The synthesis of 1,3-dialkyl substituted cyclopentadienes, C5H4RR', Cp'H (Va-g) (where R and R' are tert-butyl, isopropyl, neo-pentyl, cyclohexyl, or 1-methylcyclohexyl) is reported. These are synthesized by the nucleophilic addition of methyl or hydride anions to the corresponding 2-alkyl-6,6-dialkylfulvenes (IIIa-f) followed by hydrolysis. These substituted 1,3-cyclopentadienes have been converted to organometallic derivatives such as [Cp'Fe(CO)2]2, [Cp'M(CO)3Me] (M = Mo or W) and Cp'2Fe. The spectroscopic and electrochemical properties of selected complexes have been investigated to probe the steric and electronic properties of the substituted cyclopentadienyl ligands.
