Maleinsäure- und fumarsäureester als liganden in metallcarbonyl-komplexen: II. Gemischte dicarbonyl- und tricarbonyl-komplexe des molybdäns mit maleinsäure- und fumarsäureestern und zweizähnigen n-liganden

Abstract

The binuclear complexes [Mo(CO) 3L 2] 2 (L &2.dbnd; maleic acid or fumaric acid esters) react with the N-heterocyclics 2,2'-bipyridine (Bipy) or 1,10-phenanthroline (Phen) under elimination of CO giving the mononuclear dicarbonyl compounds Mo(CO) 2QL 2 (Q &2.dbnd; Bipy, Phen) with cis3-carbonyl ligands: [Mo(CO) 3L 2] 2 + 2 Q - 2 Mo(CO) 2QL 2 + 2 CO In the reaction of Phen together with fumaric acid esters with C 7H 8Mo(CO) 3, tricarbonyl complexes with a meridional arrangement of the CO ligands are formed: C 7H 8Mo(CO) 3 + Phen + L → mer-Mo(CO) 3PhenL + C 7-H 8 In the case of the dibutyl fumarate derivative (L &2.dbnd; DBFU), isomerization to the facial CO arrangement is effected by a small excess of the ester: ▪ In solution the mer-Mo(CO) 3PhenL complexes slowly undergo carbonyl disproportionation: ▪ Possible mechanisms for these reactions are discussed.