Tetrafluoro-p-benzoquinone (fluoranil)

The role played by C–H...O and C–H...N interactions in determining molecular packing and conformation

“…( 2) A strong argument for the role played by C-H...O interactions in determining this layer structure and other layer structures involving benzoquinone molecules is provided by the molecular arrangements in the l:l complex between thymine and 1,4benzoquinone (Sakurai & Okunuki, 1971), in the quinhydrone complex (Sakurai, 1965), in the l:l complex of benzoquinone with chlorophenol (Shipley & Wallwork, 1967) and by the observation that tetrafluoro-p-benzoquinone (Meresse, Courseille & Chanh, 1974) does not form a layer structure as in 1,4-benzoquinone. The first-mentioned crystal structure contains alternating thymine and benzoquinone layers.…”

Structure of tetrafluoro-p-benzoquinone (p-fluoranil) at 120 K

“…The results of wide ranges of molecular structure determinations generally agree within experimental errors, although, of course, the concept of chemical bond lengths is implicitly defined in different ways by the two methods. Whereas this is also true for most of the p-benzoquinone systems studied hitherto, there are significant differences between the parameters of the p-fluoranil structures as determined by Schei et aL TETRAFLUORO-p-BENZOQUINONE (1980) (electron diffraction) and Meresse et al (1974) (X-ray diffraction).…”

“…The molecular structures of a number of substituted p-benzoquinones, C60~X 4 (X= H, CH3, F 0108-2701/87/101959-03501.50 and C1) have been determined by electron (Hagen & Hedberg, 1973Schei, Hagen, Tr~etteberg & Seip, 1980) and X-ray diffraction (Trotter, 1960;Chu, Jeffrey & Sakurai, 1962;Rabinovich, Schmidt & Ubell, 1967;van Weperen & Visser, 1972;Meresse, Courseille & Chanh, 1974;van Bolhuis & Kiers, 1978). The results of wide ranges of molecular structure determinations generally agree within experimental errors, although, of course, the concept of chemical bond lengths is implicitly defined in different ways by the two methods.…”

“…Of the 1833 independent reflections measured, 1046 reflections were classified as observed, i.e./net > 3.0tr(/). The structure was refined with starting parameters from the room-temperature structure (Meresse et al, 1974). All calculations were carried out using CRYSTALS, Issue 9 (Watkin, Carruthers & Betteridge, 1985).…”

6,10-Diaminododecafluorobicyclo[4.4.0]dec-1(10)-en-2-one

“…C(2)-O(2) and C(10)-N(10) are close to the doublebond value (Sutton, 1965;Lofthus, 1959) while C(1)-C(2) and C(1)-C(10) are nearly equal and slightly (but not significantly) longer than expected for C-C bonds possessing ca 50% double-bond character. The shortness of C(2)-O(2) and C(10)-N(10) is difficult to rationalize but may be at least partially due to the effect of the highly electronegative F substituents at the adjacent C atoms (Gali, Miravitlles & Font-Altaba, 1975;Meresse, Courseille & Chanh, 1974;Yates, Ardao & Fieser, 1956). However, owing to the limited number of intensities available, the measured bond lengths are of relatively low reliability.…”