2-Bromo-5-fluorobenzaldehyde

In the title compound, C7H4BrFO, the benzaldehyde O atom is found to be trans to the 2-bromo substituent. In the crystal, short Br⋯F interactions between the bromine and fluorine substituents are observed at distances of 3.1878 (14), 3.3641 (13) and 3.3675 (14) Å. Offset face-to-face π-stacking interactions are also observed for both of the independent molecules in the asymmetric unit running parallel to the crystallographic b axis, characterized by centroid–centroid distances of 3.8699 (2) and 3.8699 (2) Å.

In the title compound, C 7 H 4 BrFO, the benzaldehyde O atom is found to be trans to the 2-bromo substituent. In the crystal, short BrÁ Á ÁF interactions between the bromine and fluorine substituents are observed at distances of 3.1878 (14), 3.3641 (13) and 3.3675 (14) Å . Offset face-to-face -stacking interactions are also observed for both of the independent molecules in the asymmetric unit running parallel to the crystallographic b axis, characterized by centroid-centroid distances of 3.8699 (2) and 3.8699 (2) Å .
Experimental 2-bromo-5-fluorobenzaldehyde was purchased from Aldrich Chemical Company, USA, and was recrystallized from chloroform.

Refinement
All non-hydrogen atoms were refined anisotropically. Hydrogen atoms on carbon were included in calculated positions and refined using a riding model at C-H = 0.95 Å and U iso (H) = 1.2 × U eq (C) of the aryl C-atoms. The extinction parameter (EXTI) refined to zero and was removed from the refinement.

Figure 1
A view of the title compound with the atom numbering scheme. F1···Br2 distance 3.1878 (14) Å. Displacement ellipsoids are shown at the 50% probability level.

2-Bromo-5-fluorobenzaldehyde
Crystal data Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.