ChemBeads: Solid Catalyst Coating on Glass Beads

Introduction to ChemBeads

Researchers and chemists continuously seek new technologies to optimize rapid screening of diverse reaction conditions for molecules of high complexity and scarcity. Solid dispensing methods for chemical reagents at the nanomole scale are challenging due to their physical properties. However, since the development of glass beads coated with solid chemical reagents, called ChemBeads, drug-delivery lab work with submilligram amounts of solids can efficiently be performed, particularly for high-throughput reaction screening, with material consumption minimized.

ChemBeads are small chemical-coated glass beads created for use in high throughput experimentation (HTE). These beads allow different solids to be easily dispensed in small amounts. The process of creating ChemBeads involves placing the catalysts or other dry chemical, like ligands and inorganic bases, in a mechanical acoustic mixer with the approximately 250 µm wide glass beads.¹ Through Van der Waals forces the solids coat the smooth round surface of the beads evenly without the use of any chemicals or surfactants. The catalyst remains coated to the bead until it is contacted with solvent, releasing the catalyst into solution.

High-throughput experimentation often uses automated robotic systems to screen multiple different catalysts or compounds on micro- to nano-scale to determine the ideal combinations of reagents and conditions for a reaction. Due to the difficulties of programming robotic platforms to dispense solids with different physical properties, these reactions often require dispensing submilligram amounts of expensive catalysts manually and this is where solid catalyst-coated glass beads are a significant benefit.² Due to the low loading of the glass beads, up to 20 wt%, ChemBeads maintain the physical properties of their host medium enabling a robotic platform to be programmed once for all ChemBeads products. This makes ChemBeads perfect for robotically dispensing nanomole concentrations of catalysts saving both time and money.

ChemBeads products can also be weighed volumetrically. Calibrated ChemBeads Scoops can be used to accurately weigh 5, 10, or 50 milligrams of ChemBeads products. They have been designed to consistently and accurately deliver the calibrated amount quickly and efficiently. The scoops are made of a chemical-resistant plastic that can be reused multiple times.

ChemBeads allow for better experimentation because of the ability to screen multiple reaction conditions in parallel​, optimize reactions with particular starting materials​, reduce utilization of expensive precious metals or building blocks (< 1 mg)​, and increase speed and output. ChemBeads have the capacity to impact researchers and chemists in academic, pharmaceutical, and industrial laboratories.

We’ll keep your work flowing with a variety of ChemBeads to help you reach new frontiers in your research and development.

Figure 1. Enlarged photos of the following ChemBeads product: Palladium (II) Chloride ChemBeads, [1,1′-Bis(diphenylphosphino)ferrocene]dichloropalladium(II) ChemBeads, Grubbs Catalyst^® M204 ChemBeads, and Tris(dibenzylideneacetone)dipalladium(0) ChemBeads (Left to right).

References

1. Tu NP, Dombrowski AW, Goshu GM, Vasudevan A, Djuric SW, Wang Y. 2019. High-Throughput Reaction Screening with Nanomoles of Solid Reagents Coated on Glass Beads. Angew. Chem. Int. Ed.. 58(24):7987-7991. https://doi.org/10.1002/anie.201900536

2. Martin MC, Goshu GM, Hartnell JR, Morris CD, Wang Y, Tu NP. 2019. Versatile Methods to Dispense Submilligram Quantities of Solids Using Chemical-Coated Beads for High-Throughput Experimentation. Org. Process Res. Dev.. 23(9):1900-1907. https://doi.org/10.1021/acs.oprd.9b00213