Special refinement was carried out for compounds 1-3. The crystals of 1, on the microscope slide and at room temperature, appear very well formed. However, when flash cooled at 120 K they give a bad diffraction pattern which was difficult to index. At 200 K the pattern was indexed using CELL_NOW as a non-merohedral twin. The two twin components are related by twin law [-1 0 0 / -0.25 1 -0.73 / 0 0 -1] and refined twin scale factor 0.449 (2). One molecule of MeCN was identified but all other electron density pertaining to solvent was handled using the SQUEEZE routine of PLATON. A total of 262 electrons per unit cell were handled this way. It is not really possible to identify the correct solvent ratio from this; 262 electrons roughly correspond with 2.8 molecules of CH2Cl2 per asymmetric unit, but the largest residual peak (before using SQUEEZE) was 4.5 electrons high; with CH2Cl2 it would be much bigger, even for disordered CH2Cl2. The moiety formula is thus reported as "... + solvent". Three of the four triflate anions were modelled as disordered over two sites. Displacement ellipsoid and geometric similarity restraints were used. The data set was cut at a resolution of 1 Å owing to rapidly increasing values of R(merge) at higher resolution.