Flower‐Like Morphology of Naphthalene Diimides Containing tetra‐L‐ and D‐Alanine. Issue 44 (27th November 2020)

• Record Type: Journal Article
• Authors: Shaikh, Dada B.; More, Kerba S.; Kobaisi, Mohammad Al; La, Duong Duc; Bhosale, Sidhanath V.; Bhosale, Sheshanath V.
• Is Part Of: ChemistrySelect. Volume 5:Issue 44(2020)
• Page Start: 14203
• Page End: 14209
• Publication Date: 2020-11-27
• Subjects: aggregation -- flower-like morphology -- naphthalene diimide -- π-π-interactions -- self-assembly; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.202003108
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: Two structural isomers of naphthalene diimide (NDI) chromophores NDI‐3 and NDI‐4, which are NDI imide position functionalised with four L‐/D‐alanine subunits. Density functional theory calculations revel that HOMO molecular orbital is localized on N‐phenyl substituent and LUMO on NDI core. Further, the UV‐vis, fluorescence measurements show that both the derivatives i. e. NDI‐3 and NDI‐4 exhibit changes in optical and photophysical properties with the addition of non‐polar i. e. methylcyclohexane in chloroform as well as water in tetrahydrofuran. From these results, it is clear that the structural isomers NDI‐3 and NDI‐4 shows a significant solvatochromic effect, which ascribed to the aggregation effect via π‐π stacking of NDI core along with hydrogen‐bonding between alanine side chains. Scanning electron microscopy (SEM) and polarized optical microscopy images clearly demonstrate formation of flower like morphology in THF:H2 O and fiber nanostructure in CHCl3 :MCH for both NDI‐3 and NDI‐4 . Interestingly, only NDI‐4 in CHCl3 :MCH (4 : 6, v/v) solvent mixture produces rose‐like flower microstructures. Abstract : Solvophobic controlled self‐assembly of naphthalene diimide bearing four L‐/D‐alanine produces two derivatives (codes as NDI‐3 and NDI‐4), which self‐assembled into supramolecular flower‐like assembly in THF:H2 O (1 : 9, v/v) solvent mixture. Whereas, both the derivatives produces fiber like morphology in CHCl3 :MCH (1 : 9, v/v) solvent mixture, interestingly, NDI‐4 produces rose‐like flower in CHCl3 :MCH (4 : 6, v/v) solvent mixture.