Amines, activation coordination

Structures have been determined for [Fe(gmi)3](BF4)2 (gmi = MeN=CHCF[=NMe), the iron(II) tris-diazabutadiene-cage complex of (79) generated from cyclohexanedione rather than from biacetyl, and [Fe(apmi)3][Fe(CN)5(N0)] 4F[20, where apmi is the Schiff base from 2-acetylpyridine and methylamine. Rate constants for mer fac isomerization of [Fe(apmi)3] " were estimated indirectly from base hydrolysis kinetics, studied for this and other Schiff base complexes in methanol-water mixtures. The attenuation by the —CH2— spacer of substituent effects on rate constants for base hydrolysis of complexes [Fe(sb)3] has been assessed for pairs of Schiff base complexes derived from substituted benzylamines and their aniline analogues. It is generally believed that iron(II) Schiff base complexes are formed by a template mechanism on the Fe " ", but isolation of a precursor in which two molecules of Schiff base and one molecule of 2-acetylpyridine are coordinated to Fe + suggests that Schiff base formation in the presence of this ion probably occurs by attack of the amine at coordinated, and thereby activated, ketone rather than by a true template reaction. ... 

The polymerization of compounds having active methyne groups has also been reported [81] (Eq. 8). The oxidative coupling polymerization of these monomers follows a mechanism similar to that of phenols. The catalytic cycle observed in the polymerization of / -phcnylcncdiaminc with Fe(edta) as the catalyst in an aqueous solution differs from that in the polymerization of phenols as follows The activation of monomers usually involves either electron transfer from the anion or elimination of a hydrogen atom from the monomer. The oxidative polymerization of phenols uses the former mechanism of the electron transfer. In contrast, in the case of the polymerization of aromatic diamines as monomers, the neutral amines are coordinated to the catalyst, followed by the subsequent electron transfer and dehydronation. The dehydronation proceeds by the reaction with 02. Another mechanism has also been proposed where dehydrogenation... 

While the advent of NHC ligands brought much new activity to the field of nickel carbene chemistry, important progress was also made with more traditional Fischer-type carbene complexes. The typical route to methoxy(amino) or bis(amino) Fischer-type carbene complexes is the nucleophilic attack of alcohols or amines on coordinated isocyanides. " A new and efficient route to heteroatom-stabilized carbene nickel(ii) complexes was recently reported to occur by a protonation reaction of the nickel(O) complex Ni(GNXyl)(triphos)." Addition of 2 equiv. of HBF4 to solution of Ni(CNXyl)(triphos) in THF affords the stable dicationic nickel carbene complex [Ni C(H)N(H)Xyl (triphos)]2+(BF4-)2 (Equation (16)). 

In a classic paper on optically active coordination compounds, Mills and Quibell reported the synthesis of a Pt complex containing one molecule of meso-stilbenediamine (H2N-CHPh-CHPh-NH2) and one molecule of isobutylenedi-amine (H2N-CH2-CMe2-NH2). Also, the complex was successfully resolved into its enantiomers. Determine whether the coordination around the metal ion is tetrahedral or square planar. Also illustrate these modes pictorially. 

Amine activatitMi pathway has been well studied in catalysis by lanthanides, early transition metals, and alkali metals. In metal amide chemistry of late transition metals, there are mainly two pathways to synthesize metal amide complexes applicable under hydroamination conditions [54], One is oxidative addition of amines to produce a metal amide species bearing hydride (Scheme 8a). The other gives a metal amide species by deprotonation of an amine metal intermediate derived from the coordination of amines to metal center, and it often occurs as ammonium salt elimination by the second amine molecule (Scheme 8b). Although the latter type of amido metal species is rather limited in hydroamination by late transition metals, it is often proposed in the mechanism of palladium-catalyzed oxidative amination reaction, which terminates the catalytic cycle by p-hydride elimination [26]. Hydroamination through aminometallation with metal amide species demands at least two coordination sites on metal, one for amine coordination and another for C-C multiple bond coordination. Accordingly, there is a marked difference between the hydroamination via C-C multiple bond activation, which demands one coordination site on metal, and via amine activation. 

Inspired by the work of Burk and Feaster ) we attempted to use (2-pyridyl)hydrazine (4.36) as a coordinating auxiliary (Scheme 4.10). Hydrazines generally react effidently with ketones and aldehydes. Hence, if satisfactory activation of the dienophile can be achieved through coordination of a Lewis acid to the (2-pyridyl)hydrazone moiety in water. Lewis-add catalysis of a large class of ketone- and aldehyde-activated dienophiles is antidpated Subsequent conversion of the hydrazone group into an amine functionality has been reported previously by Burk and Feaster ... 

Typical nucleophiles known to react with coordinated alkenes are water, alcohols, carboxylic acids, ammonia, amines, enamines, and active methylene compounds 11.12]. The intramolecular version is particularly useful for syntheses of various heterocyclic compounds[l 3,14]. CO and aromatics also react with alkenes. The oxidation reactions of alkenes can be classified further based on these attacking species. Under certain conditions, especially in the presence of bases, the rr-alkene complex 4 is converted into the 7r-allylic complex 5. Various stoichiometric reactions of alkenes via 7r-allylic complex 5 are treated in Section 4. 

Thermoplastic resins, self-reinforced, 26 Thermoplastics, preparation of, 257-258 Thermoplastic step-growth polymers, 3 Thermosetting polyester resins, 29-31 Thermosetting resins, 3-4, 19 Thermotropic compounds, 49 THF. See Tetrahydrofuran (THF) Thiobisphenol S (TBPS), 364 Thionyl chloride, 80 activation of, 111 3,3 -linked polymers, 480 Tin-amine coordination complex, 234 Tin compounds, 86, 232-233... 

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