Synthesis and spectral characterization of new 1,3,5-triaryl-2-pyrazolines highlighting effect of alkyloxy chain length on fluorescence

Asghar Abbas; Safdar Hussain; Noureen Hafeez; Aurangzeb Hasan; Muhammad Moazzam Naseer

doi:10.1016/j.saa.2014.02.025

Synthesis and spectral characterization of new 1,3,5-triaryl-2-pyrazolines highlighting effect of alkyloxy chain length on fluorescence

Spectrochim Acta A Mol Biomol Spectrosc. 2014 Jun 5:127:32-40. doi: 10.1016/j.saa.2014.02.025. Epub 2014 Feb 21.

Authors

Asghar Abbas¹, Safdar Hussain², Noureen Hafeez³, Aurangzeb Hasan⁴, Muhammad Moazzam Naseer⁵

Affiliations

¹ Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan. Electronic address: profazmi@hotmail.com.
² Department of Forensic Medicine & Toxicology, National University of Sciences and Technology, Islamabad 44000, Pakistan.
³ Department of Forensic Medicine & Toxicology, RIHS, Bahria University, Islamabad, Pakistan.
⁴ Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan.
⁵ Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan. Electronic address: moazzam@qau.edu.pk.

PMID: 24632153
DOI: 10.1016/j.saa.2014.02.025

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.

Keywords: 1,3,5-Triaryl-2-pyrazolines; Alkyloxy side chain; Fluorescence; Spectroscopy; Synthesis.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Fluorescence*
Hydrocarbons, Fluorinated / chemical synthesis*
Hydrocarbons, Fluorinated / chemistry*
Pyrazoles / chemical synthesis*
Pyrazoles / chemistry*
Spectrometry, Fluorescence

Substances

Hydrocarbons, Fluorinated
Pyrazoles