[en] The authors present a study which shows that the sulfurization of (n5-cyclopentadienyl)-n1(2,4-diphenyl-1-cyclo-butenyl-3-one) dicarbonyliron (I) by the action of P4S10 has yielded a new thioketone. The previously unknown thioketone was used to prepare new heterometallic bunuclear complexes with molybdenum and tungsten carbonyls