title: Hirshfeld Surface Investigation of Structure-Directing Interactions within Dipicolinic Acid Derivatives.
abstract: Six compounds based on dipicolinic acid esters have been synthesized and Hirshfeld surfaces used to investigate the structure-directing effects of functional groups in controlling their solid-state behavior. Compounds1-4are 4-bromo dipicolinic acid esters substituted with methyl, ethyl, propyl, and benzyl groups, respectively. The main structure-directing motif within1-3is a pairwise O···H interaction involving two carbonyl oxygen atoms and two aromatic H atoms. The introduction of bulky benzyl groups in4forces a significant change in the position of this interaction. Compounds2and4were used in Suzuki coupling reactions to prepare extended analogues5and6, respectively, and their solid-state behavior was also studied using Hirshfeld surfaces. Extension of these dipicolinic acid esters results in the complete loss of the pairwise O···H interaction in5, where the dominant structure-directing motifs are π-based interactions. However, the pairwise O···H interaction reappears for the more flexible6, demonstrating control of the solid-state structure of these dipicolinic acid derivatives through the choice of functional groups.
authors: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, U.K.
authors: Adam D
authors: AD
authors: Martin
authors: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, U.K.
authors: Joshua
authors: J
authors: Britton
authors: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, U.K.
authors: Timothy L
authors: TL
authors: Easun
authors: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, U.K.
authors: Alexander J
authors: AJ
authors: Blake
authors: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, U.K.
authors: William
authors: W
authors: Lewis
authors: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, U.K.
authors: Martin
authors: M
authors: Schröder