Reaction of the chelating diamido complexes Zr(ABAn)(CH2Ph)2 [ABA1=N,N'-(SiMe3)2-2-amidobenzylamido, ABA2=N,N'-(SiMePh2)(SiMe3)-2-amidobenzylamido] with B(C6F5)3 leads to formation of the unstable zwitterionic adducts [Zr(ABAn)(CH2Ph)][(?6-PhCH2)B(C6F5)3] 1 (n=1) and 2 (n=2), as shown by low temperature NMR experiments that, moreover, enabled an insight into the molecular structure of these compounds in solution. Two intermediates of the decomposition of 1 and 2, that leads to complexes Zr(ABAn)(C6F5)2, were identified.