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Electron Diffraction Study of the Molecular Structure of 1,3‐Diphenylpropane‐1,2,3‐trione (Diphenyl Triketone)
Author(s) -
Schultz György,
Hargittai Istvăan,
Doerner Thomas,
Gleiter Rolf
Publication year - 1991
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19911240615
Subject(s) - chemistry , intramolecular force , crystallography , molecule , hydrogen bond , crystal structure , dihedral angle , electron diffraction , bond length , molecular geometry , benzene , stereochemistry , diffraction , organic chemistry , physics , optics
The molecular structure of 1,3‐diphenylpropane‐1,2,3‐trione (diphenyl triketone) has been determined by gas‐phase electron diffraction at 130°C nozzle temperature. It has been found that the phenyl rings are nearly coplanar with the adjacent carbonyl groups, and the two C ph –C(O)–C(O)–C(O) dihedral angles are ‐ 129.5 ± 0.8 and ‐ 107.1 ± 0.8° (0° corresponds to the syn form). Bond distances (r g , Å) and bond angles (deg) with estimated total errors are CH 1.105 ± 0.006, O C 1.213 ± 0.003, < C ph –C ph > 1.404± 0.003, C ph –C(O) 1.478 ± 0.005, C(O)–C(O) 1.558 ± 0.004, C ph –C(O)–C(O) 120.0 ± 0.3, C ph C(O)O 120.8 ± 0.4, C(O)–C(O)–C(O) 117.3 ± 0.4, C ph –C ph (CO)–C ph 119.8 ± 0.6. Although there is a general agreement between the gas‐phase and crystal molecular structures there are some notable differences. One of the benzene rings is slightly turned about the C ph –C(O) axis in the opposite direction in the gas molecule as compared to the crystal. This causes a marked shortening of the O… H intramolecular contact (to 2.18 Á) between the central oxygen and an ortho ‐hydrogen.