Rn. Austin et al., SYNTHESIS AND PROPERTIES OF NOVEL SUBSTITUTED 4,5,6,7-TETRAHYDROINDENES AND SELECTED METAL-COMPLEXES, Journal of organometallic chemistry, 491(1-2), 1995, pp. 11-18
The synthesis of a complete series of substituted 4,5,6,7-tetrahydroin
denes (4,5,6,7-tetrahydroindene, 1; 1-methyl-, 1,3-dimethyl- and 1,2,3
-trimethyl-4,5,6,7-tetrahydroindene 2-4) is reported. The synthesis of
ferrocenes (8-11) from these substituted cyclopentadienes is describe
d. The electrochemistry of these ferrocenes indicates that these compl
exes are more readily oxidized than ferrocene and that the effect of m
ethyl or alkyl substituents on the ease of oxidation is additive. A si
ngle crystal X-ray structure of two of the ferrocenes, s(1,3-dimethyl-
4,5,6,7-tetrahydroindenyl)iron(II), 10, and ,2,3-trimethyl-4,5,6,7-tet
rahydroindenyl)iron(II), 11, indicates that steric hindrance causes th
e alkyl substituents to be bent away from the plane of the cyclopentad
ienyl ring. However, the structures differ in that the cyclopentadieny
l rings in 10 are staggered wheras those in 11 are eclipsed. The synth
esis of the cyclopentadienyltricarbonylmethyl compounds of molybdenum
and tungsten from 3 and 4 is also described.