Diffraction study. Suitable crystals for X-ray diffraction data were obtained by dissolving the samples in a mixture of 1:1
Data were collected at 125 K using a Bruker diffractometer. Structure resolution and refinement were performed with SHELXTL, details are included in Table 3. H atoms were calculated and constrained as riding on their bound atoms.
contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystalllographic Data Centre via