Fluorescent Liquid Tetrazines

Tetrazines with branched alkoxy substituents are liquids at ambient temperature that despite the high chromophore density retain the bright orange fluorescence that is characteristic of this exceptional fluorophore. Here, we study the photophysical properties of a series of alkoxy-tetrazines in solution and as neat liquids. We also correlate the size of the alkoxy substituents with the viscosity of the liquids. We show using time-resolved spectroscopy that intersystem crossing is an important decay pathway competing with fluorescence, and that its rate is higher for 3,6-dialkoxy derivatives than for 3-chloro-6-alkoxytetrazines, explaining the higher fluorescence quantum yields for the latter. Quantum chemical calculations suggest that the difference in rate is due to the activation energy required to distort the tetrazine core such that the [Formula: see text] [Formula: see text] and the higher-lying [Formula: see text] [Formula: see text] states cross, at which point the spin-orbit coupling exceeding 10 cm [Formula: see text] allows for efficient intersystem crossing to occur. Femtosecond time-resolved anisotropy studies in solution allow us to measure a positive relationship between the alkoxy chain lengths and their rotational correlation times, and studies in the neat liquids show a fast decay of the anisotropy consistent with fast exciton migration in the neat liquid films

A lightweight, strength and electromagnetic shielding polymer composite structure for infant carrier strollers

Electromagnetic (EM) shielding is a protection about reducing the EM fields in a space by blocking the waves with barriers including conductive materials. EM shielding has become an important concept in recent years as a result of increased EM environment pollution. Its long-term effects are still being investigated in terms of public health. Because of gaining more and more importance in daily life, there are a large number of research subjects including not only raw materials but also end-products in the literature. In this study, EM shielding characteristics and strength analysis of a diverse range of polymer composites were evaluated and compared for use in an infant carrier stroller body. This type of strollers is not only used for carrying infants, but also some parts of them are used as baby car seats which should be light and strength. Since, the strollers are commonly used in public areas which the infant is exposed to EM radiation and it is strongly recommended to protect infants from EM radiation, sample polymer composite plates have been produced and electromagnetic shielding effectiveness (EMSE) measurements in an anechoic chamber were performed. According to EMSE performances of the plates in frequency range of 700 MHz to 3 GHz, two of the nine different (carbon, aramid, hybrid, glass fiber) textiles were selected to be used in two infant carrier prototypes. After production of prototypes, samples from these prototypes were taken, tensile and impact tests were performed to determine if the molded structures were strength and light enough