Structures and conformational analysis of a 3 × 3 isomer grid of nine N-(fluorophenyl)pyridinecarboxamides

Influence of Deuteration and Fluorination on the Supramolecular Architecture of Pyridine N‐Oxide Crystals

“…For example, the investigations of selected isomeric substituted benzamides [1] benzonitriles, [2,3] phenols, [3] nitrobenzenes [4] and pyridine-carboxamides [5] clearly demonstrated that different substitution patterns lead to the formation of different types of intermolecular interactions and supramolecular synthons in crystals causing different packing of molecules. For example, the investigations of selected isomeric substituted benzamides [1] benzonitriles, [2,3] phenols, [3] nitrobenzenes [4] and pyridine-carboxamides [5] clearly demonstrated that different substitution patterns lead to the formation of different types of intermolecular interactions and supramolecular synthons in crystals causing different packing of molecules.…”

“…In general, it is well recognized that substituents strongly influence the crystal structures of organic solids. For example, the investigations of selected isomeric substituted benzamides [1] benzonitriles, [2,3] phenols, [3] nitrobenzenes [4] and pyridine-carboxamides [5] clearly demonstrated that different substitution patterns lead to the formation of different types of intermolecular interactions and supramolecular synthons in crystals causing different packing of molecules. On the other hand, it is possible to find many examples where the substitution pattern does not lead to different crystal structures as it was found for selected substituted ureas [6] or trihalogen-substituted derivatives of benzene.…”

Short C–H⋯F interactions involving the 2,5-difluorobenzene group: understanding the role of fluorine in aggregation and complex C–F/C–H disorder in a 2 × 6 isomer grid

“…1820 Our interest in fluorine chemistry arising from isomer grids e.g. NxxF, 14 Fxx, 16 is to examine relationships between H/F atoms in systematic analyses and probe fluorine in unusual, short interactions and environments.…”

“…14, 16 We now extend the original series, 14,16 to twelve difluorobenzanilides and report on their chemistry and crystal structures (Scheme 1). Typically amide…amide C(4) chains serve as the primary hydrogen bonding interaction, usually with … stacking and C-H… interactions and in a few cases augmented by short, directional C-HF contacts.…”

“…[13][14][15][16][17] Ab initio DFT geometry optimisation (B3LYP 32a ; 6-311++G, 32b ) of the twelve compound isomer grid was performed using Gaussian03/09 32c in Please do not adjust margins Please do not adjust margins gas phase (Table 5). These results provide PES diagrams showing the conformational preferences either as (syn-/anti) and rotational barriers in kJ.mol -1 (Figures 7, 8).…”