Carbonyls semibridging

Extended photolysis of Mu2(CO)io in 3-methylpentane glass gives rise to Mn2(CO)s resulting from double CO-loss and an isomer of Mu2(CO)9 with a semibridging carbonyl. Dft calculations have been used to probe possible structures of the Mu2(CO)8 species. ... 

Carbonylation metal salt reduction by CO at high pressure with M-CO bond formation Polyhydride complex of the type L MHj (x > 3) Semibridging CO unsymmetrically bridged CO... 

Weakly semibridging carbonyls, such as those in Os4(CO),4, are nearly linear but show some distortion toward the second metal. Of course it is not always clear whether departures from linearity arise from interaction with the metal or because of packing forces in the crystalline solid. All CO ligands are fully nonbridging in the puckered 034(00),, described as a metal carbonyl analogue of cyclobutane. 5 The dark red crystals of Os4(CO) j possess nearly planar OS4 units with only terminal CO ligands. 

The product (40% yield) contains semibridging carbonyl ligands ... 

The product, which is isolated in 25% yield, contains a V=V with semibridging carbonyl ligandsT Other examples of six-electron donors are more exotic. Reaction of Fe3(CO)i2 with allene leads to a bisallyl complex. ... 

The metallic isosceles triangle (Pdl-Pd2, Pd2-Col, 2.55 A Pdl-Col, 2.62 A) is capped at opposite sides by carbonyl ligands. At each side, one of the Pd-C(capping) distances results in semibridging carbonyls (Pdl-C51,2.36 A Pd2-... 

As far as the bonding mode of the carbonyl groups is concerned, it is likely that the unsaturation of the Fe2 atom in RhFe3(PPh)2(C5Me5XCO)8 is compensated by two semibridging bonds with C3 and C6. 

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