Reactive ligands

Water solubility across the group is low however, hydrolysis of the reactive ligands and/or ligand exchange in the environment or tissues of organisms could lead to the formation of species that are more soluble, casting doubt on the relevance of some of the modelled data. 

This finding a new type of catalysis will provide a useful hint for the design of molecular structures of interfacially adsorbable and strongly reactive ligands for a speeifie metal ion. 

What could be the reasons for the existence of endogenous PCP reactive ligands and receptors Do they produce a dissociated mental state following severe trauma or stress ... 

As can be seen, the catalytic process over a zeolite-supported cation, or an oxide-supported cation, can be considered as a supported homogeneous catalysis, as far as adsorbed reactants and products behave like reactive ligands. The model developed for lean DcNO. catalysts over supported cations (function 3), as well as this supported homogeneous catalysis approach, is also suitable for stoichiometric mixture (TWC) comprising CO and H2 as reductants over supported transition metal cations [20-22],... 

This proposed catalytic mechanism (Chong and Sharpless, 1977) requires four reaction steps (3 bimolecular and 1 unimolecular), which take place on a molybdenum metal center (titanium and vanadium centers are also effective), to which various nonreactive ligands (L) and reactive ligands (e g., O-R) are bonded. Each step around the catalytic cycle is an elementary reaction and one complete cycle is called a turnover. 

The chemical reactivity of cobalt cluster anions, Co (n = 2-8), toward 02, N2, and CO have been investigated using a flow tube reactor (226). The reactivity was found to be in the order 02 > CO > N2 the least reactive ligand N2 only reacted with C07 and Cog. The primary reaction of oxygen was the removal of one or two cobalt atoms from the cluster. Carbon monoxide reacts by multiple additions giving saturation limits shown in Table V. 

The closer the reactive ligand atoms get to the central metal ion, the stronger the bond, and, consequently, the greater the formation constant. This can be... 

In trimethylenemethane complexes, the metal stabilizes an unusual and highly reactive ligand which cannot be obtained in free form. Trimethylenemethanetricar-bonyliron (R=H) was the first complex of this kind described in 1966 by Emerson and coworkers (Figure 1.2) [38]. It can be obtained by reaction of bromomethallyl alcohol with Fe(CO)5. Trimethylenemethaneiron complexes have been applied for [3+2]-cycloaddition reactions with alkenes [39]. 

In relation to elemental metals, o-quinones are extremely reactive ligands [11,12,14,133,192-208], especially those containing t-butyl substituents. Complexes of o-benzoquinones, o-semiquinones, and catechols of this type have been obtained by direct interaction between metal powders and the corresponding ligands and reviewed [14]. It was established that thermal decomposition of such complexes of copper in solution leads to the formation of metallic copper and the initial o-quinone. 

The tetracoordinate silicon cation is a rather common species in solution. It may be generated by heterolytic cleavage of a bond from silicon to a reactive ligand, as a result of interaction of the silicon center with an uncharged nucleophile like amine, imine, phosphine, phosphine oxide, and amide. Since these nucleophiles are also known to be effective catalysts for many displacements at silicon including important silylation processes (86,89,235-238), the cations of tetracoordinate silicon have received attention as possible intermediates in these reactions according to Eq. (40) (78,235,239-243). 

Cations having a tetracoordinate silicon may appear by three general routes. Apart from the ionization of a silicon-reactive ligand bond, the cations can be formed by transformation of a group bound to silicon, in particular by the addition of positively charged ion. For example, the quaternization of trimethylsilylamine with methyl iodide leads to the same ionic complex as the reaction of trimethylsilyl iodide with trimethylamine [Eq. (46)] (254). 

Not unexpectedly, more reactive ligands like alkynes undergo acid-promoted transformations such as the cyclodimerization in equation (4) see Oligomerization Polymerization by Homogeneous Catalysis). 

As is evident in the above reactivity series, the cyclopentadienyl group is one of the least reactive ligands toward nucleophiles. As a result, it is widely used in organomctallic chemistry as a stabilizing ligand which will remain unreactive. In Eq. 15.124 theCp ligand remains a spectator while the alkene reacts with the Incoming nucleophile. 

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