*3.6. Single Crystal X-ray Di*ff*raction Analysis and Structure Determination*

Suitable single crystals were selected and mounted in air onto thin glass fibres. Diffraction data of **2b** and **2c** were collected at room temperature, while data from the anhydrous form **2a** were collected at 150 K on an Oxford Diffraction Xcalibur four-circle kappa geometry diffractometer with Xcalibur Sapphire 3 CCD detector, using graphite monochromated MoKα (λ = 0.71073 Å) radiation.

The essential crystallographic data from the solid forms **2a**, **2b** and **2c** are presented in Table 2.

Data reduction, correction for the Lorentz-polarization factor, scaling and multi-scan absorption correction was performed using the CrysAlisPro software package [19]. Solution, refinement and analysis of the structures were done using the programs integrated in the WinGX system [20]. The structures were solved by direct methods implemented in SHELXS [21,22]. Refinement by the full-matrix least-squares methods, based on *F* <sup>2</sup> against all reflections, was performed by SHELXL [21,22], including anisotropic displacement parameters for all non-H atoms. Hydrogen atoms bound to C and N (in **2b**) atoms were modelled by the riding model using the AFIX routine, while those bound to water oxygen atoms were located in the difference Fourier maps and refined isotropically. Analysis of the molecular geometry and hydrogen bonds was performed by PLATON [23]. The molecular graphics were done with MERCURY (Version 4.1.0) [24]. The crystal parameters, data collection and refinement results are summarized in Table 2. CCDC deposition numbers 2013658 (**2a**), 2013659 (**2b**) and 2013660 (**2c**) contain the supplementary crystallographic data for this paper. These data can be obtained free

of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html (or from the CCDC, 12 Union Road, Cambridge CB2 1EZ, UK; Fax: +44 1223 336033; E-mail: deposit@ccdc.cam.ac.uk)


**Table 2.** Essential crystallographic data for **2a**, **2b** and **2c**.
