Keywords: (η 2 -Aldehyde)zirconocene complexes / Metallaoxirane-stabilized group 4 metallocene hydride cations / Nitrile insertion / Isocyanate insertion Treatment of the [Cp 2 Zr(η 2 -acetaldehyde)/H(CH 3 )ZrCp 2 ] nitriles R 2 -CϵN (R = CH 3 , CMe 3 , p-tolyl, or ethyl) cleanly reacts with the cations 18 by addition of the Zr 2 (µ-H) moiety adduct 8 with B(C 6 F 5 ) 3 yields the dimetallabicyclic salt [Cp 2 -Zr(µ-η 1 -O:η 2 -C,O-OCHMe)(µ-H)(ZrCp 2 )] + [CH 3 B(C 6 F 5 ) 3 ] -18b. to the nitrile functionality to yield the respective aldiminiumbridged cations [Cp 2 Zr(µ-η 1 -O:η 2 -C,O-(OCHR 1 )(µ-N=CHR 2 )-Similarly, hydride abstraction from the related neutral dimetallabicyclic [Cp 2 Zr(OCHR)/H 2 ZrCp 2 ] adducts 11 (R = ZrCp 2 ] + (21-24). Complex 24d (R 1 = PhCH 2 , R 2 = C 2 H 5 ) was characterized by an X-ray crystal structure analysis. CH 3 ) or 14 (R = C 2 H 5 ) with B(C 6 F 5 ) 3 yields the systems [Cp 2 Zr(µ-η 1 -O:η 2 -C,O-OCHR)(µ-H)(ZrCp 2 )] + [HB(C 6 F 5 ) 3 ] -(18a, Similarly, treatment of the systems 18a-d with isocyanates RN=C=O (R = CMe 3 , SiMe 3 , p-tolyl, or adamantyl) gave the c) and the reaction of B(C 6 F 5 ) 3 with [Cp 2 Zr(OCHCH 2 Ph)/ H(PhCH 2 )ZrCp 2 )] + 17 gives [Cp 2 Zr(µ-η 1 -O:η 2 -C,O-(OCH-related µ-formamidato complexes 27-30. CH 2 Ph)(µ-H)ZrCp 2 ] + [PhCH 2 B(C 6 F 5 ) 3 ] -18d. A variety of [a] Organisch-Chemisches