B. G. S. Mandel, E.
Dec 1, 1975
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Influential Citations
16
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Journal
Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry
Abstract
9-Ethylguanine hemihydrochloride, CvH9NsO. 1⁄2HC1, forms triclinic crystals, space group P1, with a = 13.277(3), b=10.303(1), c=7.987(1) A, e= 93.78(1), fl=56.58(1), ),=105.81(1) ° and Z = 4 . Leastsquares refinement led to an R index of 0.040 for 3615 reflections from a twinned crystal measured by a 20 scan technique. Of the two ethylguanine moieties in the asymmetric unit, one is formally a cation while the other is neutral. However, they are joined by a hydrogen bond N(7)-H. • • N(7) across a pseudo center of symmetry, so that the two moieties are effectively indistinguishable. The N(7). • • N(7) distance of 2-637(3) A represents the shortest N H . . N hydrogen bond yet observed. It is a disordered, rather than a centrosymmetric, hydrogen bond, as the hydrogen atoms occupy with perhaps slightly different population factors sites close to one or the other of the N(7) atoms. Despite the partial positive charge on the ethylguanine moieties, they are closely stacked, with intermolecular spacings of about 3.2 A.