Anna M. Christianson

Maintaining an element of active learning in the post-COVID-19 classroom was a challenge given the absence of traditional in-person interactions. This communication describes how the author used Socrative online polls to help bridge that gap for General Chemistry students in Spring 2020. The Socrative platform provides a versatile way to incorporate real-time student participation even in a virtual environment, since it can be accessed anywhere with a web connection. The system gives the instructor many options for creating effective activities from short concept checks to class-long guided practice. Student evaluation comments indicated their positive experience of the use of Socrative polls and, more generally, the transition to online learning in the Spring 2020 General Chemistry courses. Socrative or other web-based student response systems may thus be a useful tool for instructors wishing to make their remote classroom interactive.

Modification of a BODIPY dye with a Lewis acidic antimony group affords a fluorescent fluoride and cyanide sensor.

Although phosphine ligands are ubiquitous in transition metal chemistry, few reports of fluorescent phosphines exist that explore the effect of metal coordination on the photophysical properties of a phosphine-bound fluorescent group. The coordination chemistry of a derivative of fluorescein decorated with an o-phenylene-linked phosphine group has been studied with late transition metals. An Au(I) complex of the phosphine-decorated fluorescein has been structurally characterized, showing that the metal center is held closely over the plane of the fluorophore. Despite the presence of the heavy metal center, however, the phosphine-gold complex displays greatly increased fluorescence compared to the free ligand, in which photoelectron transfer from the lone-pair-bearing phosphine causes low emission. The phosphine-decorated fluorescein ligand was tested in a simple sensing system for metal ions in aqueous solution and shows a “turn-on” response to Au, Ag, and Hg, with an especially dramatic response to Au(III) species. The selectivity for Au(III) was determined to be the result of a “double turn-on” response that is both reaction- and coordination-based.