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High-resolution single-crystal X-ray diffraction measurements at 100 K were performed for the two polymorphs of urea-barbituric acid co-crystals: (I) P2(1)/c and (II) Cc. Experimental and theoretical charge density and its properties were analysed for (I) and (II) in order to confirm the previous observation that in the polymorphs studied the barbituric(More)
The crystal structures of three polymorphs found for the addition complex of urea and barbituric acid are described and compared. Two polymorphs are monoclinic, space groups P2(1)/c and Cc, whereas the third is triclinic, P1. The displacement of electron density towards the mesomeric forms, corresponding to the tautomeric forms of higher stability, of the(More)
Analysis of the spectral properties and structural differences of two turn-on ratiometric fluorescent receptors for Zn(2+) and Cd(2+) ions, derivatives of pyrrolo[2,3-b]quinoxaline (2), and earlier published 3 (Ostrowska et al. CrystEngComm 2015, 17, 498-502) was performed. Both ligands are E/Z push-pull olefins interconverting at room temperature, with(More)
The title compound, C(19)H(13)N(5)O(3), can be obtained from the corresponding α-amido-α-amino-nitrone in a reaction with biphenyl-2,2'-diamine. The amido-amidine core has distinctive geometrical parameters including: an outstandingly long Csp(2)-Csp(2) single bond of 1.5276 (13) Å and an amidine N-C-N angle of 130.55 (9)°. Intra-molecular N-H⋯O, N-H⋯N and(More)
The asymmetric unit of the title compound, Rb(+)·C(4)H(3)N(2)O(3) (-)·C(4)H(4)N(2)O(3)·H(2)O, consists of one rubidium cation, a barbituric acid mol-ecule, a barbiturate anion and one water mol-ecule. The rubidium ion has seven close-contact inter-actions with O atoms, with Rb⋯O distances ranging from 2.8594 (16) to 3.2641 (14) Å. These seven O atoms(More)
  • Marlena Gryl
  • 2015
Active pharmaceutical ingredients (APIs), through their favourable donor/acceptor spatial distribution and synthon formation flexibility, are attractive building blocks in modern materials crystallography. The optical properties of a crystal strongly depend on two factors, i.e. the spatial distribution of molecules in the crystal structure and the(More)
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