title: Explicit spectral response of the geometrical isomers of a bio-active pyrazoline derivative encapsulated in β-cyclodextrin nanocavity: a photophysical and quantum chemical analysis.
abstract: The existence of two geometrical isomers (cis- and trans-) of a biologically significant pyrazoline derivative [5-(-1'-(4-bromo-phenyl)-3a',7a'-hexahydro-1'H-indazol-3'-yl)-3-methyl-1-phenyl-1H-pyrazole-4-carbonitrile] (PZ) has been established using a combined theoretical and experimental investigation. Solvatochromic analysis of PZ revealed the existence of said cis- and trans- isomers. The unique solvatochromic response of the PZ isomers and their preferential encapsulation within β-cyclodextrin (β-CD) nanocavity clearly shows the difference in the behavioral nature of the isomers of PZ in homogeneous and heterogeneous medium. Solvent polarity, time-resolved study, and anisotropy results also reinforce in favor of the existence of the isomers. To evaluate the actual orientation of cis and trans-PZ, the ground and excited state geometry of these isomers were optimized by the DFT/LanL2DZ and CIS/LanL2DZ methods, respectively. The experimentally observed results and the theoretically calculated results are found to be in close agreement.
authors.affiliation: Department of Chemistry, Jadavpur University, Kolkata 700032, India.
authors.forename: Soumya Sundar
authors.initials: SS
authors.lastname: Mati
authors.forename: Sunandan
authors.initials: S
authors.lastname: Sarkar
authors.forename: Pranab
authors.initials: P
authors.lastname: Sarkar
authors.forename: Subhash Chandra
authors.initials: SC
authors.lastname: Bhattacharya
mesh_terms: D008958:Models, Molecular; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry*; D055668:Photochemical Processes; D011720:Pyrazoles / Q000737:chemistry*; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D011720:Pyrazoles; D047392:beta-Cyclodextrins; C031215:betadex