Journal article
Reorganized, weak C-H center dot center dot center dot O interactions directly modify the mechanical properties and compaction performance of a series of nitrobenzoic acids
CrystEngComm, Vol.19(18), pp.2526-2535
05/14/2017
DOI: 10.1039/c7ce00238f
Abstract
Strong hydrogen-bonding interactions are predictably leveraged for local molecular docking; however, weak intermolecular interactions are being increasingly recognized as pivotal governors of extended, supramolecular assembly. In this report, a series of nitrobenzoic acids (NBA) - m-nitrobenzoic acid (3-NBA), p-nitrobenzoic acid (4-NBA), 4-methyl-3-NBA (Me-NBA), 4-chloro-3-NBA (Cl-NBA) and 4-bromo-3-NBA (Br-NBA) - are utilized to systematically adjust weak C-H center dot center dot center dot O (nitro) and C-H center dot center dot center dot O (carboxyl) bonding interactions and discriminate their influence on the crystal structure, aggregate elasticity and compaction performance. The expected carboxylic acid dimer persists across the entire NBA series; however, alternative organization of C-H center dot center dot center dot O interactions yields distinct 1-d tapes. The acoustic frequency distributions obtained from powder Brillouin light scattering (BLS) spectra provide supportive interpretation of the strength and anisotropy of the reorganized intermolecular interactions. Aggregate Young's moduli displayed a narrow range from 13.5 GPa for Br-NBA to 9.8 GPa for 3-NBA. However, the maximum longitudinal moduli (M-max), calculated from the high-frequency cutoff, revealed significant differences in the strength of intermolecular interactions along the 1-d tapes. For 3-NBA, the extended organization of several co-linear C-H center dot center dot center dot O (nitro) interactions yielded an M-max of 42.0 GPa, while the remaining NBA materials displayed an M-max near 25 GPa. From powder compaction studies, the tabletability rank order was observed as: 3-NBA > 4-NBA > Me-NBA approximate to Br-NBA approximate to Cl-NBA; however, none of the materials achieved a tensile strength greater than 1 MPa. Overall, even minor redistribution of weak intermolecular interactions significantly modifies supramolecular assembly in NBA and detailing the specific contribution of these weak forces is required for substantive structure-performance correlation.
Details
- Title: Subtitle
- Reorganized, weak C-H center dot center dot center dot O interactions directly modify the mechanical properties and compaction performance of a series of nitrobenzoic acids
- Creators
- Aditya B. Singaraju - University of IowaKyle Nguyen - University of IowaDale C. Swenson - University of IowaMamta Iyer - Campbell UniversityRahul V. Haware - Campbell UniversityLewis L. Stevens - University of Iowa
- Resource Type
- Journal article
- Publication Details
- CrystEngComm, Vol.19(18), pp.2526-2535
- Publisher
- Royal Soc Chemistry
- DOI
- 10.1039/c7ce00238f
- ISSN
- 1466-8033
- eISSN
- 1466-8033
- Number of pages
- 10
- Grant note
- Guillory-Matheson-Flanagan-Wurster Fellowship J. Keith Guillory Pharmaceutics Fellowship
- Language
- English
- Date published
- 05/14/2017
- Academic Unit
- Pharmaceutical Sciences and Experimental Therapeutics; Chemistry
- Record Identifier
- 9984366033802771
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