113204-24-3Relevant academic research and scientific papers
Assembling an isomer grid: The isomorphous 4-, 3- and 2-fluoro-N′-(4- pyrid-yl)benzamides
Donnelly, Katie,Gallagher, John F.,Lough, Alan J.
, p. o335-o340 (2008)
The three title isomers, 4-, (I), 3-, (II), and 2-fluoro-N′-(4-pyri- d-yl)benzamide, (III), all C12H9FN2O, crystallize in the P21/c space group (No. 14) with similar unit-cell parameters and are isomorphous and isostructural at the primary hydrogen-bonding level. An intra-molecular C - H...O=C inter-action is present in all three isomers [C...O = 2.8681 (17)-2.884 (2) A and C - H...O117-118°], with an additional N - H...F [N...F = 2.7544 (15) A] inter-action in (III). Inter-molecular amide-pyridine N - H...N hydrogen bonds link mol-ecules into one-dimensional zigzag chains [graph set C(6)] along the [010] direction as the primary hydrogen bond [N...N = 3.022 (2), 3.049 (2) and 3.0213 (17) A]. These are augmented in (I) by C - H...π(arene) and cyclic C - F...π(arene) contacts about inversion centres, in (II) by C - F...F - C inter-actions [C...F = 3.037 (2) A] and weaker C - H...π(arene)/C - H...F contacts, and in (III) by C - H...π(arene) and C=O...O=C inter-actions, linking the alternating chains into two-dimensional sheets. Typical amide N - H...O=C hydrogen bonds [as C(4) chains] are not present [N...O = 3.438 (2) A in (I), 3.562 (2) A in (II) and 3.7854 (16) A in (III)]; the C=O group is effectively shielded and only participates in weaker inter-actions/contacts. This series is unusual as the three isomers are isomorphous (having similar unit-cell parameters, packing and alignment), but they differ in their inter-actions and contacts at the secondary level. International Union of Crystallography 2008.
