Base-stabilized complexes

The base-stabilized compound Cp W(CO)3(BH2-PMe3) (6.27, Fig. 6) contains a four-coordinate boron centre ( b -27.6) and features the longest W-B dis- 

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While 52 stands for simple base-stabilized complexes 148), 53 is an example of a chelated base-stabilized stannylene coordinated with a transition metal149). 54 144) and 55 150) illustrate that the aggregation state of the stannylene remains unchanged in the complexes. 

Structure 1031 illustrates an internally base-stabilized complex, in which the stabilizing unit is part of the added metal fragment. This contrasts to the other molecules in this section where the chelating function is part of the organic group attached to E. 

The tetrahedrally coordinated boron center in the base stabilized complex 6 shows the expected increase of the metal-boron distances, which thus range between those of cobalt boryl complexes114,115 and cobaltaboranes.116... 

Terminally bound alanyle complexes of the type L M-A1R2 contain an electron-deficient A1 center that, in principle, may act as a Lewis acid moiety. Such complexes therefore tend to form intra- or intermolecularly coordinated structures as observed in base-stabilized complexes such as [( 7 -C5H5)(CO)2Fe-Al (CH2)3NMe2)/-Bu] and in dimeric complexes such as [(C5H4Me)(p-77 77 -C5H3Me)Mo(p-Al(H)/-Bu)]. Compound [Cp(CO)2Fe-Al(tmp)2] is the only... 

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