Phosphaalkyne cyclodimerization using iron complexes

Tricarbonyl-2,4-di-tert-butyl-1,3-diphosphacyclobutadieneiron (2) has been synthesised by reaction of tert-butylphosphaacetylene (1; 3,3-dimethyl-1-phospha-1-butyne) with nonacarbonyldiiron tricarbonyl-bis(cyclooctene)iron and characterized unambigously by mass, 13 C-, and 31 P-NMR spectroscopy