Analyzing Safety Culture in Sri Lankan Industrial Chemical Laboratories.

Background: A laboratory where chemicals are handled can be considered a hazardous environment, and hence, prudent practices should be strictly enforced. If not, deadly accidents and incidents could occur due to a lack of safety practices and poor safety culture. The purpose of this study is to analyze the existing safety culture and propose potential recommendations to enhance the level of safety education in the chemical laboratories in the Western Province of Sri Lanka. Methods: A survey questionnaire was administered among the laboratory supervisors of the chemical laboratories in the Western Province of Sri Lanka in 2019. Results: Even though 80 surveys were distributed among prospective participants, only 46 surveys were submitted, which is 58% of the response rate. Most of the individuals who participated in the survey were females below 35 years old, and approximately 96% of the participants had at least one year of working experience in the same laboratory setting. The majority considered safety as an important factor that requires further improvements with third-party safety inspections; however, 54% of the respondents mentioned that those inspections were conducted by the employees from their laboratory. Conclusion: From the study, it has been discovered that employees have knowledge of safety culture to a certain extent. A significant percentage (83%) of participants believed that further safety measures are required for a safer laboratory. However, the study revealed that the attitudes of some employees should be changed to have a better safety culture. Hence the authors would like to suggest having annual training sessions and well-formulated safety policies to improve the safety culture.

Proton-Gated Photoisomerization of Amino-Substituted Dibenzofulvene Rotors.

Derivatives of 9-(2,2,2-triphenylethylidene)-fluorene (TEF) undergo E/Z photoisomerization and are candidates for light-powered molecular actuators and switches. The 2-substituted derivatives bearing an amino group (ATEF) or a dimethylamino group (DTEF) are weakly photoactive in the absence of acids, but protonation increases photoisomerization quantum yields by factors of 30-60. Such compounds may be useful for incorporation into pH-switchable photoactive devices.

Synthesis and Photoisomerization of Substituted Dibenzofulvene Molecular Rotors.

The synthesis, spectral and structural characterization, and photoisomerization of a family of 2-substituted dibenzofulvene molecular actuators based on (2,2,2-triphenylethylidene)fluorene (TEF) are reported. The 2-substituted species investigated are nitro (NTEF), cyano (CTEF), and iodo (ITEF). X-ray structures of these three compounds and three intermediates were determined to assign alkene configuration and investigate the effects of the 2-substituents on steric gearing. The addition-elimination reaction of Z-9 with trityl anion to form Z-10 proceeded with complete retention of configuration. Rates of photoisomerization were measured at irradiation wavelengths between 266-355 nm in acetonitrile/dioxane solutions at room temperature. Photoisomerization quantum yields (φ) were calculated by means of a mathematical model that accounts for a certain degree of photodecomposition in the cases of CTEF and ITEF. Quantum yields vary significantly with substituent, having maximum values of φ=0.26 for NTEF, 0.39 for CTEF, and 0.50 for ITEF. NTEF is photochemically robust and has a large quantum yield for photoisomerization in the near-UV, making it a particularly promising drive rotor moiety for light-powered molecular devices.