Electronic structure of two isostructural `paddle-wheel' complexes: a comparative study
Contents a) Charge density studies details b) Theoretical Calculations of [Cu(DMSO) 6 ] q chromophore c) CSD search on [CuO 6 ] chromophore (different .pdf file) d) Appendix I. Comparison of multipole refinement for (I) using the non-averaged and merged data. a) Charge density studies details S1 Data collection and crystal structure refinement details Data Collection. A suitable recrystallized sample of a tetrakis(μ 2 -acetato)-diaqua-di-copper(II) (I) and tetrakis(μ 2
... to)-diaqua-di-chromium(II) (II) crystals were used for the high-resolution X-ray diffraction experiments. The data were collected at 100.0(1) K on an Oxford Diffraction Kappa geometry GEMINI R diffractometer equipped with Rubi CCD area detector using graphite monochromated MoKα X-radiation (wavelength λ = 0.71073 Å) at 50 kV and 40 mA. Crystal-todetector distance was of 60 mm. The diffraction data were collected with a huge and equally distributed redundancy at six different detector positions for (I) (2θ = ±18.695 o , ±60.0 o , -90.0 o and +96.250 o ) and eight detector positions for (II) (2θ = -18.94 o , 19.02 o , ±30.0 o , -48.97 o , 49.12 o , -72.0 o and 81.17 o where θ is the Bragg angle). The strategy was based on 198 omega runs for (I) and 70 omega runs for (II) with the frame width of 1.0 o . According to the θ-dependence of the diffracted intensities, the chosen exposure time was of 15, 60 and 80 seconds for A and of 20, 32, 90 and 180 seconds for (II), respectively. The maximum resolution reached at this experimental setting was of 1.297 Å -1 for (I) and of 1.220 Å -1 for (II). 405560 total number of reflections were collected in this long-term experiment for (I) and 153981 for (II), respectively. Integration of the diffracted intensities, the Lorentz-polarization and FACEabsorption correction were performed with CrysAlis PRO software (Rigaku OD, 2016). Average redundancy was of 31.9 with the R int = 0.026 and R(σ) = 0.005 for (I), as well as of 13.7 and R int = 0.020 and R(σ) = 0.008 for (II), respectively. After the data reduction, the .hkl files were treated with JANA2006 to obtain xd.hkl files, with the direction cosines included, for the multipolar refinement. Details of the X-ray diffraction experiment conditions and the crystallographic data for (I) and (II) are given in Table 1 . S2. Multipole model refinement details.