Bispyrrolide and Related Complexes

Bipyridine adducts of imido alkylidene bispyrrolide complexes have proven useful as intermediates in the often-unsuccessful synthesis and isolation of complexes that contain the parent pyrrolide. For example, Mo(NR)(CHCMe2R ) 

5-dimethylpyrrolide) imido alkylidene complexes are monomeric, flux-ional 18-electron species [13]. They were first employed as precursors to Mo(NR)(CHCMe2Ph)(diolate) complexes that contain the relatively electron-withdrawing binaphtholate (3,3-bis-(9-anthracenyl), 3,3 -bispentafluorophenyl, 3,3 -bis(3,5-bis(trifluoromethyl)phenyl), or biphenolate (3,3 -di-fBrt-butyl-5,5 -bistrifluoromethyl-6,6 -dimethyl-l,l -biphenyl-2,2 -diolate) ligands. In 

Other substituted pyrrolides form monomeric T, T -bispyrrolides, except when the pyrrohdes (i) can only bind in an t fashion, as is the case of the 2-mesitylpyrrohde (MesPyr) in Mo(NAr)(CHCMe2Ph)(r -MesPyr)2 [15], or (ii) are much more prone to bind in an t fashion than an t fashion, as in Mo(NAr)(CH2CMe2Ph)(r -indolide)2 [12]. If a donor functionahty is present in the pyrrolide, then it can bind to another metal to form ohgomers. 

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