Kryoflex low temperature device

The single crystal X-ray diffraction measurement of the 3c,d was conducted on a Bruker SMART APEX CCD area detector diffractometer, equipped with a Bruker KRYOFLEX low temperature device, graphite monochromator, Mo Kα radiation (λ = 0.71069 Å) at 123 K. Cell refinement and data reduction were performed with a Bruker SAINT [37 ]. The structures were solved with SHELXS [38 ] and refined with SHELX-97 [38 ]; absorption correction was performed based on a multi-scan procedure using SADABS [37 ]. Further crystallographic details of the structures in this paper are reported in Table S2.

Crystals suitable for single-crystal X-ray diffraction were selected, coated in perfluoropolyether oil, and mounted on MiTeGen sample holders. Diffraction data were collected on a Bruker Smart-Apex (compounds 5, 6, 7) or a Bruker X8 Apex II (compounds 1, 2, 4) 4-circle diffractometer with a CCD area detector using graphite-monochromated Mo-K_α radiation. The crystals were cooled using a home-made nitrogen gas jet or Bruker Kryoflex low-temperature device. Data were collected at 168 K (5, 6, 7) or 100 K (1, 2, 4). The images were processed and corrected for Lorentz-polarization effects and absorption as implemented in the Bruker software packages. The structures were solved using the intrinsic phasing method (SHELXT)³⁰ and Fourier expansion technique. All non-hydrogen atoms were refined in anisotropic approximation, with hydrogen atoms ‘riding’ in idealized positions, by full-matrix least squares against F² of all data, using SHELXL software.³⁰ Diamond³¹ software was used for graphical representation. Crystal data and experimental details are listed in Table S9 in the ESI;† full structural information has been deposited with Cambridge Crystallographic Data Centre. CCDC-2056492 (1), 2056493 (2), 2056494 (4), 2056495 (5), 2056496 (6), and 2056497 (7).