Chelating compounds reactions

Reactions of the Hydroxyl Group. The hydroxyl proton of hydroxybenzaldehydes is acidic and reacts with alkahes to form salts. The lithium, sodium, potassium, and copper salts of sahcylaldehyde exist as chelates. The cobalt salt is the most simple oxygen-carrying synthetic chelate compound (33). The stabiUty constants of numerous sahcylaldehyde—metal ion coordination compounds have been measured (34). Both sahcylaldehyde and 4-hydroxybenzaldehyde are readily converted to the corresponding anisaldehyde by reaction with a methyl hahde, methyl sulfate (35—37), or methyl carbonate (38). The reaction shown produces -anisaldehyde [123-11-5] in 93.3% yield. Other ethers can also be made by the use of the appropriate reagent. 

Furthermore we found that kasugamycin forms a chelate compound with basic cupric carbonate (7), which is stable to acid and unstable to heat and base. This evidence together with the results obtained above strongly supports the amidine structure (13) for kasugamycin. Finally the amidine compound was successfully prepared by the reaction of kasuganobiosamine with the diethyl ester of oxalimidic acid (14) and... 

A novel chiral dissymmetric chelating Hgand, the non-stabiUzed phosphonium ylide of (R)-BINAP 44, allowed in presence of [Rh(cod)Cl]2 the synthesis of a new type of eight-membered metallacycle, the stable rhodium(I) complex 45, interesting for its potential catalytic properties (Scheme 19) [81]. In contrast to the reactions of stabihzed ylides with cyclooctadienyl palladium or platinum complexes (see Scheme 20), the cyclooctadiene is not attacked by the carbanionic center. Notice that the reactions of ester-stabilized phosphonium ylides of BINAP with rhodium(I) (and also with palladium(II)) complexes lead to the formation of the corresponding chelated compounds but this time with an equilibrium be-... 

The different classes of Ru-based catalysts, including crystalline Chevrel-phase chalcogenides, nanostructured Ru, and Ru-Se clusters, and also Ru-N chelate compounds (RuNj), have been reviewed recently by Lee and Popov [29] in terms of the activity and selectivity toward the four-electron oxygen reduction to water. The conclusion was drawn that selenium is a critical element controlling the catalytic properties of Ru clusters as it directly modifies the electronic structure of the catalytic reaction center and increases the resistance to electrochemical oxidation of interfacial Ru atoms in acidic environments. 

The valency of the metal ion changes in every step so that a single atom of heavy metal (Me) may produce many free radicals. Metal chelating compounds, such as citric, tartaric or phosphoric acids, ascorbic acid, phytin or phosphatidic acids, combine with metals to form non-reactive compounds so that the oxidation reactions are inhibited and natural food antioxidants are saved. 

In a molecule of 2-phenyl-l-boraadamantane there are two markedly different types of B-C bonds two of them are boron-alkyl and one is boron-benzyl. On treatment of THF complex 34 with 8-hydroxyquinoline at 20 °C, mpture of the 1-boraadamantane core takes place, resulting in a mixture of boron chelates 52-54 (Scheme 16). When trimethylamine adduct 16 is used as the starting compound, reaction takes place only in boiling toluene. Interestingly, all the products result from the protolysis of B-CH2 bonds only <2006UP1>. 

Insertion of a carbene unit into the N—H bond of primary or secondary amines by copper salt catalyzed decomposition of diazo compounds has been known for a number of years14). The copper chelate promoted reaction of diazodiphenyl-methane 291) or 2-diazo-1,2-diphenyl-1-ethanone 292) with primary benzylamines or... 

Most five-coordinate aluminum alkyls are prepared by alkane elimination. The first structurally characterized five-coordinate simple aluminum alkyl chelate compound was reported in 1993.82 The compound AlMe[MeO2CC6H4-0-O]2 was formed by the reaction of Me3Al with 2 equiv. of MeO2GC6H4-0-OH. The commonly... 

The series of ligands Ph2P(CH2)nCH=CH2 n =0, 1, 2, 3), has been prepared and its reactions with transition metals investigated. WeU substantiated reports of chelate compounds formed from these ligands have been made for n = 2 and 3. No reports of chelate compounds where n = I have been made, while only in the case of silver has a... 

The behaviour of the phosphine complex PtBr2(ap)2 towards bromination is in marked contrast to that of PtBr2(oA)2 (the related arsine complex). Whilst the arsine complex gives platinum(IV) species on reaction with one equivalent of bromine, the phosphine complex gives the chelate compound PtBr2 (ap), and, presumably, CH2=CH CH2 ... 

Metal Chelate Compounds as Acid Catalysts in Solvolysis Reactions... 

Cu CH3[2,6 (CH3) 2CeH4N=]CCHCOCH3 2 + CfiH3NH2. After the reaction solution had been warmed for 20 hours at 100°, the solvent was distilled at reduced pressure. The residue crystallized from 95% ethanol as brown crystals (70% recovery) (m.p. 134-36°), and proved to be unreacted metal-chelate compound. 

Subsequently, an amine, R NH2, would react with the monochelated species in the manner suggested in the Verter-Frost mechanism. It seems likely that the driving force for the reaction would be the formation of the more stable metal-chelate compound. The equilibrium could also be shifted by loss of volatile amine—e.g., ammonia. 

Another set of reactions that has received considerable attention is that ui which optically active complexes, especially tris(chelate) compounds racemize ... 

A full report for the identification of salicylamide through melting point, reactions of the amide group, the phenolic group, the benzene ring, and the formation of chelate compounds has been published (9). 

Selective addition of alkenes and alkynes to aromatic compounds has also been performed by ruthenium-catalyzed aromatic C-H bond activation. Carbon-carbon bond formation occurs at the ortho positions of aromatic compounds, assisted by the neighboring functional group chelation. The reaction, catalyzed by RuH2(CO)(PPh3)3, was efficient with aromatic and heteroaromatic compounds, with various functional groups, and a variety of alkenes and alkynes [ 121 ] (Eq. 90). Activation of vinylic C-H bonds can occur in a similar manner. 

---