Experimental. The intensity data were collected on a Bruker X8 ApexII 4 K Kappa CCD diffractometer using an exposure time of ?? s/frame. A total of ??? frames were collected with a frame width of 0.5\ % covering up to θ = 28.0 ° with 99.9% completeness accomplished.Spectroscopy data: 1H NMR (300 MHz, (CD3)2CO): δ = 7.5–7.8 (m, 30H). 31P NMR (121 MHz, (CD3)2CO): δ = -1.6 (s), -143.0 (m, PF6). ν(CO): 1989, 2008, 2025 cm-1.

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.