Collect. Czech. Chem. Commun. 1988, 53, 3131-3137

Determination of the structure of p-methylbenzamidinium formate monohydrate

Bohumil Kratochvíla, Jan Ondráčeka, Jindřich Hašekb and László Csordásc

a Department of Mineralogy, Prague Institute of Chemical Technology, 166 28 Prague 6, Czechoslovakia
b Institute of Macromolecular Chemistry, Czechoslovak Academy of Sciences, 162 06 Prague 6, Czechoslovakia
c Laboratory of Surface and Interface Physics, Eotvos University, 1088 Budapest, Hungary


The molecular and crystal structure of p-methylbenzamidinium formate monohydrate, C9H14N2O3, was solved by direct methods. The positions of all the atoms were localized and the structure was refined anisotropically. The final value of the R factor equalled 0·043 for 1 150 observed reflections (I > 1·96σ(I)). The substance crystallizes in the P21/c monoclinic space group with lattice parameters a = 1 038·9(4), b = 1 146·1(5), c = 912·4(3) pm, β = 94·77(3)0, Z = 4. The molecule contains an amidinium-carboxylate bond, formed by two intramolecular hydrogen bridges of the N-H···O type. Intermolecular hydrogen bonds are formed by the side hydrogen atoms of the amidine and the hydrogen atoms of the water molecule and are of the N-H···O and O-H···O types; they form a three-dimensional network in the crystal structure. In this, the structure of p-methylbenzamidinium formate monohydrate differs from the related structures of benzamidinium pyruvate and benzamidinium bromoacetate, characterized by infinite intermolecular chains formed through hydrogen bonding.