no / The structure of 2,7-dibromocryptolepine acetic
acid solvate, C16H11N2Br2 [1.5(C2H4O2)][C2H3O2
-]
[0.5H2O], Mr = 460.17, has been determined from X-ray
diffraction data. The crystals are monoclinic, space group
P21/c with Z = 4 molecules per unit cell and a =
7.3243(3), b = 18.7804(6), c = 15.8306(7) A ° , b = 94.279(1) ,
Vc = 2171.5(2) A ° , crystal density Dc = 1.667 g/cm3. The
structure was determined using direct methods and refined
by full-matrix least-squares to a conventional R-index of
0.0496 for 4,908 reflections and 258 parameters. The cryptolepine
nucleus of the 2,7-dibromocryptolepine molecule
is highly planar and the two Br atoms are in this plane
within 0.06 and 0.01 A ° , respectively. The crystal structure
is maintained via hydrogen bonding between N(10) in the
cryptolepine nucleus and the oxygen of one of the three
solvated acetic acid molecules. The acetic acid molecules
also form hydrogen bonded chains. Acetic acid B is
deprotonated and its two C¿O bond lengths are equivalent,
unlike those in A and C. Acetic acid C lies very close to a
crystallographic centre of symmetry. To avoid overlap the
two repeats cannot exist together and are subject to 50%
statistical disorder. O(1C) of this methanol is furthest from
the two-fold axis and its occupancy refines to a value of 1.0
and is assumed to exist alternately as a water oxygen
hydrogen bonding to methanol O(1C) across the two-fold
axis at a distance of 2.775 A ° .
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/4526 |
| Date | January 2008 |
| Creators | Potter, B.S., Lisgarten, J.N., Pitts, J.E., Palmer, R.A., Wright, Colin W. |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Article, No full-text available in the repository |
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