Water‐Assisted Emission Enhancement of 2‐Hydroxynaphthaldoxime and Related Compounds

Abstract

The combined contributions from the excited‐state intramolecular proton‐transfer and aggregation‐induced emission in the photoluminescence of compounds namely 2‐hydroxynaphthaldoxime, 2‐methoxynaphthaldoxime, 2‐hydroxynaphthaldehyde and 1‐[(methylimino)methyl]naphthalen‐2‐ol were established. For such a purpose the changes in the fluorescence emission of these compounds in different solvents upon addition of water and from the fluorescence emission life‐time decay profiles were studied. 1H‐NMR titration of the 2‐hydroxynaphthaldoxime with D2O had provided clear evidence on the role of water molecules to disrupt the C−H⋅⋅⋅O interactions in assembly of 2‐hydroxynaphthaldoxime to orient the aromatic naphthalene rings differently to enhance the fluorescence emissions. Dynamic light scattering studies and scanning electron micrographs had showed that there were differences between the types of aggregation present in solid state and in solution. In solution the average size of the aggregates of 2‐hydroxynaphthaldoxime were increased upon addition of water. 2‐Hydroxynaphthaldoxime formed well defined cocrystal with tetrabutylammonium chloride but the tetrabutylammonium hydroxide formed salt of 2‐hydroxynaphthaldoxime by deprotonating hydroxy‐group. Accordingly the fluorescence emission changes of 2‐hydroxynaphthaldoxime caused by tetrabutylammonium hydroxide was different from the emission showed by the cocrystal with tetrabutylammonium chloride.

Self-Assemblies of Solvates, Ionic Cocrystals, and a Salt Based on 4-{[(4-Nitrophenyl)carbamoyl]amino}-N-(pyrimidin-2-yl)benzene-1-sulfonamide: Study in the Solid and Solution States

“…The packing pattern revealed that a grid-like structure having rectangular barricades was formed by the self-assembled anions, where the tetrabutylammonium cations were trapped (Figure c). This observation complemented our earlier findings on the encapsulation of tetrabutylammonium cations in the rectangular voids of the gridlike structure of the hydrogen-bonded anions of oxime molecules. , (TBA) + (H2Sulfaurea) – had a different in thermal stability in comparison to the DMF solvates. A themogravimetric study showed that the salt decomposed on heating above 200 °C (Figure S31).…”

“…The hydrogen bond angles involving the halide ion as the central ion in the individual cocrystal had a distorted Y shape. Depending on the hydrogen bond donors and shapes of the receptors, a halide ion may adopt different anion coordination geometries, − among which a T shape has been commonly observed.…”

A review on oxime functionality: an ordinary functional group with significant impacts in supramolecular chemistry

“…As a result, Oxm-108 , which is mildly emissive in DMSO, becomes extremely blue-emissive in a 90% water–DMSO solvent mixture. 163 Oxime derivative Oxm-110 forms various transition metal complexes with Cu( ii ), Ni( ii ), and Zn( ii ) ions. These complexes have been utilized for the selective and sensitive detection of fluoride ions, even in the presence of other competitive anions.…”

Binuclear Co(II), Ni(II) and Cu(II) Complexes of a new Bis(tridentate) Hydrazone Ligand: Synthesis, Thermal, Spectroscopic, Biological, Molecular Docking and Theoretical Studies

“…Naphthaldehyde-based compounds have numerous presentations such as electrochemical, catalytic, photoluminescence, analytical, cytotoxic, antimicrobial and in vitro anticancer, antiproliferative, antioxidant, catechol's studies [33][34][35][36][37][38][39][40][41][42][43] Transition metal compounds play important role in bio-inorganic chemistry and redox enzyme systems [44]. Copper is one of the most important elements in the human body.…”