Mixed crystals of 2-carbamoylguanidinium with hydrogen fluorophosphonate and hydrogen phosphite in the ratios 1:0, 0.76 (2):0.24 (2) and 0.115 (7):0.885 (7)

作者：Fabry Jan^*; Fridrichova Michaela; Dusek Michal; Fejfarova Karla; Krupkova Radmila

来源：Acta Crystallographica Section C-Crystal Structure Communications, 2012, 68: O76-O83.

DOI：10.1107/S0108270111054114

The title compounds, 2-carbamoylguanidinium hydrogen fluorophosphonate, C2H7N4O+center dot HFO3P-, (I), 2-carbamoylguanidinium- hydrogen fluorophosphonate-hydrogen phosphite (1/0.76/0.24), C2H7N4O+center dot 0.76HFO(3)P(-)center dot 0.24H(2)O(3)P(-), (II), and 2-carbamoylguanidinium-hydrogen fluorophosphonate-hydrogen phosphite (1/0.115/0.885), C2H7N4O+center dot 0.115HFO(3)P(-)center dot 0.885H(2)O(3)P(-), (III), are isostructural with guanylurea hydrogen phosphite, C2H7N4O+center dot H2O3P- [Fridrichova, Nemec, Cisarova %26 Nemec (2010). CrystEngComm, 12, 2054-2056]. They constitute structures where the hydrogen phosphite anion has been fully or partially replaced by hydrogen fluorophosphonate. The title structures are the fourth example of isostructural compounds which differ by the presence of hydrogen fluorophosphonate and hydrogen phosphite or fluorophosphonate and phosphite anions. Moreover, the present study reports structures with these mixed anions for the first time. In the reported mixed salts, the P and O atoms of either anion overlap almost exactly, as can be judged by comparison of their equivalent isotropic displacement parameters, while the P-F and P-H directions are almost parallel. There are strong O-H center dot center dot center dot O hydrogen bonds between the anions, as well as strong N-H center dot center dot center dot O hydrogen bonds between the 2-carbamoylguanidinium cations in the title structures. Altogether they form a three-dimensional hydrogen-bond pattern. Interestingly, rare N-H center dot center dot center dot F interactions are also present in the title structures. Another exceptional feature concerns the P-O(H) distances, which are about as long as the P-F distance. The dependence of P-F distances on the longest P-O distances in FO3P2- or HFO3P- is presented. The greater content of hydrogen phosphite in the mixed crystals causes a larger deformation of the cations from planarity.

• 出版日期2012-2