Partial ordering of tripivaloylmethane at 110 K

Area of Science:

• Solid-state chemistry
• Crystallography
• Materials science

Background:

• Tripivaloylmethane (C16H28O3) crystallizes at room temperature in space group R3m.
• Molecules are conformationally chiral, with enantiomers occupying sites equally in the room-temperature structure.

Purpose of the Study:

• To investigate the order-disorder phase transition in tripivaloylmethane single crystals.
• To characterize the structural changes and molecular ordering upon cooling.

Main Methods:

• Single-crystal X-ray diffraction at low temperatures (110 K).
• Analysis of crystal symmetry and molecular conformation changes.

Main Results:

• Partial ordering observed upon cooling to 110 K.
• Two molecules in the unit cell adopt different chiral conformations, while one remains disordered.
• Crystal symmetry changes from R3m to P3.

Conclusions:

• Tripivaloylmethane exhibits an unusual order-disorder phase transition driven by conformational changes.
• This transition involves partial ordering within the crystal lattice, affecting molecular chirality.
• The study highlights the importance of molecular conformation in solid-state phase transitions and molecular motion.