Carbon monoxide, although widely known as a toxic gas, has received great attention in the past few decades due to its promising role as a medical gas. Several classes of carbon monoxide releasing molecules (CORMs) have been synthesised with many of them having pharmacological activities under physiological conditions. Herein, we report the synthesis and structural characterization of the first example of amine carboxyborane that releases CO under physiological conditions without the aid of inducers. A representative compound hexamethylenetetramine carboxyborane (HMTA-CB) described here has a half-life of 2.7 days and gradually releases CO with the rate constant of 3.0 × 10 s. Its ability to promote cell growth shows the beneficial effect of slow CO release to supplement CO in small amounts over time.

A rapid separation of three photosynthetic pigments (chlorophyll a and b and xanthophyll) from fern (Polystichum acrostichoides) is described using microscale solvent extraction and traditional thin layer chromatography that minimizes use of harmful chemicals and lengthy procedures. The experiment introduces students to the concepts of extraction and separation of compounds. Combined with absorption and fluorescence spectroscopy using a plate reader, this laboratory experiment demonstrates the concept of light absorption by different pigments that are involved in photosynthesis as well as their photoluminescence properties. This new approach allows students to perform multilaboratory techniques within a 3 h laboratory session. The experiment has been used successfully in an introductory level course, but it may be easily adapted to second-year courses such as organic chemistry laboratory where these methods are widely used.

Elevated levels of reactive oxygen species (ROS) are associated with several detrimental diseases. Therefore, using this condition for selective treatments could be a great advantage in fighting these disorders. Here, we present amine carboxyboranes as a class of molecules for therapeutic CO gas generation and for delivering drug molecules in the presence of ROS. Our findings indicate amine carboxyboranes to be very slow CO releasers at physiological pH and temperature without any inducers but generate CO faster when reacted with a non-radical ROS (HO). Furthermore, a radical ROS (˙OH) dramatically expedites the production of CO from amine carboxyboranes. A decomposition profile shows the release of the amine group during the decarbonylation process from drug-conjugated carboxyboranes. This suggests that the carboxyborane moiety can be a useful tool for the delivery of amine-containing drugs to disease sites which display abundant ROS levels.