Structures and reactivity of doubly-bridged dicyclopentadienyl dinuclear iron complexes
摘要:
The molecular structure of the doubly-bridged bis(cyclopentadienyl) diiron complex [(eta(5)-C5H3)(2) (SiMe2)(2)]Fe-2(CO)(2)(mu-CO)(2) (1b) was determined, and compared with that of the other analogue [(eta(5)-C5H3)(2)(CMe2)(SiMe2)]Fe-2(CO)(4) (1a). The former involves two bridging and two terminal carbonyls, and a normal Fe-Fe bond distance, while the latter contains all-terminal carbonyls and a longer than normal Fe-Fe bond distance. The possible reason for different coordination modes is discussed. Complexes (1a-b) react with I-2 to give the corresponding diiodo products [(eta(5)-C5H3)(2)(EMe2)(SiMe2)]Fe-2(CO)(4)I-2 (E = C, 2a; E = Si, 2b) and with phenylacetylene to give the bridging mu-C=CHPh products [(eta(5)-C5H3)(2) (EMe2)(SiMe2)]Fe-2(CO)(2)(mu-CO)(mu-C=CHPh) (3a-b). Reaction of 1a with Na/Hg, then with MeI yields the unexpected desilylated product [(eta(5)-C5H4)(2)(CMe2)][Fe(CO)(2)Me](2) (5a). Reaction of 1b with LiBHEt3 affords the bridging methylene product [(eta(5)-C5H3)(2)(SiMe2)(2)]Fe-2(CO)(2)(mu-CO)(mu-CH2) (6b). The molecular structures of 2a and 3b were also determined by X-ray diffraction. (C) 2014 Elsevier B. V. All rights reserved.