Open AccessCooperative Self-Assembly Driven by Multiple Noncovalent Interactions: Investigating Molecular Origin and Reassessing Characterization
Author(s) -
Samaresh Samanta,
Parth Raval,
G. N. Manjunatha Reddy,
Debangshu Chaudhuri
Publication year - 2021
Publication title -
acs central science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.893
H-Index - 76
eISSN - 2374-7951
pISSN - 2374-7943
DOI - 10.1021/acscentsci.1c00604
Subject(s) - cooperativity , supramolecular chemistry , heteronuclear molecule , non covalent interactions , chromophore , chemistry , chemical physics , circular dichroism , heteronuclear single quantum coherence spectroscopy , stacking , magic angle spinning , nuclear magnetic resonance spectroscopy , crystallography , hydrogen bond , molecule , stereochemistry , photochemistry , crystal structure , organic chemistry , biochemistry
Cooperative interactions play a pivotal role in programmable supramolecular assembly. Emerging from a complex interplay of multiple noncovalent interactions, achieving cooperativity has largely relied on empirical knowledge. Its development as a rational design tool in molecular self-assembly requires a detailed characterization of the underlying interactions, which has hitherto been a challenge for assemblies that lack long-range order. We employ extensive one- and two-dimensional magic-angle-spinning (MAS) solid-state NMR spectroscopy to elucidate key structure-directing interactions in cooperatively bound aggregates of a perylene bisimide (PBI) chromophore. Analysis of 1 H- 13 C cross-polarization heteronuclear correlation (CP-HETCOR) and 1 H- 1 H double-quantum single-quantum (DQ-SQ) correlation spectra allow the identification of through-space 1 H··· 13 C and 1 H··· 1 H proximities in the assembled state and reveals the nature of molecular organization in the solid aggregates. Emergence of cooperativity from the synergistic interaction between a stronger π-stacking and a weaker interstack hydrogen-bonding is elucidated. Finally, using a combination of optical absorption, circular dichroism, and high-resolution MAS NMR spectroscopy based titration experiments, we investigate the anomalous solvent-induced disassembly of aggregates. Our results highlight the disparity between two well-established approaches of characterizing cooperativity, using thermal and good solvent-induced disassembly. The anomaly is explained by elucidating the difference between two disassembly pathways.