Bridging hydroxo groups

Observations of triply and doubly bridging hydroxo groups in otherwise low-valent carbonyl clusters is particularly exciting in view of the potentially important role of such ligands in catalytic reductions. Molecules such as Ru4(CO)i<>(C = CHPrl)(OH)(PPh2) are worthy of detailed study. 

While bridges of the type (14-1) arc most common, triply bridging hydroxo groups (14-11) arc also known.4... 

FIGURE 7 Crystal structure of [(La(H2Ll)) La(N03)2(/r3-OH) 2(La(HLl))](N03) (left) and its tetranuclear core containing two triply bridging hydroxo groups (right) (redrawn after Thompson et al., 2003). 

When the full coordination of the metal atom is not satisfied in the alkoxide, bridging hydroxo groups can be formed in place of bridging oxygen. 

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