Amines complex with

A number of less hindered monoalkylboranes is available by indirect methods, eg, by treatment of a thexylborane—amine complex with an olefin (69), the reduction of monohalogenoboranes or esters of boronic acids with metal hydrides (70—72), the redistribution of dialkylboranes with borane (64) or the displacement of an alkene from a dialkylborane by the addition of a tertiary amine (73). To avoid redistribution, monoalkylboranes are best used /V situ or freshly prepared. However, they can be stored as monoalkylborohydrides or complexes with tertiary amines. The free monoalkylboranes can be hberated from these derivatives when required (69,74—76). Methylborane, a remarkably unhindered monoalkylborane, exhibits extraordinary hydroboration characteristics. It hydroborates hindered and even unhindered olefins to give sequentially alkylmethyl- and dialkylmethylboranes (77—80). 

Macrocyclic coordination compounds formed bv condensation of metal amine complexes with aliphatic carbonyl compounds. N. F. Curtis, Coord. Chem. Rev., 1968, 3, 3-47 (78). 

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

Chiral terf-diamines complexed with LAH gave very low optical yields in reductions of prochiral ketones. A/,/V,A/, /V -Tetramethyl-l,2-cyclohexanedi-amine complexed with LAH or LiAlD4 reduced phenyl alkyl, dialkyl ketones or benzaldehyde in <15% optical yields (109). 

C6Hi4Cl2N202Pt, Platinum(ll), cw-dichlorobis-(propanoneoxime)-, 34 82 C6Hi4Cl2N202Pt, Platinumfll), trani-dichloro-bis(propanoneoxime)-, 34 83 C6H18N4, tren, Tris(2-aminoethyl)amine, complex with copper(II), 34 138 CfiNNaOsW, Tungstate(O), pentacarbonylcyano-, sodium, 34 162... 

As can be seen, the alcohol autocomplexes possess the highest strength the bond strength in the series of amine complexes with alcohol falls from the primary to the tertiary ones, which proves the decisive role of steric factors in the formation of H-complexes with amines. At low temperatures, the equilibrium constant of the A H complexes falls in the series Keql > Keq 2 > Keq3 however, at temperatures over 6Q-70 °C the series becomes reversed. It means that during the reaction at elevated temperatures not only the absolute but also the relative concentrations of the A2H... 

Amines, Complexes. A number of amine complexes with cupric chlorates, perchlorates and bromates were examined before WWII in France flnjj described mr... 

Excessive alkyl substitution on the N-donor atoms can result in the isolation of amine complexes with unusually low coordination numbers, e.g. Cr111(NPr12)3.135... 

Reaction of Co111 amine complexes with glycine esters gives products which are dependent on the solvent used (Scheme 7). In non-aqueous solvents peptide bond formation is observed.78"80 It is concluded that the reaction proceeds via the initial formation of a bidentate glycine ester complex in which the coordinated carbonyl group is activated (by the metal ion) towards nucleophilic attack by a further molecule of the glycine ester. Similar reactions have been observed with other Co111 complexes. 

Interactions of platinum amine complexes with sulfur-containing biomolecules and DNA fragments. Adv. Inorg. Chem. Radioehem. 37, 175 (1991). 

Figure 2-16. The reactions of certain cobalt(m) amine complexes with base obey second order kinetics. The kinetically inert cobalt(m) ion is unlikely to undergo rapid associative processes, and another mechanism must be found.

Most of the template syntheses of nonbenzenoid macrocycles originated with Curtis (39) and involve the condensation of metal-amine complexes with aliphatic carbonyl compounds, e.g., the reaction of acetone with tris(diaminoethane)nickel(II) perchlorate at ambient temperature leads to the isolation of three products, two of which may be represented as cts-XLIX and trans-L and the other is formed by a further interconversion of complex L in solution (39,143). With Cu(II) diaminoperchlorates, a mixture of cis and trans complexes analogous to XLIX and L is formed, but with Co(II) only the trans analog of L has been isolated. When ketones containing bulky groups are used, the reaction is much slower, e.g., there is only a small yield of LI from... 

The interchange of the stereochemically significant sec-NH proton in (20) (21) (inversion) or (22) — (23) (isomerization) is a base-catalyzed process and takes place via a deprotonation-protonation mechanism. This interchange is one of the simplest types of reaction of a coordinated ligand , and proton exchange rates have been measured for quite a number of inert transition metal-amine complexes. With suitable central metals (Pt ) or ligands,the deprotonated intermediates can be isolated and characterized. Other reactions of coordinated amine ligands will be considered in Section 7. 

According to the first hypothesis, the amine complexes with the alcohol and both the amine and this complex can function as catalysts for the reaction, the same isocyanate-base complex resulting from attack by either catalytic species. Therefore, the original mechanism is really a composite one of the following two steps ... 

Cobalt(III) Amine Complexes with Coordinated Trifluoromethanesulfonate 103... 

COBALT(III) AMINE COMPLEXES WITH COORDINATED TRIFLUOROMETHANESULFONATE... 

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