title: Synthesis and spectral characterization of new 1,3,5-triaryl-2-pyrazolines highlighting effect of alkyloxy chain length on fluorescence.
abstract: A series of new 1,3,5-triaryl-2-pyrazolines (1b-12b) having one to twelve carbon alkyloxy side chains were synthesized and characterized on the basis of their spectral (IR, (1)H &(13)C NMR and GC-MS) and microanalytical data. The UV-Vis and emission spectroscopy was used to study the effect of alkyloxy chain length on absorption and fluorescence properties of 1b-12b. All the compounds showed fluorescence in the blue region of the visible spectrum. Interestingly, the alkyloxy chain length strongly affects the emission intensity of 1,3,5-triaryl-2-pyrazoline framework without causing any major blue- or red-shift in the emission wavelength (λmax(em)). The absorption and emission maxima (λmax(abs) &λmax(em)) for compounds (1b-12b) were observed in the range of 337-364nm and 454-464nm, respectively. Furthermore, the effect of fluorine substituent on aryl ring present at 3-position of pyrazoline moiety on fluorescence properties is also discussed.
authors.affiliation: Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan. Electronic address: profazmi@hotmail.com.
authors.forename: Asghar
authors.initials: A
authors.lastname: Abbas
authors.affiliation: Department of Forensic Medicine & Toxicology, National University of Sciences and Technology, Islamabad 44000, Pakistan.
authors.forename: Safdar
authors.initials: S
authors.lastname: Hussain
authors.affiliation: Department of Forensic Medicine & Toxicology, RIHS, Bahria University, Islamabad, Pakistan.
authors.forename: Noureen
authors.initials: N
authors.lastname: Hafeez
authors.affiliation: Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan.
authors.forename: Aurangzeb
authors.initials: A
authors.lastname: Hasan
authors.affiliation: Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan. Electronic address: moazzam@qau.edu.pk.
authors.forename: Muhammad Moazzam
authors.initials: MM
authors.lastname: Naseer
mesh_terms: D005453:Fluorescence; D006845:Hydrocarbons, Fluorinated / Q000138:chemical synthesis* / Q000737:chemistry*; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D006845:Hydrocarbons, Fluorinated; D011720:Pyrazoles
keywords: 1,3,5-Triaryl-2-pyrazolines; Alkyloxy side chain; Fluorescence; Spectroscopy; Synthesis