Notes. The reaction of arenediazonium ions with cycloheptatriene (cht) and with [Fe(CO)3(η4-cht)]: azo-coupling versus hydrazone formation

Abstract

The complex [Fe(CO)₃(η⁴-cht)](cht = cycloheptatriene) and [N₂C₆H₄NO₂-p][BF₄] give [Fe(CO)₃{η⁵-C₇H₈N₂C₆H₄NO₂-p}][BF₄](1) which is deprotonated on alumina to give syn- and anti-isomers of the hydrazone complex [Fe(CO)₃{η⁴-C₇H₆NN(H)C₆H₄NO₂-p}](2); the C₇H₆NN(H)C₆H₄NO₂-p is detached from the metal on reaction with N(O)Me₃·2H₂O. By contrast, free cycloheptatriene and [N₂C₆H₄NO₂-p][BF₄] in water yield 4-hydroxy-5-p-nitrophenylazobicyclo [4.1.0] hept-2-ene.