Cp₃Zr(acetonitrile)⁺: Structure of an Electron‐Rich Organometallic d⁰‐Cation

The organometallic salt [Cp 3 Zr(N≡C‐CH 3 )] + [CH 3 B‐(C 6 F 5 ) 3 ] − ( 3a ) has been prepared by treatment of Cp 3 ZrCH 3 with B(C 6 F 5 ) 3 followed by the addition of acetonitrile. X‐ray crystal structure analysis of 3a shows that its cation consists of three uniformly coordinated η 5 ‐cyclopentadienyl ligands about the zirconium atom. The acetonitrile ligand is end‐on coordinated. In the linear [Zr] ‐N≡C‐CH 3 unit the C≡N triple bond [N‐C2 1.126(5) Å] is slightly shorter than in the free acetonitrile molecule [d C≡N = 1.141(2) Å], the structure of which was determined as a reference by X‐ray diffraction of a crystal obtained by IR‐laser‐induced zone melting on the diffractometer.