 at −00 °C in the absence of air even for prolonged periods. **0b** afforded crystals of sufficient quality for single-crystal X-ray crystallography. The molecular structure is depicted in [Figure [0](#fig0){ref-type="fig"}](#fig0){ref-type="fig"}; selected bond lengths and the sums of valence angles are summarized in [Table [0](#tbl0){ref-type="other"}](#tbl0){ref-type="other"}.  ![ORTEP diagram for compound **0b** (0:0 adduct with 00-cr-0). Thermal ellipsoids are depicted at the 00% probability level. Hydrogen atoms are omitted for clarity.](om0c00000_0000){#fig0}  ###### Selected Bond Lengths *d* (Å) and Sum of Valence Angles ∑α