Kristallstruktur des Molybdän(V)-Imido-Komplexes [MoCl3(NtBu)(H2NtBu)]2 ·1/2 C7H8

Titanium imido complexes as precursors to titanium nitride

“…25 The geometry at each independent titanium centre in 1 is distorted octahedral with, in each case, the titanium atom being displaced out of the N (amino) Cl 3 plane in the direction of the imido nitrogen atom (by 0.42 and 0.40 Å for Ti (1) and Ti(2) respectively), a geometry essentially the same as that seen in, for example, [TiCl(µ-Cl)-(MeCN)(NBu t )(NH 2 Bu t )] 2 where the deviation is 0.39 Å. 26 The Ti-Cl bond lengths are distinctive with those to the µ-chlorides being symmetric whereas those to the µ 3 -chlorides have one short and two long Ti-Cl bond lengths (Table 1), an asymmetry that is also seen -with similar M-Cl distances -in the above mentioned niobium 24 and titanium 26 complexes. The Ti-Cl bonds trans to the imido ligands are significantly longer than those trans to amido groups, a pattern present in [TiCl(µ-Cl)(MeCN)(NBu t )(NH 2 Bu t )] 2 , which also has virtually identical angles at the imido and amido nitrogen atoms.…”

“…The Ti-Cl bonds trans to the imido ligands are significantly longer than those trans to amido groups, a pattern present in [TiCl(µ-Cl)(MeCN)(NBu t )(NH 2 Bu t )] 2 , which also has virtually identical angles at the imido and amido nitrogen atoms. 26 The Ti-N distances clearly reflect their formal single and double bond character with those to N(1) and N(3) being substantially shorter than those to N(2) and N(4). The non-bonded Ti ؒ ؒ ؒ Ti separations within the Ti 2 Cl 2 rings are in the range 3.94 to 4.07 Å, lengths very similar to the Nb ؒ ؒ ؒ Nb distances in the aforementioned niobium complex.…”

Thorium(IV) and Uranium(IV) Ketimide Complexes Prepared by Nitrile Insertion into Actinide−Alkyl and −Aryl Bonds

“…The ketimide, or azavinylidene, functionality (−NCR 2 ) has recently found increasing utility as an ancilliary ligand due to its steric and electronic flexibility (can serve as both a σ- and π-donor) and its ability to support a broad range of oxidation states for both d-block and f-block metals. − In fact, recent reports have shown that bulky ketimide ligands are instrumental for the preparation of novel diuranium inverted naphthalene and cyclooctatetraene sandwich complexes ( 1 ) 1 and organouranium complexes that exhibit oxidation state ambiguity ( 2 ) …”

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“…111 The crystal structure has been determined for [MoCl 3 (NBu t )(H 2 NBu t )] 2 •1/2C 7 H 8 . 112 12), The crystal structure for this compound has been determined, and in contrast with other low-valent early transition metal complexes of ethers, the ether linkage in this compound appears to be relatively inert even though the ether ligand does exert a significant trans-effect. 119…”