Structural role of hydrogen bond networks in amino acid–acid systems. (II) The network with weakly polarizable OHO hydrogen bonds in sarcosine–p-toluenesulfonic acid (1:1) crystal

The sarcosine–p-toluenesulfonic acid (1:1) crystal crystallizes as monoclinic system and belongs to the: (i) P21/c at 293 and 200 K; (ii) P21/n at 100 K space groups. It was selected for examination of two problems: relations between different components of the amino acid–acid hydrogen bond network and a role of medium strong and weakly polarizable OHO hydrogen bond in the main structural units of the crystal: sarcosinium–p-toluenesulfonate complexes. Our observations are based on phase transitions of the crystal monitored by DSC, X-ray diffraction and temperature evolutions of selected modes of IR spectra. The O⋯O distance of the primary hydrogen bond as well as conformations of sarcosinium and p-toluenesulfonate are very sensitive on state of NHO secondary hydrogen bonds.