Chelated amines

Compounds analogous to the cobaltammines may be similarly obtained using chelating amines such as ethythenediamine or bipyridyl, and these too have played an important role in stereochemical studies. Thus ct5-[Co(cn)2(NH3)Cl] was resolved into d(+) and /(—) optical i.so-mers by Werner in 1911 thereby demonstrating. to all but the most determined doubters, its octahedral stereochemistry. More recently, the absolute configuration of one of the optical isomers of [Co(en)3] was determined (.sec Panel on p, 1125),... 

The stability of the complexes differs significantly, depending on the nature of the amine. Complexes with chelating amines persist in water for some time. 

SC4N2)2(p-dppm)4],488 or hexanuclear as [M6(p-ER)4( i-dppm)4]2+ (M=Cu (48), Ag E=S, Se) (Scheme 16).489,490 Many of these complexes present luminescence properties. There are also three-coordinated Cu(I) derivatives with chelating amine ligands as [Cu(SMes)(phenMe4)]491 or [Cu(S-Mes )(btmgp)] (btmgp=6z, s(tetramethylguanidine).492 A series of cluster... 

The first iron-containing silsesquioxanes which appeared in the literature were compounds containing ferrocenyl units as side-groups.However, these are not within the scope of this review as iron is not part of the metallasilsesquioxane skeleton. Meanwhile, several ferrasilsesquioxane complexes have been synthesized. The first iron(III) compound of this type was prepared in our laboratory according to Scheme 56. ° In 161, the coordination sphere of iron is completed by TMEDA (N,N,N, N -tetramethylethylenediamine) as a chelating amine ligand. Pale yellow, crystalline 161 was isolated in 80% yield and structurally characterized by X-ray diffraction. This compound was later used by Maxim et to prepare iron... 

They tried Ni catalysts with chelating amine and phosphine ligands in the reaction of phenylzinc bromide with A-benzoyloxymorpholine 2a and observed that in the presence of NiCl2(PPh3)2, n-alkyl, aryl and functionalized arylzinc chlorides can be aminated with A,A-disubstituted O-benzoylhydroxylamines in good yields (Schemes 20 and 21). Attempted amination of secondary and tertiary alkylzinc chlorides failed to yield the expected product. 

Indeed the alcoholysis of metal amides is an excellent method for the synthesis of alkoxides. However, some synthetic utility to this reaction has been found for the synthesis of aminoboranes where the equilibrium can be forced to the right by using either an involatile or a chelating amine.59,60 Hydrocarbon solutions of Mo2Me2(OBu )4 also react with MeNHCH2CH2NHMe (>6 equiv.) to give Mo2(MeNCH2CH2NMe)3 with the liberation of methane (2 equiv.) and /-butyl alcohol.61... 

N 59.37% OB to C02 0% white, felty ndles mp, detonates at 230°. V v si sol in w insol in nitric acid. Prepn is usually by treating an aq soln of Na NT with an aq soln of Ag nitrate in the presence of an acid. A prepn patented by Bates and Jenkins (Ref 13) consists of forming an acid soln of a complex of Cu(NT)2 with an aliphatic chelating amine, and then adding to the acid soln a soln of a soluble Ag salt to ppt the product. The Ag salt is slightly more sensitive than MF... 

Apart from the unique adduct 5150, in which two plumbylene moieties are bridged by a MgBr2(thf)4 molecule viaBr —> Pb interactions [Pb—Br 296.4(2) pm], and few cyclopen-tadienyl derivatives where chelating amines interact with the two-valent tetrel atom62, unsupported adducts of Lewis bases with tetrylenes have been restricted to carbene-type bases so far. However, only donor carbenes, such as Arduengo carbenes, isonitriles or ylids, form simple adducts with dative C —> E interactions (Table 8). Carbenes or analogous species which also exhibit a substantial acceptor ability form multiple bonds instead (see Section III). 

C. Mixed Complexes between Alkyllithiums and Chiral Lithium Amides with Chelating Amine Groups... 

Nitrogen Ligands. Iron(II) halides and other salts absorb NH3 in excess giving the [Fe(NH3)6]2+ anion but ammonia complexes are stable only in saturated excess ammonia. Stable complexes with chelating amines are formed, for example, for ethylenediamine ... 

Allylic trifluoroacetates are very reactive with Pd reagents, generating -allyl palladium trifluoroacetates (equation 51), which can react further to produce cationic 7r-aUyl complexes when reacted with chelating amines (equation 52). The cationic complexes can also be synthesized from ly -dWyl palladium trifluoroacetates by treatment with HBF4 and ligands, L, producing PdL2( -allyl)+ BF4 complexes. 

Kinetically inert low-spin cobalt (III) clathrochelates are reversibly reduced by accepting one electron to yield kinetically labile cobalt(II) complexes. In the case of the usual amines (for instance, ammonia), the reduction is, as a rule, accompanied by irreversible decay of the amine cobalt complex. This reaction is slower for chelating amines macrocyclic and especially macrobicyclic amines produce complexes with cobalt(II) ion that are stable over a long time. This fact facilitates the study of the reduction of cobalt(III) complexes to cobalt(II) ones. In most cases, the reactions of macrobicyclic ligands do not interfere with this process. 

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