No abstract

No abstract

No abstract

fl-Guanidinopropionic acid (flGP), C4H9N302, m.p. 215-220°C, is monoclinic, with the following space group and cell dimensions at room temperature: P21/a; a= 11 "818 (4), b= 7-247 (4), c= 7.311 (4)/~, fl= 98.22 (4)°; Z=4, 0ca~c = 1.403, 0 .... = 1"403 g cm -3. Sphenoidal crystals were grown from aqueous solution. Final R=0.061 on 885 observed reflexions. The molecules are folded zwitterions held by hydrogen bonds in planar sheets perpendicular to e. An intramolecular hydrogen bond is found. ExperimentalWeissenberg photographs showed systematic absences for 0k0, k odd and hOl, l odd, uniquely defining the space group as P21/a. A tape-controlled Stoe-Gfittinger diffractometer was used for data collection. Accurate cell dimensions were obtained from a least-squares refinement using the 20 values of 43 reflexions. Intensity data were collected from hnl and hkn layers (n = 0, 1,2,3) up to sin 0/2=0.622 using Ni-filtered Cu Ks radiation (1.5418 A) and a pulse-height analyser. 1131 reflexions were measured of which 106 were systematically extinct, and 85 designated as 'unobselved', i.e. with integrated intensity less than 100 counts above background. The remaining reflexions were regarded as 'observed'.

No abstract