Ligand addition reactions

B3PW91 /TZVP Calculated Energies (kcalmol-1 with zpe Correction, Ref. (24)) for Species on the Singlet and Triplet Potential Energy Surfaces for the Fe(C0)4+L Ligand Addition Reactions (L = CO, H2)... 

The four-coordinate sqnare planar iron(n) porphyrins discussed above are not only of great valne in heme protein model chemistry, but also in chemical applications, since they undergo a wealth of ligand addition reactions. For example it has been shown that TPPFe complexes are active catalysts for important carbon transfer reactions in organic chemistry and are found to catalyze the stereoselective cyclopropanation of aUcenes, olefin formation from diazoalkanes, and the efficient and selective olefination of aldehydes and other carbonyl compounds. The active species in these carbon transfer reactions are presumably iron porphyrin carbene complexes. " It was also found that ferrous hemin anchored to Ti02 thin films reduce organic halides, which can pose serious health problems and are of considerable environmental concern because of their prevalence in groundwater. ... 

The mechanism of the ligand addition reactions are associative and a detailed kinetic study of the Os3(CO)io(/u-H)2 + CO system revealed that both the addition of CO and its loss are both single-step concerted processes with the observed rate constant for the system as it approaches equilibrium being ... 

In organometallic chemistry, many reactions involve several electronic states, in particular, states of different spin. Historically, these reactions were referred as spin forbidden. Later, since reactions with spin state changes were observed to occur, a spin blocking effect that may slow reactions down associated to a hypothetical raise in the activation barriers due to the requirement of spin flip between different state spin multiplicities was proposed.134 However, several kinetic studies of ligand addition reactions with spin changes showed that they can be as fast as spin-allowed processes.135... 

Hydrogenation of the aUcene in a nucleophilic ligand addition reaction ... 

Figure 5 Two examples of the mechanochemical synthesis of coordination polymers by ligand addition reactions (a) the synthesis of a 1-D coordination polymer from copper(II) acetylacetonate and bipy and (b) illustration of the difference in mechanochemical reactivity of bipy towards anhydrous CoClj and CoClj bHjO...

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