Acta Crystallographica Section B

Structural Science

Volume 64, Part 2 (April 2008)

research papers

Acta Cryst. (2008). B64, 206-216 [ doi:10.1107/S0108768108000232 ]

Conformations of substituted benzophenones

P. J. Cox, D. Kechagias and O. Kelly

Abstract: The inclination of the two aryl rings (ring twists) in a series of benzophenone molecules has been examined. For each structure the dihedral angle (between the planes of the two sets of six aromatic C atoms) relates to both the steric considerations of the single molecule and the packing forces related to the crystal structure. Six new benzophenone structures are incorporated into the study including 2,2'-dihydroxy-4,4'-dimethoxybenzophenone (I), C₁₅H₁₄O₅, that appears to have the smallest reported twist angle, 37.85 (5)°, of any substituted benzophenone reported to date. Three further benzophenones, 4,4'-bis(diethylamino)benzophenone (II), C₂₁H₂₈N₂O, 3,4-dihydroxybenzophenone (III), C₁₃H₁₀O₃, and 3-hydroxybenzophenone (IV), C₁₃H₁₀O₂, have similar ring twists [49.83 (5), 49.84 (5) and 51.61 (5)°, respectively] that are comparable with the value of 54° found for the orthorhombic form of unsubstituted benzophenone. 4-Chloro-4'-hydroxybenzophenone (V), C₁₃H₉ClO₂, has a ring twist of 64.66 (8)° that is close to the value of 65° found in the metastable monoclinic form of unsubstituted benzophenone and 2-amino-2',5-dichlorobenzophenone (VI), C₁₃H₉Cl₂NO₂, has a large ring twist of 83.72 (6)°. Comparisons with a further 98 substituted benzophenone molecules from the Cambridge Structural Database (CSD) have been made.

Keywords: conformation; benzophenones; dihedral angles.


	Structure factor file (CIF format) (134.6 kbytes) [ doi:10.1107/S0108768108000232/ws50602d4dsup2.hkl ] Contains datablock 2d4d

	Structure factor file (CIF format) (207.2 kbytes) [ doi:10.1107/S0108768108000232/ws5060orla1sup3.hkl ] Contains datablock orla1

	Structure factor file (CIF format) (111.7 kbytes) [ doi:10.1107/S0108768108000232/ws5060orla2sup4.hkl ] Contains datablock orla2

	Structure factor file (CIF format) (105.8 kbytes) [ doi:10.1107/S0108768108000232/ws50603hbz2sup5.hkl ] Contains datablock 3hbz2

	Structure factor file (CIF format) (103.2 kbytes) [ doi:10.1107/S0108768108000232/ws5060dimit1sup6.hkl ] Contains datablock dimit1

	Structure factor file (CIF format) (133.0 kbytes) [ doi:10.1107/S0108768108000232/ws5060dimit2sup7.hkl ] Contains datablock dimit2

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