Precision Deuteration Using Cu-Catalyzed Transfer Hydrodeuteration to Access Small Molecules Deuterated at the Benzylic Position.

A highly regio- and chemoselective Cu-catalyzed aryl alkyne transfer hydrodeuteration to access a diverse scope of aryl alkanes precisely deuterated at the benzylic position is described. The reaction benefits from a high degree of regiocontrol in the alkyne hydrocupration step, leading to the highest selectivities reported to date for an alkyne transfer hydrodeuteration reaction. Only trace isotopic impurities are formed under this protocol, and analysis of an isolated product by molecular rotational resonance spectroscopy confirms that high isotopic purity products can be generated from readily accessible aryl alkyne substrates.

Sapphire dilatometer cell for measuring the thermal expansion of solids.

Capacitive-based dilatometry is used to determine the thermal expansion of solid specimens over a broad temperature range and for the study of structural and thermodynamic phase transitions. It can detect length changes of 0.1 Å or better. Dilatometer cells have been constructed of metals, such as copper or silver, and non-metals, such as silicon and fused silica. Sapphire is a good candidate for the construction of a dilatometer cell. It has excellent thermal conductivity, a well-behaved thermal expansion of moderate magnitude, especially below ∼60 K, and is readily available. The design, fabrication, and testing of a sapphire dilatometer cell are described herein.