Recommended for grades 13–16.
An organometallic compound is one that contains a carbon-metal bond. The key feature of many of these compounds is that the carbon on the carbon-metal bond carries a partial negative charge. The partial negative charge on carbon makes it basic and nucleophilic; this latter property can be exploited in organic synthesis to help construct carbon-carbon bonds. Organomagnesium compounds are referred to as Grignard reagents.
Crystal violet is a triarylmethane dye which is commonly used in general chemistry classrooms to study spectrophotometry and basic chemical kinetics. Here, you will synthesize crystal violet by preparing a Grignard reagent from the bromine-containing compound 4-bromo-N,N-dimethylaniline. Addition of this Grignard to diethyl carbonate followed by acid hydrolysis ultimately leads to the triarylmethane dye.
In this experiment, you will
- Prepare a Grignard reagent from 4-bromo-N,N-dimethylaniline, illustrating the synthetic process of carbon-carbon bond formation.
- Synthesize crystal violet from this Grignard reagent.
- Analyze the purity of the synthesized crystal violet spectrophotometrically.
Sensors and Equipment
This experiment requires each of the following Vernier sensors and equipment (unless otherwise noted):
You may also need an interface and software for data collection. What do I need for data collection?
Download Experiment Preview
The student-version preview includes:
- Step-by-step instructions for computer and LabQuest data collection
- List of materials and equipment
The preview does not include essential teacher information, safety tips, or sample data. We strongly recommend that you purchase the book before performing experiments.
No standards correlations for this experiment.