SYNTHESIS AND PROPERTIES OF NOVEL SUBSTITUTED 4,5,6,7-TETRAHYDROINDENES AND SELECTED METAL-COMPLEXES

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.