Manganese sandwich structure

After the difficulties of separating the two isomers formed in the reaction were overcome, proton magnetic resonance studies provided the necessary evidence for the now accepted sandwich structure of the 7r-allylmetal system (1, 81). Essentially concurrent with these studies, other workers prepared allyl complexes of cobalt and manganese (52, 51, 77, 63), and, again primarily using the evidence of proton magnetic resonance spectra, they similarly proposed the sandwich structure. 

Hexanuclear manganese complexes of polyhedral silsesquioxanes, supported on Si02, C, or A1203, evolve 02 from H20 when oxidized by Ru(bpy)33+ [166], The Mn ions (Figure 34) form a sandwiched ring structure and are octahe-drally coordinated by four equatorial x2-siloxy groups, one axial i6-chloridc ion, and one O from H20 or ROH. 

A crystal structure of the 1 1 adduct of 1,10-phenanthroline and the seven coordinate species, [Mn(199)(H20)2](C104)2, indicates that the phenanthroline molecule is not coordinated to the manganese but is sandwiched between [Mn(I99)(H20)2]2+ units in a lamellar structure.136 The phenanthroline nitrogens are hydrogen bound to water molecules in adjacent complex ions the structure also appears to be held together by it donor/rc acceptor and dispersion forces. 

Figure 7 Structures of some tropylium and arene half-sandwich compounds of chromium and manganese disoussed in Section 12.04.1.2.3.

Pazos F, Heredia P, Valencia A et al. Threadii structural model of the manganese-stabilizing protein 33 kDa protein reveals presence of two possible P-sandwich domains. Proteins Struct Funct Genet 2001 45 372-381. 

---