Dioxygen binding characteristics

This paper reports on the dioxygen binding characteristics of some bisphenolic complexes and their polychelates with aromatic acid chlorides. 

E° = —196 mV) to the ferric P450CAM heme iron to produce the ferrous state of the protein, 3. Dioxygen binds to the ferrous heme iron to form the ferrous oxy complex, 4a/4b, whose valence structure can be presented either as the ferrous-02, 4a, or as the ferric superoxide, 4b, complex. Addition of carbon monoxide to 3 yields a ferrous carbon monoxide adduct, 5, with its characteristic absorbance peak at 450 nm [37],... 

As mentioned above, much less is known about the structural characteristics and mechanisms of the nonheme metal-containing monooxygenase enzymes. From the similarities of the overall stoichiometries of the reactions and the resemblance of some of the enzymes to dioxygen-binding proteins, it is likely that the initial steps are the same as those for cytochrome P-450, i.e., dioxygen binding followed by reduction to form metal-peroxide or hydroperoxide complexes. It is not obvious that the next step is the same, however (i.e., O—O bond cleavage... 

Type III. EPR-silent binuclear copper site that binds dioxygen as peroxide and exhibits unusual physicochemical characteristics (1) diamagnetism, (2) two characteristic absorption bands at 350 and 580 nm, and (3) a low O—O vibration stretching frequency (-750 cm-1). 

The most common dioxygen carriers of nature, the heme proteins hemoglobin and myoglobin, bind Oj in a characteristic structure. The Oj molecule binds to the metal atom through one of its atoms, and the M—O—O unit is angular in shape. Studies on small molecules that bind O2 in this way have concentrated on two classes of ligands, porphyrins and Schiff bases.In the first case, bulky superstructures are usually appended to the porphyrin ligand this superstructure inhibits autoxidation of the metal atom in the... 

Although the O2-binding transition metal complexes have been studied extensively, the nature of their bond formation has long been the subject of some controversy. Vaska (1976) showed that almost all currently known transition metal dioxygen complexes can be divided into two types according to the characteristics of the dioxygen ligand. They are the (type I) superoxo (02 ) and the (type 11) peroxo (02 ) complexes. These complexes are further classified... 

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