Fe(III)–azido complex with tetragonally compressed octahedral FeN6 geometry: synthesis, spectroscopic and X-ray single crystal analysis of [Fe(cyclam)(N3)2](ClO4)

Abstract An Fe(III)–azido complex with the formula [Fe(cyclam)(N 3 ) 2 ]ClO 4 (cyclam=1,4,8,11-tetraazacyclotetradecane) has been synthesized from the reaction of cis -[Fe(cyclam)Cl 2 ]Cl with sodium azide in methanol. The X-ray structural analysis reveals that the Fe(III) atom possesses a tetragonally compressed octahedral geometry with a trans configuration of two azido ions. Variable-temperature (4.5–295 K) magnetic susceptibility measurements show that the complex is low spin over the whole temperature range. 57 Fe Mossbauer spectral measurements also suggest the same spin state of the Fe(III) ion.