ORIGINAL PAPER Novel Stilbene-triazine Symmetrical Optical Brighteners: Synthesis and Applications Aamer Saeed & Ghulam Shabir & Iram Batool Received: 1 February 2014 /Accepted: 7 April 2014 # Springer Science+Business Media New York 2014 Abstract A series of new high light fastness, hot pressing fastness optical brighteners was efficiently synthesized by a three-step approach involving the successive replacement of the three chloro groups of 2,4,6-trichloro-1,3,5-triazine under different conditions of temperature and pH. Thus, 2,4,6- trichloro-1,3,5-triazine was treated with different anilines and the resulting dichlorotriazinyl intermediates (3a-I) were further condensed with 4,4-diaminostilbene-2,2′-disulfonic acid to afford bis-monochlorotriazine (5a-I) followed by nu- cleophilic substitution with ethanolamine to furnish the final hybrid brighteners (7a-I). All of the newly synthesized com- pounds were characterized by Fourier-Transform Infrared (FT-IR), UV-visible absorption, NMR spectroscopy and the elemental analyses. The synthesized optical brighteners were also assessed for their efficacy as fluorescent brightening agents. Keywords Optical brightening agents (OBAs) . UV-visible spectra . Fastness properties Introduction Optical brightening agents (OBA) have become an integral part of our everyday life and culture; finding an increasing number of applications in diverse fields. These are commonly used in the HYP-containing pulp also known as bleached chemi-thermo mechanical pulps (BCTMP) and paper industry is to increase their whiteness and brightness stability; in cos- metics and to increase the visibility of fabrics and in night vision devices [1]. Brighteners are also added to laundry soaps, detergents, or cleaning agents, where they adsorb to fabrics or materials during the washing or cleaning process and when illuminated by ultraviolet light they fluoresce and fabrics appear brighter [2]. Brighteners are highly susceptible to adsorption. They are removed from surface and ground water by adsorption onto soil and organic material. They operate through the process of fluorescence. They absorb invisible ultraviolet (UV) radiation at wavelengths below 400 nm and through an electrophysical change, emit light mostly in the blue end of the visible spectrum at about 400–450 nm [3]. Optical brighteners have been used in experimental mycology for quantization of fun- gal cells or studying cell wall architecture but most important, brighteners are used in histopathology of mycosis in derma- tology and diagnosing pneumocystosis. Another conceivable feature of the brighteners in medical mycology is their poten- tial use as homing agents for systemically applied antifungals. This may be particularly effective with those antifungals that act on the cell wall as is the case with the candins [4]. In additions to coumarins, imidazolines, diazoles, triazoles, benzoxazolines and biphenyl-stilbenes; 4,4′ - bis-(triazinylamino) stilbene-2,2′-disulfonate derivatives are one of the important classes of OBAs. These are widely used to create intense and bright white shades in textiles, pulps and papers, and are additives to laundry detergents [5]. Triazine-stilbene compounds showed a high degree of whiteness with moderate UV blocking properties [6]. It has been shown that stilbene optical brighteners could enhance the biological activities of NPVs against pests like the tobacco budworm, Heliothis Electronic supplementary material The online version of this article (doi:10.1007/s10895-014-1392-1) contains supplementary material, which is available to authorized users. A. Saeed (*) : G. Shabir : I. Batool Department of Chemistry, Quaid-I-Azam University, Islamabad 45320, Pakistan e-mail: asaeed@qau.edu.pk A. Saeed e-mail: aamersaeed@yahoo.com J Fluoresc DOI 10.1007/s10895-014-1392-1