In the title compound, C21H16Br2N2, the central pyrazole ring adopts an flattened envelope conformation, with the stereogenic C atom in the flap position. The deviations from planarity for this ring are relatively minor (r.m.s. deviation = 0.045 Å) and the dihedral angles formed with the N- and Cimine-bound benzene rings are 7.73 (13) and 11.00 (13)°, respectively. By contrast, the benzene ring bound at the chiral C atom is almost orthogonal to the rest of the molecule; the dihedral angle formed between this ring and the pyrazole ring is 79.53 (13)°. In the crystal, the packing is stabilized by C—H
N and C—H
Br interactions.
N and C—H
Br interactions.


This article has been ![[triangle]](/corehtml/pmc/pmcents/rtrif.gif)


2 = 251.7 (14) ° (Cremer & Pople, 1975). That
being
stated, the maximum deviations from the five atoms of the ring are 0.052 (2)
and -0.064 (3) Å for the N2 and C1 atoms, respectively; the r.m.s. deviation
= 0.0450 Å. The N2- and C3-bound benzene rings are approximately co-planar
with the central ring as seen in the dihedral angles formed between their
respective least-squares planes and that through the pyrazole ring of 7.73
(13) and 11.00 (13) °; the dihedral angle between these benzene rings is 4.32
(12) °. By contrast, the C1-bound benzene ring is almost orthogonal to the
remaining molecule with a dihedral angle of 79.53 (13) ° formed between it
and the pyrazole ring. To a first approximation, the overall conformation in
(I) resembles that in the analogous 1,3,5-triphenyl-2-pyrazoline "parent"
compound although the deviations from planarity are slightly greater in the
literature structure (Foces-Foces et al., 2001). Further, the
N1–N2
[1.369 (3) Å] and N1═C3 [1.291 (3) Å] bond distances in (I) are
comparable to the equivalent distances in 1,3,5-triphenyl-2-pyrazoline of
1.387 (5) and 1.285 (7) Å, respectively.