Novel N-bridging cyclopentadienyl heteropolynuclear organometallamacrocycles with M–Sn (M = Mo or W) bonds

Reaction of PhN(CH2CO2Et)2 with cyclopentadienyl sodium in a 1:2 ratio yields N-bridging dicyclopentadienyl dianion [PhN(CH2COCp)2]2−, which subsequently reacts with M(CO)6 to give N-bridging dicyclopentadienyl metal dianions [PhN(CH2COCpM(CO)3)2]2− (M = Mo or W). Treatment of these metal dianions with Ph2SnX2 yields tetranuclear heterodimetallic complexes PhN(CH2COCpM(CO)3SnPh2X)2 (X = Cl or Br), while treatment with CH2(SnPh2Br)2 results in octanuclear heterodimetallic organometallamacrocycles [PhN(CH2COCpM(CO)3)2]2[(SnPh2)2CH2]2. All of these new compounds have been characterized by elemental analysis and spectroscopic properties. The crystal structure of complex [PhN(CH2COCpMo(CO)3)2]2[(SnPh2)2CH2]2 determined by X-ray crystallography indicates a novel 24-membered organometallic metallamacrocyclic ring system in which four Mo–Sn units are linked by two N-bridging dicyclopentadienyl ligands and two bridging methylene groups.