Dibenzofuran, metal complexes

The use of metal-complex mediators was applied by Nunnecke and co-authors (Nunnecke and Voss 1999) to the dechlorination of chlorinated benzenes and diben-zofurans. The main products were chlorobenzene and unsubstituted dibenzofurans, respectively. 

Kanemasa et al.63 reported that cationic aqua complexes prepared from the /ram-chelating tridentate ligand (i ,f )-dibenzofuran-4,6-diyl-2,2,-Mv(4-phcnyloxazolinc) (DBFOX/Ph) and various metal(II) perchlorates are effective catalysts that induce absolute chiral control in the Diels-Alder reactions of 3-alkenoyl-2-oxazolidinone dienophiles (Eq. 12.20). The nickel(II), cobalt(II), copper(II), and zinc(II) complexes are effective in the presence of six equivalents of water for cobalt and nickel and three equivalents of water for copper and zinc. 

Fly ash from municipal waste and industrial waste incinerators contains polychlorinated dibenzo-p-dioxins (PCDDs), including tetrachlorodibenzo-/j-dioxin (TCDD) and polychlorinated dibenzofurans (PCDFs), which are lipophiles, and heavy metals, including chromium, copper, manganese, vanadium, and lead, which are hydrophilesJ29-31 These chemicals have multiple toxicities and are known to impact the human liver, immune system, respiratory system, thyroid, male reproductive function, and CNS J32 34l Several are human carcinogensJ32 35 Enhanced toxic effects are observed in the mixtures of some of theseJ21,22 36 The mixtures of toxicants present in fly ash are complex and the mechanisms for their action on the human body are largely unknown. It is known that occupational exposure to fly... 

The M[ZnEt4] derivatives (M = Ca, Sr, Ba) react with 2 mol PhC=CH to give M(C=CPh)2 mixed with ZnEt2, probably as an ate complex. However, M[ZnEt4] complexes are less active in Et20 than PhCal toward anisole, dibenzofuran and dibenzothiophene [e.g., from the latter substrate 4-metallated dibenzothiophene is obtained in < 1 % yield (M = Ca, Sr, Ba)]. ... 

If one or both cobalt atoms were replaced by other metal atoms, hydrogen peroxide was formed either as the main product or as an intermediate. Chang et al. [40] fotmd that dicobalt diporphyrins anchored on dibenzofuran (DBD) and xanthene (DPX), Fig. 7.8A, exhibited remarkable conformational flexibility, and in both cases, the complexes were able to reduce oxygen directly to water despite having large differences ( 4 A) in the interplanar separation of their metal centers. Two other anchoring systems, anthracene and bisphenylene, have also been successfully used to... 

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