Imido complexes homoleptic

A very interesting study of the reaction of methyl Grignard reagents with homoleptic imido complexes of Tc(VI) has been performed [104]. Reduction of 91 with Na in THF gave the first homoleptic Tc(VI)-imido complex [Tc2(N-Ar)6] (Ar = 2,6-dimethylphenyl) [105], Under more vigorous conditions dimerization to the second homoleptic Tc(VI)-imido complex [Tc2(N-Ar)4(/i-N-Ar)2] (94)... 

Scheme 22. Reaction of homoleptic dinuclear Tc-imido complex 94 with methyl Grignard reagent...

The Tc complex [TcI(N—Ar)s] (28) (see Section 5.2.2.1.2) can be reduced with Na° in THE to yield the green, nonbridged, dinuclear compound [Tc2(NAr)6] (46), in which three imido-ligands are bound to the Tc center and connected by a single bond to the second technetium. The molecule has a staggered, ethane-like structure and is diamagnetic. Reduction of (28) yields another homoleptic imido-complex of Tc, the imido-bridged, tetrahedral, dinuclear compound [Tc2(/u-NAr )2(NAr )4] (47) (Ar = 2,6-diisopropylphenyl). The conformation could be confirmed by X-ray structure analysis the assumption of a Tc Tc bond is confirmed by the... 

This review deals with the chemistry and coordination complexes of isoelectronic analogues of common oxo-anions of phosphorus such as PO3, POl", RPOl" and R2POy. The article begins with a discussion of homoleptic systems in which all of the 0x0 ligands are replaced by imido (NR) groups. This is followed by an account of heteroleptic phosphorus-centered anions, including [RN(E)P(/<-NR )2P(E)NR]2-, [EP(NR)3]3-, [RP(E)(NR)2] and [R2P(E)(NR )] (E=0,S, Se, Te). The emphasis is on the wide variety of coordination modes exhibited by these poly-dentate ligands, which have both hard (NR) and soft (S, Se or Te) centers. Possible applications of their metal complexes include new catalytic systems, coordination polymers with unique properties, and novel porous materials. 

While inorganic complexes of osmium in oxidation states +4 through +8 have been known for many years, the study of high-valent alkyl and aryl complexes of osmium is much more recent. The organometallic complexes include homoleptic see Homoleptic Compound) alkyls and aryls, oxo alkyls and aryls, nitrido/imido alkyls and aryls, and cyclopentadienyl see Cyclopentadienyl) alkyls and aryls. The majority of these are complexes of osmium(VI). 

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