Manganese electron donors

Hammarstrom L, Sun L, Aakermark B, Styring S. A biomimetic approach to artificial photosynthesis Ru(II)-polypyridine photosensitizers linked tyrosine and manganese electron donors. Spectrochim Acta 2001 37 2145-60. 

The reductase in Geobacter sulfurreducens is located in the outer membrane and a soluble Fe(III) reductase has been characterized from cells grown anaerobically with acetate as electron donor and Fe(III) citrate or fumarate as electron acceptor (Kaufmann and Lovley 2001). The enzyme contained Fe, acid-labile S, and FAD. An extracellular c-type cytochrome is distributed in the membranes, the periplasm, and the medium, and functions as a reductase for electron transfer to insoluble iron hydroxides, sulfur, or manganese dioxide (Seeliger et al. 1998). 

The 1,2-oxaborolide anion (Figure 1), an analog of furan, has been prepared by two different routes and sandwich complexes with ruthenium and manganese 136, 137 have been characterized.153 Comparison of IR stretching frequencies suggests that oxaborolide is a weaker electron donor and better electron acceptor than cyclopentadienyl. 

Ghiorse WC (1989) Manganese and iron as physiological electron donors and acceptors in aerobic-anaerobic transition zones. In Microbial mats. Cohen Y, Rosenberg E (eds) ASM Press, Washington DC, p 163-179... 

Following our early studies (89, 90), we have recently investigated derivatives of manganese carbonyl obtained from reactions between Mn(CO)5X (X usually Br) and organic sulfur ligands (93). Manganese carbonyl chelate complexes are formed in which sulfur is covalently bonded to manganese, or forms a coordinate bond as an electron donor. 

Additives are also used to improve the solubility of halide donors [382, 383]. Metal(II) halides such as magnesium chloride, calcium chloride, barium chloride, manganese chloride, zinc chloride and copper chloride etc. are used as halide sources. In order to increase the solubility of the halides they are reacted with electron donors which have been previously described for the increase of solubility of Nd-components [338,339]. The number of catalyst components is further increased if two Al-compounds (alumoxane + aluminum (hydrido) alkyl) are used. In addition, a small amount of diene can also be present during the preformation of the different catalyst components as described by JSR. In some catalyst systems the total number of components reaches up to eight [338,339]. Such complex catalyst systems are also referred to in other JSR patents [384,385] (Sect. 2.2.6). 

Iodolabeling studies on photosystem II particles from higher plants and cyanobacteria (221) and on a PSII complex (227) specifically labeled the herbicide-binding protein. As 1 is believed to donate electrons to Z, the secondary electron donor which is believed to accept electrons from the photosynthetic manganese complex, these experiments indicate a role for this protein on the oxidizing side of PSII. Consequently, Z must at least be located near, if not in, the herbicidebinding polypeptide (222). 

Only one complex in which a phospholyl ring acts as a (4 + 3) electron donor through its diene and its phosphorus atom taken separately, is structurally characterized. It has been prepared from a (l-phenylphosphole)-Mn2(CO)7 complex, in which the diene and the phosphorus atom are already complexed, (see Sect, n.4.) by cleavage of the phosphorus-phenyl bond with manganese carbonyl under UV at low temperature ... 

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