Synthesis and performances of extended conjugated stilbene fluorescent dye

Abstract

PurposeThe purpose of this paper is to explore the optic performance of extended stilbene derivative.Design/methodology/approachFive steps were adopted to synthesise novel 4, 4′-bis (2-cyanostyryl) stilbene, which contained three vinyl units in the skeleton (S3E). The structure of S3E was characterised by 1H NMR and EI-MS. Its absorption and emission spectra were also given.FindingsCompared to C.I. Fluorescent Brightener 199, which contains two vinyl units in the skeleton, S3E showed obvious bathochromic shifts in both UV-VIS and FL spectra. The maximum absorption wavelength and fluorescent wavelength were at 390 nm and 464 nm, respectively, with Stoke’s shift of 74 nm. The absolute fluorescence quantum yield was 0.42. Thermogravimetric analysis (TGA) revealed that the weight loss of S3E was less than 5 per cent at 300 °C. Moreover, the light resistance test showed that S3E in PVC plate can keep the good fluorescent intensity for more than seven days exposed to xenon light. Therefore, it is believed that S3E could satisfy the requirements of colouring PVC as a fluorescent dye.Practical implicationsS3E can be used as a candidate of fluorescent dye in the development of thermoplastics.Originality/valueThe present paper designed and synthesised a new derivative of stilbene, which showed its preference to be a colourant of thermoplastics.