Structural and spectroscopic evidence for multiple .alpha.-agostic interactions in dialkyl complexes of niobium

Effects of the [OC6F5] moiety upon structural geometry: crystal structures of half-sandwich tantalum(V) aryloxide complexes from reaction of Cp*Ta(N t Bu)(CH2 R)2 with pentafluorophenol

“…3.1. Crystal structure of (3) revealing a-agostic interactions 3is indicative of the presence of weak -agostic interactions (Poole et al, 1993) and this is supported herein by an X-ray structural determination (Fig. 2).…”

Niobium and Tantalum

“…199 ' 211 A number of imido complexes of the general formula (r|-C 5 R 5 )M(=NR)R 2 have been prepared (Table 6). 215 ' 257 Bis(cyclopentadienyl) alkyl and aryl complexes are especially common. Unlike the typical d°m onokis r| 5 complexes described above, many d l and d 2 (T|-C 5 R 5 ) 2 M alkyl species are known.…”

Synthesis and Characterization of Chelating Bis(silane) Complexes [RuH2{(η2-HSiMe2)2X}(PCy3)2] (X = C6H4, O) Containing Two Ru−(η2-Si−H) Bonds

“…Furthermore, reactivity studies of the resulting complexes have intensified over the past few years . However, complexes accommodating more than one σ bond are rare: a few bis-agostic compounds are known, and to date only two examples of thermally stable bis(dihydrogen) complexes have been isolated, RuH 2 (H 2 ) 2 (PCy 3 ) 2 ( 1 ) and Tp*RuH(H 2 ) 2 no mononuclear complexes containing two M−(η 2 -Si−H) bonds have been isolated so far.…”