The synthesis and fluorescence behavior of a series of bis(trisilylalkyl)anthracene molecules is described. The photodegradation of these molecules under UV light has been monitored and compared to a commercially available fluorescent optical brightener. There is a relationship between the structure and the rate of photo decay. The materials with more bulky substituents exhibit the greater stability towards UV. For bis(triphenylsilyl)anthracene the photostability appears to be comparable with a commercially available optical brightener, but the molecule may be susceptible to thermal decay. 1. Introduction The development of environmentally friendly routes towards improved crop production is a goal of global concern. One particularly attractive proposition studied by a number of groups including the team at Reading, is the development of spectral filters in polyethylene cladding used for commercially grown protected crops. For example, a reduction in plant height has been observed in a range of species under polyethylene films containing a far-red blocking dye, thereby, offering an alternative method of producing compact high quality plants without using chemical growth regulators [1–4]. In this approach the polymer film controls the red/far red light balance by means of a phthalocyanine dye system absorbing in a narrow band at 730？nm. The dye is designed to be soluble in polyethylene, and thus plants can be grown in a horticultural tunnel with low levels of far red light. In this paper we extend our studies into modifying the film’s absorption in the short wavelength end of the visible spectrum. It has been shown that UV blocking films may provide an environmentally friendly way of reducing pests and disease; for example, it has been found that whitefly incidence is considerably reduced for crops grown under such films [5]. In addition, it has been shown that the presence of UVB and UVA radiation increases the presence of phenolic compounds in Lollo Rosso lettuce albeit with a considerable reduction in plant mass [6]. In this presentation we discuss the further application of the production of films which absorb near ultraviolet radiation and which fluoresce in the short-wavelength visible region. Such films have been found to reduce the sporulation of Botrytis cinerea in crops grown in horticultural tunnels [7]. Initial studies of these films with commercially available fluorescent materials as additives for polyethylene cladding for horticultural tunnels have revealed a number of difficulties, the most obvious of which is the limited lifetime of the
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