Formate ligand

While high-affinity binding due to ternary complex formation (ligand binding to the receptor followed by... 

The bidentate formate ligand of OsH(K2-02CH)(CO)(P,Pr3)2 is converted into a monodentate group by carbonylation. Thus, the reaction of this compound with carbon monoxide gives 0sH K1-0C(0)H (C0)2(P Pr3)2. Similarly, the addition of a stoichiometric amount of trimethylphosphite yields 0sH k -0C(0)H (C0) P(OMe)3 (P Pr3)2, and the addition of a stoichiometric amount of ethyne di-carboxylic methyl ester leads to 0sH K1-0C(0)H (C0)(r 2-Me02CC=CC02Me) (P Pr3)2, which in solution partially dissociates the alkyne. As is shown in... 

If back donation occurs to a ligand, the flow of electron density from the metal leaves less electron density to be donated in the opposite direction. It seems that this should have little effect on the donation of a pair of electrons on the ligand in the trans position to form a a bond. Accordingly, the major factor appears to be the stabilization of a five-bonded (trigonal bipyramid) transition state as a result of 7r bond formation. Ligands that readily form 1r bonds include some of those that generate the largest trans effect. 

Scheme 17.6 Transition states for the transfer of a hydrogen atom from a molecular hydrogen ligand to a formate ligand a) four-centered b) four-centered and base-assisted [66] and c) six-centered [59].

This study demonstrated the power of NMR spectroscopy whereby the use of carbon-13, nitrogen-15, and, more specifically, oxygen-17 in these oxo systems proved that the different species in the protonation, complex formation, ligand exchange, and condensation of the Re(V) system can be exceptionally well characterized in solution. The re-... 

These discussions will embrace homogeneous solutions of polymer-metal complexes. Of course one of the important advantages offered by the use of a polymer ligand, especially a crosslinked polymer ligand, in catalysis is the insolubilization of the attached complexes the insolubility of the polymer catalyst makes it very easy to separate from the other components of the reaction mixture. Several polymer-metal complexes have been used for this purpose, although such applications are not covered in this article. The aim here is (1) to characterize polymer-metal complexes and their behavior in such simple but important elementary reactions as complex formation, ligand substitution, and electron transfer, and (2) to describe their catalytic activity. 

B-48 2152 241 Intestine Chylomicron formation ligand for liver chylomicron receptor... 

In all of these instances involving bridging formato ligands it has not been defined as to whether the metal - hydride bond forming process occurs at the same metal center containing the bound formate ligand [as is depicted in Eq. (13)] or at an adjacent metal center. This intimate mechanistic detail must await further experimental observations. 

The efficiency of /-elements in catalysis originates from unconventional electrophilic pathways. In contrast to rf-elements oxidative addition/reductive elimination sequences are not accessible. Instead, substrate adduct formation, ligand exchange and insertion reactions rule the mechanistic scenarios. Therefore, the main emphasis is put on the fine-tuning of the spectator ligand of the precatalyst. 

As part of these studies a rare one pot reaction sequence consisting of three different steps (adduct formation, ligand exchange and CH4 elimination) has been observed (Eq. 24) [93]. The molecular structure of the resulting complex is shown in Fig. 28. 

Ru(HCS2)2(PPh3)2] 0.059 octahedral co-ordination with dithio-formate ligands bidentate via S atoms e... 

Wienold et al. (2003) XAS, TGA Ammonium heptamolybdate Phase formation ligand removal, sub-oxides + + + Propene oxidation, oxidation and reduction of oxide... 

A mononuclear complex with formate ligands has been structurally characterized (97).478 Each unit of K2[V0(HC02)4] has the vanadium in a pseudo-octahedral geometry, with the coordination of an adjacent molecule s free carbonyl (C=0) group serving as the sixth ligand.478 The... 

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