H 2 )} 3 Zr-FeCp(CO) 2 ] (1) reacts with 1,2-diphenylcyclopropenone to give [HC{SiMe 2 N(2,3,4-F 2). A single-crystal X-ray structure analysis has now established the molecular structure of the product of oxygen transfer of the cyclopropenone to a carbonyl ligand. The chiral Fe center in complex 2 bears a carbonyl, a cyclopropenylidene ligand, and the C atom of a µ 2 -η 3 -bridging CO 2 ligand.

Reaction of the tripodal amido complexes [MeSi{SiMe 2 N(4-CH 3 C 6 H 4 )} 3 ZrCl] and [MeSi-{SiMe 2 N(4-CH 3 C 6 H 4 )} 3 HfCl] with LiSnPh 3 in toluene yielded the Zr-Sn and Hf-Sn complexes [MeSi{SiMe 2 N(4-CH 3 C 6 H 4 )} 3 ZrSnPh 3 ] (1) and [MeSi{SiMe 2 N(4-CH 3 C 6 H 4 )} 3 -HfSnPh 3 ] (2), while attempts to synthesize the corresponding Ti-Sn complex resulted in the oxidative coupling of the stannate to give Ph 3 Sn-SnPh 3 and unidentified titanium species. More stable group 4-group 14 complexes were obtained by reaction of the triamido stannate complex [MeSi{SiMe 2 N(4-CH 3 C 6 H 4 )} 3 SnLi(OEt 2 )] with the metallocene dichlorides [Cp 2 MCl 2 ] of all three titanium group metals, giving [MeSi{SiMe 2 N(4-CH 3 C 6 H 4 )} 3 SnM(η 5 -C 5 H 5 ) 2 (Cl)] (M ) Ti, 3; Zr, 4; Hf, 5). X-ray diffraction studies of 4 and 5 established Zr-Sn and Hf-Sn bond lengths of 3.02313(17) and 2.9956(3) Å, respectively.