title: Synthesis and spectral characterization of new homologous 1,3,5-triaryl-2-pyrazolines: Influence of alkyloxy chain length on fluorescence.
abstract: Twelve new homologous 1,3,5-triaryl-2-pyrazolines (1c-12c) have been synthesized and characterized on the basis of their spectral (IR, (1)H and (13)C NMR and MS) data and microanalysis. The influence of alkyloxy chain length on absorption and fluorescence properties of 1c-12c was studied by UV-Vis and emission spectroscopy. For all the compounds, fluorescence was observed in the blue region of the visible spectrum. Furthermore, a strong influence of alkyloxy chain length was found on the emission intensity of 1,3,5-triaryl-2-pyrazolines, without causing any major blue- or red-shift in the emission wavelength (λmax(em)). The absorption and emission maxima (λmax(abs) and λmax(em)) for all the compounds were observed in the range of 408-416nm and 471-476nm, respectively. The effect of chloro-substituent present on the conjugated backbone of 1,3,5-triaryl-2-pyrazoline moiety 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, Rawalpindi Institute of Health Sciences (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. Electronic address: moazzam@qau.edu.pk.
authors.forename: Muhammad Moazzam
authors.initials: MM
authors.lastname: Naseer
mesh_terms: D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D054879:Halogenation; D009682:Magnetic Resonance Spectroscopy; D011720:Pyrazoles / Q000138:chemical synthesis / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005456:Fluorescent Dyes; D011720:Pyrazoles
keywords: 1,3,5-triaryl-2-pyrazolines; Fluorescence; Spectral characterization; Substituents effect