Trinuclear dodecacarbonyl

Trinuclear dodecacarbonyl species, 16 63 3,4,6-Tri-0-acetyl-l,5-anhydro-2-deoxy-D-... 

In crystalline trinuclear dodecacarbonyls of ruthenium and osmium, the metal atoms form an equilateral triangle by metal-metal bonds. Each metal atom is bound to four terminal carbonyl groups, as shown in Figure 23. Two carbonyl groups are nearly perpendicular to (and the other two are parallel to) the plane of the triangle. 

The black trinuclear iron complex Fe3(CO)8(Ph2C2)2> one of two isomers obtained by the reaction of excess tolane with dodecacarbonyl iron, contains not only a heterocyclic iron atom similar to that first observed by Hock and Mills (36) but also has two iron atoms lying symmetrically on either side of the heterocyclic ring (42) in a manner similar to that suggested by the author on theoretical grounds (20) (Fig. 9). 

The first experiments which were carried out in the author s laboratory on organometallic phase-transfer catalysis were concerned with the reduction of nitrobenzenes (4) to anilines (5) by triiron dodecacarbonyl. Such a conversion was reported to occur in benzene containing methanol at reflux for 10-17 h, with the hydridoundecacarbonyltriferrate anion as the likely key intermediate (16). It was our expectation that the trinuclear iron hydride should be generated by phase-transfer catalysis and if so, effect reduction of nitro compounds (4) under exceedingly mild conditions. Indeed this was the case, as illustrated by the results shown in Table I (17). Not only is the reaction complete in 2 h or less using sodium hydroxide as the aqueous phase, benzene as the organic phase, and benzyltrieth-ylammonium chloride as the phase-transfer catalyst, but it occurs at room temperature and requires less metal carbonyl than when the reaction was... 

All three Group 8 metals form trinuclear clusters M3(CO)i2. However, while all carbonyl ligands in ruthenium and osmium dodecacarbonyl complexes coordinate to the metal center as terminal carbonyls, there are two bridged carbonyl groups in iron dodecacarbonyl. This may be due to the smaller van der Waals radius of the iron atom. In this section, Fe(CO)5, Fe2(CO)9and Na2[Fe(CO)4] are reviewed. 

Trinuclear Os3(CO),2 has the triangular framework common to the Group 8 trinu-clear dodecacarbonyl complexes. However, the triangular framework of Os. is 1c>n readily broken down to mononuclear fragments than that of the Ru, framework. 

Bridges between trinuclear metal clusters [of Ru, Os] Synthesis of ruthenium and osmium carbonyl clusters with unsaturated organic rings Oxyligand derivatives of triosmium dodecacarbonyl... 

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