Inorganic & Supramolecular Chemistry Lab
Our Research
As a supramolecular chemistry lab, we incorporate non-covalent interactions i.e. resonance-assisted-hydrogen bonding (RAHB), pi-pi interaction, hydrophobic interaction to Host small organic molecules or macrocycles to design Chemosensors (Fluorescent probe) for Guest molecular recognition via ESIPT, PET, FRET, ICT, CHEF, CHQF, IDA fluorescence mechanism. Goal of our research is making portable sensor for remote sensing and cell imaging. We are committed to conducting cutting-edge research to push the boundaries of chemical science.
Fluorescent probe for relay recognition of ions
Incorporating enamine moiety to hydroxy coumarin allows molecular probe to form two new ring through resonance-assisted-hydrogen-bonding (RAHB) which enhance conjugation via double ESIPT mechanism. This weak Conjugation (RAHB) can be perturbed by certain anions (F-, CH3COO-, PO43-) and generate tetradentate ligand. Subsequently hard and borderline acids such as Cu2+ and Ni2+ can form coordinated complex with the tetradentate ligand as ligand is a combination of Hard-Soft bases. Thus, molecular probes act as relay recognition sensor for anions and cations(Manuscript in preparation).
Fluorescent probe for metal ions and cell imaging
Two quinidine-functionalized coumarin molecular probes have been designed & synthesized and have been found to bind metal cations (Cd2+, Co2+, Cu2+, Fe2+, Hg2+, Ni2+, and Zn2+) with high affinity in organic–aqueous media (DMSO–HEPES). The chemodosimeters coordinate with the Zn2+ ions in a two-to-one ratio (molecular probe : Zn2+) with a log β of 10.0 M−2. Upon the addition of the closed-shell metal ions studied, a fluorescence turn-on via an excimer formation is seen due to the quinaldine moiety adopting a syn arrangement when coordinated to the metal Zn2+ ions. Confocal microscopy monitored free Zn2+ions in the Human Embryonic Kidney cell line HEK293 by coordinating with the chemodosimter (Org.Biomol.Chem., 2023,21, 9379-9391).
Bifunctional chemodosimeter
A Fluorescent bifunctional sensor were design and synthesized in five steps. In the presence of the nerve agent tabun mimic diethylcyanophosphonate (DECP), the bifunctional coumarin–enamine chemodosimeter is first phosphorylated and subsequently attacked by the released cyanide ions. The reaction is disclosed in both the UV-vis and fluorescence spectra and confirmed by NMR experiments (1H-/13C/31P, APT, DEPT, HSQC, HMBC). DFT calculations support that the bis-adduct as the most thermodynamically stable species and LoD found to be 11 ppb. The X-ray structure of the chemodosimeter is also reported (New J. Chem., 2022,46, 21278-21286).
Multi-chromophoric Macrocyclic cage
Triazole and pyridine are well known for metal coordination which was incorporated with pillar[5]arene macrocycle and synthesized in five steps. The macrocycle was found to undergo conformational changes, leading to the formation of four major isomers cone, partially cone (pacone), and two alternate isomers. Only the cone isomer can coordinate the Al3+ ions at the bottom rim of the macrocycle over the other metals (Zn2+, Cd2+, Hg2+, Pb2+, Co2+, Ni2+, Cu2+, Mg2+, Ca2+, Cr3+, Ag+, Na+, K+) with response ratio 103-fold enhancement via fluorescence spectroscopy. 1H-NMR titration, UV-vis, fluorescent, fluorescent lifetime, mass-spectrometry experiment also carried out to confirm host-guest complex, binding constant and limit of detection also calculated. Crystal structure of 'cone' conformer also reported (Manuscript in preparation)
