A new polymorph of tetraphenyldiboroxane

Area of Science:

• Solid-state chemistry
• Crystallography
• Organoboron compounds

Background:

• Tetraphenyldiboroxane (C24H20B2O) is an organoboron compound with known crystalline forms.
• Polymorphism, the ability of a solid material to exist in more than one crystalline form, is common in molecular compounds.

Purpose of the Study:

• To report the discovery and characterization of a new polymorph of tetraphenyldiboroxane.
• To compare the structural features and packing of the new polymorph with the previously known form.

Main Methods:

• Single-crystal X-ray diffraction was used to determine the crystal structure of the new polymorph.
• Crystallographic data analysis, including space group determination and refinement.
• Comparison of molecular conformation and unit cell parameters between the two polymorphs.

Main Results:

• A new monoclinic polymorph of tetraphenyldiboroxane, designated (Ia), was identified.
• Both polymorphs (Ia and Ib) crystallize in the P2(1)/c (or P2(1)/n) space group.
• Differences in the rotational orientations of phenyl rings around B-C bonds were observed between the two polymorphs.
• Markedly different packing patterns and unit cell dimensions were found for the new polymorph (Ia).

Conclusions:

• The existence of at least two distinct polymorphic forms of tetraphenyldiboroxane is confirmed.
• The observed conformational differences in phenyl ring rotations are responsible for the varied packing and cell dimensions.
• This finding contributes to the understanding of structure-property relationships in organoboron compounds.