Photochemical and thermal reactions of iron pentacarbonyl with dimethyldiacetylene (DMDA): spectral characterization of reaction complexes

Abstract

A series of photochemical and thermal reactions has been carried out with iron pentacarbonyl and the conjugated alkadiyne dimethyldiacetylene (DMDA). One product (DMDA)Fe(CO) 6, was prepared directly from starting materials in tetrahydrofuran under photochemical conditions. Previously analogs of this complex had been prepared only under thermal conditions from complex intermediates. An X-ray analysis has established the structure of this complex; 13C NMR and other spectral data reported here are in agreement. Under thermal conditions in xylene, three isomeric forms of a tricarbonylferroleiron tricarbonyl (DMDA) 2Fe 2(CO) 6 complex were prepared. Separation and purification of two of these isomers was achieved; selected spectral data are reported. Infrared and mass spectra are also reported for the complex (DMDA) 2Fe(CO) 4 resulting from the photochemical reaction of starting materials in cyclohexane.