A second monoclinic polymorph of (E)-phen-yl(pyridin-2-yl)methanone oxime

Area of Science:

• Crystallography
• Solid-state chemistry
• Organic chemistry

Background:

• Polymorphism in organic compounds influences material properties.
• Understanding crystal structures is key to predicting chemical behavior.
• Previous research documented one polymorph of (E)-phenyl(pyridin-2-yl)methanone oxime.

Purpose of the Study:

• To characterize a newly discovered monoclinic polymorph of (E)-phenyl(pyridin-2-yl)methanone oxime.
• To elucidate the crystal structure and intermolecular interactions of this new form.
• To compare its structural features with the previously reported polymorph.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the crystal structure.
• Analysis of crystallographic data identified the space group and unit cell parameters.
• Intermolecular interactions, including hydrogen bonding and C-H···π interactions, were analyzed.

Main Results:

• A second monoclinic polymorph of (E)-phenyl(pyridin-2-yl)methanone oxime was identified, crystallizing in space group P2(1)/n (Z=4).
• This new polymorph exhibits a different crystal packing compared to the previously reported C2/c polymorph (Z=8).
• Bifurcated O-H⋯(N,O) hydrogen bonds form inversion dimers, which are further linked by C-H⋯π interactions into linear arrangements.

Conclusions:

• The discovery of a second polymorph highlights the structural diversity of (E)-phenyl(pyridin-2-yl)methanone oxime.
• The specific arrangement of hydrogen bonds and π-interactions dictates the crystal packing in this new form.
• Detailed structural analysis provides insights into structure-property relationships for this class of compounds.