87.49(5) x+1/2, −y+3/2, z+1/2
147.30(5) −x+3/2, y−1/2, −z+1/2
72.76(5) x+1/2, −y+3/2, z+1/2
114.52(8) x, y+1, z−1
2
3
161.86(7) x+1, y, z−1
75.58(9)a −x, −y+1, −z+2
178.7(2) −x+1/2, y, z−1/2
82.4(2) −x+1, −y+1, z−1/2
110.5(2) −x+1/2, y+1, z−1/2
132.8(2) x−1/2, −y+2, z
109.5(2)
104.32(9)
168.37(9)
77.97(9)
164.53(9)
115.5(2) −x+1, −y+2, z−1/2
153.74(9) −x+1/2, y−1/2, −z+1/2
84.74(9) x+1/2, −y+1/2, z+1/2
163.21(8) −x+1, −y+1, −z+1
110.79(12) x−1, y, z−1
4
5
6
106.19(11) 158.48(12) x−1, y, z
b
81.48(7)
137.58(6)
143.39(7)
108.71(5)
156.44(6)
133.73(6)
84.99(6)
157.71(7) x+1/2, −y+1/2, −z+1
140.32(7) −x+1/2, −y+1, z−1/2
90.40(7) −x+1, y+1/2, −z+1/2
167.31(6) x−1/2, −y+3/2, z+1/2
82.57(6) −x+1/2, y−1/2, −z+1/2
97.34(6) −x+3/2, y−1/2, −z+1/2
157.40(6) −x+1, −y+1, −z
7
a
Angles equal by symmetry; b a symmetry-equivalent interaction is observed at x − 1/2, −y + 1/2,
−
z+1.
independent Br···Br contacts ranging in length from label these rings as R(20,7) and other rings accord-
˚
3
.76 to 3.97 A; there are no other such contacts shorter ingly. The layers, parallel to (111), are linked in pairs
˚
than 4.2 A. Two of the contacts are clearly type I; the (Fig. 2c) by the third and longest Br···Br contact; the
others have an intermediate form, with one angle ap- rings form an infinite stack parallel to the a axis via
◦
◦
proximately 90 and the other ca. 130 – 140 . It may symmetry operators −x, 1 − y, 1 − z and 1 − x, 1 − y,
be that the geometric constraints of forming a con- 1−z (referred to the molecule of the asymmetric unit)
˚
densed system of contact triangles does not allow type with two independent π···π distances of 3.7 A. Only
◦
II contacts with ideal 180 angles. The hydrogen bonds the shortest hydrogen bond H8B···Br1 is observed
H7A···Br3 and H8B···Br3, not shown explicitly in the within a given double layer; it supports the stacking
Figure, support the two interactions from Br1 to the interaction.
Br3 atoms (they are formed between the same pairs of
˚
Compound 3 is an isomer of 2, whereby the sub-
molecules). The shortest π···π contact is 4.03 A (op- stituents are permuted; its packing is, at least in two
erator 1 − x, 1 − y, 1 − z) and is probably of marginal dimensions, closely related to that of 2. Again, the two
significance.
shortest Br···Br contacts are Br1···Br3 and Br2···Br3
The packing of compound 2 is in marked contrast (both in this case corresponding reasonably well to
to that of 1; it involves only three Br···Br contacts, type II); they again combine to form highly corru-
but they are appreciably shorter (although only one gated layers parallel to the ac plane, consisting of
of them approximates to a type II contact and the R(20,7) rings (Fig. 3b). The equivalent molecules are
others are clearly type I). The two shortest, both ca. generated by a c glide plane and a 2 screw axis.
1
˚
3
.53 A, involve only translational symmetry; they com- The other three, appreciably longer, Br···Br contacts
bine to form highly corrugated layers consisting of 20- are formed to neighbouring layers but the correspond-
membered rings, seven atoms of which are bromine ing diagrams are highly complex. The main hydrogen
atoms (Fig. 2b). As an ad hoc notation related to the bond is a symmetric three-centre interaction, one com-
familiar graph sets for hydrogen bonds [17], we shall ponent of which, H3···Br1, lies within the layer.