Synthesis and properties of azole-substituted ferrocenes

4-Ferrocenyltriazole, 4-(4-ferrocenylphenyl)triazole, 4-ferrocenyltetrazole, and 4-(4-ferrocenylphenyl)tetrazole have been prepared. Redox potentials and decomposition temperatures were evaluated and all the compounds were crystallographically characterized; in most cases, weak intermolecular CH⋯N hydrogen bonds (H⋯N dist. = 2.3–2.5 Å) were formed between the azole moieties. Two polymorphs were found for 4-ferrocenyltetrazole, formed with either CH⋯N or π–π interactions.